Cross Suture Research Articles

Biomechanical Comparison of a Horizontal Mattress, Cross Suture and Vertical Mattress for Repair of a Tendon Weave in a Porcine Model.

Background: An effective suture method enables early active motion exercises and optimal post-surgical outcomes. The aim of this study is to evaluate the tensile strength of three suture configurations - horizontal mattress (HM), vertical mattress (VM) and a cross suture for repair of a tendon weave. We hypothesised that the direction of mattress sutures relative to the tendon fibres would affect the tensile strength of tendon repair. Methods: Using porcine flexor tendons and the same number of surgical sutures, three tendon weave constructs differing in the method of suture were compared: HM suture configuration (conventional technique), cross-stitch (CS) configuration (conventional technique) and VM suture configuration (novel technique). Ten pairs of each group were mounted in a material testing machine and subjected to a simple tensile test and a cyclic loading test for their biomechanical comparison. Results: The VM group and CS group had significantly higher ultimate failure load, linear stiffness and fatigue strength as compared to the HM group. The failure mode was suture breakage or tendon rupture for the VM and the CS group, while the suture pullout of the tendon only occurred in the HM group. Conclusion: Among the three techniques used for repair of a tendon weave, the VM suture technique was demonstrated to have the greatest tensile strength and least associated with suture pull-out. The direction of the mattress suture in relation the direction of tendon fibres affects the strength of repair.

Biomechanical Analysis of Four Suturing Techniques for Radial Meniscal Tears Demonstrated the Advantage of the Cross-Tie Grip Suture

Objectives:The “Tie Grip suture” was designed to fix radial meniscal tears more rigidly than simple conventional sutures. However, one shortcoming was residual gapping at the central margin of the tear. We modified the original method to address this point and named it the “Cross Tie Grip suture”. The purpose of this study was to perform biomechanical tests to compare suture strength and stability between four suturing techniques; the original “Tie Grip suture”, the “Cross Tie Grip suture” and two conventional suture methods, the double horizontal and cross sutures. It was hypothesized that the Cross Tie Grip suture will show the least displacement and resist the greatest maximum load.Methods:Forty fresh-frozen porcine knees were dissected to acquire 80 menisci. 20 menisci were tested in each group: original Tie Grip, Cross Tie Grip, double horizontal, and cross suture groups. A radial tear was created from the central margin to 2 mm to the menisco-capsular junction at the middle third of the meniscal body, equidistance from the anterior and posterior horns. Suture configurations are shown in Figure 1. The sutured menisci were set in a custom clamp, with a metric ruler positioned parallel to the clamp to serve as a measurement scale. All menisci underwent preconditioning from 5 to 20 N for 300 cycles at 0.5 Hz. Subsequently, submaximal loading was performed for 500 cycles from 5 to 20 N at 1 Hz. The cycle was paused at cycles 0, 100, 250, and 500 for digital photographs to be taken under a 5 N load. An image processing software (ImageJ; US National Institutes of Health) was utilized to analyze the digital photographs for gap measurement. Load to failure testing was done at 5 mm/min and failure mode was recorded. An a priori power analysis based on preliminary experiments with statistical power of 80%, and significance set at .05, sample size required was at least 18 per group. The data was analyzed by one-way analysis of variance and Tukey-Kramer post hoc test. P-values <0.05 were considered statistically significant.Results:Displacement after 500 submaximal cycles was significantly small in the Cross Tie Grip suture group (0.4 ± 0.3 mm) compared to the 3 other suture methods (Table 1). Displacement was, 0.9 ± 0.6 mm, 1.2 ± 0.7 mm, 1.4 ± 0.6 mm (P < .05) for Tie Grip, double horizontal, and cross suture groups, respectively. Maximum failure load was significantly greater in the Cross Tie Grip (154.9 ± 29.0N) and Tie Grip (145.2± 39.1N) groups compared to the double horizontal (81.2±19.9N) and cross suture (87.3±17.7N) groups (P < .05) (Table 1). Tissue failure was the most common mode of failure in all groups.Conclusions:The Cross Tie Grip suture showed greater resistance to displacement compared to the original method and both conventional methods, the double horizontal and cross sutures. In respect to maximum load, the Cross Tie Grip suture was equivalent to the original method. Both Tie Grip sutures showed greater maximum load compare to the other conventional sutures; double horizontal and cross.Table 1.Ultimate load and submaximal load data. Ultimate failure load was significantly greater in the Cross Tie Grip and Tie Grip groups compared to the double horizontal and cross suture groups. Gapping was significantly small in the Cross Tie Grip and Tie Grip groups compared to the double horizontal and cross suture groups. Displacement after 500 cycles was significantly small in the Cross Tie Grip group. Original tie grip Cross tie grip Double horizontal Cross Ultimate failure load (N)145.2 ± 39.1154.9 ± 29.081.2 ± 19.987.3 ± 17.7Gapping after cyclic load (mm)0 cycles1.2 ± 0.70.7 ± 0.51.7 ± 1.02.4 ± 1.2100 cycles1.6 ± 0.80.1 ± 0.72.2 ± 1.12.8 ± 1.4250 cycles1.8 ± 0.81.2 ± 0.72.5 ± 1.23.4 ± 1.5500 cycles2.1 ± 0.81.3 ± 0.72.9 ± 1.63.8 ± 1.6Displacement after 500 cycles (mm)0.9 ± 0.60.4 ± 0.41.2 ± 0.71.4 ± 0.6

