Quantitative neurohistological features of frontotemporal degeneration

Frontotemporal degeneration (FTD) is a neurodegenerative condition that has been principally associated with frontal lobe dementia. In this study, we compared neuropathological abnormalities in frontal, hippocampal, and calcarine cortices from patients assigned a diagnosis of FTD, normal elderly and Alzheimer's disease (AD). Densities of Nissl-stained neurons and lesions which were immunolabeled for tau, beta-amyloid (Abeta), alpha- and beta-synuclein, ubiquitin, glial fibrillary acidic protein (GFAP) and CD68 antigen were determined using computer-assisted, non-biased quantitative microscopy. We found that FTD frontal and hippocampal regions exhibited marked neuron loss, abundant ubiquitin-immunoreactive (ir) dystrophic neurites, GFAP-ir astrocytes, and CD68-ir microglia, while calcarine cortex was spared. No alpha- or beta-synuclein-ir lesions were observed, and neither the density of tau-ir neurofibrillary tangles nor that of Abeta-ir plaques in FTD exceeded normal controls. In addition, there were no neuropathological differences between FTD subjects who presented clinically with a frontal lobe dementia versus an AD-like dementia. These findings indicate that FTD is a category of neurodegnerative dementias with varying clinical presentations that is characterized by the progressive degeneration of select populations of cortical neurons. The molecular neurodegenerative mechanisms that lead to FTD remain to be elucidated.

Absence of neurodegeneration in the thalamus and caudate of elderly patients with schizophrenia

The cognitive and functional deterioration observed in many 'poor-outcome' patients with schizophrenia suggests an ongoing neurodegenerative process. Diagnostic neuropathologic studies have excluded known neurodegenerative diseases as the cause of this dementia, and in a previous quantitative investigation of neurodegeneration and neural injury in this population we found no abnormalities in the cerebral cortex. However, it is possible that the deterioration observed in these patients could be due to subcortical neurodegenerative processes. Neurodegeneration and neural injury in the caudate nucleus and mediodorsal nucleus of the thalamus were investigated in a postmortem study of 11 prospectively accrued, clinically well-characterized elderly people with schizophrenia, 11 elderly control subjects with no neuropsychiatric illness, and 12 subjects with Alzheimer's disease. Traditional and immunohistochemical staining and unbiased computerized counting methods were used to quantify common markers of neurodegeneration and neural injury (neuron loss, neurofibrillary tangles, astrocytosis, microgliosis). No statistically significant differences were found between schizophrenia and control subjects for the densities of any markers. There is no evidence that abnormal neurodegeneration occurs in these two important subcortical structures.

Absence of neurodegeneration and neural injury in the cerebral cortex in a sample of elderly patients with schizophrenia

BACKGROUND

The cognitive and functional deterioration that is observed in many "poor-outcome" patients with schizophrenia suggests a neurodegenerative process extending into late life. Previous diagnostic studies have excluded known neurodegenerative diseases as explanations for this dementia. However, we hypothesized that relatively small accumulations of age- or disease-related neurodegenerative lesions occurring in an otherwise abnormal brain could result in deterioration in schizophrenia.

METHODS

Postmortem studies were conducted using 23 prospectively accrued elderly persons with chronic schizophrenia for whom clinical ratings had been determined before death, 14 elderly control patients with no neuropsychiatric disease, and 10 control patients with Alzheimer disease. Immunohistochemistry and unbiased stereological counting methods were used to quantify common neurodegenerative lesions (ie, neurofibrillary tangles, amyloid plaques, and Lewy bodies) and cellular reactions to a variety of noxious stimuli (ubiquitinated dystrophic neurites, astrocytosis, and microglial infiltrates) in the ventromedial temporal lobe and the frontal and the calcarine (primary visual) cortices.

RESULTS

No statistically significant differences were found between the patients with schizophrenia and the control patients without neuropsychiatric disease for the densities of any of the markers, while both groups exhibited fewer lesions than did the control group with Alzheimer disease. Correlation analyses in the schizophrenia sample failed to identify significant correlations between cognitive and psychiatric ratings and densities of any of the neuropathologic markers.

