Plasmodium vivax and P. chabaudi: inter-species cross-reacting antigens

A monoclonal antibody raised by immunization of BALB/c mice with erythrocytic stages of Plasmodium vivax was shown to react with asexual erythrocytic stages of P. chabaudi. The cross-reactivity molecules are antigens of 200 and 148 kDa in P. vivax and of 190 and 70 kDa in P. chabaudi. Immunofluorescence studies of the erythrocytic stages of P. vivax and P. chabaudi indicated that expression of these antigens increased as the parasites' developed from the ring stage to the schizont stage. In the mature trophozoites of P. chabaudi, immunoelectron microscopy revealed clusters of antigen distributed in the cytoplasm of the parasitized erythrocyte. In the schizont, packets of antigen were found associated with the parasitophorous vacuole and the cytoplasm of the infected host cell. Received: 19 March 1996 / Accepted: 28 August 1996     

Distinct mechanisms of splicing regulation in vivo by the Drosophila protein Sex-lethal

The protein Sex-lethal (SXL) controls pre-mRNA splicing of two genes involved in Drosophila sex determination: transformer (tra) and the Sxl gene itself. Previous in vitro results indicated that SXL antagonizes the general splicing factor U2AF⁶⁵ to regulate splicing of tra. In this report, we have used transgenic flies expressing chimeric proteins between SXL and the effector domain of U2AF⁶⁵ to study the mechanisms of splicing regulation by SXL in vivo. Conferring U2AF activity to SXL relieves its inhibitory activity on tra splicing but not on Sxl splicing. Therefore, antagonizing U2AF⁶⁵ can explain tra splicing regulation both in vitro and in vivo, but this mechanism cannot explain splicing regulation of Sxl pre-mRNA. These results are a direct proof that Sxl, the master regulatory gene in sex determination, has multiple and separable activities in the regulation of pre-mRNA splicing.     

Antiparasitic properties of homoallylamines and related compounds

A study of some antiparasitic properties of several homoallylamines and related tetrahydroquinolines and quinolines, previously described, was carried out using in vitro activity assays against the epimastigote form of Trypanosoma cruzi and against Trichomonas vaginalis. Unspecific cytotoxicity against murine macrophages was also studied. Although the antichagasic and trichomonacidal activities are not comparable to those of the standard drugs, nifurtimox and metronidazole, some of the compounds exhibit an interesting specific antiparasitic activity.     

Prevalence of knee abnormalities in patients with osteoarthritis and anterior cruciate ligament injury identified with peripheral magnetic resonance imaging: a pilot study.

OBJECTIVES: 1) To assess, with a peripheral magnetic resonance imaging system (pMRI), the prevalence of bony and soft tissue abnormalities in the knee joints of normal subjects, osteoarthritis (OA) patients, and individuals who have suffered an anterior cruciate ligament (ACL) rupture; and 2) to compare the prevalence among groups. METHODS: Magnetic resonance (MR) images of 28 healthy, 32 OA, and 26 ACL damaged knees were acquired with a 1.0-T pMRI system. Two radiologists graded the presence and severity of 9 MR image features: cartilage degeneration, osteophytes, subchondral cyst, bone marrow edema, meniscal abnormality, ligament integrity, loose bodies, popliteal cysts, and joint effusion. RESULTS: Ten of 28 healthy (35.7%), 24 of 26 ACL (92.3%), and all OA knees (100%) showed prevalent cartilage defects; 5 healthy (17.9%), 20 ACL (76.9%), and all OA knees (100%) had osteophytes; and 9 normal (32.1%), 21 ACL (80.8%), and 29 OA knees (90.6%) had meniscal abnormalities. One-half of the knees in the OA group (16 of 32, 50%) had subchondral cysts, and almost one-half had bone marrow edema (15 of 32, 46.9%). These features were not common in the ACL group (7.7%, and 11.5%, respectively) and were not observed in healthy knees. The OA group had the most severe cartilage defects, osteophytes, bone marrow edema, subchondral cysts, and meniscal abnormalities; the ACL group showed more severe cartilage defects, osteophytes, and meniscal abnormalities than did normal subjects. CONCLUSION: The results suggest that knees that have sustained ACL damage have OA-like reatures; most subjects (19 of 26, 73.1%) could be identified as in the early stage of OA. The prominent abnormalities present in ACL-damaged knees are cartilage defects, osteophytes, and meniscal abnormalities.     

Epilepsy syndromes associated with hypothalamic hamartomas.

PURPOSE: Hypothalamic hamartoma (HH) related epilepsy presents with gelastic seizures (GS), other seizure types and cognitive deterioration. Although seizure origin in GS has been well established, non-GS are poorly characterized. Their relationship with the HH and cognitive deterioration remains poorly understood. We analyzed seizure type, spread pattern in non-GS and their relationship with the epileptic syndrome in HH. METHODS: We documented all current seizure types in six adult patients with HH-epilepsy with video-EEG monitoring, characterized clinical-electrographic features of gelastic and non-gelastic seizures and correlated these findings with cognitive profile, as well as MRI and ictal SPECT data. RESULTS: Only four seizure types were seen: GS, complex partial (CPS), tonic seizures (TS) and secondarily generalized tonic-clonic seizures (sGTC). An individual patient presented either CPS or TS, but not both. GS progressed to CPS or TS, but not both. Ictal patterns in GS/TS and in GS/CPS overlapped, suggesting ictal spread from the HH to other cortical regions. Ictal SPECT patterns also showed GS/TS overlap. Patients with GS-CPS presented a more benign profile with preserved cognition and clinical-EEG features of temporal lobe epilepsy. Patients with GS-TS had clinical-EEG features of symptomatic generalized epilepsy, including mental deterioration. CONCLUSIONS: Video-EEG and ictal SPECT findings suggest that all seizures in HH-related epilepsy originate in the HH, with two clinical epilepsy syndromes: one resembling temporal lobe epilepsy and a more catastrophic syndrome, with features of a symptomatic generalized epilepsy. The epilepsy syndrome may be determined by HH size or by seizure spread pattern.     

T-wave alternans: predicting the unpredictable?

Sudden cardiac death (SCD) due to ventricular arrhythmias hasa high morbidity and mortality. It is no wonder that cardiologists,rather than patching up survivors, are dedicated to findingpredictors of cardiac electrical instability to prevent SCD.The implantable cardiac defibrillator (ICD) has evolved as theultimate strategy for sudden arrhythmic death. In secondaryprevention, individuals are recognized by an aborted arrhythmicevent. By stratifying according to left ventricular ejectionfraction (LVEF) below 35%, SCD may also be prevented by an ICDin individuals without any prior arrhythmic event.¹ However,the relative SCD risk based