Ecchordosis Physaliphora: Does It Even Exist?

The term ecchordosis physaliphora (EP) has been used historically to describe a benign notochordal remnant with no growth potential, most commonly occuring in the central clivus. Unfortunately, the radiologic appearance of EP overlaps considerably with the appearance of low-grade chordomas, which do have the potential for growth. In this article, we review new pathologic terminology that better describes this family of diseases, and we propose new radiologic terms that better address the uncertainty of the radiologic diagnosis. The surgical importance of accurate terminology and the implications for patient care are discussed.

Optical pupillometry in traumatic brain injury: neurological pupil index and its relationship with intracranial pressure through significant event analysis.

Primary Objective: Treatment paradigms for traumatic brain injury (TBI) rely on invasive monitoring of intracranial pressure (ICP) for planning intervention. Optical pupillometry is a non-invasive, objective monitoring method, measuring parameters of pupillary response and displaying a scalar value - a neurological pupil index (NPi). An impaired response on NPi has been tentatively correlated with ICP, through analysis of mean/peak NPi and ICP readings. We sought to evaluate this relationship more closely. Research Design: Prospective observational. Methods and Procedures: We obtained hourly pupillometry readings, alongside ICP values, from 40 patients with TBI requiring invasive ICP monitoring. Significant events were identified for analysis based on the significant aberration of ICP or NPi. Main Outcomes and Results: On average, individuals experienced a few significant events. There was a weak relationship between ICP events and a preceding NPi event. The results show that there is a weak but statistically insignificant relationship between NPi and ICP, where reduced pupil reactivity may indicate a raised ICP. The strength of this trend appears to diminish post-decompressive surgery. Conclusions: Whilst pupillometry may not be a reliable surrogate marker for ICP, NPi may still prove to be a useful tool in a multimodal prognostic assessment of the patient with acute brain injury.

Experimental Naegleria fowleri meningoencephalitis in sheep: light and electron microscopic studies.

A sheep infected intranasally with Naegleria fowleri of human origin died 7 days after inoculation. The olfactory lobes were distinctly soft and friable. Histologic findings indicated suppurative leptomeningitis and hemorrhagic necrosis in the olfactory lobes. Protozoa were disseminated in the necrotic areas, particularly in perivascular locations; vasculitis was also observed. Meningitis and perivascular cuffing with lymphocytes were evident in the cerebrum, cerebellum, pons, medulla, and cervical spinal cord. Electron microscopy disclosed trophozoites only in the olfactory lobes. The amebae contained a central nucleus with a distinct, electron-dense nucleolus. The cytoplasm contained myelinated figures, lipid-like vacuoles, open vesicles, electron-dense granules, mitochondria, numerous free ribosomes, scant rough endoplasmic reticulum, and occasionally a phagocytized erythrocyte. Trophozoites were grouped close to arterioles, except when phagocytized by a neutrophil or endothelial cell.

A case of keratitis due to Acanthamoeba in New York, New York, and features of 10 cases.

A man in New York, New York, contracted keratitis caused by Acanthamoeba castellanii. The diagnosis was delayed because amoebae were not initially suspected as the infectious organism. The culture isolate and the amoebae in corneal sections were identified as A. castellanii by immunofluorescence using antiserum to plasma membranes of this species. With the rapid agar disk diffusion method, the amoebae were shown to e susceptible to pimaricin (0.5%) and resistant to greater than 1,000-micrograms/ml levels of paromomycin, polymyxin B-bacitracin-neomycin, acriflavine, 5-fluorocytosine, amphotericin B, gentamicin, and trimethoprim-sulfamethoxazole. The infection responded to treatment with pimaricin administered with several other drugs. This infection is the eighth case reported in the literature of acanthamoebic keratitis and emphasizes the need for clinicians to consider acanthamoebic infection in the differential diagnosis of eye infections that fail to respond to bacterial, fungal, and viral therapy.

Primary amoebic meningoencephalitis: a report of two cases and antibiotic and immunologic studies.

In the summer of 1978, two children who had recently been swimming in freshwater lakes in Florida died from primary amoebic meningoencephalitis. Despite early and intensive treatment with amphotericin B, both patients died three to five days after the onset of illness. Amoebae were observed in wet preparations of cerebrospinal fluid and in sections of cerebral tissue and were identified as Naegleria fowleri by the indirect immunofluorescent antibody technique. The amoebae were highly virulent in mice. The isolate of N. fowleri was extremely sensitive in vitro to amphotericin B (minimal inhibitory concentration [MIC], 0.15 microgram/ml), somewhat sensitive to miconazole (MIC, 25 micrograms/ml), and resistant to rifampin (MIC, less than or equal to 100 micrograms/ml). Treatment with amphotericin B (7.5 mg/kg of body weight per day) administered intraperitoneally protected 60% of the mice. Lower doses of amphotericin B alone or in combination with miconazole (100 mg/kg) or rifampin (220 mg/kg) were not protective. These results suggest that amphotericin B remains the single effective agent in treatment of primary amoebic meningoencephalitis.

Experimental infection of sheep with Naegleria fowleri of human origin.

