Biomedical subjects
Publications and source records attributed to P Marx.
A study is presented mainly of the supratentorial structures that play an important role in saccadic eye movements and smooth pursuit. Eye-movement impairments associated with stroke in the corresponding brain region are then described.
Diagnostic procedures for cerebral ischemia make clear strategies mandatory. Careful recording of case history, internal and neurological investigation either substantiate or make unlikely TIA and stroke. CT scan not only differentiates bleedings, tumors etc from ischemia but also can give very valuable information about the underlying vascular pathology. Multiple lacunes are characteristic of cerebral microangiopathy. Territorial and branch occlusion infarcts mostly indicate embolic occlusion of pial vessels from either cardiac or arterial sources. Endzone and borderline infarctions are seen with high grade stenosis or occlusion of the internal carotid artery. The identification of embolic sources necessitates cardiological (including echocardiography) and angiological (Doppler sonography and in selected cases angiography) investigations. Therapeutic and prophylactic measures depend on the etiology of TIA and stroke and are briefly dealt with.
An inactivated whole simian immunodeficiency virus (SIV) immunogen given to healthy, seropositive rhesus macaques 4 months after infection had no effect on the humoral immune response to SIV, the presence of antigenemia, cell-associated viremia, or disease course. Further immunotherapeutic trials in this highly susceptible animal model should be carried out sooner after exposure, before significant loss of CD4 cells has occurred. The SIV infected macaque model will continue to serve an essential role in development and testing of anti-AIDS drugs and immunogens.
Experimental und clinical data suggest a negative influence of diabetes mellitus and hyperglycemia on the outcome of cerebral ischemia. In a retrospective analysis of 135 consecutive patients with cerebral ischemia we found more severe clinical defects in diabetics and patients with initial hyperglycemia but without previously known diabetes mellitus than in patients with initial normoglycemia. This was especially true for blood glucose above 10 mmol/l. Before drawing therapeutic conclusions, further prospective studies are necessary.
Benign mediastinal teratomas are rare entities, representing 8 to 18% of all mediastinal tumors. Two cases of benign teratomas with a rapid growth suggesting malignancy are reported. CT and MR allowed precise characterization of the multi-tissue composition of the tumor (various CT densities were noted corresponding to adipose, cystic, calcified and hemorrhagic components), and definition of the extension of the process before surgical removal. The per-operative pathological analysis in one patient confirmed the benign nature of the lesion based on the absence of immature tissue, allowing complete surgical removal. The final pathological examination showing mucus secretion by bronchial glandular tissue and intra-tumoral hemorrhage may explain the rapid growth of this kind of lesion. The post-operative follow-up of these benign teratomas is favourable.
In 51 consecutive patients with acute transitory cerebral ischaemia cross-sectional echocardiograms, 24-hour electrocardiograms (ECG) and exercise ECGs were recorded. The subsequent observation period averaged 13 (3-30) months. The echocardiogram was abnormal in 27 of 46 patients (58%). A holosystolic mitral-valve prolapse was found in eight: cerebral ischaemia recurred in five. There was no correlation between arrhythmias in the 24-hour ECG and renewed cerebral ischaemia. In addition to the 14 patients who--according to history and resting ECG--had already had a myocardial infarction, the exercise ECG revealed probably coronary heart disease in a further 11, i.e. half of the patients had coronary heart disease. Renewed attacks of cerebral ischaemia occurred in 13 patients during the follow-up period; four patients died, all of them also having had coronary heart disease. Because of the high prevalence of coronary heart disease (often previously undiagnosed) in the whole group, routine exercise ECGs are recommended for patients with transitory ischaemic attacks, protracted ischaemic neurological deficit or "minimal stroke", while 24-hour ECG monitoring does not seem essential. Randomized trials are needed to determine whether patients with cerebral ischaemia and echocardiographic evidence of mitral-valve prolapse should be treated prophylactically.
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80S ribosomes and ribosomal subunits were isolated from fibroblasts, muscle tissues and blood cells of patients with different muscular dystrophies (MD) as well as of controls and were used for in vitro measurement of ribosomal protein synthesis (RPS) in a poly(U)-directed polyphenylalanine synthesis system. The activity of ribosomes from the patients showed a disease-dependent decrease compared to normal controls. Examination of hybrid 80S ribosomes consisting of 40S and 60S subunits of patients and the corresponding control cells revealed that the loss of RPS activity was related to one or both of the ribosomal subunits depending on the type of MD.
