The interaction of murine cytomegalovirus with murine neutrophils: effect on migratory and phagocytic activities.

To investigate the interaction of cytomegalovirus (CMV) with neutrophils, we studied the effects of in vitro incubation of murine neutrophils with murine CMV (MCMV). Neutrophils incubated with MCMV for 4 h had depressed chemotactic activity, mean chemotactic index of 1.34 +/- 1.43 for MCMV-treated neutrophils vs 3.22 +/- 2.11 for controls. Engulfment of latex spheres by MCMV-treated neutrophils was also reduced. These differences were not attributable to loss of cell viability. UV-inactivation of MCMV pools abolished the inhibitory effects of MCMV, indicating that these effects were related to infectivity of the virus. Electron microscopic studies at 4 h demonstrated virus particles within the phagosomes of occasional neutrophils. These studies demonstrate that neutrophil functions can be altered by an in vitro interaction with infectious CMV and suggest that a direct effect of CMV on neutrophils could account for the abnormal neutrophil functions observed during animal CMV infections.

Murine cytomegalovirus infection of reaggregate cultures of fetal mouse brain.

We used cultures of reaggregate embryonic mouse brain cells to study murine cytomegalovirus (MCMV) infection of neural tissues. After 21 to 28 days in culture, aggregates were infected with MCMV and studied sequentially for 14 days using virus assay, electron microscopy and indirect immunofluorescence. Infectious virus could be recovered from aggregate cultures beginning three days after infection, and peak virus titers were observed on day 7 in aggregate tissues and on day 14 in culture fluids. By transmission electron microscopy, intranuclear viral nucleocapsids were identified in neural cells at the periphery of the aggregates on day 3. Infection then spread centripetally into aggregate tissues so that by day 14 the majority of neural cells contained intranuclear inclusions, numerous nucleocapsids, and mature virus particles. Virion production in neural cells was the result of a sequence of events that included budding of nucleocapsids from the nucleus and envelopment of cytoplasmic virus particles by membranes of the Golgi apparatus. These studies indicate that MCMV infection of murine brain aggregate cultures is a potentially useful in vitro system for the study of CMV infections of neural tissue.

Human cytomegalovirus infection and disorders of the nervous system.

Infection with human cytomegalovirus (CMV) occurs in nearly 1% of live-born infants, and from 60% to 80% of the inhabitants of the United States acquire CMV infection by mid adulthood. While neurologic disorders do not develop in the majority of congenitally infected infants, congenital CMV infection can severely damage the developing nervous system, causing microcephaly, psychomotor retardation, seizures, and deafness. Furthermore, approximately 10% of infants who are asymptomatic at birth subsequently exhibit sensorineural hearing loss. In the adult, CMV infection has been associated with the Guillain-Barré syndrome, meningoencephalitis, and retinitis. Although Guillain-Barré syndrome can accompany CMV infections in previously healthy adults, meningoencephalitis and retinitis occur more commonly in immunosuppressed patients, particularly among organ transplant recipients. In total, at least 7,000 persons in the United States each year have neurologic disorders attributable to CMV infection.

Magnetic resonance imaging of the spine in children.

We reviewed the magnetic resonance imaging (MRI) scans of the spine of 42 children who had neurologic signs compatible with lesions of the spinal cord. Twenty-three of the children had abnormalities identified by MRI. The spectrum of abnormalities included posttraumatic lesions, tumor, tethered cord, and syringohydromyelia. Tethered cord with or without lipoma and syringohydromyelia were the most common findings, affecting six and four children, respectively. Thirteen children studied by MRI also underwent conventional metrizamide myelography and/or computed tomography. In 12 cases, the findings of MRI were comparable to those of myelography and computed tomography. These observations indicate that MRI effectively detects lesions of the spinal cord in children. Because MRI can be performed on an outpatient basis and avoids the risks of metrizamide myelography, we conclude that MRI should be considered to be the preferred screening technique for children with suspected spinal cord disorders.

Cytomegalovirus and dual infection in infants.