A strain of Naegleria fowleri, isolated from a child who died of primary amebic meningoencephalitis in Florida, was instilled in the nostrils of a sheep to determine whether livestock are susceptible to infection with free-living amebae. The animal died 7 days later from amebic infection of the central nervous system. N. fowleri were recovered from the brain and spinal cord of the animal. A control, saline-instilled sheep that had been pair-caged with the infected animal remained healthy.

Keratitis due to Acanthamoeba castellani. A clinicopathologic case report.

Trophozoites and cysts of amebas were found within the necrotic cornea of an enucleated eye. The organism was identified, by indirect immunofluorescent staining using specific antiserum, to be Acanthamoeba castellani. This case report illustrates the difficulty of clinical diagnosis and typical inefficacy of medical therapy shown in other reports of this rare keratitis.

Experimental pneumonitis induced by Naegleria fowleri in mice.

An environmental Naegleria isolate, from a cooling lake receiving thermal additions from an electric power plant, caused both primary amoebic meningoencephalitis (PAM) and pneumonitis in mice after intranasal inoculation. Amoebae, recovered from brains and lungs of mice inoculated with the environmental isolate, produced both brain and lung infections in repeated mouse passages. Electron microscope examination of infected lungs revealed a moderate inflammatory reaction with slight necrosis. Amoebae re-isolated from mice with PAM and pneumonitis were identified as N. fowleri by the indirect immuno-fluorescent antibody technique using anti-N. fowleri serum. The results suggest that in addition to PAM, N. fowleri may be capable of causing subacute and acute respiratory infections in man.

Retrospective identification of Acanthamoeba culbertsoni in a case of amoebic meningoencephalitis.

Acanthamoeba culbertsoni was identified retrospectively in a case of amoebic meningoencephalitis, previously reported by Jager and Stamm (Lancet, 2, 1343, 1972). This is the second report of this species causing secondary infection in man. Positive results were obtained only with anti-A. culbertsoni sera when the brain sections were stained by the indirect immunofluorescence antibody test with various antisera produced against different Acanthamoeba species. Antiserum raised against purified plasma membranes of A. culbertsoni showed once more its highly specific diagnostic value.

Acanthamoeba royreba sp. n. from a human tumor cell culture.

A new species of Acanthamoeba was isolated from a culture of an established line of human choriocarcinoma cells. The identification of this strain, originally called the Oak Ridge strain, and the establishment of a new species for it were based on morphologic, serologic, and immunochemical studies. In general, the structure of the trophozoite did not differ significantly from that of other species of Acanthamoeba, except that a body which more closely resembled a centriole than material described previously as centriolar satellites was observed in trophozoites examined with the electron microscope. The dimensions of the trophozoite were the smallest among the species of Acanthamoeba. The cyst was typical of the genus, but differed from those of other species by its smaller size and the presence of numerous ostioles. Studies of the Oak Ridge strain by immunofluorescence using antisera developed against the isolate and Acanthamoeba culbertsoni, A. castellanii, A. polyphaga, A. rhysodes, A. astronyxis, and A. palestinensis revealed the antigenic uniqueness of the Oak Ridge strain. It was demonstrated by immunoelectrophoretic analyses of the soluble proteins of the Oak Ridge strain that shared approximately 1/2 of its antigenic structure with A. castellanii and A. culbertsoni. The antigenic differences of the isolate from other species of Acanthamoeba were deduced from comparison of the antigenic constitution of these species and the Oak Ridge strain with A. culbertsoni and A. castellanii. Although the strain was initially recognized by its cytopathogenicity for cultures, it did not produce acute infections in mice after intranasal inoculation of 1 X 10(4) ameba/mouse. The foregoing results constituted the basis for the establishment of the Oak Ridge strain as a new species, A. royreba sp. n., in the genus Acanthamoeba.

Isolation of the etiological agent of primary amoebic meningoencephalitis from artifically heated waters.

To determine whether artificial heating of water by power plant discharges facilitates proliferation of the pathogenic free-living amoebae that cause primary amoebic meningoencephalitis, water samples (250 ml) were taken from discharges within 3,000 feet (ca. 914.4 m) of power plants and were processed for amoeba culture. Pathogenic Naegleria fowleri grew out of water samples from two of five lakes and rivers in Florida and from one of eight man-made lakes in Texas. Pathogenic N. fowleri did not grow from water samples taken from cooling towers and control lakes, the latter of which had no associated power plants. The identification of N. fowleri was confirmed by pathogenicity in mice and by indirect immunofluorescence analyses, by using a specific antiserum.

Indirect immunofluorescent identification of Acanthamoeba causing meningoencephalitis.

The majority of primary amoebic meningoencephalitis cases in man have been caused by Naegleria, although three new cases have been identified due to Acanthamoeba. These cases showed a somewhat chronic course and death occurred 2 to 6 weeks after onset. The etiological agent in two cases was identified as belonging to the group of A. castellanii and the third case was identified as due to A. culbertsoni. The identification was performed post-mortem.

Immunoassays of Acanthamoeba castellanii plasma membranes. Preliminary results.

To facilitate future diagnosis of Acanthamoeba infections in man, studies have been initiated to elicit antibodies to purified membranes from Acanthamoeba species. Specifically in this communication, preliminary results are reported on A. castellanii. Immunoprecipitation and immunofluorescent analyses suggest that the membrane antisera may allow specific identification at the species level and possibly strain identification.