Vasotocin fibers and neurons in the brain of the domestic fowl (Gallus gallus domesticus)

Vasotocin fibers (VIFs) and neurons (VINs) in the brain stem of the domestic fowl (Gallus gallus domesticus) were described using an immunohistochemical technique. Attention was especially focused on the VIF network. VIFs were seen in the preoptic area around the septomesecephalic tract, periventricular nuclei of the hypothalamus, the lateral geniculate nucleus, the superficial synencephalic nucleus, the triangular nucleus, the ovoidal nucleus, the ectomammillary nucleus, the superficial layer (IIa-d) of the tectum, the locus ceruleus, the caudal lineal nucleus, the descending nucleus of the trigeminal nerve and the nucleus of raphe. VIFs in the retinorecipient nuclei such as the lateral geniculate nucleus and tectum indicated the possibility of interplay between the visual and the vasotocinergic nervous systems. Moreover, VIFs in the non-retinorecipient nuclei mentioned above suggested that the vasotocinergic nervous system was related not only to the visual but also to other functions, such as the autonomic and sensory nervous systems. VINs were found in the preoptic area, the lateral and the medial hypothalamus, including the nucleus periventricularis magnocelullaris, and the dorsolateral thalamus. The dorsolateral thalamic VINs were found lateral and dorsal to the lateral forebrain bundle, lateral to the nucleus periventricularis magnocellullaris, and around the nucleus rotundus.

Benign intracerebellar cyst without epithelial lining

A case of benign intracerebellar cyst is reported in a 61-year-old woman who presented progressive neurological deficits. MRI and operative findings could not reveal any evidence of neoplastic growth. The biopsied cyst wall revealed normal cerebellar tissue. The simple cyst of the cerebellum is rare, thus we discuss the clinical features and etiology of this rare entity.

Opioid actions on neurons of rat lateral amygdala in vitro

Intracellular recordings were made from neurons in the lateral nucleus of the amygdala, in a slice of rat brain that was superfused in vitro. [Met5]enkephalin (3-30 microM) and the mu receptor selective agonist DAMGO (Tyr-D-Ala-Gly-MePhe-Gly-ol; 0.3-3 microM) hyperpolarized about 50% of cells; this was blocked by naloxone and by the mu receptor antagonist CTOP (D-Phe-Cys-Tyr-D-Trp-Orn-Thr-Pen-Thr-NH2). The pA2s for naloxone and CTOP were 8.3 and 7.7, respectively. DPDPE (Tyr-D-Pen-Gly-Phe-D-Pen: delta receptor selective) and U50488 (trans-(+-)-3,4-dichloro-N-methyl-[2-(1-pyrrolidinyl)cyclohexyl] benzeneacetamide methane sulfonate; kappa receptor selective) had no effect. Synaptic potentials mediated by gamma-aminobutyric acid (GABA) acting at GABAA receptors were elicited by focal stimulation of the slice in a combination of 6-cyano-2,3-dihydroxy-7-nitroquinoxaline (10 microM) and 4-aminophosphonovaleric acid (30 microM). They were inhibited by up to 60% by DAMGO and by DPDPE. The action of DAMGO was blocked by CTOP but not by the delta-selective antagonist ICI174864 (N,N-bisallyl-Tyr-Aib-Aib-Phe-Leu-OH, Aib = aminoisobutyrate). The action of DPDPE was blocked by ICI174864 but not by CTOP. Depolarizations elicited by addition of GABA to the superfusing solution were not affected by opioids. It is concluded that activation of mu opioid receptors hyperpolarizes about 50% of lateral amygdala neurons. Activation of either mu or delta receptors also inhibits presynaptically the release of GABA.

