Accessory Bundles Research Articles

Spatial relationships between masticatory muscles and their innervating nerves in man with special reference to the medial pterygoid muscle and its accessory muscle bundle.

The relationships between the positional arrangement of the surrounding and innervating nerves of the muscles supplied by the mandibular nerve, in particular those medial to the main trunk of the nerve, were examined in 24 head halves from 12 Japanese cadavers by dissection from the inside after removal of the bony elements except for the mandible. In ten sides of five heads, the lingual nerve pierced the medial pterygoid muscle, and the bundle lateral to the nerve was found to be separated as an accessory muscle bundle. The accessory bundle was frequently attached to the mylohyoid muscle. In addition, the inferior alveolar nerve and the lingual nerve frequently communicated, and in four specimens a branch from the lingual nerve entered the mylohyoid to communicate with the proper nerve. The innervation pattern indicated that the medial pterygoid muscle consists of the anteromedial and the posterolateral main parts, and sometimes has an accessory bundle. Based on the present findings and the previous studies of the positional relationships between the muscles and nerves by our research group, we propose that the muscles innervated by the mandibular nerve could be classified as an inner group (the lateral pterygoid) and an outer group (the other muscles). A possible scheme of the positional relationships between the muscles and nerves is presented.

Distribution of myelinated and unmyelinated nerve fibers and their possible role in blood flow control in crotaline snake infrared receptor organs.

We used transmission electron microscopic montages to examine the composition of nerve bundles serving the infrared pit organs of two species of crotaline snakes, Agkistrodon blomhoffii and A. brevicaudus. In the three main bundles, the myelinated fibers totaled 2,200-3,700, and unmyelinated fibers 2,400. We also discovered for the first time two accessory bundles composed almost entirely of unmyelinated fibers running alongside the main bundles, containing an average total of 3,300 unmyelinated fibers vs. an average of 10 myelinated fibers. Thus, the average total of unmyelinated fibers was nearly twice that of myelinated fibers. To study the nature of the unmyelinated fibers, we did double staining immunohistochemistry with antibodies for substance P (SP) and vasoactive intestinal polypeptide (VIP) in combination with and without capsaicin pretreatment. SP and VIP immunoreactive varicose fibers ran straight toward the center of the pit membrane in parallel with arterioles and venules, and also formed a dense network around the periphery of the membrane. There were three types of fibers: fibers containing only SP, fibers containing only VIP, and fibers containing both peptides. SP-only fibers were distributed singly throughout the pit membrane and in small bundles around the periphery. SP+VIP fibers were distributed sparsely in the pit membrane and around its periphery. VIP-only fibers were distributed throughout the pit membrane and were of smaller diameter than SP and SP+VIP fibers. After treatment with capsaicin, most of the three types of varicose fibers disappeared from the central part of the pit membrane, but those around the periphery remained unaffected. The capsaicin-sensitive fibers may be unmyelinated sensory types, and the unaffected ones may be autonomic nerve fibers.

Mechanics of the antebrachial interosseous membrane: response to shearing forces.

The interosseous membrane functions to maintain the structural integrity of the forearm; however, the age-related mechanical properties of the intact membrane are incompletely defined. The purpose of this study is to quantify the mechanical properties of the interosseous membrane by applying a quasi-equilibrium shearing force between the radius and ulna. A 5-cm section of the central (main and accessory bundles) fiber from 11 (5 male and 6 female) fresh-frozen cadaver arms (age, 74 +/- 6.9 years) was isolated with the radial and ulnar attachments, measured, and positioned into the testing apparatus. A shear force was applied at 12.7 mm/min to produce a quasi-equilibrium state, and the applied force and elongation were monitored. The average ultimate force, ultimate strength, and elastic modulus were 1101 +/- 191 N, 13.98 +/- 4.85 MPa, and 135.29 +/- 41.57 MPa, respectively. Age-related changes were also noted with an increase in thickness by 0.056 mm per year of age and a decrease in fiber stiffness of 4.78 MPa/yr. The age-related mechanical properties of the intact interosseous membrane are necessary for modeling forearm stability in normal and pathologic conditions. This information is required for analysis of repair or reconstructive procedures.

