Distribution of parvalbumin-containing interneurons in the hippocampus of the gerbil--a qualitative and quantitative statistical analysis.

In the gerbil (Meriones unguiculatus) hippocampal formation, the calcium-binding protein parvalbumin (PV) shows a unique species-specific distribution: it is present in the perforant path from the entorhinal cortex to the stratum molecular of the dentate are and cornu ammonis. A possible relation of this to the seizure-sensitivity of gerbils has been suggested. In addition, as in other species, PV is contained in a subpopulation of GABAergic nerve cells of the gerbil hippocampus. The characteristics of these PV-containing neurons are here described. Distribution and shape of the PV-positive neurons in general agreed with the features described for rat hippocampus with two notable exceptions: in CA2 PV-containing perikarya were densely crowded and gave rise to an intense immunoreactive plexus around the pyramidal cells and, in CA1, the number of stained neurons was variable, often much lower than in rats and occasionally not a single PV-positive neuron was present. In parasagittal brain sections of the lateralities 1.0, 1.6 and 2.2 mm from the midline, obtained from 27 male gerbils, the number of PV-containing neurons was determined. The data set obtained in CA3 and dentate area resembled unimodal distributions, while in CA1 a bimodal frequency distribution was present. Since parametric and non-parametric correlation tests rely on a unimodal distribution of the data set, they gave falsely significant values in CA1. The bimodal distribution suggests that, with respect to the PV-containing interneurons in CA1, two different populations of gerbils were included in our sample, those with many positive neurons and those with only a few. Since the nerve terminal staining is preserved also in those gerbils with only a few positive perikarya in CA1, it seems possible that an unknown factor influenced PV expression and storage in the soma. Sex, age, seasonal or circadian rhythm or quality of immunocytochemical staining did not influence the outcome of the quantitative analysis. However, a relation of the expression of the high affinity calcium buffering PV in interneurons and the individual seizure sensitivity of the gerbil is considered.

Prognostic relevance of urinary neopterin in non-Hodgkin's lymphomas.

Neopterin excretion levels were assessed in 66 consecutive patients affected by non-Hodgkin's lymphomas (NHL). The logarithm of the mean value of the whole series was 2.71 (log [mumol neopterin/mol creatinine]), significantly higher (P less than 0.001) than the control value (2.12). Fifty-six of 66 patients had a raised excretion of neopterin in amounts statistically related to the stage of disease. The mean value (2.51) of patients in Stages I-II was lower than the mean value (2.86) of patients in Stage III-IV (P less than 0.001). The 2-year probability of survival was 64% for patients in Stages I-II and 34% for patients in Stages III-IV. However, patients with lower neopterin excretion (less than 2.65) fared better than patients with higher neopterin excretion, regardless of the stage. Longitudinal analysis showed a trend toward a correlation between response to therapy and neopterin excretion. In NHL, the raised neopterin excretion appears to be a consequence of activation of the host immune system rather than a product of the malignant cells. But this excessive activation of the monocytes-macrophages, as reflected by urinary neopterin levels, is not accompanied by a better outcome. In conclusion, although neopterin cannot be considered a typical tumor marker, nevertheless it is an useful prognostic marker in NHL.

Urinary neopterin levels in hematologic malignancies.

We studied urinary excretion levels of neopterin in 30 cancer patients affected by non-Hodgkin's lymphomas, Hodgkin's disease and multiple myeloma compared to 30 healthy subjects. Mean value of neopterin excretion in cancer patients (576.01 +/- 620.37) appeared significantly increased (p less than 0.001) compared to normal controls (134.40 +/- 41.65). A neopterin excretion above the upper normal limit was observed in 23/28 (82%) patients with active disease. A trend to an increased urinary level of neopterin with more advanced stage was observed, namely in patients with bone marrow involvement and constitutional symptoms. We suggest that the evaluation of urinary neopterin levels may be of value in the diagnosis and follow-up of hematologic malignancies.

Terminals of intralaminar thalamic neurons in the pallidum externum of Saimiri sciureus.

Stereotactic coagulations of intralaminar thalamic nuclei in 6 squirrel monkeys Saimiri sciureus produced dark degenerations only of type IV synapses in pallidum externum, according to the classification of Hassler and Chung often preserving the slightly asymmetric contact and subsynaptic densities. Other type IV boutons underwent semidark degeneration, whereas others showed crystalloid degeneration. Some of type IV boutons show the deposition of many dense core vesicles and mitochondria with loss of most synaptic vesicles. Enlarged type IV boutons are sometimes overcrowded with irregularly shaped lysosomes. Thus, a monosynaptic connections of intralaminar thalamic nuclei to pallidum externum could be demonstrated.

Functional role of pallidum revealed by its electrical stimulation and coagulation in unanesthetized squirrel monkeys.

Pallidum-induced direction-specific movements in squirrel monkeys were studied with stimulation or coagulation of this brain structure. The reactions to pallidum externum stimulation were small rapid and phasic head movements, mainly towards the contralateral side. Stimulation of pallidum internum produced a contralateral turning of the head. After high-frequency coagulation of one pallidum, the direction of unrestrained locomotion was exclusively to the lesioned side. Lesions that included the most medial parts of the pallidum produced a continuous ipsiversive circling behavior. These results demonstrate the crucial role of the pallidum in directing contraversive turning movements around the vertical axis of the body.