Radial Meniscal Tears Are Best Repaired by a Modified "Cross" Tie-Grip Suture Based on a Biomechanical Comparison of 4 Repair Techniques in a Porcine Model.

Background:The tie-grip suture can fix radial tears more rigidly than simple conventional sutures. However, one shortcoming is the residual gap at the central margin of the tear. The tie-grip suture was modified to address this issue and named the “cross tie-grip suture.”Purpose/Hypothesis:The purpose of this study was to compare the suture stability and strength among 4 suturing techniques: the original tie-grip, cross tie-grip, and 2 conventional sutures (double horizontal and cross). It was hypothesized that the cross tie-grip suture would show the least displacement and resist the greatest maximum load.Study Design:Controlled laboratory study.Methods:A total of 40 fresh-frozen porcine knees were dissected to acquire 80 menisci; 20 menisci were tested in each suture group. A radial tear was created at the middle third of the meniscal body. Repair was performed with the following: original tie-grip, cross tie-grip, double horizontal, and cross sutures. The mechanical strength of sutured menisci was evaluated using a tensile testing machine. All menisci underwent submaximal loading and load to failure. The gap distance and ultimate failure load were compared using analysis of variance. The failure mode was recorded after load-to-failure testing.Results:Displacement after 500 cycles was significantly smaller in the cross tie-grip group (0.4 ± 0.3 mm) compared with the tie-grip (0.9 ± 0.6 mm), double horizontal (1.2 ± 0.7 mm), and cross suture groups (1.4 ± 0.6 mm) (P < .05). The ultimate failure load was significantly greater in the cross tie-grip (154.9 ± 29.0 N) and tie-grip (145.2 ± 39.1 N) groups compared with the double horizontal (81.2 ± 19.9 N) and cross suture groups (87.3 ± 17.7 N) (P < .05). Tissue failure was the most common mode of failure in all groups.Conclusion:Upon repair of radial meniscal tears, the cross tie-grip suture showed less displacement compared with that of the tie-grip, double horizontal, and cross sutures and demonstrated equivalent load to failure to that of the tie-grip suture at time zero.Clinical Relevance:The cross tie-grip suture provided high resistance to displacement after repair of radial tears and may be advantageous in healing for radial meniscal tears.

Utility of Cross Suture Technique For Stabilize The Intraocular Lens Against Vitreous Pressure During Penetrating Re-Keratoplasty: Case Report

Utility of Cross Suture Technique For Stabilize The Intraocular Lens Against Vitreous Pressure During Penetrating Re-Keratoplasty: Case Report

Cross suture closure technique of the perineal wound following abdominoperineal resection