CONCLUSIONS

No significant evidence of neurodegeneration or ongoing neural injury in the cerebral cortex was found in this sample of elderly persons with schizophrenia. Furthermore, the behavioral and cognitive deterioration observed in late life did not correlate with age-related degenerative phenomena.

Ribonuclease H renaturation gel assay using a fluorescent-labeled substrate

Ribonucleases H (RNases H) are enzymes that specifically degrade the RNA of RNA-DNA hybrids. These enzymes are involved in DNA replication, reverse transcription (RT) and antisense oligodeoxyribonucleotide-mediated arrest of translation. One of the most valuable tools for assaying RNase H activity is the renaturation gel assay with which such activities can be detected using purified protein preparations or crude extracts. Radioactive substrates [32P labeled poly(rA)-poly(dT) hybrid] are commonly used with exposure of the gel to X-ray film; this is possible at any time without disturbing the renaturation-degradation process. Here, we describe a method using fluorescent-labeled substrates. RNA-DNA substrates are synthesized by first transcribing DNA with T7 RNA polymerase using Bodipy-TR-14-UTP and the four normal nucleoside triphosphates. The run-off transcript is annealed to a short oligomeric DNA complementary to the 3'-end of the transcript, and the DNA portion of the hybrid is formed by RT. This RNA-DNA is added to the polyacrylamide mixture before polymerization, and SDS-PAGE is performed as usual. After various periods of renaturation, the gel is scanned to detect fluorescent substrate using the red-excited laser of a fluorescence scanner. This fluorescence method has all of the advantages of using radio-labeled substrates and none of its disadvantages, and the sensitivities of the two methods are comparable. In addition, we show that the sensitivity of this procedure can be increased if damaging chemicals remaining in the gel after polymerization are eliminated by simultaneous electrophoresis of the RNase H and a protein with higher mobility.

Further evidence of abnormal cytoarchitecture of the entorhinal cortex in schizophrenia using spatial point pattern analyses

Previous studies have reported cytoarchitectural abnormalities in superficial laminae of rostral portions of the entorhinal cortex in schizophrenia, including decreased densities of neurons, poorly formed layer II neuron islands, and apparent displacement of layer II-type neurons deep into layer III; however, findings have been controversial, given the qualitative nature of the descriptions and the normal heterogeneity of cytoarchitecture of the region. The x, y coordinates of Nissl-stained neurons were mapped in layers II, III, and V of entorhinal subdivision ER in 8 prospectively accrued patients with schizophrenia and 8 nonneuropsychiatric controls. Indices of neuron dispersion, nearest neighbor distances, and effective radius were determined. An abnormally clustered dispersion of neurons in layer III was present in schizophrenics compared to controls along with a reduced neuron effective radius, whereas the mean nearest-neighbor distance was normal. In layer II, there was a significantly increased effective radius, whereas other indices were normal. No between-group differences were noted in layer V for any variable. These data provide further evidence for subtle aberrant cytoarchitecture in superficial laminae of the entorhinal cortex in schizophrenia and are consistent with neurodevelopmental models of abnormal neuronal pruning, "miswiring," and/or migration in the illness.

Inositol 1,4,5-trisphosphate receptor expression in odontoblast cells

The cellular distribution of inositol 1,4,5-trisphosphate receptors was examined in rodent maxillary incisor teeth. In situ hybridization studies with a transmembrane probe of type I inositol 1,4,5-trisphosphate receptor indicated that this receptor/channel was highly expressed in odontoblast cells of incisor teeth. In contrast, very low labeling was observed in dental pulp. Northern analysis showed a message size of approximately 9.5 kilobases for this receptor, and demonstrated that type III inositol 1,4,5-trisphosphate receptor was expressed in incisor teeth. Immunocytochemical studies confirmed that types I and III inositol 1,4,5-trisphosphate receptors were both highly expressed in odontoblasts while very low expression was detected in dental pulp. Finally, antibodies that recognized alpha subunits of the Gq class of GTP binding proteins also stained odontoblasts. These results indicate that receptor-mediated regulation of calcium release through inositol 1,4,5-trisphosphate receptors may occur in odontoblasts of rat incisor teeth. These findings also suggest that inositol 1,4,5-trisphosphate receptor/channels regulate calcium flux in odontoblasts during mineralization of dentin, or in growth and differentiation of incisor tissue.

