Disseminated BK type polyomavirus infection in an AIDS patient associated with central nervous system disease.

A 27-year-old man with hemophilia type A and acquired immunodeficiency syndrome developed a subacute meningoencephalitis, associated with a normotensive internal hydrocephalus, 14 weeks before his death. From cerebrospinal fluid and brain autopsy material, a virus could be isolated and was classified by Southern blot analysis and restriction endonuclease reactions as the human polyomavirus BK. The postmortem findings of polyomavirus antigen and BK virus DNA in various cell types of the kidneys, lungs, and central nervous system strongly suggest that BK virus was the causative agent of a tubulointerstitial nephropathy, an interstitial desquamative pneumonitis, and a subacute meningoencephalitis with accentuation of the ventricular and meningeal surfaces of the brain. Besides distinctive cytopathic effects, the presence of intranuclear inclusions was a prominent histopathological feature. Therefore, the human polyomavirus BK should be regarded as a new candidate on the still growing list of opportunistic pathogens in acquired immunodeficiency syndrome.

Inhibition of non-specific leukocyte esterase activity. Absence of monocyte esterase activity due to phosphoric and thiophosphoric acid ester intoxication.

In vitro evaluation of the effect of five insecticidal phosphoric and 11 thiophosphoric acid esters on different, non-specific human leukocytes esterases indicated that most of the organic phosphor compounds studied inhibited the activity of neutral alpha-naphthylacetate esterase, alpha-naphthylbutyryl esterase, and naphthol AS acetate esterase, i.e. the monocyte esterases. The extent of inhibition was dose dependent; the inhibiting dose being identical for the various non-specific esterases. Reactivation with Obidoxim was not successful. Monocyte esterase activity in a human survivor of E 605 intoxication was detectable only after serum acetylcholinesterase had returned to normal levels. The organic phosphor compound studied, however, inhibited neither acid alpha-naphthylacetate esterase nor naphthol AS-D chloroacetate esterase activity.

Destruction of intracerebrally applied red blood cells in cervical lymph nodes. Experimental investigations.

In rabbits, intracerebrally applied erythrocytes can move with the cerebrospinal fluid along connecting pathways between the subarachnoid space and the cervical lymph nodes. This study compares the time dependency for the degradation of intracerebrally injected erythrocytes in the brain as well as in the cervical lymph nodes. Rabbits were killed at various predetermined intervals after the intracerebral erythrocyte injection. Microscopic and histologic examination of the brain and the cervical lymph nodes revealed the following findings: (1) Erythrophages first appeared in the brain 24 h after the injection; siderophages, 4 days after the injection. Siderophages were still demonstrable at the conclusion of the study, i.e. 240 days after the injection. (2) In the cervical lymph nodes erythrophages were first observed 1 h after the injection; siderophages, 9 h after the injection. Only isolated erythrophages and siderophages were found in the lymph nodes 12 days after intracerebral injection of red blood cells. Later on no erythrocytes or siderophages were observed in the lymph nodes. The findings indicate that non-phagocytized red blood cells arriving at the lymph nodes were ingested by local macrophages. The extremely rapid ingestion and digestion of the red blood cells by lymph node macrophages as well as the possible reasons were discussed.

Cytochemical marking of T lymphocytes in human cerebrospinal fluid.

Demonstration of nonspecific acid alpha-naphthyl acetate esterase activity is a simple and practical method for classifying mononuclear cells in the cerebrospinal fluid. In addition to mononuclear phagocytes, T lymphocytes may also be characterized.

Cytochemical markers for mononuclear phagocytes as demonstrated in reactive microglia and globoid cells.