In four unrelated infants without underlying immunodeficiency, dual infections with cytomegalovirus (CMV) and another microorganism developed. The patients included the following: (1) a 3-month-old girl with congenital CMV and perinatal cutaneous herpes simplex virus; (2) a 5-week-old girl with CMV and Pneumocystis carinii; (3) a 12-week-old girl with CMV and Haemophilus influenzae meningitis; and, (4) a 2 1/2-month-old girl with CMV and Escherichia coli meningitis. In all four cases, the patient's initial symptoms were referable not to CMV, but to the companion infecting organism. The diagnoses of CMV infection were made, respectively, by a high index of clinical suspicion in the first three cases and on the basis of a lucent parenchymal defect on computerized tomographic scan in the fourth patient. These cases provide additional evidence that CMV infection may predispose to secondary infection. We recommend that infants who have signs of infection and evidence of CNS abnormalities have cultures made for CMV. Both human CMV and experimental murine CMV infections have been associated with suppressed cellular and possibly humoral immunity.

Kaposi's sarcoma metastatic to the CNS.

Metastatic lesions of the CNS developed in two male patients with disseminated Kaposi's sarcoma. One patient was a homosexual, but the second patient had no apparent risk factors for disseminated Kaposi's sarcoma. These cases indicate that CNS involvement by tumor should be suspected in patients with Kaposi's sarcoma who exhibit abnormal neurologic signs or symptoms.

Brain abnormalities in infants with Potter syndrome (oligohydramnios tetrad).

We examined the brains of seven unrelated infants with Potter syndrome (oligohydramnios tetrad), a lethal neonatal disorder characterized by abnormal facies, lung hypoplasia, limb deformities, and classically, renal agenesis. All infants had defects of neuronal migration. The brains were small for gestational age in five of seven infants, and in four infants, the middle and inferior temporal gyri were incompletely demarcated. Cerebellar heterotopia occurred in five infants. All had abnormal hippocampi and abnormal lamination of the cerebral cortex. These neuropathologic abnormalities suggest that Potter syndrome may not be the result of a single toxic or infectious insult but may represent a polygenic inherited disorder.

CT scans in Menkes disease.

The clinical courses and serial computerized tomography (CT) scans of four patients with Menkes disease are described. Although the initial clinical presentations were similar, head growth and serial CT scans showed striking individual differences. The CT scans varied from showing no abnormalities early in the disease to showing diffuse cortical atrophy, subdural accumulation of fluid, or multifocal areas of ischemic infarction. The pathologic findings in one patient showed only cerebral and cerebellar atrophy, whereas the findings in another patient showed areas of ischemic infarction, probably secondary to abnormal vessels. Menkes disease should be suspected in male infants with psychomotor deterioration and seizures, or when trauma is suspected from subdural hematoma and multiple fractures.

Paroxysmal kinesigenic dyskinesia and infantile convulsions: clinical and linkage studies.

OBJECTIVE: To clinically characterize affected individuals in families with paroxysmal kinesigenic dyskinesia (PKD), examine the association with infantile convulsions, and confirm linkage to a pericentromeric chromosome 16 locus. BACKGROUND: PKD is characterized by frequent, recurrent attacks of involuntary movement or posturing in response to sudden movement, stress, or excitement. Recently, an autosomal dominant PKD locus on chromosome 16 was identified. METHODS: The authors studied 11 previously unreported families of diverse ethnic background with PKD with or without infantile convulsions and performed linkage analysis with markers spanning the chromosome 16 locus. Detailed clinical questionnaires and interviews were conducted with affected and unaffected family members. RESULTS: Clinical characterization and sampling of 95 individuals in 11 families revealed 44 individuals with paroxysmal dyskinesia, infantile convulsions, or both. Infantile convulsions were surprisingly common, occurring in 9 of 11 families. In only two individuals did generalized seizures occur in later childhood or adulthood. The authors defined a 26-cM region using linkage data in 11 families (maximum lod score 6.63 at theta = 0). Affected individuals in one family showed no evidence for a shared haplotype in this region, implying locus heterogeneity. CONCLUSIONS: Identification and characterization of the PKD/infantile convulsions gene will provide new insight into the pathophysiology of this disorder, which spans the phenotypic spectrum between epilepsy and movement disorder.

Neurologic history and examination results and their relationship to human immunodeficiency virus type 1 serostatus in hemophilic subjects: results from the hemophilia growth and development study.

