Parvalbumin and calbindin D-28 k immunoreactivity in dorsal root ganglia in acquired immunodeficiency syndrome

Various degrees of neuronal degeneration have been found in lumbosacral dorsal root ganglia of patients with acquired immunodeficiency syndrome (AIDS). To characterize the subpopulations of primary sensory neurons affected in AIDS, we immunostained dorsal root ganglion tissues from 11 AIDS patients and six controls using antibodies to the calcium binding proteins, parvalbumin and calbindin D-28 k. In controls, the proportion of neurons containing parvalbumin and calbindin was 18.0% and 22.4%, respectively. The majority of parvalbumin-positive neurons, which are thought to be proprioceptive neurons, were of medium to large size, while calbindin was found in both large- and small-sized neurons. The density of parvalbumin-immunoreactive neurons was reduced by 7.3% in AIDS patients, but the density of calbindin-immunoreactive neurons was preserved. Furthermore, in AIDS cases, the number of parvalbumin-positive neurons was reduced more in dorsal root ganglia in which human immunodeficiency virus (HIV) antigen was detected than in HIV-negative ganglia. These results suggest that specific subpopulations of sensory neurons positive for parvalbumin may be differentially affected over the course of AIDS, and that this could be related to peripheral neuropathy which frequently occurs in the late stages of AIDS.

Fluid-attenuated inversion recovery (FLAIR) for assessment of cerebral infarction. Initial clinical experience in 50 patients

BACKGROUND AND PURPOSE

Our aim was to evaluate fluid-attenuated inversion recovery (FLAIR) sequence in the diagnosis of cerebral infarction with MRI.

METHODS

A retrospective review was undertaken of 50 consecutive MRI studies ordered for suspected cerebrovascular accident. All studies included FLAIR and rapid acquisition with relaxation enhancement (RARE) T2-weighted spin-echo sequences. The two sequences were compared independently by four observers at two different institutions. Detectability of lesions and image quality were scored.

RESULTS

Overall, FLAIR sequences proved superior in 10 patients, detecting acute cortical infarcts missed with RARE spin-echo technique in five patients. In five additional patients, improved characterization of chronic infarction and improved detection of microangiopathic deep hemispheric changes were observed. One brain stem infarct was missed with the FLAIR sequence.

CONCLUSIONS

FLAIR offers advantages in detection of acute infarcts affecting the cortical ribbon, is a useful, rapid adjunct to conventional T2-weighted spin-echo sequences, and has the potential to replace these in the future.

A MERRF/PEO overlap syndrome associated with the mitochondrial DNA 3243 mutation

We describe a two-generation family with combined clinical features of myoclonic epilepsy, progressive external ophthalmoplegia (PEO), proximal myopathy, pigmentary retinopathy, progressive deafness, basal ganglia calcification, and ragged-red fibers in a muscle biopsy specimen. One family member died unexpectedly at age 22 years. The molecular tests revealed an A-to-G transition at nucleotide position 3243 of the mitochondrial tRNA(Leu(UUR)) gene. No one in this family had stroke-like episodes. Although the propositus (a 28-year-old woman) had a significant number of white hairs, the percentage of mutant mtDNA in white-hair roots was not different from that in the colored-hair roots. Our findings suggest that the 3243 mutation can be associated with mixed clinical features of myoclonic epilepsy with ragged-red fibers (MERRF) and PEO and that a preferential increase in the levels of the mutant mtDNA is not related to graying of hair, and hence to the hypothesized production of premature aging of cells.

Increased NADPH-diaphorase reactivity and cytokine expression in dorsal root ganglia in acquired immunodeficiency syndrome

