Imaging parallel fiber and climbing fiber responses and their short-term interactions in the mouse cerebellar cortex in vivo

A major question in the study of cerebellar cortical function is how parallel fiber and climbing fiber inputs interact to shape information processing. Emphasis has been placed on the long-term effects due to conjunctive stimulation of climbing fibers and parallel fibers. Much less emphasis has been placed on short-term interactions and their spatial nature. To address this question the responses to parallel fiber and climbing fiber inputs and their short-term interaction were characterized using optical imaging with Neutral Red in the anesthetized mouse in vivo. Electrical stimulation of the cerebellar surface evoked an increase in fluorescence consisting of a transverse optical beam. The linear relationship between the optical responses and stimulus parameters, high spatial resolution and close coupling to the electrophysiological recordings show the utility of this imaging methodology. The majority of the optical response was due to activation of postsynaptic alpha-amino-3-hydroxyl-5-methyl-4-isoxazole propionate (AMPA) and metabotropic glutamate receptors with a minor contribution from the presynaptic parallel fibers. Stimulation of the inferior olive evoked parasagittal bands that were abolished by blocking AMPA glutamate receptors. Conjunctive stimulation of the cerebellar surface and inferior olive resulted in inhibition of the climbing fiber evoked optical responses. This lateral inhibition of the parasagittal bands extended out from both sides of an activated parallel fiber beam and was mediated by GABA(A) but not GABA(B) receptors. One hypothesized role for lateral inhibition of this type is to spatially focus the interactions between parallel fiber and climbing fiber input on Purkinje cells. In summary optical imaging with Neutral Red permitted visualization of cerebellar cortical responses to parallel fiber and climbing fiber activation. The GABA(A) dependent lateral inhibition of the climbing fiber evoked parasagittal bands by parallel fiber stimulation shows that cerebellar interneurons play a short-term role in shaping the responses of Purkinje cells to climbing fiber input.

Association between outcome and telomere DNA content in prostate cancer

PURPOSE

To perform an initial retrospective investigation of the relationship between outcome in patients with organ confined prostate adenocarcinoma and the tumor cells' content of telomere DNA.

MATERIALS AND METHODS

The case-controlled study group was composed of eighteen men diagnosed with prostatic adenocarcinoma prior to 1993. The group was selected so that approximately one half died within ten years of diagnosis and one half survived ten years or longer. Archival, paraffin-embedded tumor tissue was recovered for each patient. DNA was extracted from newly cut sections, fixed to nylon membranes and hybridized with P32-labeled centromere- and telomere-specific probes. Telomere DNA contents were quantitated from the hybridized radioactivities. The relationships between telomere DNA content and survival, and telomere DNA content and disease recurrence in men receiving prostatectomies were determined.

RESULTS

Death and disease recurrence were associated with reduced telomere DNA content (p <0.0001, p <0.0001, respectively).

CONCLUSIONS

Telomere DNA content may differentiate high-risk patients with metastatic prostate cancer from men with indolent disease who can be spared the unnecessary side effects and expense of treatment by management with "watchful waiting."

Association between outcome and telomere DNA content in prostate cancer

PURPOSE

To perform an initial retrospective investigation of the relationship between outcome in patients with organ confined prostate adenocarcinoma and the tumor cells' content of telomere DNA.

MATERIALS AND METHODS

The case-controlled study group was composed of eighteen men diagnosed with prostatic adenocarcinoma prior to 1993. The group was selected so that approximately one half died within ten years of diagnosis and one half survived ten years or longer. Archival, paraffin-embedded tumor tissue was recovered for each patient. DNA was extracted from newly cut sections, fixed to nylon membranes and hybridized with P32-labeled centromere- and telomere-specific probes. Telomere DNA contents were quantitated from the hybridized radioactivities. The relationships between telomere DNA content and survival, and telomere DNA content and disease recurrence in men receiving prostatectomies were determined.

RESULTS

Death and disease recurrence were associated with reduced telomere DNA content (p <0.0001, p <0.0001, respectively).

CONCLUSIONS

Telomere DNA content may differentiate high-risk patients with metastatic prostate cancer from men with indolent disease who can be spared the unnecessary side effects and expense of treatment by management with "watchful waiting."

Serum cytosolic beta-glucosidase elevation and early ischemic injury to guinea pig small intestine

BACKGROUND

The lack of an early, sensitive marker for intestinal ischemia has led to delay in diagnosis and worsended outcome for patients with acute onset of this condition. Our preliminary studies revealed that guinea pig cytosolic beta-glucosidase (CBG) is expressed predominantly in the small intestine, with lower levels in the liver and pancreas and undetectable levels in other organs. Cytosolic beta-glucosidase was investigated as a serum marker of small intestinal ischemia in a guinea pig model.

METHODS

Guinea pigs underwent anesthesia, sham laparotomy, 30 minutes of mesenteric ischemia followed by 6 hours of reperfusion 6 hours of sustained mesenteric ischemia, or closed-loop small bowel obstruction. Serum samples were assayed for CBG activity. At the conclusion of the ischemia/reperfusion experiments, small bowel samples were assayed for residual enzyme activity, and paraffin sections were graded for the severity of histologic injury.