The aim of this study is to introduce a new type of cross suture in closing peritoneal incision after abdominoperineal resection (APR) for rectal cancer. This new type of cross suture was firstly proposed and applied in a small cohort in our hospital. In this study, we reported its efficacy and safety. From Feb 2018 to May 2018, 8 cases (5 male, 3 female) of rectal cancer from the Sixth Affiliated Hospital of Sun Yat-Sen University receiving APR with new cross suture, were analyzed retrospectively. The median age was 45.5 years and the median distance between tumor distant border and anal verge was 2.5 cm. Three patients received neoadjuvant therapy. The detailed procedures of new cross suture are listed as follows: (1)Marking the margin: an oval circle around the anus is designed. The anterior incision reaches middle peritoneum, and the posterior incision is close to the coccyx apex. Two triangle incisions are made at the 3 and 9 point directions of lithotomy position, respectively. (2)Tumor resection: purse string suture is made to close the anus, then cut open the peritoneal skin and fatty tissue according to the principles of total mesorectal resection(TME). Reserve the fatty tissue in the ischiorectal space as much as possible. R0 resection is required. Approximate the pelvic muscles and fatty tissue in the ischiorectal space to reduce residual cavity; (3)Close the peritoneal incision by absorbable stitch: Two intracutaneous stiches in the anterior and posterior parts of the incision are made. Then four intracutaneous circle stiches along the two triangles are performed. The incision appears like a "cross" after tighting these stiches. A drainage was placed in presacral space. All procedures were successfully conducted in 8 cases and no severe complication occurred after surgery. The median volume of whole surgery bleeding was 100 ml and the median time of the peritoneal surgery was 50 minutes. The median volume of drainage was 95 ml in the first 3 postoperative days. The median time of drainage removal was 5 days. Seven cases received primary wound healing without superficial(wound infection and dehiscence) or deep perineal wound(perineal abscess and presacral abscess) complications. Presacral abscess occurred in one case. The median time of primary wound healing was 11 days. The new cross suture for perineal incision after APR procedure is simple with satisfying efficacy. The drainage of residue cavity in the presacral space is complete. The cross suture reduces the time of primary wound healing and decreases scars.

Irreversible changes occurring in long-term denervated Schwann cells affect delayed nerve repair.

OBJECTIVE Multiple factors may affect functional recovery after peripheral nerve injury, among them the lesion site and the interval between the injury and the surgical repair. When the nerve segment distal to the lesion site undergoes chronic degeneration, the ensuing regeneration (when allowed) is often poor. The aims of the current study were as follows: 1) to examine the expression changes of the neuregulin 1/ErbB system during long-term nerve degeneration; and 2) to investigate whether a chronically denervated distal nerve stump can sustain nerve regeneration of freshly axotomized axons. METHODS This study used a rat surgical model of delayed nerve repair consisting of a cross suture between the chronically degenerated median nerve distal stump and the freshly axotomized ulnar proximal stump. Before the suture, a segment of long-term degenerated median nerve stump was harvested for analysis. Functional, morphological, morphometric, and biomolecular analyses were performed. RESULTS The results showed that neuregulin 1 is highly downregulated after chronic degeneration, as well as some Schwann cell markers, demonstrating that these cells undergo atrophy, which was also confirmed by ultrastructural analysis. After delayed nerve repair, it was observed that chronic degeneration of the distal nerve stump compromises nerve regeneration in terms of functional recovery, as well as the number and size of regenerated myelinated fibers. Moreover, neuregulin 1 is still downregulated after delayed regeneration. CONCLUSIONS The poor outcome after delayed nerve regeneration might be explained by Schwann cell impairment and the consequent ineffective support for nerve regeneration. Understanding the molecular and biological changes occurring both in the chronically degenerating nerve and in the delayed nerve repair may be useful to the development of new strategies to promote nerve regeneration. The results suggest that neuregulin 1 has an important role in Schwann cell activity after denervation, indicating that its manipulation might be a good strategy for improving outcome after delayed nerve repair.

Chronically denervated distal nerve stump inhibits peripheral nerve regeneration.

Chronically denervated distal nerve stump inhibits peripheral nerve regeneration.

Transcurrent nature of the Teisseyre–Tornquist Zone in Central Europe: results of the POLCRUST-01 deep reflection seismic profile

