Effects of human recombinant calcitonin on a rat osteopenia model induced by TPTX and arotinoid.

Recombinant human calcitonin (rh-CT) has been developed as an agent for patients with excessive bone resorption to replace calcitonins from animal species, which are associated with tolerance problems. In this study, inhibitory effects of rh-CT against bone resorption were examined in thyroparathyroidectomized (TPTX) rats, the animal model of accelerated bone resorption induced by administering a synthetic retinoid (arotinoid). The arotinoid-treated TPTX rats exhibited signs of stimulated bone resorption, such as hypercalcemia, reduced bone mineral density, and inferior bone strength. Significant improvements were seen in all of these changes after a daily treatment with rh-CT (30, 300 U/kg s.c.) for 1 week. A histomorphometrical analysis showed that the treatment with rh-CT markedly suppressed the reduction of trabecular bone volume and that of cortical thickness in the femur of arotinoid-treated TPTX rats. These results suggest that rh-CT may prevent osteopenia caused by accelerated bone resorption.

Localization and ontogeny of cells expressing preprodynorphin mRNA in the rat cerebral cortex.

The regional distribution of preprodynorphin (PPD) mRNA-containing cells (PPD cells) in the rat cerebral cortex was investigated by in situ hybridization histochemistry using a synthetic oligonucleotide probe. In the isocortex, PPD cells were small or medium-sized and were mainly located in layer V. While they were less numerous in the allocortex than in the isocortex. Only a few labeled cells were seen in the piriform and entorhinal cortices. In the hippocampal formation, labeled cells were observed in the granular layer of the dentate gyrus. An ontogenetic study revealed that PPD mRNA-containing cells appeared on postnatal day 7 in the isocortex and the allocortex and on day 14 in the dentate gyrus. Thereafter, they increased in number and signal intensity to reach a plateau on postnatal day 14 in both the isocortex and the allocortex and on day 35 in the dentate gyrus. The time-course of development of PPD mRNA-containing neurons in the cerebral cortex suggested that PPD-derived peptide has a neuromodulator and/or neurotransmitter role in these regions of the brain.

Presence of VIP fibers of sensory origin in the rat trachea.

The presence of vasoactive intestinal peptide (VIP) immunoreactive nerve fibers (LI) in the respiratory tract of mammals is well documented. These fibers are known to originate from parasympathetic postganglionic neurons and to be associated with blood vessels, submucosal glands, and with smooth muscle. We found that, in addition to this, the epithelial layer of the rat trachea also contains VIP-LI fibers. Vagotomy or ligation of the cervical portion of the vagus nerve resulted respectively in a decrease of VIP-LI fibers within the epithelium or in the accumulation of VIP in axons proximal to the site of transection or ligation, whereas no changes were seen in other parts of the trachea. On the other hand, capsaicin pretreatment also caused similar changes to the surgical procedures. These findings indicate that VIP-LI fibers in the tracheal epithelium of the rat are supplied by the sensory ganglia of the vagus nerve.

[A case of spontaneous spinal epidural hematoma presenting Brown-Séquard syndrome].

Although there have been a few reports of spontaneous spinal epidural hematoma, it may be difficult to make a correct diagnosis of the lesion because of atypical clinical symptoms. The authors reported a case of spontaneous spinal epidural hematoma presenting Brown-Séquard syndrome, with a review of literature. This 75-year-old male experienced a sudden onset of severe dorsal neck pain during sleep associated with right hemiparesis which deteriorated quickly to hemiplegia, without loss of consciousness, nausea, vomiting and vertigo. The patient has a history of hypertension and has been treated for chronic hepatitis for one year. On admission, neurological examination revealed right hemiplegia with normotensive deep tendon reflexes, and loss of pain and temperature sensations below the level of C5 on his left side. Position sense of fingers and toes was diminished on his right side, and hyperesthesia was recognized at the area of C4 level. Consciousness disturbance, cranial nerve signs, and urinary incontinence were not seen. Right retrograde vertebral angiograms showed no abnormal vascular shadow, even though anterior spinal artery was visible at the level of C8 through C5. Cervical CT scan revealed a left-side dominant extradural high density mass which situated dorsally at around the upper part of C2 body changing it's position to dorsolaterally as it descended to the lower part of C5. On contrast enhancement study, only the margin of the lesion was partially enhanced, which might be the hematoma membrane. On the third day after the onset, laminectomy from C2 to C5 was performed and the epidural hematoma was evacuated.(ABSTRACT TRUNCATED AT 250 WORDS)