Descending projections to coccygeal spinal segments in the cat

The descending projections to coccygeal spinal segments influencing tail movement were studied by retrograde wheat germ agglutinin-horseradish peroxidase (WGA-HRP) tracing methods in 12 cats. WGA-HRP solution was injected into the 3rd and 4th coccygeal segments and hemisection of the right side of the spinal cord was performed at the 3rd sacral-1st coccygeal segmental level. Labelled propriospinal neurons were distributed in laminae III-VIII and X of the spinal cord between the cervical and lumbosacral spinal segments, predominantly on the left. The greatest density of labelled cells as in the lumbar enlargement. In the brainstem a high density of labelled cells was observed mainly in the lateral vestibular, gigantocellular reticular and magnocellular reticular nuclei on the left side, and the nucleus raphe magnus, pallidus and obscurus. These findings indicate significant descending projections to the coccygeal spinal cord in the cat which could be responsible for tail movements in the cat.

Triiodothyronine increases desipramine with changing the concentrations of monoamines, in the brain of rat given imipramine

After treatment with triiodothyronine (T3) for 5 days, rats received a single i.p. injection of imipramine. The concentrations of imipramine and desipramine decreased and increased, respectively, in the brains of T3-treated rats, and the elimination half-time of desipramine was increased. In rats that had received imipramine for 7 days, cotreatment with T3 also resulted in reduced imipramine and elevated desipramine concentrations in the brain. Coadministration of T3 with imipramine appeared to accelerate the desipramine-induced changes in norepinephrine and 3-methoxy-4-hydroxyphenylglycol concentrations in brain. Since T3 treatment elevated the 5-hydroxyindole acetic acid concentration in the brain, the concentration in rats receiving both drugs was equivalent to that of vehicle-treated rats.

Body composition measurement by electrical bio-impedance method to establish the effect of daily physical training in adolescents

As part of an ongoing study on the effect of daily physical training on adolescents, body composition (percentage fat) was measured using the electrical bio-impedance method in a sample of Japanese students aged 15 years (77 sedentary males, 137 active males, 66 sedentary females and 54 active females), who were selected on the basis of their answers in a questionnaire about physical activity in a cardiac study involving 227.361 high school students. Subjects were divided into 4 weight categories (underweight, normal weight, overweight and severe overweight) using an obesity index. ECG and ultrasound cardiography (UCG) were used for all subjects to measure their left ventricular mass (LVM), which was taken as an indicator of the effect of training. Among the 4 weight category groups, a significant difference in the percentage of fat between sedentary and active subjects was found in the normal weight category of males. Correlation between the percentage of fat and the obesity index was significant in both sedentary and active subjects of both the genders, but correlation coefficients were lower for active subjects than for sedentary ones. The percentage of fat tended to be very low in subjects with increased LVM. Additionally, a significant difference in the amount of fat was found between runners and soccer players in active males with normal weight. These results suggest that there were differing degrees of the effect of training on reducing body fat and that this effect is most notable in males with normal weight.(ABSTRACT TRUNCATED AT 250 WORDS)

Electrophysiologic detection of choroidal detachment in eyes with rhegmatogenous retinal detachment

The base values of electrooculograms (EOGs) of 39 patients with new, unilateral rhegmatogenous retinal detachment and clear media were studied. None of the patients had a history of ocular surgery. Ophthalmoscopic examinations revealed choroidal detachment in 11 eyes. The mean (+/- SD) amplitude, expressed as a percentage of the amplitude recorded for unaffected fellow eyes, was 116 +/- 31% in the 28 eyes without choroidal detachment, and 39 +/- 10% in the 11 eyes with choroidal detachment. This difference was statistically significant (P < 0.0001). There was no significant correlation in either group between baseline value and extent of retinal detachment or intraocular pressure. These results indicate that choroidal detachment associated with rhegmatogenous retinal detachment can be revealed electrophysiologically by the baseline value of an EOG.