Anatomical studies in West Malaysian Icacinaceae

On the basis of a comparative anatomical study of the leaf lamina and petiole of six genera of Icacinaceae in West Malaysia, these genera can be classified into four closely knit groups by virtue of their many shared characters: Group I comprises Cantleya, Gomphandra and Stemonurus whereas Groups II and III are made up of Gonocaryum and Sarcostigma, respectively. The climber genus Iodes is classified into Group IV. Taxonomically useful characters include the shape of the vascular bundles in both the midrib and petiole, the presence of funnel-shaped palisade cells, foliar sclereids, tannin crystals, hypodermis layer and accessory or wing bundles in the petiole. A key to the genera and the descriptions of each species and variety based on anatomy are given. Phylogenetic relationship among the genera are also discussed based on the study with data supplemented from other taxonomic sources.

Experience with a multichannel system for biomagnetic study

The components of the biomagnetic multichannel system Krenikon are described. The combination of biomagnetically yielded localizations with anatomic images gained from MR or CT is discussed as well as the enhancement of the signal-to-noise ratio by using a correlation technique. The overall localization accuracy is tested with technical phantoms. With volunteers measurements of auditory, visual and somatosensory evoked fields are performed to evaluate the system performance in vivo. The data acquisition time typically is 2-10 min which is tolerable both for the patient and the clinical staff. Electric potentials even with invasive electrodes can be recorded simultaneously with the magnetic fields. MEG gives important information for the presurgical diagnosis of epileptic patients and for the understanding of the epilepsy genesis. With MCG, centres of biologic excitation such as ventricular ectopies or accessory bundles in WPW syndrome have been successfully localized.

Allozyme Electrophoresis and the Taxonomy of Two Species of Isoetes in the Southeastern Appalachians

Recent research in the genus Isoetes has included both a continued effort to locate and describe new and little understood taxa as well as a new effort to understand their population biology and mechanisms of speciation. Gel electrophoresis has only recently been used to aid in the latter research. Taylor et al. (1985) and Taylor and Luebke (1988) have compared North American taxa using several enzyme systems, and Hickey et al. (1989b) have used electrophoresis to examine species relationships and population biology in Isoetes. Although electrophoresis may be utilized to distinguish taxa of Isoetes, practical methods of species sorting and identification in the genus continue to utilize characters of spore morphology, habitat preference, and geographical location. The purpose of the present study was to utilize the techniques of gel electrophoresis to explore the relationship between I. engelmannii A. Br. var. engelmannii and var. caroliniana Eaton (1900a). Data gathered as part of this study were also used to better understand the population biology of both taxa and to investigate the usefulness of electrophoresis for examining relationships between presumably closely and more distantly related taxa. Braun (1846) originally described I. engelmannii (Engelmann's quillwort) from specimens collected by Engelmann in 1842 from a Missouri pond near St. Louis. Later Engelmann (1867, 1882) described several varieties of the species: var. valida from Pennsylvania and Delaware, var. gracilis for small plants from southern New England, and var. georgiana for extremely large and robust plants from Floyd County, Georgia. Eaton (1905) recognized var. fontana for plants with accessory bast bundles in the leaves, spotted sporangia, and larger spores with broken reticulations. Isoetes engelmannii var. caroliniana was described by Eaton (1900) from Mitchell County, North Carolina, based on a wide velum covering up to two-thirds of the sporangia and megaspores with jagged crests to a broken reticulate pattern. This variety of I.

Systemic venous flow during cardiac surgery examined by intraoperative transesophageal echocardiography