Inositol 1,4,5-trisphosphate receptor expression in mammalian olfactory tissue

Two cDNAs encoding inositol 1,4,5-trisphosphate (IP3) receptors were amplified from rat olfactory tissue, and both exhibited 100% sequence identity to the short (Segment II - ) variant of type I IP3 receptor. Type III IP3 receptor was also expressed in olfactory tissue. The distribution of IP3 receptors included the olfactory epithelium, lamina propria, and glandular tissue. These results demonstrate the co-expression of multiple IP3 receptor subtypes in olfactory cells, and suggest multiple functions for IP3 receptors in this tissue.

Synaptic loss in the central nucleus of the inferior colliculus correlates with sensorineural hearing loss in the C57BL/6 mouse model of presbycusis

Between 3 and 25 months of age, light and electron microscopic features of principal neurons in the central nucleus of the inferior colliculus of the C57BL/6 mouse were quantitated. This mouse strain has a genetic defect producing progressive sensorineural hearing loss which starts during young adulthood (2 months of age) with high-frequency sounds. During the second year of life, hearing is severely impaired, progressively involving all frequencies. The hearing loss was documented in the present study by auditory brainstem recordings of the mice at various ages. The cochleas from many of the same animals showed massive loss of both inner and outer hair cells beginning at the base (high-frequency region) and progressing with age along the entire length to the apex (low-frequency region). In the inferior colliculi, there was a significant decrease in the size of principal neurons in the central nucleus. There was a dramatic decrease in the number of synapses of all morphologic types on principal neuronal somas. The percentage of somatic membrane covered by synapses decreased by 67%. A ventral (high frequency) to dorsal (low frequency) gradient of synaptic loss could not be identified within the central nucleus. These synaptic changes may be related to the equally dramatic physiologic changes which have been noted in the central nucleus of the inferior colliculus, in which response properties of neurons normally sensitive to high-frequency sounds become more sensitive to low-frequency sounds. The synaptic loss noted in this study may be due to more than the loss of primary afferent pathways. It may represent alterations of the complex synaptic circuitry related to the central deficits of presbycusis.

Cortical Lewy bodies in Alzheimer's disease

Forty-eight cases of pathologically verified Alzheimer's disease were examined for the presence of ubiquitin-positive cortical Lewy bodies (CLBs). Thirty-four (71%) of 48 cases of Alzheimer's disease had CLBs compared with 4 (44%) of nine patients with idiopathic Parkinson's disease, and 2 (20%) of 10 patients with multi-infarct dementia. None of the 18 cognitively intact elderly controls we examined had CLBs. Among Alzheimer's disease patients, there was a strong correlation between CLBs and degenerative changes in the substantia nigra. We also found an association between the presence of CLBs and extrapyramidal symptoms. Among Alzheimer's disease patients, there was no association of CLBs with either senile plaques or neurons containing neurofibrillary tangles in hippocampus, neocortex, or ventral striatum. The incidence of CLBs among pathologically verified Alzheimer's disease cases is high when a careful search for these inclusions is performed with a sensitive method such as anti-ubiquitin immunocytochemistry.

Pancoast syndrome caused by a high grade B cell lymphoma

The case history is presented of a 20 year old man with Pancoast syndrome caused by a high grade B cell lymphoma.

Radiological evidence of progression of bronchiectasis

Radiological evidence of progression of bronchiectasis was sought in a group of 84 consecutive adult patients admitted to a tertiary unit with a particular interest in the disease. Methodical comparison for each patient of the earliest and most recent chest X-rays (n = 84), bronchograms (n = 1) and thoracic computed tomography (CT) scans (n = 32) was performed. Fifteen patients (18%) were considered to show radiological evidence of progression of bronchiectasis, 14 on chest X-ray, two of whom also showed progression on CT scans, and in one patient on bronchography alone. The likelihood of finding evidence of radiological progression increased the longer the interval between examinations. Serial radiology allows identification of patients with progression of disease and indicates the need to review management strategy.

