Ultrastructure of lentigo maligna in the oral cavity

A rare case of lentigo maligna in the oral cavity was investigated by light and electron microscopy. Cutaneous lentigo malignas often develop to malignant melanomas. However, the electron microscopic examination revealed that even though there were a large number of melanosomes, most of them were late stage and had membrane structure, and positive staining with HMB-45 was not recognized. From our findings, it is difficult to conclude that oral lentigo malignas develop malignant melanomas, and thus further studies are needed.     

A Combination of Speckled Lentiginous Nevus with Patch-type Blue Nevus

A peculiar case of “nevus on nevus” was reported. A 67-year-old man had had a pigmented lesion in the left hypochondrial area since birth. The clinicopathologic findings of the pigmented lesion revealed a combination of speckled lentiginous nevus and patch-type blue nevus. This case of “nevus on nevus” is not described under the term of combined nevus as is current in the literature; it was considered to be a subtype of the type II atypical blue nevus described by Kawamura.     

Select types of supporting cell in the inner ear express aquaporin-4 water channel protein

Aquaporins (AQPs) confer a high water permeability on cell membranes and play important parts in secretory and absorptive epithelia in kidney and other organs. Here we investigate whether AQPs are expressed in the sensory epithelia of the inner ear, where a precise volume regulation is crucial. By use of specific antibodies it was found that the inner ear contains AQP1 and 4 while being devoid of detectable levels of AQP2, 3 or 5. Immunofluorescence and postembedding immunogold labelling revealed a strictly non-epithelial distribution of AQP1, confirming previous data. In contrast, AQP4 protein and mRNA (visualized by in situ hybridization) were concentrated in select types of supporting cell, including Hensen's cells and inner sulcus cells. Immunogold particles signalling AQP4 were confined to the basolateral plasma membrane of Hensen's cells and to the basal plasma membrane of Claudius cells and inner sulcus cells. AQP4 was also found in supporting cells of the vestibular end organs, but was absent from transitional epithelial cells and dark cells. Strong labelling for AQP4 and AQP4-mRNA was associated with the central part of the cochlear and vestibular nerves. Hair cells were consistently unlabelled. Our findings indicate that AQP4 may facilitate osmotically driven water fluxes in the sensory epithelia of the inner ear and thus contribute to the volume and ion homeostasis at these sites.     

Right pneumonectomy syndrome: Report of two cases

We report herein the cases of two infants who developed right pneumonectomy syndrome, both of whom were born with gross C-type esophageal atresia (EA/TEF), and a hypoplastic right lung arising from the lower esophagus, being a bronchopulmonary foregut malformation (BPFM). Appropriate and well-timed treatments for a variety of sequelae primarily caused by the mediastinal shift must be considered after right pneumonectomy in early childhood.     

Comparison of the size of neuronal and non-neuronal histamine pools in the brain of different rat strains

Summary The size of the neuronal and non-neuronal histamine pools in the brain of three different strains of rats was measured by assuming that the -fluoromethylhistidine-induced maximal decrement of histamine represents the size of the neuronal pool. Although the total histamine levels in the brain showed a considerable interstrain variation, no significant interstrain difference was observed in the neuronal histamine level. These results suggest that the size of the neuronal histamine pool in the brain is relatively stable, whereas the size of the non-neuronal histamine pool is variable.     

MR imaging of intraspinal tumors—Capability in histological differentiation and compartmentalization of extramedullary tumors

Summary Magnetic resonance (MR) images of 29 consecutive patients with intraspinal neoplasms (9 intramedullary tumors, 20 extramedullary tumors) were reviewed to evaluated the utility of MR imaging in distinguishing the intraspinal compartmental localisation and signal characteristics of each lesion. Compartment and histology of all neoplasms were surgically proven. MR correctly assigned one of three compartments to all lesions, 9 intramedullary, 14 intradural extramedullary (6 schwannomas, 3 neurofibromas, 5 meningiomas), and 6 extradural (3 schwannomas, 1 meningioma, 1 cavernous hemangioma, 1 metastatic renal cell carcinoma). All intramedullary tumors showed swelling of the spinal cord itself. In all five extradural tumors a low intensity band was visualized between the spinal cord and tumor. On the other hand, a low intensity band was demonstrated in no cases with intradural tumors. Visualization of this low intensity band is important in differentiating extradural from intradural-extramedullary lesions. We call this low intensity band, the extradural sign. Signal intensity of intradural tumors varied with histology. In extramedullary tumors, signal intensity of schwannomas was similar to that of the cerebrospinal fluid (CSF) both on T1 weighted (inversion recovery) and T2 weighted spin echo (SE) images. On the other hand, meningiomas tended to be isointense to the spinal cord on both T1 and T2 weighted SE images. We found relatively reliable signal characteristics to discriminate meningioma from schwannoma.     