Patterns of systemic venous return change after cardiac surgery. However, the exact timing and underlying mechanisms are not well understood. To analyze these changes transesophageal echocardiography was used to evaluate 21 patients (mean age 56 ± 17 years) during cardiac surgery. Eleven patients underwent coronary bypass grafting, 2 had ablation of accessory bundles, 4 had mitral and 4 had aortic valve replacements. All were in sinus rhythm and were undergoing their first cardiac operation. Hepatic and pulmonary venous flow, tricuspid annular motion, and signs of tricuspid regurgitation were recorded sequentially 5 times: (A) with chest closed, (B) with chest open and pericardium closed, (C) with both chest and pericardium open, (D) after cardiopulmonary bypass with chest open, and (E) after cardiopulmonary bypass with chest closed. The hepatic venous Doppler flow velocity integrals (cm) changed, from stage A to stage E: systolic flow decreased from 5.9 ± 5.2 to 2.2 ± 1.4 (p < 0.01); diastolic flow increased from 3.1 ± 1.5 to 4.8 ± 3.3 (p < 0.001); and systolic to diastolic ratio decreased from 2.0 ± 1.2 to 0.7 ± 0.6 (p < 0.001). Reversed flow at the end of ventricular systole was present in 9 patients (43%) at stage A and in all patients at stage E. Decreased tricuspid annular motion was noted in all but 1 patient after cardiopulmonary bypass. No patient presented significant tricuspid regurgitation at any stage. In conclusion, the significant change in the pattern of systemic venous return after open heart surgery is not due to opening of the chest wall or parietal pericardium, or to tricuspid regurgitation. The decrease in tricuspid annular motion after cardiopulmonary bypass suggests abnormalities in right-sided cardiac function (stage D) and addition of mechanical restriction to cardiac motion after closure of the chest wall (stage E) as major mechanisms responsible for the observed flow changes.

On the organization of the Plexus lumbalis. I. On the recognition of the three-layered divisions and the systematic description of the branches of the human femoral nerve.

The arrangement of the nerve bundles at the branching point of the femoral nerve (F), the interrelations of the branches each other and toward other nerves in the anterior region of the thigh, and the patterns and the anatomical features of both the running courses and the distributions of the branches were macroscopically studied, whereby some special findings were observed and the following results were obtained: 1) The periphery of the femoral nerve was fundamentally divided into superficial-deeply arranged three-layered divisions. Including the femoral branch of the genitofemoral nerve (Rf) and the femoral lateral cutaneous nerve (Cfl), the nerve branches at the anterior region of the thigh were totally divided into five-layered divisions. 2) The cutaneous branches of each division including Rf or Cfl could be classified in three groups: the medial cutaneous branches (m), the anterior cutaneous branches (a), and the lateral cutaneous branches (l). Based on the above results, the branches could be described systematically. Parallelly, several accessory bundles of F penetrating the psoas major muscle were observed, and two types of accessory femoral nerves (F') could be distinguished: One was higher on the segmentation and mainly flew into the 1st division of F. While the other distributed only to the medial region of the thigh. To clarify the segmental or stratifical natures of the branches of each division, F', and the interrelations among them, analyses of the nerve fibers were undertaken under the operational microscope. Consequently, the segmental differences between the divisions were distinct, and the medial branches or F'm obviously contained ventral components. Thus, when a component originated from the higher segments, it distributed to the proximal region generally taking a superficial course; when it originated from the lower ones, it distributed to the distal region of the thigh forming the deeper division; when it belonged to the ventral stratum, it distributed to the medial region; and when it belonged to the dorsal stratum, it distributed to the lateral region. On the occasion of the fiber analysis, it was found that each root of the lumbar nerve was generally divided into two or three subsegmentally-arranged subroots that divided themselves into some fasciculi arranged micro-segmentally. A minute analysis of the segmentations of the nerves became possible because of the above characteristics.

Surgical cure of cardiac arrhythmia

The first surgical procedure undertaken for the intended purpose of curing a patient with recurrent tachycardia was performed by Sealy in 1968, and the report of that operation was published in The Annals of Thoracic Surgery in 1969. The first attempted accessory bundle ablation was successful, marked the beginning of cardiac arrhythmia surgery, and has set the standard against which other methods of arrhythmia control must be measured.

Cryosurgical ablation of left parietal wall accessory atrioventricular connections through the coronary sinus without the use of extracorporeal circulation

A simplified technique for surgical treatment of preexcitation syndrome caused by left-sided accessory atrioventricular connections without the use of extracorporeal circulation has been elaborated experimentally and used in 21 patients with tachycardia refractory to medical treatment. Cryoablation of the accessory bundles was performed by means of local cryothermia using a specially designed cryoinstrument introduced into the coronary sinus through the right atrial wall. The operations were performed after thoracotomy on the working closed heart. The signs of preexcitation and paroxysms of tachycardia disappeared in 19 of 21 patients. Coronary sinus ligation was necessary in two patients. In the rest of the patients the patency of the sinus was preserved and there were no surgical complications. This original cryosurgical technique offers a number of advantages in selected patients with Wolff-Parkinson-White syndrome.