Membrane properties and synaptic potentials of three types of neurone in rat lateral amygdala

1. Intracellular recordings were made from the lateral nucleus of the amygdala in tissue slices cut from rat brain and maintained in vitro. 2. Three types of neurones were distinguished according to the after-potential that followed an action potential. Type 1 cells (44%, n = 225) had depolarizing after-potentials, resulting from a calcium-dependent chloride conductance. Type 2 cells (48%) had long-lasting (> 250 ms) hyperpolarizing after-potentials and type 3 cells (8%) had shorter hyperpolarizing after-potentials. The average resting potentials of the three cell types were -78, -69 and -62 mV respectively. Intracellular labelling with biocytin showed that type 1 cells were pyramidal neurones; type 2 and type 3 cells were non-pyramidal. 3. Experiments with receptor antagonists identified synaptic potentials mediated by excitatory amino acids and by GABA (acting at GABAA receptors) in all three cell types. A longer duration inhibitory synaptic potential resulting from activation of GABAB receptors was present in type 1 (pyramidal) and type 2 cells. 4. Cholecystokinin (100 nM to 1 microM) depolarized type 2 and type 3 cells but had no effect on type 1 (pyramidal) cells. Baclofen (1-3 microM) hyperpolarized type 1 and type 2, but not type 3 cells. [Met5]enkephalin (1-10 microM) hyperpolarized only type 2 cells. 5. It is concluded that the lateral nucleus of the amygdala contains pyramidal neurones and two types of non-pyramidal neurone; these can be differentiated by membrane properties, synaptic inputs and sensitivities to transmitters.

[Morphometric and immunohistochemical studies of the suprachiasmatic nucleus in the hereditary microphthalmic rat]

Morphometric and immunohistochemical analyses of the suprachiasmatic nucleus (SCN) were performed on hereditary microphthalmic rats. In normal rats, the number of cells and the volume of the SCN were 11, 631 and 6.7 x 10(-2) mm3 (an average taken from 12 SCNs). However, the neuronal population and volume of the SCN in hereditary microphthalmic rats were 7,450 and 4.5 x 10(-2) mm3 (an average taken from 14 SCNs), respectively. There were no significant differences in the size of neurons between normal and microphthalmic SCN neurons. Immunohistochemical studies showed that a considerable number of antivasopressin positive neurons were present in microphthalmic rats, despite their lack of the optic nerve. However, further detailed studies revealed that the number of antivasopressin positive neurons present in microphthalmic rats was only 68% of those found in normal rats. These findings suggest that the complete development of the SCN and vasopressin neurons depends on the visual input.

Involvement of protein kinase C in serotonin-induced spike broadening and synaptic facilitation in sensorimotor connections of Aplysia

1. Plasticity at the connections between sensory neurons and their follower cells in Aplysia has been used extensively as a model system to examine mechanisms of simple forms of learning. Earlier studies have concluded that serotonin (5-HT) is a key modulatory transmitter and that it exerts its short-term actions via cAMP-dependent activation of protein kinase A. Subsequently, it has become clear that other kinase systems such as protein kinase C (PKC) also may be involved in the actions of 5-HT. 2. Application of phorbol esters, which activate PKC, produced a slowly developing spike broadening but had little effect on excitability (a process known to be primarily cAMP dependent). Moreover, the effects of phorbol esters and 5-HT on spike duration were not additive, suggesting that they may share some common mechanisms. 3. The protein kinase inhibitor staurosporine suppressed both 5-HT-induced slowly developing spike broadening and, under certain conditions, facilitation of transmitter release. Staurosporine did not inhibit 5-HT-induced enhancement of excitability. The effectiveness of staurosporine on spike broadening was dependent on the time at which spike broadening was examined after application of 5-HT. Staurosporine appeared to have little effect on spike broadening 3 min after application of 5-HT, whereas it inhibited significantly 5-HT-induced spike broadening at later times. The staurosporine-insensitive component of 5-HT-induced spike broadening may be mediated by cAMP. 4. The results suggest that the activation of PKC plays a key role in components of both 5-HT-induced spike broadening and facilitation of synaptic transmission.(ABSTRACT TRUNCATED AT 250 WORDS)