In a prospective study of the growth and neuropsychologic function of hemophilic subjects, 333 boys, median age of 12.3 years, had baseline neurologic examinations. The study population included 207 individuals (62%) who were seropositive for human immunodeficiency virus type 1 (HIV-1). Overall results indicated that 11% had abnormalities of cranial nerve function, 17% had abnormal deep tendon reflexes, 23% had abnormal strength, 25% had abnormal coordination, and 31% had abnormal tone, bulk, or range of motion. By contrast, 2% or fewer displayed abnormal movements or had abnormal pain or vibratory sensation, or altered mental status. Abnormalities were more common in older hemophilic subjects (eg, 67 [38%] of 177 subjects > or = 12 years of age had abnormal tone, bulk, or range of motion vs 36 [23%] of 156 subjects < 12 years of age). When compared with regard to HIV-1 status, HIV-seronegative and HIV-seropositive subjects did not differ with regard to head circumference or the frequency of abnormalities of cranial nerve function, sensation, muscle strength, or coordination. However, deep tendon reflexes and tone, bulk, or range of motion were more frequently abnormal in HIV-1-seropositive individuals. More HIV-1-positive subjects had at least one increased deep tendon reflex (13/207 [6.3%] vs 1/126 [0.8%] in seronegatives) and more had non-hemophilia-related decreases in muscle bulk (7/207 [3.4%] vs 0/126 in seronegatives). These results indicate that hemophilia causes substantial neurologic dysfunction and that certain findings, such as changes in muscle-stretch reflexes or muscle bulk, may also reflect the neurologic consequences of HIV infection.

Reye syndrome associated with aspirin therapy for systemic lupus erythematosus.

A 14-year-old girl in whom Reye syndrome developed during aspirin therapy for an inflammatory disorder proven to be systemic lupus erythematosus is reported. This case and similar cases of Reye syndrome in patients with juvenile rheumatoid arthritis suggest that an etiologic relationship exists between salicylate therapy and Reye syndrome in children with collagen vascular disorders.

Effects of human immunodeficiency virus and immune status on magnetic resonance imaging of the brain in hemophilic subjects: results from the hemophilia growth and development study.

To determine the effects of hemophilia and human immunodeficiency virus (HIV) infection on the nervous system, the authors examined the relationship of brain magnetic resonance imaging (MRI) findings to immunologic function and neurologic examination findings. Baseline examinations included physical and neurologic examination, immunologic and virologic testing, and MRI of the brain. On neurologic examination, muscle atrophy was considered to be related to hemophilia if adjacent joints had arthropathy due to bleeding. Muscle atrophy was considered non-hemophilia-related if unrelated to arthropathy or if muscle atrophy was diffuse. Subjects were boys aged 6 to 19 years, enrolled in a multicenter study of the effects of hemophilia and HIV infection on growth and development, all with congenital coagulopathies requiring factor infusions. Three hundred ten subjects had complete data including neurologic examination, T-cell subsets, HIV antibodies, and MRI. Subjects with HIV infection whose CD4+ counts were < 200/microL were compared with subjects with HIV infection and CD4+ counts > or = 200/microL and with HIV-negative subjects, all of whom had CD4+ counts > 200/microL. MRI studies were normal in 230. Abnormal MRI studies were more frequent in HIV-positive subjects with CD4+ counts < 200 (29.4% abnormal compared with 17% in HIV-positive subjects with CD4+ counts > or = 200 and 15.3% in HIV-negative subjects). Diffuse atrophy accounted for most of the excess abnormalities in HIV-positive subjects with CD4+ counts < 200 (77.3% of abnormal scans). Diffuse atrophy on MRI was associated with decreased muscle bulk on neurologic examination, but not with abnormal tendon reflexes.(ABSTRACT TRUNCATED AT 250 WORDS)

Murine cytomegalovirus ocular infection in immunocompetent and cyclophosphamide-treated mice. Potentiation of ocular infection by cyclophosphamide.