We studied lumbosacral dorsal root ganglia (DRGs) from 10 patients with acquired immunodeficiency syndrome (AIDS) and five controls using immunocytochemistry, in situ hybridization and NADPH-diaphorase (NADPHd) histochemistry. Human immunodeficiency virus (HIV)-1 RNA was detected in five AIDS cases, and HIV-1 p24 antigen was found in four of these patients. The densities of nodules of Nageotte (nN), macrophages and major histocompatibility complex-class II-positive cells were significantly increased in the DRGs of AIDS patients compared to controls. Cytomegalovirus antigen was observed in the DRGs of four AIDS cases and one control, but without its presence being related to neuronal degeneration. Furthermore, we detected tumor necrosis factor, interferon-gamma, interleukin (IL)-1 beta, and IL-6 in the DRGs from AIDS patients. Using NADPHd histochemistry, we showed that the number of NADPHd-positive neurons was significantly increased in the DRGs of AIDS patients compared to controls, implying upregulation of nitric-oxide (NO) production in AIDS DRGs. Generally, there were increased numbers of nN in DRGs which contained more NADPHd-positive neurons. Additionally, immunoreactivity for an inducible form of NO synthase was detected in interstitial cells in AIDS DRGs. These results suggest that reactive inflammation, including the production of cytokines, occurs in the DRGs of AIDS patients and that excessive production of NO may be related to neuronal degeneration in AIDS DRGs.

Normal-pressure hydrocephalus: evaluation with cerebrospinal fluid flow measurements at MR imaging

PURPOSE

To evaluate magnetic resonance (MR) imaging-based quantitative phase-contrast cerebrospinal fluid (CSF) velocity imaging for prediction of successful shunting in patients with normal-pressure hydrocephalus (NPH).

MATERIALS AND METHODS

Eighteen patients (mean age, 73 years) with NPH underwent routine MR imaging and CSF velocity MR imaging before ventriculoperitoneal (VP) shunting. The calculated CSF stroke volume and the aqueductal CSF flow void score were compared with the surgical results.

RESULTS

All 12 patients with CSF stroke volumes greater than 42 microL responded favorably to CSF shunting. Of the six patients with stroke volumes of 42 microL or less, three improved with shunting while three did not. The relationship between CSF stroke volume greater than 42 microL and favorable response to VP shunting was statistically significant (P < .05). There was no statistically significant relationship between aqueductal CSF flow void score and responsiveness to shunting.

CONCLUSION

CSF velocity MR imaging is useful in the selection of patients with NPH to undergo shunt formation.

Testosterone therapy and the pathogenesis of Kennedy's disease (X-linked bulbospinal muscular atrophy)

The mutation in X-linked bulbospinal muscular atrophy (XBSMA) is an increased CAG triplet repeat coding for a polyglutamine domain in the gene for the androgen receptor. This might impair the effect of testosterone on motor neurons, leading to their progressive degeneration. We report a trial of high-dose oral testosterone therapy in two brothers with XBSMA. Patient 1 received 37.5 mg of testosterone daily for more than 18 months, and Patient 2 received 25 mg per day for six months, both in combination with exercise therapy. Patient 1 showed improvement of up to 300% in muscle work output. Patient 2, who did less exercise, had no symptomatic improvement. These results indicate that exogenous testosterone therapy is not harmful, and may produce functional improvement when combined with exercise. We hypothesize that high-dose testosterone may reduce a toxic gain of function that the mutation produces, perhaps by inhibiting glutamate neurotoxicity.

Relationship between tumor necrosis factor alpha and feline immunodeficiency virus expressions

The presence of feline immunodeficiency virus (FIV) proviral DNA, expression of FIV p26 core protein, and production of tumor necrosis factor alpha (TNF-alpha) were assessed in sequential biopsies of spleen and lymph node sections, of mononuclear cells of the peripheral blood, and of the serum of specific-pathogen-free cats during the acute phase of FIV infection. A temporal relationship between TNF-alpha production and FIV p26 expression was noted. Two months following FIV infection, and preceding the detection of FIV viremia, levels of TNF-alpha in serum increased significantly (P = 0.04), and they remained elevated during FIV viremia in the third month postinfection. Immunoprecipitates representing expression of TNF-alpha and of FIV p26 were localized in common foci of lymph nodes of FIV-infected cats during this period of active viremia. With the advent of anti-FIV antibodies, circulating levels of TNF-alpha and p26 antigen and expression of TNF-alpha and p26 in the lymph nodes decreased during the fifth month postinfection, and p26 production became undetectable. With clearance of viremia, burden of proviral DNA in peripheral blood mononuclear cells became reduced (P = 0.041), with provirus remaining integrated principally within lymph nodes (P = 0.046). During aviremia, p26 expression was undetectable in any tissue but remained inducible in vitro. During acute FIV infection, TNF-alpha production and p26 expression are intimately linked.