Three-dimensional organization of tubular and filamentous nuclear inclusions and associated structures in sympathetic neurons as revealed by serial sections and tilting experiments

Fifty nuclear inclusions (N.I.) in neurons of cat superior cervical, celiac, and stellate ganglia were examined by serial sections and tilting experiments. The two basic elements, i.e., microfilaments and microtubules, are assembled in five main types of N.I., two of which are described for the first time in the three ganglia. Furthermcre, use of both techniques allows to identify four so-called associated structures: dense bodies, a granulofibrillar envelope, granulofibrillar bodies, and an accessory microtubular bundle. The three-dimensional organization and dimensions of each type of N.I. and their associated structures are established. Particularly the two types of crystalloids lie in a right prism with a lozenge-shaped base whose two axes display a constant length. These ultrastructural data, analyzed in light of previously experimental observations, are compatible with a working hypothesis according to which the simplest N.I. could evolve toward more complex ones (crystalloids) and are discussed with respect to biochemical studies on nuclear contractile proteins.

Concealed accessory pathway and dual av conduction: Drug‐dependent reentrant tachycardia

Electrophysiological studies were performed in a patient with paroxysmal supraventricular tachycardia and a normal surface ECG at the time of the study. Premature atrial stimulation revealed dual AV conduction and an echo zone during AV conduction over the fast and the slow pathway. The prolongation of the AV conduction time by a calcium antagonist, Ro 11-1781, permitted the induction of tachycardias via both pathways. Premature ventricular stimulation yielded constant VA conduction times with activation of the low right atrium before the high right atrium before the left atrium. During the tachycardia, premature right ventricular beats conducted to the atrium at a time when the AV node and the His bundle would be refractory. The study suggests the simultaneous occurrence of an occult accessory bundle connecting the right ventricle to the right atrium and dual AV conduction.

Immunocytochemical demonstration of somatostatin-containing neurons in the hypothalamus of the domestic mallard.

In the hypothalamus of the adult domestic mallard, small to medium-sized perikarya are stained specifically with rabbit antiserum against cyclic somatostatin (PAP technique of Sternberger). The somatostatin-immunoreactive material is located in neurons different from those containing immunoreactive LHRH, vasotocin or mesotocin. Somatostatin-containing perikarya are observed 1) in a chain-like arrangement extending from the area of the median division of the supraoptic nucleus to the caudal end of the paraventricular nucleus; 2) as single cells in the preoptic region; and 3) as a conspicuous formation in the optic tract division of the supraoptic nucleus. In the rostral portion of the median eminence, somatostatin-immunoreactive axons penetrate into the external zone. Fine accessory fiber bundles project to the neural lobe.

Accelerated atrioventricular conduction during acute myocardial infarction

Three cases are described in which accelerated atrioventricular conduction occurred during an acute myocardial infarction. The first patient, an 82-year-old woman, developed a WPW syndrome suggesting posterior right ventricular preexcitation, a pattern which persisted for four months until her death. An accessory bundle was found on autopsy. Fibrotic changes, associated with acute lesions (hemorrhage, polymorphonuclear infiltrates) were present in the atrioventricular node and His-Purkinje system. Two men, of 47 and 74 years, developed a short PR interval associated with supraventricular tachycardia during the course of an acute myocardial infarction. The PR interval returned to its initial value in one case and remained unchanged for three months in the other. Accessory atrioventricular connections which became functional during myocardial ischemia may explain the various electrocardiographic patterns of preexcitation.

ANATOMICAL STUDIES OF CYATHEA AND TRICHIPTERIS (CYATHEACEAE)

Comparative anatomical studies of the mature stems of two species each of Trichipteris and Cyathea (Cyatheaceae) are described. The outermost boundary of the stem is typically a two‐layered hypodermis. Mucilage‐sac cells are randomly distributed in all parenchymatous areas of the stem and form articulated laticifer systems. Localized areas of sclerenchyma tissue occur in the cortex of both T. microphylla and C. suprastrigosa. All species studied possess medullary bundles, whereas cortical bundles are found only in T. trichiata. Accessory bundles occasionally are associated with indentations in the internal stelar sheath of T. trichiata. The stelar pattern in each genus is a dictyostele and consists of individual meristeles. Distinctive cubical cells typically occur wherever sclerenchymatous fibers and parenchyma cells abut one another. Tangential cells occur within the primary phloem of each meristele, and occasionally within the larger accessory bundles. The primary xylem of the adventitious roots is typically diarch, although triarch and tetrarch xylem may occur. Leaf traces and petiole strands are similar anatomically to the accessory bundles. Based upon this study Trichipteris and Cyathea show striking anatomical similarities, and appear to be closely‐related taxa.