Several cytochemical characteristics of mononuclear phagocytes which are used as identifying markers were studied in reactive microglia from traumatically damaged brain tissue of guinea pigs and humans as well as in globoid cells from a child with familial globoid cell leukodystrophy (Krabbes' disease). The following cytochemical methods were used: acid phosphatase, lysozyme, peroxidase, alpha-naphthyl acetate esterase, alpha-naphthyl butyrate esterase, adenosine triphosphatase, and the periodic acid-Schiff reaction (PAS reaction). Distinct activity of almost all enzymes and the PAS reaction were demonstrable in reactive microglia and globoid cells. Peroxidase however could not be demonstrated in globoid cells. The similarity of the cytochemical characteristics for mononuclear phagocytes, reactive microglia, and globoid cells tends to indicate a common identity for these cell types. The lack of peroxidase in globoid cells may be due to a final maturation and differentiation after the monocyte stage.

Postmortal diffusion of plasma albumin in rat brain.

After i.v. injection of Evans blue solution (EB), the postmortal diffusion of plasma albumin and its relationship to the postmortal interval (0 to 48 h) were studied in rat brain. A decrease in intravascular plasma albumin with increasing evidence of the same fraction in relation to the length of the postmortal interval was observed via diffuse EB fluorescence in the perivascular, periventricular, and subpial neuropil. Stained nerve cells and single endothelial cells were found grouped around individual vessels, particularly in the region of the basis encephali. The EB-fluorescent cells proved to be hyperchromatic when subsequently stained with cresyl violet; the nerve cells therefore were considered dark neurons. EB-fluorescent dark neurons were also found around the lesion in experiments involving postmortal traumatic damage of cerebral tissue. Since all EB-fluorescent nerve cells proved to the dark neurons, but not all dark neurons exhibited EB fluorescence, it was concluded that dark neurons possess a capacity for intensifying the absorption of plasma albumin. No fluorescence was demonstrated in control studies of cerebral tissue in which EB had not been injected.

[A modification of microglia impregnation (author's transl)]. / Modifikation der Mikroglia-Darstellung.

A modification of the Weil and Davenport (1933) silver carbonate method for microglia impregnation is described. Formalin-dextran-CaCl2 solution was used as a fixation solution. The technique is simple, reproducible and improved. The staining method includes the demonstration of as well resting as progressive microglia.

Features and distribution of intracerebrally injected peritoneal macrophages.

Radioactively labeled macrophages were injected intracerebrally in order to acquire additional criteria for the identity of certain intracerebral cell types with cells of the monocyte-macrophage series. The intracerebral distribution of the labeled cells, their reactive ability following silver impregnation, and the formation of processes were considered as indications for ameboid motility. The localization, reactive ability, and structure of the cells were similar to that found in cells inside the brain which are considered to be monocyte derivatives, i.e., intraventricular cells such as epiplexus cells and supraependymal cells, progressive microglia, free subarachnoidal cells, and perivascular cells of intracerebral vessels. A survival time of 2 months was assumed for the cells since isolated, intracerebrally administered, peritoneal macrophages can still be demonstrated inside the subarachnoid space 2 months after the injection.

Lymphatic efflux of intracerebrally injected cells.

Following intracerebral injection of labeled erythrocytes, lymphocytes and/or peritoneal macrophages, cervical and inguinal lymph nodes were subjected to histologic examination. Labeled cells of all cell types were found in the cervical lymph nodes, but they were not observed in the inguinal lymph nodes. No labeled cells were demonstrated in the lymph nodes following intravenous injection of cell suspensions. It is assumed that an efflux of cells occurs in the perineural spaces of the exiting nerve fibers. The anatomic relationships were discussed.

Experimental studies on kinetics and functions of monuclear phagozytes of the central nervous system.

The described experimental studies on rabbits gave evidence of the hematogenous - obviously monocytic - origin, the lymphatic drainage, and the IgG- and complement-receptor sites of monocytoid CSF-cells, epiplexus cells, perivascular cells of the intracerebral vessels, and of some cells within damaged brain tissue - so-called progressive microglia. - Becuase of their identical kinetics and functions these types of mononuclear cells of the CNS were placed in a system known as 'Mononuclear Phagocyte System".