Distal Hook Research Articles

Three new species of Dichromadora (Nematoda: Chromadorida: Chromadoridae) from the Yellow Sea, China

Three new species of free-living marine nematodes belonging to Dichromadora Kreis: Dichromadora major sp. nov., Dichromadora multisetosa sp. nov., Dichromadora sinica sp. nov. from the Yellow Sea, China are described and illustrated. Dichromadora major sp. nov. is characterized by the combination of the presence of a clearly anterior pharyngeal bulb, crescent-shaped amphides, nine precloacal supplements, arcuate spicules and gubernaculum with a lateral swelling about the middle. Dichromadora multisetosa sp. nov. is characterized by the presence of a clearly anterior dorsal pharyngeal bulb and rounded posterior one, long somatic setae and a broad dorsal caudal apophysis of gubernaculum. Dichromadora sinica sp. nov. is characterized by the presence of double posterior pharyngeal bulb, four longitudinal files of lateral punctations, spicules with distal hook, four (3 + 1) precloacal supplements and paired subventral double-jointed postcloacal papillae in males.

Descripción de una especie nueva de <i>Meloe</i> Linnaeus, 1758 del subgénero <i>Eurymeloe</i> Reitter, 1911 (Coleoptera, Meloidae) del norte de Marruecos

We describe a new species of Meloe (Coleoptera: Meloidae), subgenus Eurymeloe , included in the M. rugosus species group, related to species of the M. murinus subgroup. The specimens of the new species studied were found along the western Rif mountain chain (Talassemtane National Park) in northwestern Morocco, and were located in hiperhumid montane forest habitats. The new species is characterized by having: a dull black coloration with greyish hue; a very short, curved, and not dense, yellow-whitish pilosity, which does not form tufts; a subrectangular transverse pronotum with a marked median grove and two longitudinal lateral depressions; head and pronotum punctures well impressed and subconfluent; elytra sligtly rugose; tarsomeres with slightly developed ventral pads; aedeagus with curved parameres, laterally depressed, apically pointed, with the distal ventral hook of median lobe close to apex. The new taxon es phenetically similar to M. nanus, M. baudueri and M. flavicomus , but distinguished from all of them by the mentioned morphological external and male genitalia characters. The distribution of the new species, only known from its type locality, overlaps those of M. murinus, M. nanus and possibly M. baudueri , but so far it has not been found in strict sympatry with any of them. The habitat type inhabited by the new species, mountain areas with mixed forests of Pinus pinaster hamiltonii var. maghrebiana, P. nigra mauritanica and Abies maroccana (endemic taxa of the limestone northwestern Rif mountain chain), contrasts with other habitat types recorded for species of the M. (E). murinus species subgroup of the subgenus Eurymeloe .

Jaw growth and replacement in 'Diopatra aciculata' (Annelida:Onuphidae)

Jaw development was studied in 1- to 45-day old 'Diopatra aciculata' (fertilisation to 44-chaetigers). Both mandibles and maxillae became visible in 4- to 6-chaetiger worms. The initial protomandibles become embedded in the adult mandibles. The larval maxillae consist of a left fang-like and right small serrated element, a pair of serrated plates, distal ridges, and a single carrier. Larval maxillae were replaced by juvenile maxillae in 14- to 15-chaetiger worms. Juvenile maxillae have adult-like carriers, MII and MIV, but MI are proximally dentate with a distal hook; MIII and MV are absent. First adult maxillae were seen in 21-chaetiger worms. Each subsequent moult results in larger but otherwise identical apparatuses. The moult increment (difference in size between successive moults) was established as 1.34 and used to extrapolate estimates of size classes. Based on these calculations our largest worms had their fourth set of adult maxillae, having moulted the adult maxillae every three to four days.