[Quantitative analysis of the isthmo-optic nucleus and projection neurons to the retina in adult fowl (Gallus gallus domesticus)]

Quantitative analysis of the isthmo-optic nucleus (IO) and centrifugal projection to the retina in the fowl was made using Nissl preparation and retrograde horseradish peroxidase (HRP) methods. Seven adult fowls (Gallus gallus domesticus) were used for Nissl stain. Serial sections were cut on a freezing microtome at 60 microns and stained with cresyl violet. IO was situated just medial to the caudal part of the tectum and laterodorsal surface of the brain stem. Rostrocaudal extension of IO was about 800-1,000 microns. The average total volume and neuronal population of the IO was 280 x 10(-3) mm3 and 5,600 neurons, respectively. Eight animals were used for HRP study. One hundred microliters of 30% HRP solution in physiological saline was injected into the vitreous body of one eye of each hen. Serial transverse sections of 60 microns were treated with tetramethyl benzidine (TMB). Many labeled neurons were found in contralateral brain stem. Average total number of contralateral HRP-labeled cells in IO and peri-IO were 5,268 and 1,492, respectively. Labeled neurons peri-IO were mainly distributed ventrally and rostrally to IO. No labeled neurons in IO, and only a few labeled neurons peri-IO were found ipsilaterally. The number of HRP-labeled neurons in IO corresponded to the neuronal population of IO in Nissl preparation, which suggested that most of isthmo-optic neurons might be projecting to the contralateral retina. In contrast to the round and small IO neurons (long axis 15-20 microns, short axis 10-20 microns), peri-IO neurons were multipolar and longer (long axis 15-30 microns, short axis 10-25 microns).

Fundus albipunctatus associated with cone dystrophy

We describe five unrelated patients in whom the typical signs of fundus albipunctatus were accompanied by colour vision defects, bull's eye or similar macular lesions, and severely diminished full-field cone electroretinograms indicating widespread damage to cones outside the macula. All patients had noticed night blindness from childhood. Signs of retinitis punctata albescens, a disease of similar appearance but with characteristics resembling retinitis pigmentosa, were absent. We cannot be sure whether these patients represent a process of fundus albipunctatus or a distinct disease entity or a casual combination of fundus albipunctatus and cone dystrophy.

Fastigiofugal fibers encoding horizontal and vertical components of saccades as determined by microstimulation in monkeys

To identify the routes by which oculomotor vermis signals control eye movements (saccadic signals), saccades evoked by microstimulation were studied in the region of the uncinate fasciculus (UF) and juxtarestiform body (JB) in the macaque monkey. Anatomical pathways of axons from the fastigial oculomotor region (FOR) were studied by anterograde transport of wheatgerm agglutinin conjugated horseradish peroxidase (WGA-HRP). The routes were identified by comparing maps of low threshold for evoking saccades with the anatomical map of anterogradely labeled axons arising from the FOR. Microstimulation of a region of the UF and JB demonstrated that saccadic signals are carried exclusively by decussated FOR axons which leave the cerebellum via the contralateral UF. The fibers in the JB do not carry saccadic signals. The horizontal component of saccadic signals is conveyed by fibers in the descending limb of the UF, while the vertical component is conveyed by a smaller group of fibers which separate from the UF and enter the midbrain with the contralateral superior cerebellar peduncle.

Evolutionary pattern of the H 3 haemagglutinin of equine influenza viruses: multiple evolutionary lineages and frozen replication