Teisseyre–Tornquist Zone (TTZ) corresponds to a crustal boundary between the Precambrian East European Platform (EEP) and the Palaeozoic West European Platform. Although the zone has been controlling Phanerozoic evolution of large parts of Central Europe, its course, geometry and origin are still poorly constrained. Deep reflection seismic profile POLCRUST-01, recently acquired in SE Poland, for the first time allowed a precise comparison of the Ediacaran and later tectonic patterns to the deep crustal features of the TTZ and adjacent areas. The TTZ corresponds to the subvertical Tomaszow Fault separating the Radom–Kraśnik Elevation, composed of the typical EEP crust, from the Bilgoraj–Narol Block (BNB) in the SW, with a thinned crystalline basement showing affinities to the EEP crust. The BNB is a part of the larger Caledonian Łysogory Terrane as evidenced by its Lower Palaeozoic stratigraphy and gravity data. Thus, for the first time, the proximal Baltican affinity of this unit has been documented unambiguously. The Łysogory Terrane is delimited from the SW by the subvertical Cieszanow Fault Zone, corresponding to the Holy Cross Suture. The adjacent Malopolska Terrane is characterized by a distinct Early Palaeozoic stratigraphy, and lower-middle crust exhibiting SW-dipping reflective packages interpreted as NE-verging thrust and shear zones of a Neoproterozoic orogen. The observations from the POLCRUST-01 profile and regional comparisons indicate that the TTZ is a major Caledonian transcurrent zone between Poland and East Romania. In central Poland, the TTZ likely forms a narrow subvertical contact between the EEP and a proximal Kuiavia Terrane, as constrained by the deep refraction seismic data. To the NW, the zone extends towards the Pomeranian part of the Caledonide fold-and-thrust belt related to the Avalonia–Baltica collision zone (Thor Suture). South-east of Poland the TTZ corresponds to the Rava Ruska Fault Zone established as a Caledonian suture separating adjacent terrane, probably of a Baltican affinity. The East Romanian part of the TTZ conforms with the Sfântu Gheorghe Fault separating reworked EEP crust of the Pre-Dobrogean Depression from the North Dobrogea unit bearing a strong Variscan and Cimmerian overprint.

Riparazione Trans-Vaginale di Fistola Neovescico-Vaginale

Introduction Neobladder vaginal fistula is a known complication after cystectomy and orthotopic neobladder in women. The exact incidence is still unknown, even if in some of the largest series is reported in about 5% of female patients. We present our personal experience with a case of neobladder vaginal fistula. Methods A fifty-year old woman affected by T2G3 bladder cancer underwent radical cystectomy and orthotopic neobladder in December 2007. Definitive pathological examination revealed pT3aN0G3 urothelial cancer with squamous aspects. Two cycles of neoadjuvant chemotherapy were administered before cystectomy. Three weeks after cystectomy, a retrograde cystography revealed a fistula between vagina and neobladder. At first, the patient was treated conservatively, keeping the urethral catheter for two months. Cystographies, repeated every month, recorded a reduction in size of the fistula but not the complete closure. A surgical correction was planned. Preoperative cystoscopy showed the neobladder opening of the fistula on the posterior wall. Then a transvaginal approach with fistula excision and a two layer cross suture were performed. Results At the cystography performed 1 month after surgical repair no fistula was detected, and the patient was completely dry. At 3 months follow-up the patient was completely dry. Conclusion The development of a neobladder-vaginal fistula is a significant, even if infrequent, complication after cystectomy. In our case, we performed a transvaginal approach without tissue interposition, with good results. Such procedure is easy and effective and, in our opinion, can be tempted as first line surgical treatment.

In vitro biomechanical comparison of three different types of single- and double-row arthroscopic rotator cuff repairs: Analysis of continuous bone-tendon contact pressure and surface during different simulated joint positions

We assessed bone-tendon contact surface and pressure with a continuous and reversible measurement system comparing 3 different double- and single-row techniques of cuff repair with simulation of different joint positions. We reproduced a medium supraspinatus tear in 24 human cadaveric shoulders. For the 12 right shoulders, single-row suture (SRS) and then double-row bridge suture (DRBS) were used. For the 12 left shoulders, DRBS and then double-row cross suture (DRCS) were used. Measurements were performed before, during, and after knot tying and then with different joint positions. There was a significant increase in contact surface with the DRBS technique compared with the SRS technique and with the DRCS technique compared with the SRS or DRBS technique. There was a significant increase in contact pressure with the DRBS technique and DRCS technique compared with the SRS technique but no difference between the DRBS technique and DRCS technique. The DRCS technique seems to be superior to the DRBS and SRS techniques in terms of bone-tendon contact surface and pressure.

The neurotrophin receptors, trkB and p75, differentially regulate motor axonal regeneration.