Similarities between the relaxations induced by vasoactive intestinal peptide and by stimulation of the non-adrenergic non-cholinergic neurons in the rat stomach

Summary The characteristics of the non-adrenergic, noncholinergic inhibitory response of the rat stomach fundus to transmural nerve stimulation were compared with the relaxation induced by vasoactive intestinal polypeptide (VIP). Treatment with -chymotrypsin (5 U/ml) or VIP antiserum (1:200) significantly reduced the relaxation induced by transmural nerve stimulation at 30 Hz, indicating that the possible transmitter in the non-adrenergic, non-cholinergic nerves is a peptide and may be VIP or a closely related peptide. VIP was able to relax, fully and dose-dependently, the stomach fundus that had previously been constricted by treatment with 10^–6 M serotonin, and the IC₅₀ value for VIP was 2.4 × 10^–9 M. VIP elevated levels of cyclic AMP in a dose-dependent manner and the EC₅₀ value was 2.8 × 10^–9 M in the presence of 10^–6 M atropine and 10^–6 M guanethidine. The stomach fundus was relaxed by transmural nerve stimulation (30 Hz, 50 mA) and transmural nerve stimulation also caused production of cyclic AMP in the rat stomach in the presence of atropine and guanethidine. The basal level of cyclic AMP in the stomach was 8.7 ± 0.26 pmole/mg protein. When transmural nerve stimulation was applied for 5 min, the contraction of the stomach, induced by 10^–6 M serotonin, was inhibited by 54% in the presence of atropine and guanethidine and the level of cyclic AMP was increased to 13.0 ± 0.73 pmol/mg protein. Apamin inhibited the transmural nerve stimulation-induced relaxation and shifted the dose-response curve for VIP to the right. These results suggest that one of the putative neurotransmitter from non-adrenergic, non-cholinergic nerves in the rat stomach is VIP and that VIP-induced relaxation may be mediated by the production of cyclic AMP and by the opening of apamin-sensitive K⁺-channels.Send offprint requests to K. Kamata at the above address     

Histamine turnover in the brain of morphine-dependent mice

Summary The turnover of brain histamine was examined in mice implanted subcutaneously with a morphine pellet (50 mg free base). The numbers of naloxone-precipitated jumpings and body shakes were maximum 2 and 3 days after implantation, respectively. The brain tele-methylhistamine level significantly increased (50% to 115%) during 12 h3 days after implantation of a morphine pellet, whereas the histamine level remained unchanged. The accumulation of tele-methylhistamine by pargyline treatment was significantly enhanced when pargyline was administered 12 h after implantation, suggesting an enhancement of histamine turnover. However, a similar degree of the tele-methylhistamine accumulation was induced by pargyline during 1–5 days after implantation, as compared with the accumulation in the control mice implanted with a placebo pellet. In mice undergoing morphine withdrawal by either the removal of morphine pellet or the treatment with naloxone 3 days after implantation, the degree of the pargyline-induced telemethylhistamine accumulation or the (S)--fluoromethylhistidine (-FMH)-induced histamine decrease was similar to that observed in the placebo pellet-control mice. The numbers of naloxone-precipitated jumpings and body shakes occurring in mice 3 days after implantation were not significantly affected by any of l-histidine, -FMH or metoprine. These results suggest that turnover of histamine in the brain is enhanced by acute morphine treatment and returns to the normal rate in the stage of chronic treatment and remains unchanged during the state of withdrawal. Send offprint requests to K. Saeki     

Age-related decrease of 11C-N-methylspiperone in vivo binding to human striatum detected by PET

The effect of aging on 11C-N-methylspiperone binding to living human striatum was demonstrated using positron emission tomography. The 11 normal volunteers (22 to 72 years old) participated in this study. The uptake of 11C-N-methylspiperone in the brain following intravenous injection was highest in the striatum in individual subject. And the uptake in the striatum only gradually increased until the end of the study. The uptake of 11C-N-methylspiperone in cerebellum peaked within 10 minutes following injection and then rapidly dropped. The association rate constant "k3" was calculated from the slope of the radioactivity-ratio of striatum to cerebellum versus the equivalent time. The equivalent time was calculated from the radioactivity of cerebellum as an input function. The exponential decrease of the k3 value with aging was observed. The k3 value of the youngest subject (22 years old, male) was 0.035/min, while that of the oldest one (72 years old, male) was found to be 0.020/min. These data suggested that the dopaminergic activity through D2 dopamine receptors reduces with aging in human striatum.     

Tolerance to N2O-induced alterations in somatosensory evoked potentials

The effect of nitrous oxide (N2O) on somatosensory evoked potentials from the cortical (CEP) and spinal cord (SCP) regions in response to forepaw stimulation was studied in ketamine-anesthetized and mechanically ventilated rats. The CEP was recorded from the skull over the contralateral somatosensory area; the SCP was recorded from the supraspinous ligament at C57-6 and L1-2 levels of the spine. Rats were exposed to 70% N2O for 5 h, whereupon N2O was withdrawn for 2 h. Thereafter, the rats were re-exposed to N2O for 10 min. The N13-P21 component of the CEP, the slow positive wave (P2) of the segmental SCP, and the heterosegmental positive cord dorsum potential (HSP) were significantly suppressed by N2O, while the large negative (N1) component of the segmental SCP remained unchanged. A partial recovery of the CEP and HSP was observed during the 5 h of N2O anesthesia, while significant recovery of the P2 component of the SCP was not observed. The withdrawal from N2O following 5 h exposure caused an augmentation of the CEP (When compared to the control values). Re-exposure of rats to N2O again caused the suppression of these potentials as in the initial exposure. The results suggest that the phenomenon of tolerance to N2O in terms of evoked potentials develops within 5 h in the brain but not in the spinal cord.