Cystacanths of Acanthocephala in notothenioid fish from the Beagle Channel (sub-Antarctica)

The morphology of relaxed cystacanths of polymorphid acanthocephalans collected from notothenioid fishes in the Beagle Channel (Magellanic subregion of sub-Antarctica) is described. A parasite of birds, Andracantha baylisi (Zdzitowiecki, 1986), was found in Patagonotothen longipes and Champsocephalus esox. It has: a proboscis 0.82-0.89 mm long; a proboscis hook formula of 16 rows of 9/10-10/11, including 4-5 basal hooks; distal hooks with the longest blades; a fore-trunk not separated from the hind-trunk by a constriction; large somatic spines arranged in two zones separated by a zone of small, loosely dispersed spines; and only the anterior 36-40% of ventral side of the trunk is covered with spines. One male specimen of Corynosoma sp. was found in Patagonotothen tessellata. It differs from A. baylisi in that the distal proboscis hooks are similar in length to the prebasal hooks, it has a smaller proboscis (0.77 mm) and in the distribution of the somatic spines, which are contiguous with the genital spines on the ventral side of the trunk and lack a zone of small spines between zones of larger spines. A parasite of seals and fur seals, Corynosoma evae Zdzitowiecki, 1984, was found in P. longipes and Champsocephalus esox. It has: a proboscis 0.61-0.78 mm long; a proboscis hook formula of 20-22 rows of 12-13, including 3/4-4 basal hooks; prebasal hooks with the longest blades; a trunk divided into fore-trunk and hind-trunk; somatic spines covering the anterior 64-74% of the ventral side of the trunk; genital spines present only in males; and a terminal genital opening in both sexes. Corynosoma beaglense n. sp. was found in Champsocephalus esox. It has: an almost cylindrical proboscis (length 0.52-0.56 mm); a proboscis hook formula of 16 rows of 9/10-10/11, including 4-4/5 basal hooks; distal hooks shorter than the prebasal hooks; a fore-trunk not separated from the hind-trunk by a constriction; somatic spines contiguous with the genital spines on the ventral side of the trunk of the male and covering the entire length of the ventral side of the female trunk, and the presence of genital spines surrounding the terminal genital pore of the male. The definitive host of this species is unknown.

A new genus of monstrilloid copepods (Crustacea) with anteriorly pointing ovigerous spines and related adaptations for subthoracic brooding

Maemonstrilla gen. nov., known exclusively from females, is proposed for Monstrilla longipes A. Scott, 1909, M. turgida A. Scott, 1909, and five new species from coral reef plankton in the Ryukyu Islands, Japan: Maemonstrilla hyottoko sp. nov. (type species), M. polka sp. nov., M. spinicoxa sp. nov., M. simplex sp. nov. and M. okame sp. nov. A syntype of M. turgida was examined, but the holotype of M. longipes is lost; the latter species, being similar to several of the new species, is regarded as unidentifiable, and the identity of specimens assigned to it by several authors is put in doubt. Until now, all known female monstrilloids have had posteriorly trailing ovigerous spines, but in Maemonstrilla gen. nov. these spines point anteriorly and hold the egg mass between the legs beneath the thorax. This is the first known instance of subthoracic brooding in a planktonic copepod; its functional significance is discussed, and brooding habits of non-planktonic copepods are briefly reviewed. The intercoxal sclerites of legs 1–4 in Maemonstrilla gen. nov. are very wide, making room for the eggs. In all species except M. turgida comb. nov., the inner seta of the proximal segment of each leg ramus is either absent or reduced to a nub; this may lessen interference of the egg mass with leg movement. All species have a uniramous leg 5 with two setae, except M. turgida comb. nov. (biramous with setae on both rami); M. turgida comb. nov. is evidently the sister-group of its congeners, each sister-group in the genus being defined by additional autapomorphies. Scanning electron micrographs of all the Ryukyuan species except M. simplex sp. nov. are provided; these constitute a preliminary survey of monstrilloid integumental organs and cuticular ornamentation. Among the unusual features are two lobes at the base of the coxa in legs 1–4 of M. polka sp. nov. and M. spinicoxa sp. nov. and two pairs of posterodorsal spine-like scales on the first and second free pedigers of M. turgida comb. nov. Newly hatched nauplii of M. okame sp. nov., examined by scanning electron microscopy, are generally similar to those of Monstrilla hamatapex Grygier & Ohtsuka, 1995, but with a different mandibular structure in which the distal hook and seta clearly represent the endopod, not enditic armament of the basis. © 2008 The Linnean Society of London, Zoological Journal of the Linnean Society, 2008, 152, 459–506.