Neurotrophic factors that support neuronal survival are implicated in axonal regeneration after injury. Specifically, a strong role for BDNF in motor axonal regeneration has been suggested based on its pattern of expression after injury, as well as the expression of its receptors, trkB and p75. Despite considerable in vitro evidence, which demonstrate specific and distinct physiological responses elicited following trkB and p75 activation, relatively little is known about the function of these receptors in vivo. To investigate the roles of the trkB and p75 receptors in motor axonal regeneration, we have used a tibial (TIB)- common peroneal (CP) cross suture paradigm in p75 homozygous (-/-) knockout mice, trkB heterozygous (+/-) knockout mice, as well as in their wild-type controls. Contralateral intact TIB motoneurons, and axotomized TIB motoneurons that regenerated their axons 10 mm into the CP distal nerve stump were identified by fluorescent retrograde tracers and counted in the T11-L1 spinal segments. Regeneration was evaluated 2, 3, 4, 6, and 8 weeks after nerve repair. Compared to wild-type animals, there are significantly fewer intact TIB motoneurons in p75 (-/-), but not trkB (+/-) mice. The number of motoneurons that regenerated their axons was significantly increased in the p75 (-/-) knockout mice, but significantly attenuated in the trkB (+/-) mice compared to wild-type controls. These results suggest that p75 is important for motoneuronal survival during development, but p75 expression after injury serves to inhibit motor axonal regeneration. In addition, full expression of trkB is critical for complete axonal regeneration to proceed.

Two year follow-up of astigmatism after phacoemulsification with adjusted and unadjusted sutured versus sutureless 5.2 mm superior scleral incisions

Purpose: To evaluate changes in astigmatism 6 months to 2 years after 5.2 mm superior scleral incision phacoemulsification using 3 closures.Setting: Department of Ophthalmology, Vejle Hospital, Vejle, Denmark.Methods: This long-term follow-up study included 75 consecutive phacoemulsification patients who were randomly allocated to 1 of 3 incision closures: 1 intraoperatively adjusted cross suture, 1 unadjusted cross suture, no suture. Postoperative astigmatism after 1 and 2 years was evaluated by keratometric cylinder, induced astigmatism (Naeser's polar values), induced cylinder (Jaffe's vector analysis), and vector decomposition (Olsen). The data were compared with 1 week values.Results: In the previous study, median astigmatism after 6 months was similar in all 3 groups, but only the sutureless group showed early stability. Significant againstthe-rule (ATR) changes were seen in the sutured cases (P < .01). The 1 and 2 year follow-up showed continued stability in the sutureless cases. The adjusted-suture group exhibited stability after 6 months, while the unadjusted-suture group showed a further tendency to change ATR. At 2 years, median ranges of astigmatism were -0.49 to -0.90 diopter (D) (Naeser), 0.77 to 1.02 D (Jaffe), and 96% to 98% ATR (Olsen). The intergroup differences were not statistically significant.Conclusion: Two year follow-up confirmed that sutureless closure led to early astigmatism stability. Using a suture prolonged the postoperative period of astigmatism instability, and if used without intraoperative adjustment, a tendency toward a less predictable outcome persisted after 2 years.

Astigmatism after phacoemulsification with adjusted and unadjusted sutured versus sutureless 5.2 mm superior scleral incisions

Purpose: To evaluate changes in astigmatism in the first 6 months after 5.2 mm superior scleral incision phacoemulsification using three different closures.Setting: Department of Ophthalmology, Vejle Hospital, Denmark.Methods: This study comprised 75 consecutive patients who had 5.2 mm superior scleral incision phacoemulsification. Patients were randomly assigned to one of three groups based on type of incision closure: Group 1, one intraoperatively adjusted cross suture; Group 2, one unadjusted cross suture; Group 3, no suture. Inclusion criteria were preoperative astigmatism of 2.00 diopters (D) or less (range of median 0.74 to 0.81 D) and no eye disease except cataract. Postoperative astigmatism was evaluated by keratometric cylinder, induced astigmatism (Naeser), and induced cylinder (Jaffe) on the first day and after 1 week and 1, 3, and 6 months. Time before stability was estimated.Results: All groups had the same level of postoperative keratometric cylinder with no significant change between 1 week and 6 months (range of median 0.81 to 1.06 D). The groups reached the same level of induced astigmatism (Naeser) 3 to 6 months after surgery (range of median −0.44 to −0.64 D). Group 3 (sutureless) reached that value after 1 week, and induced astigmatism was stable thereafter. Both sutured groups (Groups 1 and 2) had a highly significant change between the first week and third month (P < .01). There were no significant intergroup differences in induced cylinder (Jaffe), which stabilized after 1 week in Groups 1 and 2 and after 1 month in Group 3 (range of median 0.61 to 0.87 D). During the early postoperative period, variation was highest in Group 2.Conclusions: Keratometric cylinder, induced astigmatism, and induced cylinder 3 to 6 months postoperatively were similar among the three groups, but early stability was only seen in the sutureless group. If a suture is used, intraoperative adjustment seems to result in lower variations in the early postoperative period.