Vascular Organization in Shoots of Cactaceae. I. Development and Morphology of Primary Vasculature in Pereskioideae and Opuntioideae

Primary shoot vasculature has been studied for 31 species of Pereskioideae and Opuntioideae from serial transections and stained, decorticated shoot tips. The eustele of all species is interpreted as consisting of sympodia, one for each orthostichy. A sympodium is composed of a vertically continuous axial bundle from which arise leaf- and areole-trace bundles and, in many species, accessory bundles and bridges between axial bundles. Provascular strands for leaf traces and axial bundles are initiated acropetally and continuously within the residual meristem, but differentiation of procambium for areole traces and bridges is delayed until primordia form on axillary buds. The differentiation patterns of primary phloem and xylem are those typically found in other dicotyledons. In all species vascular supply for a leaf is principally derived from only one procambial bundle that arises from axial bundles, whereas traces from two axial bundles supply the axillary bud. Two structural patterns of primary vasculature are found in the species examined. In four species of Pereskia that possess the least specialized wood in the stem, primary vascular systems are open, and leaf traces are mostly multipartite, arising from one axial bundle. In other Pereskioideae and Opuntioideae the vascular systems are closed through a bridge at each node that arises near the base of each leaf, and leaf traces are generally bipartite or single. Vascular systems in Pereskiopsis are relatively simple as compared to the complex vasculature of Opuntia, in which a vascular network is formed at each node by fusion of two sympodia and a leaf trace with areole traces and numerous accessory bundles. Variations in nodal structure correlate well with differences in external shoot morphology. Previous reports that cacti have typical 2-trace, unilacunar nodal structure are probably incorrect. Pereskioideae and Opuntioideae have no additional medullary or cortical systems.

VASCULAR ORGANIZATION IN SHOOTS OF CACTACEAE. I. DEVELOPMENT AND MORPHOLOGY OF PRIMARY VASCULATURE IN PERESKIOIDEAE AND OPUNTIOIDEAE

Primary shoot vasculature has been studied for 31 species of Pereskioideae and Opuntioideae from serial transections and stained, decorticated shoot tips. The eustele of all species is interpreted as consisting of sympodia, one for each orthostichy. A sympodium is composed of a vertically continuous axial bundle from which arise leaf‐ and areole‐trace bundles and, in many species, accessory bundles and bridges between axial bundles. Provascular strands for leaf traces and axial bundles are initiated acropetally and continuously within the residual meristem, but differentiation of procambium for areole traces and bridges is delayed until primordia form on axillary buds. The differentiation patterns of primary phloem and xylem are those typically found in other dicotyledons. In all species vascular supply for a leaf is principally derived from only one procambial bundle that arises from axial bundles, whereas traces from two axial bundles supply the axillary bud. Two structural patterns of primary vasculature are found in the species examined. In four species of Pereskia that possess the least specialized wood in the stem, primary vascular systems are open, and leaf traces are mostly multipartite, arising from one axial bundle. In other Pereskioideae and Opuntioideae the vascular systems are closed through a bridge at each node that arises near the base of each leaf, and leaf traces are generally bipartite or single. Vascular systems in Pereskiopsis are relatively simple as compared to the complex vasculature of Opuntia, in which a vascular network is formed at each node by fusion of two sympodia and a leaf trace with areole traces and numerous accessory bundles. Variations in nodal structure correlate well with differences in external shoot morphology. Previous reports that cacti have typical 2‐trace, unilacunar nodal structure are probably incorrect. Pereskioideae and Opuntioideae have no additional medullary or cortical systems.