Patterns of contrast enhancement in the pediatric spine at MR imaging with single- and triple-dose gadolinium

PURPOSE

To assess patterns of nerve root and spinal cord contrast enhancement in the pediatric spine at magnetic resonance (MR) imaging with single- and triple-dose gadolinium.

MATERIALS AND METHODS

In three control patients with no suspected pathologic spinal condition and 19 patients with a suspected condition, spinal cords were evaluated prospectively for potential spread of tumor to cerebrospinal fluid ("drop metastases") (n = 18) or Guillain-Barré syndrome (n = 1). After enhancement with 0.1 mmol/kg gadolinium, patients without definite drop metastases (n = 8) received a booster of 0.2 mmol/kg gadolinium 30-40 minutes later; clinical follow-up was obtained 12 1/2 to 19 months later.

RESULTS

Drop metastases appeared as nodular areas of enhancement in 11 patients. Vascular enhancement related to the spinal cord surface and emerging nerve roots was observed in images obtained in all control patients, as well as in patients with negative findings at lumbar puncture and at clinical or MR imaging follow-up examination (n = 6). Vascular and nerve root enhancement increased with triple-dose gadolinium and was greater in patients after radiation therapy (n = 17) than in control patients (n = 3).

CONCLUSION

Use of triple-dose gadolinium did not result in detection of additional cases of drop metastases.

Future cost-effective MRI will be at high field

The most cost effective MR imaging system is the one that provides the highest quality images (allowing the earliest possible diagnosis), the largest number of applications (allowing bundling of services and one-stop shopping for consumers), and the highest throughput (should it become necessary to scan a large number of patients in a capitated world). When all other parameters are normalized (eg, the skill and training of the radiologist and technologist as well as the RF, computer, and gradient subsystems), high field provides faster, higher resolution, thinner slice, and higher contrast MR images than low field. For these reasons, high field MRI will remain more cost effective than its lower field counterparts in the future.

Suspected multiple sclerosis: MR imaging with a thin-section fast FLAIR pulse sequence

PURPOSE

To compare thin-section, sagittal, fast fluid-attenuated inversion-recovery (FLAIR) magnetic resonance (MR) imaging with conventional axial spin-echo (SE) imaging for early detection of multiple sclerosis (MS) in the brain.

MATERIALS AND METHODS

Conventional 5-mm axial proton-density- and T2-weighted SE images and sagittal 2-mm fast FLAIR images of the brain in five healthy volunteers and 25 patients with clinically suspected MS were evaluated and graded as normal or as showing possible or probable MS in a double-blind study.

RESULTS

Fast FLAIR was judged better than SE in 37% of cases, equal to SE in 63%, and never worse than SE. In 43% of patients considered to have normal SE images, fast FLAIR images showed abnormalities consistent with MS. A subependymal striated appearance observed in several cases is believed to represent early inflammation and/or demyelination around subependymal veins in MS.

CONCLUSION

Sagittal thin-section fast FLAIR is superior to conventional axial proton-density- and T2-weighted SE pulse sequences for detection of MS plaques in the brain.

MR angiography of the central nervous system. Basic flow phenomena

To properly understand MR angiography and its artifacts, one needs to be firmly grounded in the basic physics of MR flow. Concepts such as "flow-related enhancement" are crucial to a proper understanding of time-of-flight MR angiography. Phase contrast MR angiography draws from the same principles used to explain "even echo rephasing." This article not only provides a physical basis for MR angiography but also explains the flow phenomena observed on routine MR images.

