Lipophosphoglycan expression and virulence in Ricin-resistant variants of Leishmania major

Lipophosphoglycan (LPG) of Leishmania is a polymorphic molecule comprising an alkylglycerol anchor, a conserved oligosaccharide core and a species-specific polymer of oligosaccharide repeats joined by phosphodiester bonds. This molecule, together with the membrane polypeptide gp63, has been implicated as a parasite receptor for host macrophages. To examine the role of LPG in parasite infectivity glycosylation variants of Leishmania major were generated by chemical mutagenesis of a virulent cloned line V121 and variants with modified LPG selected using the galactose-specific lectin Ricinus communis II (RCA II). Twenty RCA II-resistant primary clones were generated. Analysis of LPG profile by immunoblotting using LPG-specific monoclonal and polyclonal antibodies revealed that some of the clones were LPG-deficient. Three clones that did not bind any LPG-specific antibodies but expressed normal levels of the M_r 63 000 glycoprotein (gp63), a second parasite receptor for host, were chosen for detailed studies.All three clones expressed, at least to some extent, a surface molecule which could be labeled by mild periodate oxidation and sodium borotritide and behaved like LPG by hydrophobic interaction chromatography. All clones also bound a well-characterized monoclonal antibody L157 directed to the core oligosaccharide of LPG, but did not bind another monoclonal antibody, CA7AE, to an epitope on a repeating unit shared by Leishmania donovani and L. major LPG. A third monoclonal antibody, 5E6, recognizing LPG on the surface of wild-type V121 promastigotes bound only to RCA II-resistant clone 3A2-C3 and was restricted to an internal structure. The LPG molecule that this clone expressed was a form of LPG by its chromatographic behavior and by its monosaccharide and alkylglycerol composition. Clone 3A2-C3 was the only one to infect mice in vivo and survive in macrophages in vitro, albeit at a much reduced rate compared to wild-type V121 promastigotes. The data suggest that some form of LPG may be necessary to ensure parasite infectivity.     

Further delineation of the Beemer–Langer syndrome using concordance rates in affected sibs

Six familial cases of the Beemer–Langer syndrome (BLS) were analyzed to further elucidate the spectrum and frequency of anomalies observed in this disorder. Preaxial polydactyly was found in 3/6 affected sibs, and, therefore, its frequency previously may have been underestimated. Some patients, described as infants affected with the Majewski syndrome (MS) or “atypical” short rib-poly-dactyly conditions, may indeed have BLS. A high frequency of brain defects (16/26) and cleft tongue, oral frenula, and/or natal teeth (13/29) widens the list of typical findings in this syndrome. The specific type of tibial defect seems to be the most important discrimination of the MS and the BLS. © 1994 Wiley-Liss, Inc.     

The measurement of fibrinogen by the DuPont aca and Dade methods in patients receiving streptokinase infusions

To assess the discrepancies noted in fibrinogen measurement by the DuPont aca and Dade methods, nine patients receiving streptokinase (SK) by either the intracoronary (IC) (240,000 IU/60 minutes) (two patients) or intravenous (IV) (1,500,000 IU/45 minutes) routes (seven patients) for acute myocardial infarctions were studied over 48-72 hours. All nine patients showed a rapid and profound fall in fibrinogen to unrecordable levels (30 mg/dL) by the Dade method. Three patients showed a similar response to unrecordable levels (less than 50 mg/dL) with the DuPont aca method. Six others had less of a decrease with the DuPont aca method compared with the Dade method. One patient showed a gradual fall by the DuPont aca method to reach 60% of the preinfusion level at 30 hours, whereas the minimal value by the Dade method, 81% of the preinfusion level, was reached within 12 hours. There was no difference in fibrinogen levels by the Dade method after absorption of heparin-like activity with triethylamino ethyl (TEAE) cellulose. Fibrinogen degradation products (FDPs) were elevated in all patients post-SK infusion. These studies show that fibrinogen estimation by DuPont aca and Dade methods may yield discrepant results in approximately 66% of patients treated with SK. This may have some clinical relevance to clinicians who rely on the DuPont aca fibrinogen estimation to monitor effectiveness of SK therapy.     

The effect of the illumination time when treating port-wine stains

This paper reports the electron microscopy results obtained from two patients who were treated with 5 W of yellow (578 nm) light from a copper vapour laser with an illumination time of 3.6 ms and a 0.3 mm spot diameter. The endpoint of treatment was transient blanching. Following treatment, erythema was observed. There was minimal damage to the epidermis and non-vascular tissue such as the nerve fibres. There was severe damage to the endothelial cells of the ectatic vessels. Twenty-four hours after treatment, platelet activation and collagen were present, indicating that these vessels were no longer viable. Theoretical calculations are used to determine the flow of heat within and away from a 50m diameter vessel. From this, heating of the entire vessel is shown to occur with illumination times of 4 ms, with minimal heating of the non-vascular tissue. Shorter illuminations do not heat the entire vessel, while the use of longer illumination times will cause excessive damage to the surrounding non-vascular tissue. Illumination times close to 4 ms must be regarded as optimal.     

Actinomyces and nocardia infections in immunocompromised and nonimmunocompromised patients

A retrospective survey of nocardia and actinomyces infections in five local hospitals was conducted over a 3-year period in El Paso, Texas, a border city, in the southwestern United States. The medical records of 42 patients with suspected nocardiosis or actinomycosis were reviewed. One patient was diagnosed with actinomyces and 12 patients with nocardia. Microbiological data included morphologic characteristics, biochemical profile, and susceptibility testing. Predisposing factors included leukemia, renal insufficiency, renal transplant, and lymphoma. No predisposing factors were found in 67% (n = 8) of patients (including the patient with actinomycosis). Twenty-three percent (n = 3) of patients had disseminated disease without evidence of underlying disease or immunosuppression. The mortality and morbidity of these infections appeared to be low.     

Cerebral vasculitis in a case of Sydenham's chorea

A 10-year-old girl with acute-onset hemichorea had multiple areas of abnormal signal seen on magnetic resonance imaging of the brain, associated with middle and anterior cerebral artery vasculitis seen on cerebral angiography. Her serology and clinical course were supportive of the diagnosis of Sydenham's chorea. Other causes of cerebral vasculitis were excluded. Follow-up studies revealed resolution of changes seen on magnetic resonance imaging and partial resolution of angiographic abnormalities. This is the first report of abnormal cerebral angiography in Sydenham's chorea.