In vitro and in vivo effects of ribavirin on human respiratory epithelium

The effects of ribavirin, a broad spectrum antiviral agent, on the structure and function of normal human nasal epithelium have been studied in vitro, as has also the in vivo effect of treatment with nebulised ribavirin on nasal mucociliary clearance of saccharin in four patients. Ciliary beat frequency was measured by a photometric technique, and changes in epithelial and ciliary ultrastructure were assessed by transmission electron microscopy. Ribavirin solution at the recommended concentration of 20 mg/ml had no adverse effects on ciliary activity in vitro; at concentrations of 50 mg/ml and above it slowed ciliary beating significantly and at 60 mg/ml caused ciliostasis associated with epithelial disruption. Nasal inhalation of ribavirin at 60 mg/ml for up to 20 minutes, however, did not slow nasal mucociliary clearance, nor did it adversely affect the ciliary beating or structure of nasal ciliated epithelium examined in vitro immediately after inhalation.

Microwave: an alternative to electric heating in the treatment of peripheral lymphedema

The results of a new method of treating chronic lymphedema with heat, using microwaves, are described in 98 patients with peripheral lymphedema. Thirteen had bilateral lymphedema and were included only to provide additional evidence of the lack of side-effects using this technique. The remaining 85 patients showed a significant (p less than .001) reduction in the amount of peripheral edema with edema reduction greater than 50% in three-fourths of the patients. The incidence and severity of secondary acute inflammation ("erysipelas") were also sharply reduced (p less than .001). The microwave method of heat application has a number of advantages over an older technique which used electrically-powered heating elements.

Medial leg skin flap: vascular anatomy and clinical applications

A new medial leg skin flap was reported with 100% success in 17 clinical cases. The surgical anatomy and the details of the technique are described.

Venous versus lymphatic duct autotransplantation in the treatment of experimental lymphedema

Experimental autologous lymphatic duct transplantation is technically feasible and therapeutically effective in the treatment of chronic lymphedema of the extremity. However, we demonstrate that the risk of inducing lymphedema in the donor limb is evident; therefore, the clinical application of lymphatic transplantation is compromised. To obviate this risk, a vein graft was substituted in experimental animals with good prophylactic results. Postoperative lymphangiography showing free passage of contrast media through the interposed vein, rapid disappearance of acute lymphedema in the recipient limb (28.6%), and no risk of inducing lymphedema of the donor limb all favor the possibility of using a vein graft transfer in clinically treating chronic lymphedema of the extremity.

Experimental model of chronic limb lymphedema and determination of lymphatic and venous pressures in normal and lymphedematous limbs

Experimental studies on chronic lymphedema of the extremities were performed using dogs, and an improved technique after the method of Danese in the preparation of chronic limb lymphedema is described. The incidence of chronic lymphedema in this model was 81.8%, whereas with Danese's method, it was only 66.7%. In addition, the measurement of lymphatic and venous pressure was studied in experimental animals. In the normal limb, the lymphatic pressure was always lower than the venous pressure, while in the chronic lymphedematous limb, the lymphatic pressure was higher than the venous pressure. Thus, after a lymphaticovenous anastomosis, a pressure gradient reversal exists between the two sides of the anastomosis. Although the high lymphatic pressure gradually dropped as the anastomosis became patent, ultimately the venous pressure was often higher than the lymphatic pressure. A venous back flow can be ensured by the anastomosis and the resulting thrombosis, which obstructs the lymphaticovenous anastomosis, is inevitable.

The involvement of phosphatidate phosphohydrolase and phospholipase A activities in the control of hepatic glycerolipid synthesis. Effects of acute feeding with glucose, fructose, sorbitol, glycerol and ethanol

Rats were fed by stomach tube with a single dose of glucose, sorbitol, fructose, glycerol or ethanol of equivalent energy contents or with 0.15 M-NaCl. They were killed 6 h later and the relative rates of phosphatidate deacylation and dephosphorylation measured in the microsomal and supernatant fractions of the livers. Treatment with sorbitol, fructose, glycerol and ethanol increased phosphohydrolase activities in the microsomal and supernatant fractions. The only significant change in deacylase activity was an increase in the microsomal fraction produced by ethanol. It is proposed that hepatic triacylglycerol synthesis is partly controlled by the balance between phosphatidate phosphohydrolase and phospholipase A-type activities.