Long-term repopulation of hematolymphoid cells with only a few hemopoietic stem cells in mice

A PCR-based assay has been devised for the detection and semiquantitation of cells originating from a few donor hematopoietic stem cells (HSCs) in a background of recipient cells. Upon sequencing a segment of murine Y chromosome contained in the plasmid pY2, oligonucleotide primers were designed for specific amplification of the Y chromosome-restricted segment. The HSCs were isolated from the bone marrow of mice on day 4 following a single i.v. injection of 5-fluorouracil and were readily distinguished from other bone marrow elements by the characteristics of low density, absence of lineage-specific surface markers, lack of expression of transferrin receptor, and a high expression of major histocompatibility complex class I antigen. Injection of as few as four such HSCs was shown to produce donor-derived cells (including lymphoid cells) for at least 8 months after transplantation into syngeneic female recipients. Retransplantation, employing 10(6) bone marrow cells from the initial recipients, also yielded clear evidence of repopulation with detectable levels of male donor cells. On statistical grounds, it is clear that long-term repopulation in vivo may result from even a single HSC having the characteristics defined herein.

Dehydroepiandrosterone inhibits replication of feline immunodeficiency virus in chronically infected cells

Dehydroepiandrosterone (DHEA) is a steroid hormone produced by the adrenal cortex that serves as an intermediary in sex steroid synthesis. DHEA is produced in abundance by humans and most other warm-blooded animals. Based upon previous reports demonstrating the antiviral and immunostimulatory activities of DHEA and DHEA-sulfate (DHEAS) we sought to determine whether introduction of these compounds would affect replication of feline immunodeficiency virus (FIV) in chronically infected cells. When cell number, cell viability, cellular DNA synthesis, and levels of FIV reverse-transcriptase (RT) were measured in cell cultures treated with various dilutions of DHEA or DHEAS it was found that the production of FIV RT was inhibited by DHEA at levels where cellular viability and DNA synthesis were not affected. At the concentrations tested DHEAS did not inhibit FIV replication or impact on cellular viability or proliferation.

Conspicuity of tumors of the head and neck on fat-suppressed MR images: T2-weighted fast-spin-echo versus contrast-enhanced T1-weighted conventional spin-echo sequences

OBJECTIVE

The purpose of this study was to compare the conspicuity of tumors of the head and neck on MR images acquired with T2-weighted fat-suppressed fast-spin-echo and contrast-enhanced T1-weighted fat-suppressed conventional spin-echo sequences.

MATERIALS AND METHODS

The MR images of 29 patients with 36 pathologically proved tumors of the head and neck were retrospectively analyzed. The conspicuity of these tumors was assessed on the T2-weighted sequence (4700/108 [TR/TE]) and on the contrast-enhanced T1-weighted sequence (500/16) with a 1.5-T system. Qualitative tumor-to-background contrast was graded separately against background muscle, fat, and mucosa (0 = not visualized, 1 = poorly visualized, 2 = fairly well visualized, 3 = well visualized), and the best overall sequence was noted for each tumor. Quantitative tumor-to-background ratios were measured for 10 of the tumors by using the same background markers.

RESULTS

The mean overall qualitative tumor-to-background contrast grades for the T2-weighted sequence were tumor/muscle = 2.84, tumor/fat = 2.20, and tumor/mucosa = 1.23, and for the contrast-enhanced T1-weighted sequence, they were tumor/muscle = 2.02, tumor/fat = 1.58, and tumor/mucosa = 0.73. Overall, 86% of the tumors were better or equally well visualized on the T2-weighted images. The mean overall quantitative tumor-to-background ratios for the T2-weighted sequence were tumor/muscle = 7.93, tumor/fat = 3.34, and tumor/mucosa = 0.68, and for the contrast-enhanced T1-weighted sequence, they were tumor/muscle = 2.43, tumor/fat = 2.28, and tumor/mucosa = 0.85.

CONCLUSION

The T2-weighted fat-suppressed fast-spin-echo sequence offers better contrast between tumors and adjacent muscle, fat, and mucosa than does the contrast-enhanced T1-weighted fat-suppressed spin-echo sequence and thus improves overall tumor conspicuity. In addition, the T2-weighted sequence does not require IV contrast material and can be performed more rapidly than can the contrast-enhanced T1-weighted sequence. The contrast-enhanced T1-weighted sequence may offer complementary information on the precise characterization of complex tumors and on the potential determination of tumor extent.