Three new species of Protogyrodactylus Johnston & Tiegs, 1922 (Monogenoidea: Dactylogyridae) from the gills of the longtail silverbiddy Gerres longirostris (Teleostei: Gerreidae) in the Red Sea

Twenty-one specimens of the longtailed silverbiddy Gerres longirostris (Gerreidae) were examined for dactylogyrid parasites from the Nabq Managed Resource Protected Area, Ras Mohammed National Park (Red Sea) near Sharm El-Sheikh, South Sinai, Egypt. The diagnosis of Protogyrodactylus Johnston & Tiegs, 1922 was amended, and three new species, P. federicae n. sp., P. zullinii n. sp. and P. alatus n. sp., were recovered and described; the prevalence of each species was 100%. P. federicae most closely resembled P. alienus Bychowsky & Nagibina, 1974, but differed from it by possessing two anteromedial projections on the ventral bar, a claw-like ventral anchor sclerite and spatulate dorsal bars. P. zullini was most similar to P. quadratus Johnston & Tiegs, 1922, from which it differed by having a distal hook on the superficial root of the dorsal anchor, an evenly curved ventral anchor shaft and point, and a flange on the bulbous base of the male copulatory organ. P. alatus was closest to P. youngi Bychowsky & Nagibina, 1974, from which it differed by having delicate anchors and two prominent anteromedial processes on the ventral bar.

A Pedicle Screw Construct Gives an Enhanced Posterior Correction of Adolescent Idiopathic Scoliosis When Compared With Other Constructs

Tricenter retrospective cohort study of 72 patients who underwent posterior correction of Lenke 1 adolescent idiopathic scoliosis (AIS). Each center represented a single surgeon using only one type of construct. Compare the initial postoperative and 2-year follow-up correction of Lenke 1 AIS curves, after accounting for the preoperative flexibility of the curves. There are multiple reports in literature of the enhanced posterior corrective ability of the pedicle screw in the treatment of AIS. Unfortunately, none of these reports took into account the preoperative flexibility of the curve. It stands to reason that rigid curves will not correct as much as flexible curves irrespective of the nature of the construct. Groups were as follows: Group 1 (proximal and distal hooks and segmental intraspinous collar button wires), 24 patients; Group 2 (proximal hooks, distal screws, and apical sublaminar wires), 23 patients; and Group 3 (pedicle screws only), 25 patients. The postoperative correction percentage was expressed as a ratio of the preoperative flexibility and was termed Cincinnati correction index (CCI). Mathematically speaking the CCI equals (postoperative correction/preoperative erect Cobb angle) divided by (supine bending preoperative correction/preoperative erect Cobb angle). The postoperative sagittal correction was also measured. CCI 2 (at 2-year follow-up) for Group 1 was 1.71, for Group 2 was 1.34, and for Group 3 was 1.41. The differences were not statistically significant. Within Group 1, however, there was a statistically significant difference between CCI (1.95) and CCI 2 (1.71), indicating a statistically significant loss of correction over 2 years. However, in terms of absolute values, there was only a 4 degree (average) difference between the initial and the 2-year postoperative Cobb measurement, rendering the loss off correction clinically insignificant. No such statistically or clinically significant differences were noted within Groups 2 and 3. Group 1 and Group 3 constructs further lordosed the curve by 8 degrees and 11 degrees, respectively, whereas the Group 2 construct retained or marginally increased the preoperative kyphosis. The Group 3 (pedicle screw only) construct did not give an enhanced correction of Lenke 1 AIS, when the preoperative flexibility of the curve was considered. Also, contrary to popular belief, the pedicle screw construct has a lordosing effect on the thoracic spine. Therefore, we think that there is no significant advantage in using a relatively expensive pedicle screw construct in the correction of Lenke 1 AIS.