The nucleotide and deduced amino acid sequences of the haemagglutinin genes coding for the HA 1 domain of H3N8 equine influenza viruses isolated over wide regions of the world were analyzed in detail to determine their evolutionary relationships. We have constructed a phylogenetic model tree by the neighbour-joining method using nucleotide sequences of 15 haemagglutinin genes, including those of five viruses determined in the present study. This gene tree revealed the existence of two major evolutionary pathways during a twenty five-year period between 1963 to 1988, and each pathway appeared to consist of two distinct lineages of haemagglutinin genes. Furthermore, our analysis of nucleotide sequences showed that two distinct lineages of equine H3N8 viruses were involved in an equine influenza outbreak during the period of December 1971-January 1972 in Japan. The number of nucleotide changes between strains was proportional to the length of time (in years) between their isolation except for three of the HA genes. However, there are three exceptional strains isolated in 1971, 1987, and 1988, respectively. The haemagglutinin gene in these strains showed a small number of nucleotide substitutions after they branched off around 1963, suggesting an example of frozen replication. Although the estimated rate (0.0094/site/year) of synonymous (silent) substitutions of the haemagglutinin gene of equine H3N8 viruses was nearly the same as that of human H 1 and H 3 haemagglutinin genes, the rate of nonsynonymous (amino-acid changing) substitutions of the former equine virus gene was estimated to be 0.00041/site/year--that is about 5 times lower than that estimated for the human H 3 haemagglutinin gene. The present study is the first demonstration that multiple evolutionary lineages of equine H3N8 influenza virus circulated since 1963.

5-hydroxytryptamine is a fast excitatory transmitter at 5-HT3 receptors in rat amygdala

A fast excitatory synaptic potential mediated by 5-hydroxytryptamine (5-HT) was recorded in rat lateral amygdala neurons in brain slices. The synaptic potential has brief duration (tens of milliseconds), is mimicked by 5-HT, is potentiated by a 5-HT uptake inhibitor, and is blocked by selective 5-HT3 receptor antagonists. The underlying synaptic current reversed polarity at about 0 mV. This is an example of fast neurotransmission in the mammalian brain mediated by an amine rather than an amino acid. The antiemetic, anxiolytic, and perhaps antipsychotic actions of 5-HT3 antagonists might result from blockade of such synapses.

Synaptic inputs to GABAA and GABAB receptors originate from discrete afferent neurons

gamma-Aminobutyric acid (GABA) inhibits neurons by acting at GABAA and GABAB receptors but it is not known whether the two receptors are associated with discretely separate afferent inputs or whether GABA released from a single presynaptic neuron activates both receptors. Intracellular recordings were used to show that, in the lateral amygdala and ventral tegmental area of the rat, distinct sets of GABA-containing neurons provide the synaptic input to GABAA and GABAB receptors. Synaptic potentials resulting from GABAA receptor activation (blocked by bicuculline) and from GABAB receptor activation (blocked by 2-hydroxysaclofen) occurred spontaneously but as unrelated events. Furthermore, the two components of evoked synaptic potentials were differentially inhibited by agonists acting presynaptically (muscarine and 5-hydroxytryptamine). The finding that GABA acting at GABAA and GABAB receptors originates from distinct sets of presynaptic fibers suggests that two groups of GABA-containing neurons might be generally distinguishable in the mammalian nervous system.

[Retinal projections to the pretectum in the fowl (Gallus gallus domesticus)]