Mammary and submandibular gland epidermal growth factor expression is reduced by calorie restriction

Calorie restriction reduces mammary mitogenesis and tumorigenesis. To test whether epidermal growth factor (EGF) levels are influenced by calorie intake, 72 four-week-old C3H/HeOu mice were separated into two groups and either fed ad libitum (group AL) or calorie-restricted at a mean 19% (group CR). Three mice from each group were evaluated when 6, 8, 10, and 12 weeks old for submandibular gland transcription of EGF and beta-actin RNA for levels of EGF protein in the submandibular gland, mammary gland, and serum and for immunohistological evidence of EGF protein within the submandibular and mammary glands. Submandibular levels of EGF RNA and protein and mammary and serum levels of EGF protein were similar between dietary groups when mice were 6 and 8 weeks old. Mean EGF:beta-actin RNA transcription in submandibular glands of 12-week-old mice were approximately 10-fold greater in AL compared to CR mice (ratio means, 1.499 versus 0.157, respectively; P < 0.01). Mean submandibular levels of EGF protein were greater in 10-week-old AL compared to CR mice (7017.4 versus 4098.5 ng/mg protein, respectively; P < 0.05) and even greater in 12-week-old AL compared to CR mice (4342.6 versus 137.9 ng/mg protein; P < 0.001). Mean mammary levels of EGF protein were greater among 12-week-old AL compared to CR mice (7.8 versus 5.0 ng/mg protein; P < 0.05). Serum levels of EGF did not differ between dietary cohorts. More anti-EGF immunoprecipitate was present in submandibular and mammary gland sections of 10- and 12-week-old AL compared to CR mice. Lowered EGF levels may contribute to the antiproliferative and antineoplastic effects of calorie restriction.

Role of immune activation and cytokine expression in HIV-1-associated neurologic diseases

Central nervous system (CNS) involvement is common during human immunodeficiency virus type-1 (HIV-1) infection. The neurologic disease of the CNS most frequently observed during acquired immunodeficiency syndrome (AIDS) is HIV-1-associated cognitive/motor complex or AIDS dementia complex (ADC), which is most likely a direct consequence of HIV-1 infection of the CNS. The peripheral nervous system (PNS) is also affected in HIV-1-infected individuals and there are several features of immune- and cytokine-related pathogenesis in both the CNS and PNS that are reviewed. Several lines of evidence demonstrate aspects of immune activation in the CNS and peripheral nervous system (PNS) of HIV-1-infected individuals. The relative paucity of HIV-1 expression in contrast to widespread functional and pathologic changes in the CNS and PNS of AIDS patients, and the lack of evidence of productive infection of HIV-1 in neuronal cells in vivo lead to the possibility of indirect or immunopathogenic mechanisms for HIV-1-related neurologic diseases. Proposed mechanisms of neuronal and glial cell damage are injury of oligodendrocytes by tumor necrosis factor-alpha (TNF-alpha) released from activated macrophage/microglia, calcium-dependent excitoneurotoxicity induced by gp120 HIV-1 envelope protein, N-methyl-D-aspartate (NMDA) receptor-mediated neurotoxicity by quinolinic acid (a product of activated macrophages), cell injury by HIV-1-specific cytotoxic T cells, and apoptosis of oligodendrocytes or neurons triggered by interaction between cell surface receptors and HIV-1 gp120 protein. Common to those mechanisms is the dependence on cellular activation with expression of proinflammatory cytokines (TNF-alpha, interleukin-1). Amplification of activation signals through the cytokine network by macrophage/astrocyte/endothelial cell interactions, and cell-to-cell contact between activated macrophages and neural cells by upregulation of adhesion molecules dramatically enhances the toxic effect of macrophage products. Expression of immunosuppressive cytokines such as interleukin-4, interleukin-6, and transforming growth factor-beta is also increased in the CNS and PNS of HIV-1-infected patients. This may serve as neuroprotective and regenerative mechanism against insults to nervous system tissue.