Conventional virologic and in situ nucleic acid hybridization methods were used to study immunocompetent and immunosuppressed 3-week old BALB/c mice inoculated intravitreally with 10(4) plaque-forming units (pfu) of murine cytomegalovirus (MCMV). Immunocompetent mice experienced a self-limited ocular infection with peak virus titers of 10(3.5) pfu/ml in the retina-choroid fraction on day 4 of infection. Using biotinylated MCMV DNA probes, MCMV DNA was detected in cells of the iris, ciliary body, and rarely, the retina or choroid on days 4 and 7 of infection. With few exceptions, retinal architecture was preserved. By contrast, mice immunosuppressed with cyclophosphamide (200 mg/kg on day 0 and 100 mg/kg on days 5 and 11 after MCMV inoculation) had progressive ocular infection that culminated in a necrotizing retinitis. Virus titers in the retina-choroid fraction rose progressively (nearly 10(5) pfu/ml in cyclophosphamide-treated mice on day 11 versus 10(1.5) pfu/ml in immunocompetent mice). The MCMV DNA was detected in the iris and ciliary body of the immunosuppressed mice on days 4 and 7 and in the retina, on days 7, 11, and 14. On day 14 abundant MCMV DNA was found in most retinal layers, and extensive retinal necrosis was observed. These studies indicate that immunosuppression with cyclophosphamide potentiates MCMV ocular disease in mice, a finding analogous to CMV retinitis in immunosuppressed humans.

The pathogenesis of murine cytomegalovirus ocular infection. Anterior chamber inoculation.

To investigate the pathogenesis of ocular cytomegalovirus infections, 3-week-old BALB/c mice were inoculated with 10(4) plaque-forming units of murine cytomegalovirus (MCMV) by the right anterior chamber and studied sequentially with the use of virus assays and in situ nucleic acid hybridization methods. During acute infection, MCMV was recovered from the right vitreous, lens, cornea, retina/choroid, and optic nerve. Titers of MCMV exceeded 10(3) per ml of homogenate on days 4 and 7 after inoculation. With the use of biotinylated MCMV DNA probes, MCMV nucleic acids were detected in and adjacent to cells of the iris and ciliary body and occasionally within inflammatory lesions of the cornea. During chronic infection, MCMV was recovered, with the use of co-cultivation or explant methods, from ocular tissues of occasional mice inoculated with MCMV 1 yr earlier. Infectious MCMV was also recovered from the ocular homogenates of a group of mice immunosuppressed with antilymphocyte serum and cortisone. These studies indicate that cells of the uveal tract are permissive for MCMV and suggest that intrinsic persistence or latency of cytomegalovirus in ocular tissues could contribute to the pathogenesis of ocular infections in immunosuppressed hosts.

Magnetic resonance imaging of the brain in childhood herpesvirus infections.

We used magnetic resonance imaging (MRI) to evaluate nine children with neurologic disorders caused by infections with members of the herpesvirus family. MRI studies were abnormal in eight children and demonstrated a wide range of central nervous system lesions, including cystic encephalomalacia, ventricular enlargement, cerebral atrophy and focal parenchymal lesions. When compared with conventional computed tomographic scanning, MRI was more sensitive in detecting abnormalities of white matter and in defining the extent of parenchymal lesions. These studies indicate that MRI scans are highly useful in children with herpesvirus infections involving the central nervous system.

Risk of cytomegalovirus infection among educators and health care personnel serving disabled children.

To determine the risk of cytomegalovirus (CMV) infection for personnel who provide services to young disabled children, we studied the prevalence of CMV infection among such children and determined the seroconversion rate among exposed personnel. The prevalence of CMV excretion was 9.8% among children aged 0 to 5 years in a University-based outpatient program vs. 3.3% in 3- to 5-year-old children attending community-based preschools. Initial serologic studies of personnel demonstrated no differences in CMV seropositivity rates among staff with occupational child contact vs. staff without such contact (40% (40 of 99) vs. 34% (26 of 77] (P = 0.37). However, 21 of the 31 personnel 40 years and older who had occupational child contact were seropositive vs. 10 of 26 personnel of comparable age who had no occupational child contact (P = 0.026). During a 1-year follow-up, 2 of 86 (2.3%) susceptible personnel seroconverted. Rates were 4.4% (2 of 45) among staff with occupational child contact vs. no seroconversions (0 of 41) for those without (P = 0.27). These results indicate that the risk of CMV infection for personnel who work with disabled children is low. However, we cannot exclude the possibility that there may be a small cumulative risk of CMV infection that may exceed that of adults who do not have occupational contact with children.

The epidemiology of cytomegalovirus infection among patients with burns.