Swimming and cleaning in the free‐swimming phase of Argulus larvae (crustacea, branchiura)—Appendage adaptation and functional morphology

The free-swimming early larval stages of Argulus foliaceus (Linneaus) (Branchiura) are studied using digital video, light microscopy, and SEM. We analyze and document the mode of swimming in the hatching stage of A. foliaceus and the subsequent juvenile stages with fully developed thoracopods. We present new observations and an analysis of the functional morphology of a cleaning behavior in the first stage. This stage swims very efficiently using the large exopods of the second antennae in concert with the mandibular palp (naupliar limbs), while the subsequent stages use the now developed thoracopods for propulsion. This posterior shift in propulsion is similar to--but independent from--what is seen in other crustaceans. The hatching stage has previously been referred as a "metanauplius" but as the first and second maxillae are developed and active, and buds of all four thoracopods are present, it is too advanced to be included in the naupliar phase. The hooks of the first antennae and the distal hooks of the maxillae are demonstrated to function not only as attachment organs (to the host), but also to play a significant role in the cleaning of the naupliar swimming appendages. A digital video-based analysis of the swimming mode is provided. The larval swimming pattern is generally similar to that of other crustaceans such as Branchiopoda and Cirripedia, but autapomorphies of the Branchiura include the following: 1) While actively swimming, the naupliar appendages are almost straight during the recovery stroke and 2) they have a relatively small deflection during movement ( approximately 25 degrees or approximately 35 degrees for mandible and second antenna respectively), 3) the larval mandible has a uniramous palp which is the retained exopod. The morphological implications of the transition from the possibly nonfeeding pelagic, or free-swimming, first larval stage to the feeding, parasitic second stage are discussed and compared with other crustaceans.

Surgical Treatment for Scoliosis in Marfan Syndrome

Review of results of patients with Marfan syndrome treated with instrumented posterior fusion alone for scoliosis. To analyze the results of surgical treatment for scoliosis in Marfan syndrome. Few studies have been reported in the literature on surgical treatment for scoliosis in Marfan syndrome, analyzing long-term results of posterior instrumented fusion. Twenty-three patients with Marfan syndrome with a mean age of 17 years (range, 11-31 years) were treated surgically from 1982 to 1995 for scoliosis, using a posterior instrumented fusion alone (Harrington rod with sublaminar wires in the first 16 cases, and a more recent hybrid instrumentation in the remaining 7 cases). All of the patients received a long posterior instrumented fusion, including 12.3 levels on average (range, 9-17), extending the fusion area to vertebrae that were neutral and stable in both coronal and sagittal planes before surgery. Patients were analyzed as two different groups (Group 1 and Group 2) according to the different posterior instrumentations employed: Group 1 included 16 patients treated by the Harrington distraction rod technique with sublaminar wires, while Group 2 included 7 patients treated using more recent hybrid instrumentations. Presentation features, complications, and results were analyzed. At a minimum follow-up of 7 years (maximum, 18 years), all 23 patients were reviewed. The mean age was 26.8 years (range, 20-38 years). The average preoperative scoliosis value of 69.91 degrees was initially corrected to 38.17 degrees, averaged 40.89 degrees 1 year after surgery, and was finally equal to 44.09 degrees at the last follow-up. Differences in terms of scoliosis correction achieved with different instrumentations (Groups 1 and 2) did not reach statistical significance. In Group 2 patients, the percentage of postoperative correction was slightly lower (44.23%) than that of Group 1 (46.55%) but remained more stable at the last follow-up (40.97% vs. 36.38% of Group 1). There were 11 complications in 10 of the 23 patients (43.4%); two complications occurred in 1 patient. Intraoperatively, dural tears occurred in 2 cases (8.6%). Pseudarthrosis with instrumentation failure in 2 cases (8.6%) required revision surgery. Five (21.7%) distal hook dislodgements with moderate loss of scoliosis correction, 1 (4.3%) mild loss of correction without instrumentation failure, and 1 asymptomatic cervicothoracic junctional kyphosis. did not require surgery. All complications occurred among the 16 Group 1 patients, treated using the Harrington rod instrumentation with sublaminar wires. These results seemed to demonstrate that a satisfactory stabilization of scoliosis can be achieved by posterior instrumentation alone in patients with Marfan syndrome. Instrumented posterior fusion should be extended to include vertebrae that are neutral and stable in both coronal and sagittal planes before surgery, in order to ensure stabilization of the deformity and reduce the risks of decompensation of the spine.