Overview of motor neuron disease: classification and nomenclature

Amyotrophic lateral sclerosis (ALS), although a disease that has been well recognized for nearly 150 years, still causes problems of diagnosis and management, as there is no definitive diagnostic test, and the disease is pleomorphic. Research criteria were developed for the categorization of definite, probable, and possible ALS at the El Escorial Workshop (published in 1994). The principal features are upper and lower motor neuron signs at several levels of the neuraxis, without involvement of other neurological systems. Separation of ALS or motor neuron disease (MND) from the spinal muscular atrophies or hereditary spastic paraplegia can be difficult. The relatively rapid progression to death in an average of 5 years is one of the hallmarks of ALS. However, some cases are relatively more benign. The recent finding that mutations of the SOD1 gene underlie about 20% of familial cases of ALS has allowed the recognition that all phenotypes can occur in different members of the same family with the same mutation, clarifying earlier suggestions that different phenotypes represent different diseases. Until the cause and cure of ALS are found, neurologists and rehabilitation specialists must continue to provide essential support for patients with this devastating disease.

[The international classification of WHO diseases (ICD-10) and its application in neurology (ICD-10 NA)]

The 10th Revision of the International Disease Classification (ICD-10) was published in English in September 1992 and in French in January 1993. Chapter VI (main code G) deals with diseases of the nervous system. There are 11 chapters covering the main categories of aetiologies. The subdivisions designated by the three-character codes are used to define the main diagnostic categories as divided according to aetiology, localization or symptoms. The three-character codes so formed are the legal basis for codifying causes of death in all the member states of the WHO. Supplementary 4-digit codes can be used for more precise definitions of morbidity; ICD-10 NA, the Application to Neurology, is a detailed classification of diseases of neurological origin or expression, based on the original ICD-10. Thus it also contains a table of inclusion and exclusion terms and a detailed alphabetical index. The inclusion terms are names of diseases, affections or syndromes associated with each ICD code. The exclusion terms are listed so that the disease in question is classified elsewhere. Thus it is easy to find the correct category even for similar or related diseases which may be classified in different chapters of the ICD-10 NA. The coding system of the ICD-10 NA is exactly the same as for the ICD-10 since cross-referencing requires that specialization classifications such as the ICD-10 NA derived from the ICD must have the same 3 and 4 digit codes as those in the original ICD-10. Within these limits, the 5th, 6th and 7th digits of the subdivision codes, and the generalization of multiple coding used to describe both aetiologies and manifestations, have greatly increased the discriminating power and precision of neurological diseases classification based on the parent ICD.

Methionine enkephalin combined with AZT therapy reduce murine retrovirus-induced disease

AZT (7.5 or 15 mg/kg/dose) and the neuropeptide methionine enkephalin (Met-ENK, 1 or 3 mg/kg/dose) were used in a combined protocol for therapy of established murine retroviral infection. In both models used, Friend virus leukemia (FV) and BM5 complex (lymphadenopathy and immune deficiency), the drug combination was able to reduce mortality and splenomegaly. While increasing mean survival time of those animals that did not survive infection by FV, when compared to infected control mice or mice treated with AZT alone, Met-ENK used alone at 1 and 3 mg/kg/mouse had no effect in reducing morbidity or mortality due to either virus. This suggested that Met-ENK had no direct antiviral effect at the concentrations used. In fact, mice treated with either single drug therapy or the combination still yielded virus in their spleen, even when splenomegaly was absent. The data suggest that Met-ENK, which has been reported to be immunostimulatory, acts in combination to improve the efficacy of AZT in reducing progression of disease in murine retrovirus models for human AIDS.

Hemorrhage and hemorrhagic infections in the brain

Hemorrhage in the brain can be accurately staged using a combination of T1- and T2-weighted MR images. The MR appearance depends on the form of hemoglobin present and on whether hemolysis has occurred. The stages of hemorrhage distinguishable by MR imaging are: hyperacute (less than 1 day, intracellular oxyhemoglobin), acute (1-3 day, intracellular methemoglobin), late subacute (7-14 days, extracellular methemoglobin) and chronic (14+ days, hemosiderin rim).

Kinematic magnetic resonance imaging of the knee

The emergence of kinematic MR imaging has added a new dimension to imaging of the knee. Ultrafast scan techniques can be used to detect patellofemoral malalignment and tracking abnormalities. Sensitivity can be increased by using a quadriceps loading device.