Fumiaki Amemiya

Primary vestibular projections in the hagfish, Eptatretus burgeri.

The VIIIth cranial nerve projections in the hagfish, which has only one circular canal in the ear, were studied by transganglionic HRP transport. This nerve has two branches, the nervus utricularis (N. utr.) and the nervus saccularis (N. sac.), each with its own ganglion, the ganglion utriculare (G. utr.) and the ganglion sacculare (G. sac.), respectively. Although the G. sac. has uniformly small cells, the G. utr. consists of two separate cell masses, a ventral mass of large cells and a dorsal mass of small cells. The small cells were labeled in both ganglia after horseradish peroxidase (HRP) injection into the endolymphatic space. The greater part of the terminal areas of these two branches overlapped in the ventral nucleus of the area acoustico-lateralis, but the terminals of the N. sac. extended slightly further in a caudal direction. No projections to the primordial cerebellum and no retrogradely labeled cells in the brain were found. The large cells in the ventral part of the G. utr. seem to be general cutaneous neurons, and the dorsal part of the area acousticolateralis seems to receive lateral line input.

MICROVASCULATURE OF CROTALINE SNAKE PIT ORGANS : POSSIBLE FUNCTION AS A HEAT EXCHANGE MECHANISM

The infrared sensory membranes of the pit organs of pit vipers have an extremely rich capillary vasculature, which has been noted passim in the literature, but never illustrated or studied in detail.

Ultrastructure of the crotaline snake infrared pit receptors: SEM confirmation of TEM findings

Crotaline snakes possess a pair of infrared‐sensing pit organs that aid the eyes in the detection and apprehension of prey. The morphology of the receptors in the pit organs has been studied by light and transmission electron microscopy, and the ultrastructure of the receptors has been inferred from the results of this work. But this theoretical reconstruction has never been confirmed by any kind of three‐dimensional imaging.

Effects of prone and supine position on heart rate, respiratory rate and motor activity in fullterm newborn infants

Polygraphic recordings were obtained for 24 normal full-term neonates on their 4th or 5th day of life. Thirteen of the infants were first fed, laid supine for 3 hours, fed again around noon and laid prone for 3 more hours. The other 11 were first laid prone and then supine. The awake state was observed more in the supine than the prone position (P less than 0.001). Wakefulness occurred at the expense of state 1 and/or state 2. The heart rate (HR) was higher in babies lying prone. It was also higher in the afternoon than in the morning. No such relationship was found for the respiratory rate (RR). There was higher average EMG activity during state 1 in the prone position. The cross-correlation between HR and EMG activity was positive during state 2, and states 4 and 5, regardless of the position. The cross-correlation between the RR and the EMG was usually negative in state 2, and in states 4 and 5, there being many exceptions. The cross-correlation between breathing and heart-beat was mostly negative during state 2, but it eventually became positive due to periodic breathing, central apnoeas with bradycardia, stretches, and crawling movements.

Nickel sulfate-specific suppressor T cells induced by nickel sulfate in drinking water

Suppressor T cell function was studied in nickel sulfate (NiSO4) delayed type hypersensitivity (DTH). NiSO4 in drinking water administered orally to normal mice for 10 weeks elicited no significant footpad swelling. However, after drinking water for 7 weeks, suppression of footpad swelling response was not detected. Suppression of footpad swelling response was mediated by CD4-8+ T cells. However, these suppressor T cells did not overcome CD4+8- helper T cells by co-transfer to recipient mice. Unresponsiveness to NiSO4 by oral administration of antigen was due to suppressor T cells.

Brain and liver pathology in a patient with carnitine deficiency.

The ultrastructural brain and liver pathology in an infant, who died of acute encephalopathy due to systemic carnitine deficiency (CD), an important condition mimicking Reyes syndrome (RS), was reported. The major finding in the brain was swelling of astrocyte cytoplasm. Expanded mitochondria in nerve cells and myelin sheath splitting in the white matter, which have been reported to be specific to RS, were not observed. Also in contrast to findings in RS, hepatocytes were filled with macrovesicular fat droplets without expanded mitochondria. These findings suggest significant differences in the pathophysiology of acute encephalopathy in CD and RS, although the clinical and laboratory findings during an episode of acute encephalopathy in the former are usually very similar to those in the latter.

Myelin splitting in the spongy lesion in Leigh encephalopathy

A spongy lesion consists of numerous vacuoles, mainly in the central gray matter, and is a characteristic finding in subacute necrotizing encephalopathy (Leigh encephalopathy); the cause of this lesion is unknown. An ultrastructural study on the vacuolated lesions in the left putamen of a patient with subacute necrotizing encephalopathy due to a deficiency of mitochondrial enzyme complexes I and IV revealed that the vacuoles were formed through the splitting of myelin. Because myelin splitting is commonly caused by toxic or metabolic diseases in humans and experimental animals, we believe that the vacuolation was due to the splitting of myelin which was caused by abnormal mitochondrial metabolism, even though this lesion is most commonly found in the white matter. We do not know whether the spongy lesion is formed only through myelin splitting in patients with subacute necrotizing encephalopathy; however, myelin splitting must play an important role in the formation of the spongy lesion.

Cystinuria with congenital myotonic dystrophy.

Two brothers with congenital myotonic dystrophy also had cystinuria with large renal stones. This report is the first to document the concurrence of cystinuria and congenital myotonic dystrophy. It is uncertain whether these two conditions are coincidental or share a common pathogenesis.

Somatosensory and visual correlation in the optic tectum of a python, Python regius: a horseradish peroxidase and Golgi study

In snakes with infrared receptors the optic tectum receives infrared input in addition to visual and general somatosensory inputs. In order to observe their tectal termination patterns in ball pythons, Python regius, we injected horseradish peroxidase (HRP) into the nucleus of the lateral descending trigeminal tract (LTTD) which mediates infrared information, the optic nerve, and the nucleus of the trigeminal descending tract (TTD) which relays general somatosensory information. Fibers from LTTD were found in layers 5-13 of the contralateral optic tectum, and were especially dense in layers 7a-8. Optic nerve fibers terminated in layers 7a-13 of the contralateral tectum, and mainly in layers 12-13. TTD fibers were few, and could be seen in only the rostral half of the contralateral tectum. These fibers were found in layers 5-7b, but mainly in layers 6-7a. Among various types of neurons stained by the Golgi-Cox method, we focused on six types of neurons whose dendritic arborization overlapped with the distribution of the terminals of these sensory afferents described above. It is possible that these different sensory modalities converge on a single neuron of the various types.

509 Substance P and calcitonin gene-related peptide immunoreactivity in the pit membrane of the mamushi

Tetsuo Kadota, Masato Nakano, Yoshitoshi Atobe, Kengo Funakoshi, Fumiaki Amemiya, Richard C. Goris, Reiji Kishida The pit vipers, exemplified by the mamushi, Agkistrodon blomhoffi, have a membrane in the infrared organ containing the receptor terminals of warm fibers and a capillary network, both in a highly developed state. The distribution of nerve fibers containing substance P and calcitonin gene-related peptide immunoreactivity was studied in the pit membrane. These nerve fibers were distributed throughout the pit membrane, but the receptor terminals were completely free of immunoreactivity. The pit membrane is innervated by the ophthalamic and maxillary branches of the trigiminal nerve. Fibers containing substance P entered the caudorostral part of the pit membrane through the course of the ophthalamic branch, the rostrodorsal part through the course of the deep branch of the maxillary, and the ventral part through the course of the superficial branch of the maxillary. Fibers containing calcitonin gene-related peptide showed a similar course and distribution.