The retinal projection to the pretectum was examined in the adult domestic fowl by means of anterograde transport of horseradish peroxidase (HRP). At the same time, the cytoarchitecture of the pretectum was studied in Nissl preparation. Fifteen fowls (Gallus gallus domesticus) were used for the HRP study, and four were used for the cytoarchitectural study. One hundred microliters of a 30% HRP solution in physiological saline were injected into the vitreous body of the unilateral eye under sodium pentobarbital anesthesia (30 mg/kg body weight). After a postoperative period of 48 hours, the animals were deeply anesthetized and perfused intracardially with 1,000 ml of Ringer solution, followed by 2,000 ml of 1% paraformaldehyde and 1.25% glutaraldehyde in a 0.1 M phosphate buffer (pH 7.4) which was then followed by 1,000 ml of 10% sucrose in the same buffer. The brain was cut into serial transverse sections at 60 microns on a freezing microtome. Every section was treated with tetramethyl benzidine (TMB). Based on cytoarchitectural and HRP results, the pretectum of the adult hen was divided into the following eight nuclei: nucleus principalis pretectalis (P), nucleus subpretectalis (SP), nucleus principalis precommissuralis (PPC), nucleus medialis pretectalis (PTM), nucleus pretectalis dorsalis (APd), nucleus area pretectalis (AP), nucleus spiriformis lateralis (SPL), and nucleus spiriformis medialis (SPM). The SPL and SPM lay closely adjacent to each other, although the boundary between them can be easily defined in any section. Furthermore, the SPM could be divided into two subnuclei: the dorsal part of the SPM (SPMd) located just under the SMT and dorsomedial to the P, and the ventral part of the SPM (SPMv), which was located above the PPC and ventromedial to the P. Retinal projections were found in the APd, the PTM, the AP and the SPM, contralaterally. APd was the smallest nucleus among the pretectal nuclei lying just above the tractus septomesencephalicus (SMT) and received the heaviest retinal inputs. In the PTM, clear terminals were distributed over the whole of the nucleus, whereas strong labeled terminals were also found around the principal pretectal nucleus. Slight retinal inputs were found in the ventral part of the SPM. Furthermore, heavily labeled terminals were found in the medial part of the AP designated as the interstitial nucleus of the posterior commissure by Niimi. Terminals in the ventral part of the SPM and the medial part of the AP have not been reported in the previous studies in the chick and pigeon. There were no terminals in the contralateral P, SPL, SP, PPC, and the ipsilateral brain stem.

[Analysis of electrically evoked response (EER) in relation to the central visual pathway of the cat (2). Response characteristics of the lateral geniculate neurons]

To analyze the electrically evoked response (EER) in relation to the central visual pathway, the response characteristics of the lateral geniculate neurons (LGNs) of the EER in 35 anesthetized adult cats were studied. Responses of the LGNs showed interindividual variation of more than one log unit in terms of the stimulus threshold for electrical stimuli. As the stimulus intensity increased, the spikes with constant latencies were recorded, which showed bursts with much stronger stimuli. The latencies of the spikes were closely correlated with those of negative components of EER. The LGNs were divided into two major groups by the latency. The periodical and alternative excitation of these neurons contributed to form the first negative wave of EER. The latency of these two major groups of LGNs was reversed when the electrode polarity was changed. At higher stimulus intensities, the components with short latency became dominant and those with longer latency were suppressed. The above results suggested that the periodical excitation of LGNs and the formation of the prominent EER components may result from the interaction between on- and off-type retinal ganglion cells and amacrine cells. It was also suggested that the origins of the wavelets in negative waves of EER at strong stimuli are the bursts of the spikes of the visual cortex neurons.

Brainstem mossy fiber projections to lobules VIa, VIb,c, VII and VIII of the cerebellar vermis in the rat

The brainstem mossy-fiber projections to lobules VIa, VIb,c, VII and VIII of the cerebellar vermis were studied by retrograde transport of horseradish peroxidase in the rat. The distribution of labeled cells indicated that these lobules received major projections from topographically different locations of the basilar pontine nuclei and the nucleus reticularis tegmenti pontis. Lobules VIa and VIII received an additional strong projection from the lateral reticular nucleus. Moderate projections were found to reach lobule VIa from the raphe pontis and external cuneate nucleus; lobules VIb,c from the raphe pontis, lateral reticular nucleus, and a group of cells in the lateral tegmentum; lobule VII from the spinal vestibular nucleus and a lateral tegmental cell group; and lobule VIII from the medial and spinal vestibular nuclei, nucleus intercalatus and Roller of the perihypoglossal nuclei, and the main cuneate nucleus. The quantitative and topographical differences in the origin of mossy fibers suggest that these lobules may subserve slightly different functions.