The Electrophysiologic Studies on Wolff-Parkinson-White (WPW) Syndrome : With Special Reference to His Bundle Pacing on WPW Syndrome

For a long time many theories have been postulated with regard to the cause of WPW syndrome, more than 60, according to Scherf and Cohen. But the accessory bundle theory is mostly accepted as the outcome of anatomically proved accessory conduction pathway, the result of epicardial mapping for type B WPW syndrome and the therapeutic results obtained by the interruption of accessory conduction pathway. The author has attempted to examine functional property of the accessory conduction pathway of WP syndrome using the His bundle electrogram, atrial pacing and the His bundle pacing. Functional evaluation on the accessory conduction pathway is not only important for clarifying the mechanism of WPW syndrome, but also it is particularly important when surgical interruption of the accessory conduction pathway is attempted. Up to the present there has been no repot of successful His bundle pacing in many cases of WPW syndrome, so in this paper the author will mainly report the findings obtained by the His bundle pacing on WPW syndrome. Materials and Methods: Twenty patients were studied. All patients had the typical WPW pattern, i.e., a shortened PQ interval, delta wave and a widened QRS complex. It involves 10 cases of type A and 10 cases of type B. the technics of His bundle electrogram recording introduced by Scherlag and co-workers were used. A bipolar electrode catheter (distance between electrodes is 10mm) was introduced through the right femoral vein under local anesthesia and was positioned fluoroscopically close to the septal leaflet of the tricuspid valve. Another bipolar electrode catheter was introduced through the same vein and was positioned above the right atrium, and it was used for atrial pacing the recording of high right atriogram.

COMPARATIVE STUDIES OF THE NODAL AND VASCULAR ANATOMY IN THE NEOTROPICAL CYATHEACEAE. I. METAXYA AND LOPHOSORIA

Comparative studies of the nodal and vascular anatomy in the monotypic genera Metaxya and Lophosoria are discussed as they relate to the taxonomy and phylogeny of the Cyatheaceae. Both genera are distinctive and primitive with respect to habit, stem and petiole indument, stelar pattern, and nodal anatomy. Metaxya possesses a prostrate, dorsiventral rhizome, whereas a short, upright radial stem occurs in Lophosoria. Trichomes occur on the stems and leaf petioles of these genera. Both Metaxya and Lophosoria have a spiral phyllotaxy, and adventitious buds occur on the petiole bases. The stelar pattern is basically a siphonostele, although frequently a dictyostele is found in Lophosoria. Accessory bundles are lacking in both genera. A characteristic petiole pattern is found in these genera, with an increase in complexity from an undivided strand in Metaxya to the three‐parted petiole pattern in Lophosoria. Data from nodal and vascular anatomy indicate that these taxa are distinct from the other genera in the Cyatheaceae and belong in an independent position at the base of the Cyatheoid line, although in some respects an affinity to members of the Dicksoniaceae is indicated.

Usefulness of vectorcardiography combined with his bundle recordings and cardiac pacing in evaluation of the preexcitation (Wolff-Parkinson-White) syndrome

Vectorcardiograms (Frank system) were recorded simultaneously with His bundle electrograms during atrial stimulation in 3 patients with intermittent preexcitation Wolff-Parkinson-White (WPW) syndrome. In 2 cases with classic WPW, type A, loops were obtained during (1) exclusive conduction through the normal pathway, (2) coexisting accessory bundle and normal pathway conduction, and (3) exclusive accessory pathway conduction. Combination beats (resulting from ventricular depolarization through both pathways) showed an initial delay associated with anteriorly placed QRS loops and maximal vectors. When exclusive accessory bundle conduction occurred, a rightward and anteriorly oriented terminal delay was added to the initial slowing. This terminal delay was not ascribed to right bundle branch block but to the specific pattern of activation of an impulse apparently propagating from the posterosuperior wall of the left ventricle. In fact, these vectorcardiograms were similar to those recorded from patients with ectopic impulses originating at the posterosuperior left ventricular wall. When exclusive conduction through the normal pathway was associated with right bundle branch block, the prolonged St-V interval coexisted with a loop showing only terminal conduction disturbances. The loops seen during exclusive accessory bundle conduction in the patient with WPW, type B, had a leftward, posterior and superior orientation. The spatial delay was diffuse, although more marked toward the end of depolarization. This terminal (leftward) conduction defect was not attributed to right bundle branch block. The sequence of ventricular activation (as recorded at the body surface) was similar to that occurring during right ventricular apical pacing. Resemblance between vectorcardiograms showing exclusive accessory bundle conduction and those produced by direct stimulation of specific ventricular sites suggests, but certainly does not prove, that the electrical impulse is propagated from equivalent sites.