RESULTS

Serum CBG activity rose rapidly after intestinal ischemia with and without reperfusion. Peak enzyme activities were elevated 23-fold for reperfused animals (P < .001) by 4 hours. For nonreperfused animals, peak serum CBG activities reached 29-fold above baseline and were significantly higher than the CBG activities of reperfused animals at 4 hours (P < .01) and at 6 hours (P < .05). Mucosal injury ranged from undetectable to moderate and corresponded in severity with both peak serum enzyme activity and decreased residual activity in the small bowel. In animals subjected to closed-loop obstruction, there was a mean increase of serum CBG of 9.2-fold from 4 to 6 hours after establishment of obstruction (P < .05).

CONCLUSIONS

In the guinea pig model, CBG is a sensitive marker of ischemic injury caused by arterial occlusion or closed-loop obstruction of the small bowel.

Tissue distribution of hantavirus antigen in naturally infected humans and deer mice

The Sin Nombre virus (SNV) is the etiologic agent of hantavirus pulmonary syndrome in humans but does not cause disease in chronically infected deer mice (Peromyscus maniculatus), the natural host. In this study, murine antiserum raised against recombinant SNV nucleocapsid protein was utilized to localize viral antigen immunohistochemically in tissues from both humans (n = 20; 11 positive, 9 negative) and deer mice (n = 6; 4 positive, 2 negative). Viral infection status was confirmed by Western blot or reverse transcriptase-polymerase chain reaction. SNV antigen was detected in pulmonary and cardiac endothelium in both species, but positive cells in deer mice were rare. Other deer mouse tissues, including kidney, were negative; in contrast, vascular elements of several tissues from infected humans were positive, with strong staining of renal endothelium. The paucity of positive cells in chronically infected mice suggests a low virus burden compared with that of acutely infected humans.

Hantavirus pulmonary syndrome: clinical, diagnostic, and virologic aspects

Hantavirus pulmonary syndrome is an acute pneumonitis with a high mortality rate that is caused by a newly recognized hantavirus. Four Corners virus (also known as Muerto Canyon virus and Sin Nombre virus) is enzootic among deer mice (Peromyscus maniculatus). Incidental transmission to humans can result in a disease characterized by rapidly progressive respiratory insufficiency, diffuse noncardiogenic pulmonary edema, vascular volume contraction with hemoconcentration, lactic acidosis, depressed cardiac output, and cardiac dysrhythmias preterminally. The onset of pulmonary edema is preceded by a prodrome of fever and severe myalgias. Characteristic laboratory abnormalities include thrombocytopenia, leukocytosis with prevalent immature myeloid cells, and the presence of immunoblastic lymphocytes in the peripheral blood. Agent-specific diagnosis is based on the detection of Four Corners virus-specific antibodies in serum by Western blot assays and the detection of Four Corners virus RNA in peripheral blood mononuclear cells by the reverse transcriptase-polymerase chain reaction. Effective treatment depends on the rapid institution of intensive care support.

Unusual mesenchymal and mixed tumors of the salivary gland. An immunohistochemical and flow cytometric analysis of three cases

Histological, immunohistochemical, and flow cytometric characteristics of three unusual parotid gland tumors are described. The patients were adult white men with carcinoma ex pleomorphic adenoma, true malignant mixed tumor, and primary parotid gland chondrosarcoma. The carcinoma ex pleomorphic adenoma showed evidence of simultaneous epithelial, myoepithelial, and mesenchymal differentiation by immunohistochemistry. The true malignant mixed tumor exhibited variable positivity for two keratins, vimentin, proliferating cell nuclear antigen, Ki67, and p53. The chondrosarcoma initially stained for vimentin, S100, muscle-specific actin, proliferating cell nuclear antigen, and Ki67, but it lost actin expression in its first recurrence, accompanied by more extensive Ki67 staining. DNA ploidy varied from diploid to aneuploid with intratumoral variation in the carcinosarcoma. S-phase fractions ranged from 2.43% to 13.9%. The findings underscore the diversity of tumors that may be pathogenetically related to, and at times derived from, pleomorphic adenoma.

Direct evidence for intrastrand DNA inversion of kappa immunoglobulin gene segments in two murine plasmacytomas

The products of kappa immunoglobulin gene recombination have been characterized in two murine plasmacytomas to examine the relationship between V-J products and reciprocal elements. By cloning, sequencing, hybridization, and application of the polymerase chain reaction, we have established the direct relationship of the kappa recombination products in these cells. The results provide stronger support for the intrastrand mechanism of kappa gene recombination as well as demonstrating a role for secondary, corrective recombinations.

Inflammatory pseudotumor (pseudosarcoma) of the bladder

Inflammatory pseudotumor (pseudosarcoma) of the bladder is a benign proliferative lesion of the submucosal stroma easily mistaken for a malignant neoplasm clinically and histologically. The lesion was first described as a separate entity in a report of 2 patients. Three additional cases have been reported since then. We describe pseudosarcomatous bladder tumors arising in 2 adolescents. Both patients presented with sudden onset of gross painless hematuria related to large polypoid and ulcerated bladder masses found on endoscopy. Initial pathological analysis was interpreted as poorly differentiated sarcoma in both patients but subsequent reviews were consistent with a benign process resembling nodular fasciitis. Simple excision in both patients has been successful in eradicating the lesion. The findings in these 2 patients are described with a discussion of the pathophysiology and review of the literature.