Bloom Thinning `Loadel' Cling Peach with a Surfactant

Hand thinning fruit is required every season to ensure large fruit size of `Loadel' cling peach [Prunus persica (L.) Batsch] in California. Chemical thinning may lower costs of hand thinning. A surfactant, Armothin {[N,N-bis 2-(omega-hydroxypolyoxyethylene/polyoxypropylene) ethyl alkylamine]; AKZO-Nobel, Chicago; AR}, was sprayed at 80% of full bloom (FB), FB, and FB + 3 days. The spray volume was 935 liters/ha. Concentrations of AR were 1%, 3%, and 5% (v/v). An early hand thinning in late April, a normal hand thinning at 13 days before standard reference date (early May), and a nonthinned control were compared to bloom-thinned trees for set, yield, and fruit quality. AR resulted in no damage to fruit; however, slight leaf yellowing and burn and small shoot dieback were seen at the 5% concentration. Fruit set, and therefore, the number of fruit that had to be hand thinned, were reduced with 3% AR applied at 80% FB and 5% AR applied at all bloom phenophases (stages of bloom development). Thinning time was reduced by 37% (5% AR applied at 80% FB), 28% (5% applied at FB), and by 20% (3% applied at 80% of FB), compared to the normally hand-thinned control. Although AR resulted in early size (cross suture diameter and weight) advantages, at harvest there were no significant differences in fruit size among all AR treatments and the normally hand-thinned control. Total and salable yields of AR treatments and the normally hand-thinned control were equal. Armothin shows promise for chemical thinning of peach when used as a bloom thinner.

A CASE OF PRIMARY LEIOMYOSARCOMA IN THE INFERIOR VENA CAVA

A 41-year-old woman was admitted to our hospital with the chief complaints of right lower abdominal pain andedema in the lower extermities. The diagnosis of gallstone disease associated with a retroperitoneal tumor of the infiltrated range was was made by using ultrasonography, computed tomography angiography. Primary tumor in the inferior vena cava or invasion of retroperitoneal tumor was suggested by postcavarography and magnetic resonanse imaging test. First of all, cholecystectomy was performed because of the complication of cholelithiasis. The tumor was a yellowish-white massive one with approx. 6 cm in diameter sitting to the lower surface of the liver, and internal and upper regions of the right kidney, and existed so as to eject from the inferior vena cava. The combined resection of the right kidney was performed, because resections of the partial postcaval walls and the tumor, and its ablastions were difficult. The double lineserial cross suture of the amputation stump of the inferior vena cava was carried out. The chemotherapy was concomitantly used as an auxotherapy. The postoperative couse was favorable, and the patient is under observation on ambulatory basis as of now progressed for 4 months. Eighteen cases of primary leiomyosarcoma in theinferior vena cava including this case have been reported in our country so faras we studied, and we also presented a discussion of some references because of its seldom occurrence.

Long-lasting behavioral and dendritic spine deficits in the monocularly deprived albino rat

Monocular deprivation in the rat from the time of normal eye opening until 45 days of age significantly reduces the density of dendritic spines in visual cortex contralateral to the deprived eye. In addition, these animals are severely impaired in their ability to discriminate complex visual pattern using the deprived eye. In the present experiment we tested the ability of monocularly deprived rats to recover from these deficits if given 30 days of visual experience with the deprived eye beginning at 45 days of age. Animals to be tested behaviorally were trained to discriminate between columns and rows of 5-mm squares. We found that rats cross-sutured at 45 days of age and given 30 days of visual experience with the deprived eye were not significantly different from animals who began training within 2 days of cross suture. Both groups were significantly impaired in the acquisition of this discrimination relative to animals trained using their nondeprived eye. Two groups of animals were examined to assess the effects of 30 days of experience on dendritic spine density in the deprived hemisphere. One group was killed immediately at 45 days of age, the other group had the deprived eye opened at that time and then had 30 days of visual experience prior to killing. No significant recovery in spine density was found. These results have implications for a possible structure-function relationship between dendritic spines and visual behavior in the rat.

Experiments on the restoration of paralysed muscles by means of nerve anastomosis. Part II.—Anastomosis of the nerves supplying limb muscles

The part of the research into the anastomosis of nerves dealt with in this paper has reference to the restoration of function of a group of muscles in the limb. Following the early experiment of Flourens, several workers (Rawa, Stefani, Howell and Huber, Cunningham, and the author) published investigations on the effects of nerve crossing, or the division of two nerves in the limb and cross suture of the ends.