The amount of hemoglobin in cerebrospinal fluid was quantitated in 15 patients with subarachnoid hemorrhage and in 35 subjects without subarachnoid hemorrhage (controls). The photometric determination of the hemoglobin content in cerebrospinal fluid indicated that patients with subarachnoid hemorrhage in contrast to controls showed a significant increase (P greater than 0.01) of hemoglobin (Mann-Whitney test). In 5 of the patients with subarachnoid hemorrhage it was possible to determine the amount of hemoglobin in cerebrospinal fluid over a period of time. Possible correlations between clinical course and hemoglobin concentration as well as the use of hemoglobin quantitation in late diagnosis of subarachnoid hemorrhage are discussed.
In summary, these considerations show that the hemodynamic role of blood rheology in cerebrovascular insufficiency or stroke is still not clear. However, the arguments and data presented allow some conclusions that are of practical and theoretical value in the process leading to further clarification: Changes of blood viscosity as determined by coaxial viscometry cannot be used to predict quantitatively the changes of cerebral blood flow occurring. It is likely that characteristic rheological phenomena such as red cell aggregation and deformability, plasma viscosity, and protein composition are more important for the rheological aspects of microcirculatory supply function than is reflected by their contribution to macroscopic viscosity of the blood. Further studies of blood rheology in stroke should therefore certainly include quantification of those rheological properties that are more closely related to the in vivo flow behavior of blood and thus the magnitude and distribution of flow in the cerebral microcirculation.
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Sera from 526 Old-World monkeys and apes, representing 50 species and 20 genera and living in US zoos and vivaria, were screened for antibodies to HTLV-I, HTLV-III/LAV, and simian-AIDS retrovirus, type I (SRV-I). Sera were screened initially by ELISA, and ELISA-positive sera, as well as ELISA-negative sera from cage contacts, were further tested by Western blotting. A large number of false-positive and a small number of false-negative ELISA sera were identified. Although most true positive reactions were directed to a single retrovirus, a number of individuals from 4 species were positive for more than one retrovirus. Specific seroreactivity to HTLV-I was found in 39/526 (7%) animals of 15 species. True positive reactions to SRV-I were found in 21/516 (4%) animals, including talapoins and 2 species of macaques. Specific serologic reactions to HTLV-III/LAV were detected in 23/526 (4%) monkeys. Many of the HTLV-III/LAV seropositive animals were from one mixed-species zoo exhibit, containing sooty mangabeys, mandrills, Kolb's guenons, and talapoins. A type D virus was isolated from the blood of 3/10 SRV-I antibody-positive Tonkeana macaques, but from none of 11 seropositive talapoins. A lentivirus was isolated from the blood of 4/7 HTLV-III/LAV seropositive sooty mangabeys, but not from seropositive talapoins in the same exhibit or from 2 seropositive colobus from another zoo. The sooty mangabey lentivirus produced generalized lymphadenopathy, leukopenia, and decreased levels of T4 lymphocytes in 2 experimentally infected rhesus macaques.
Sera from 526 old-world primates representing 50 different species were screened by ELISA for antibodies to human T-lymphotropic viruses I and III, and simian retrovirus type 1 (SRV-1). About one-fourth of the sera were positive by ELISA. There was a tendency, however, for the same sera to be positive for all three human and simian retroviruses. Only about one in five of the ELISA antibody-positive sera were confirmed to be positive by Western blotting. False-positive ELISA antibody tests were particularly common among sera from mandrills, crab-eating macaques, lion-tailed macaques, African green monkeys, and DeBrazza's and moustached guenons. Sera that were falsely positive in ELISA antibody tests to the three human and simian retroviruses were found to contain antibodies that reacted at comparable intensity with feline leukemia, infectious peritonitis and panleukopenia viruses. The false anti-viral activity of these sera was found to be due to antibodies that reacted with non-viral proteins that were copurified with all five virus preparations. These proteins were present in normal cat and human cells used to grow the various viruses and in gelatin. The implications of nonspecific cell-protein antibodies in primate sera were discussed in the light of this and previous seroepidemiologic studies of man and old-world monkeys.
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