The precocious oncomiracidium of Neoentobdella parvitesticulata (Monogenea: Capsalidae: Entobdellinae)

The oncomiracidium (larva) of the entobdelline Neoentobdella parvitesticulata (Monogenea: Capsalidae), adults of which parasitise the skin of the stingray Himantura fai (Dasyatidae) at Heron Island, Great Barrier Reef, Queensland, Australia, is described. The larva undergoes precocious development (progenesis) in the freely deposited egg. At >600 microm long, the fully embryonated, free-swimming oncomiracidium is more than twice as long as the larva of the related species N. diadema. Furthermore, the larva of N. parvitesticulata has a total of 60 flame bulbs compared with only 18 in N. diadema. The anterior hamuli in the oncomiracidium of N. parvitesticulata have well-developed distal hooks and may already be functional for secure attachment whereas those of N. diadema are rod-shaped, have no distal hook and would be unable to function in this way in newly attached larvae.

Novel technique and instrumentation for laparoscopic application of hemostatic clips

A novel device for applying hemostatic clips in laparoscopic surgery incorporates a distal hook into a multiple-firing titanium clip applier. The hook may be used for blunt dissection of tissue, and to displace and control ducts and vessels during clip application. A single instrument may be used to achieve hemostasis in areas that are difficult to reach, and past pointing problems encountered with straight on clip appliers are alleviated. Comparative testing of the holding force of the curved clips used with this device versus the straight clips used in conventional multiple-clip appliers demonstrated a higher mean pull-off force of 0.473 lbs versus 0.33 lbs. Clinical application of the device in laparoscopic procedures including cholecystectomy, vaginal hysterectomy, Nissen fundoplication, vagotomy, varicocelectomy, and lymphadenectomy show the utility of the hook clip applier.

A caliper-hook for strabismus surgery.

An instrument to assist in resection surgery consists of a telescoping hook within a second hook that can be spread a calibrated distance. Its primary purpose is to maintain a constant tension and an accurate measure of tendon length during suture passage. Additionally, the grooved distal hook supports the needle and protects the globe from needle trauma.

Lumbosacral Fusions with Harrington Rods and Intersegmental Wiring

Harrington rods are a valuable adjunct for fusion of the lumbosacral spine. Major limits of distractions are achieved with these rods. Greater amounts of decompression are possible. Decompression, alignment, and stability are maintained. Intersegmental wiring increases security and eliminates the problem of hook and rod displacement and loss of lumbar lordosis. A variety of methods are available for sacral fixation to avoid neurologic complications from the distal hooks. Three- and four-level Harrington rod distraction lumbosacral fusions have proven to be successful in returning severely-disabled spinal stenotic, obese, and osteoporotic patients to normal activities.

A new method for continuous intraoperative measurement of Harrington rod loading patterns.

A new method has been developed for continuous intra-operative monitoring of bone and implant loading patterns in the operative correction of scoliosis using the Harrington distraction rod. The method incorporates a strain gauge instrumented, distal Harrington hook and similarly equipped Harrington operating instruments (outrigger and distractor). These latter instruments are used to calibrate the hook's response to bone loads under existing operative conditions. Alternative methods of monitoring loading patterns were explored and rejected because they were noncontinuous, more difficult to use, altered the mechanics of the system, or required more expensive components. The method established is being used to avoid bone rupture or rod damage while gaining maximum spinal correction and to determine the effect of auxiliary implant components on loading patterns.