Distinct muscarinic receptors inhibit release of gamma-aminobutyric acid and excitatory amino acids in mammalian brain

Intracellular recordings were made from neurons of rat lateral amygdala, nucleus accumbens, and striatum in vitro. Synaptic potentials mediated by gamma-aminobutyric acid and by excitatory amino acids were isolated pharmacologically by using receptor antagonists, and their amplitudes were used as a measure of transmitter release. Muscarine and acetylcholine inhibited the release of both gamma-aminobutyric acid and excitatory amino acids, but measurements of the dissociation equilibrium constants for the antagonists pirenzepine, 11-(2-[(diethylamino)methyl]-1-piperidinyl)acetyl-5,11-dihydro-6H-pyrido [2,3-b][1,4]benzodiazepine-6-one, methoctramine, and hexahydrosiladifenidol indicated clearly that different muscarinic receptors were involved (M1 and probably M3, respectively). The differential localization of distinct muscarinic receptor subtypes on terminals releasing the major inhibitory and excitatory transmitters of the brain could be exploited therapeutically in some movement disorders and Alzheimer disease.

Pathways and terminations of axons arising in the fastigial oculomotor region of macaque monkeys

The majority of axons from the fastigial oculomotor region (FOR) decussated in the cerebellum at all rostrocaudal levels of the fastigial nucleus (FN) and entered the brainstem via the contralateral uncinate fasciculus (UF). Some decussated axons separated from the UF and ran medial to the contralateral superior cerebellar peduncle and ascended to the midbrain. Uncrossed FOR axons advanced rostrolaterally in the ipsilateral FN and entered the brainstem via the juxtarestiform body. The decussated fibers terminated in the brainstem nuclei that are implicated in the control of saccadic eye movements. In the midbrain, labeled terminals were found in the rostral interstitial nucleus of the medial longitudinal fasciculus, a medial part of Forel's H-field, the periaqueductal gray, the posterior commissure nucleus, and the superior colliculus of the contralateral side. In the pons and medulla, FOR fibers terminated in a caudal part of the pontine raphe, the paramedian pontine reticular formation, the nucleus reticularis tegmenti pontis, the dorsomedial pontine nucleus of the contralateral side, and the dorsomedial medullary reticular formation of both sides. In contrast, FOR projections to the vestibular complex were bilateral and were mainly to the ventral portions of the lateral and inferior vestibular nuclei. No labeled terminals were found in the following brainstem nuclei which are considered to be involved in oculomotor function: oculomotor and trochlear nuclei, interstitial nucleus of Cajal, medial and superior vestibular nuclei, periphypoglossal nuclei, and dorsolateral pontine nucleus. Labeling appeared in the red nucleus only when HRP encroached upon the posterior interposed nucleus.

Pancreatic pseudocyst in the left hepatic lobe: a report of two cases

The ultrasound and computed tomographic imaging features in a rare pancreatic pseudocyst of the liver are described in two patients. The pseudocysts occurred in the left lobe in both cases, one after a traumatic injury and the other after alcoholic pancreatitis. The possible topographical sequences with which pancreatic secretions entered the left hepatic lobe to form a cyst are discussed.

Molecular evolution of hemagglutinin genes of H1N1 swine and human influenza A viruses

The hemagglutinin (HA) genes of influenza type A (H1N1) viruses isolated from swine were cloned into plasmid vectors and their nucleotide sequences were determined. A phylogenetic tree for the HA genes of swine and human influenza viruses was constructed by the neighbor-joining method. It showed that the divergence between swine and human HA genes might have occurred around 1905. The estimated rates of synonymous (silent) substitutions for swine and human influenza viruses were almost the same. For both viruses, the rate of synonymous substitution was much higher than that of nonsynonymous (amino acid altering) substitution. It is the case even for only the antigenic sites of the HA. This feature is consistent with the neutral theory of molecular evolution. The rate of nonsynonymous substitution for human influenza viruses was three times the rate for swine influenza viruses. In particular, nonsynonymous substitutions at antigenic sites occurred less frequently in swine than in humans. The difference in the rate of nonsynonymous substitution between swine and human influenza viruses can be explained by the different degrees of functional constraint operating on the amino acid sequence of the HA in both hosts.