To determine the epidemiology of cytomegalovirus (CMV) infections among patients with burns, we prospectively studied 120 burn patients admitted to the University of Iowa Burn Center over a two-and-one-half year period. At the time of their admission, 44% of the patients had serologic evidence of prior CMV infection. Among 44 seropositive patients, 23 (52%) had four-fold or greater rises in CMV antibody titers. These patients had more severe burns (mean body surface area burn [BSAB] 26.8%) than those who did not exhibit titer rises (mean BSAB 16.2%, p = .04). Among 43 seronegative patients observed for at least 65 days after discharge from the center, eight (18.6%) seroconverted. Patients who seroconverted had longer hospital stays (p = .03), trends toward more severe burns (p = .08) and a younger age (p = .15) than patients who remained seronegative. Despite frequent serologic evidence of CMV infection, CMV did not contribute, either directly or indirectly, to the morbidity or mortality of burns in these patients.

Rapid epidemiologic characterization of cytomegalovirus strains from pediatric bone marrow transplant patients.

BACKGROUND: DNA amplification by the polymerase chain reaction (PCR) of human cytomegalovirus (CMV) nucleotide sequences recently has been reported for differentiation of CMV strains. DESIGN: Retrospective study. OBJECTIVE AND PATIENTS: Evaluate the strain patterns of 15 CMV-positive buffy coat specimens from five pediatric bone marrow transplant patients. SETTING: Pediatric bone marrow transplant unit. METHODS: We perform PCR using primers corresponding to two distinct regions of the CMV genome, the major immediate-early (MIE) region and the a-sequence region, with subsequent restriction enzyme analysis of the amplified products. RESULTS: Restriction enzyme analysis with Hae III and Hinf I of products amplified with nested PCR for the MIE region revealed distinguishable digestion patterns between patients but similar patterns for samples from each patient. All were distinct from the CMV Towne laboratory control strain. In contrast to these results, amplification of specimens with a-sequence primers, followed by restriction enzyme analysis, did not allow differentiation between all patients. CONCLUSION: Our results indicate that nested amplification directly from buffy coat specimens using primers for the CMV MIE gene allows rapid CMV strain characterization that is useful for laboratory quality control and epidemiological studies. Distinct CMV strains were found in each patient, suggesting horizontal transmission was not responsible for acquisition of CMV infection in these patients.

Experimental murine cytomegalovirus infection of ocular structures.

To study experimental cytomegalovirus (CMV) infection of ocular structures, 3-week-old Swiss-Webster mice were inoculated intraperitoneally with a 0% to 20% lethal inoculum of murine CMV (MCMV). Murine cytomegalovirus was recovered from homogenates of eye tissues on days 3, 5, and 7 after inoculation. Peak virus titers, mean of 2.93 +/- 0.67 log plaque-forming units of MCMV per gram of ocular tissue occurred on day 5. Urine cytomegalovirus was recovered from explant cultures of eye and optic nerve 14, 21, 60, 90, and 120 days after MCMV inoculation. Murine cytomegalovirus also persisted in intraocular fluids for as long as 90 days. Murine cytomegalovirus infection was confirmed by immunofluorescence antibody staining and transmission electron microscopy. These experiments indicate that MCMV infects the ocular tissues of mice during systemic MCMV infection, and persists in ocular tissues for as long as 120 days after infection. These studies may be directly relevant to ocular disorders that occur during acquired CMV infections of humans, and suggest that ocular tissues may be a site of CMV persistence or latency.

Effect of long-term valproic acid administration on the efficiency of carnitine reabsorption in humans.

To elucidate the etiology of valproic acid-induced carnitine deficiency, we tested the hypothesis that long-term valproic acid administration decreases the rate of carnitine reabsorption. Thirteen healthy men participated in a 34-day protocol in which carnitine clearance was measured before and after 28 days of valproic acid administration. During valproic acid administration (days 6 to 33), plasma free and total carnitine concentrations decreased (18% and 12%, respectively, P<.05) by 16 days, but returned to pretreatment concentrations by 28 days. From day 14 to day 30, the rate of free carnitine excretion was 50% lower than at baseline (day 4, P<.05). Free and total carnitine clearance, indexed to the glomerular filtration rate, was lower after valproic acid administration (P<.01). Contrary to our hypothesis, after 28 days of valproic acid administration, the rate of carnitine reabsorption was enhanced independent of the glomerular filtration rate and filtered load. Changes in the plasma concentration, rate of excretion, and clearance were specific for carnitine and were not generalized in magnitude or direction to the other amino acids. We conclude that the kidney adapts to conserve carnitine during valproic acid administration and therefore does not cause valproic acid-induced carnitine depletion in adults.