LONG-TERM ANATOMIC AND FUNCTIONAL CHANGES IN PATIENTS WITH ADOLESCENT IDIOPATHIC SCOLIOSIS TREATED BY HARRINGTON ROD FUSION

One hundred patients from the Gothenburg Scoliosis Data Base were studied. They met the following criteria: (1) adolescent idiopathic scoliosis (2) completion of treatment before age 20, (3) a minimum follow-up of five years thereafter, (4) a minimum age of 22 years at final follow-up, and (5) operation performed by the senior author. Of these, 95 were personally examined. The surgical technique from 1968 to 1973 included a two-stage Harrington distraction, with fusion added at the second operation (52 patients). From 1973 to 1975, 48 patients were treated with a one-stage distraction and fusion after a week of preoperative Cotrel traction. Postoperatively, all patients were treated with a Milwaukee brace. A spinal examination and functional assessment, including a questionnaire and pain drawing, full standing anterior-posterior (AP), and lateral roentgenograms of the spine, was performed by independent observers. Eighty-five subjects without scoliosis served as a control group. The radiographic evaluation showed the usual nearly 50% permanent correction at the follow-up examination averaging nine years postoperatively. Lateral roentgenograms, however, demonstrated in 52% flattened or kyphotic cervical spines producing no significant complaints, non-significant flattening of the thoracic kyphosis, but significant lowering of the lumbar lordosis. Fifteen of the 24 patients with distal hook insertion and fusion including L4 or L5 demonstrated retrolisthesis. All had significant low-back pain. Degenerative facet joint changes and disc space narrowing was noted in 11 patients, again with a distal hook purchase in L4 or L5. Compared to the controls, the operated patients, as a group, revealed no lessened activity or back pain at any location.(ABSTRACT TRUNCATED AT 250 WORDS)

Long-Term Anatomic and Functional Changes in Patients with Adolescent Idiopathic Scoliosis Treated by Harrington Rod Fusion

One hundred patients from the Gothenburg Scoliosis Data Base were studied. They met the following criteria: (1) adolescent idiopathic scoliosis (2) completion of treatment before age 20, (3) a minimum follow-up of five years thereafter, (4) a minimum age of 22 years at final follow-up, and (5) operation performed by the senior author. Of these, 95 were personally examined. The surgical technique from 1968 to 1973 included a two-stage Harrington distraction, with fusion added at the second operation (52 patients). From 1973 to 1975, 48 patients were treated with a one-stage distraction and fusion after a week of preoperative Cotrel traction. Postoperatively, all patients were treated with a Milwaukee brace. A spinal examination and functional assessment, including a questionnaire and pain drawing, full standing anterior-posterior (AP), and lateral roentgenograms of the spine, was performed by independent observers. Eighty-five subjects without scoliosis served as a control group. The radiographic evaluation showed the usual nearly 50% permanent correction at the follow-up examination averaging nine years postoperatively. Lateral roentgenograms, however, demonstrated in 52% flattened or kyphotic cervical spines producing no significant complaints, non-significant flattening of the thoracic kyphosis, but significant lowering of the lumbar lordosis. Fifteen of the 24 patients with distal hook insertion and fusion including L4 or L5 demonstrated retrolisthesis. All had significant low-back pain. Degenerative facet joint changes and disc space narrowing was noted in 11 patients, again with a distal hook purchase in L4 or L5. Compared to the controls, the operated patients, as a group, revealed no lessened activity or back pain at any location.(ABSTRACT TRUNCATED AT 250 WORDS)

An introducer to facilitate nasotracheal intubation.

An introducer to facilitate nasotracheal intubation is described. The instrument is passed orally and a distal hook engages in the Murphy foramen of a P.V.C. nasal tube to direct it atraumatically into the trachea.