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PubMed1997

TGF-beta 1, TGF-beta 2, and TGF-beta 3 exhibit distinct patterns of expression during cranial suture formation and obliteration in vivo and in vitro.

Cranial sutures function as bone growth centers while themselves remaining unossified. Rat frontonasal sutures become obliterated by neonatal day 21 (N21), while coronal sutures do not fuse over the life of the animal. Coronal sutures induced to undergo osseous obliteration in vitro after removal of the dura mater were found to require soluble, heparin-binding factors present in dura mater to resist osseous obliteration. Transforming growth factor beta 1 (TGF-beta 1), beta 2, and beta 3, heparin-binding factors known to regulate bone cell proliferation and differentiation, were considered likely candidates. The presence and distribution of these factors in calvarial tissues both in vivo and in vitro were established by immunohistochemical analysis, while reverse transcription followed by polymerase chain reaction (RT/PCR) was employed to determine the presence of transcripts for these factors in mRNA isolated from microdissected dura mater. Results indicated that the presence of TGF-beta 1 and TGF-beta 2 were associated with developing coronal and frontonasal sutures, and that the continued presence of these factors was associated with osseous obliteration of the frontonasal suture. However, increased TGF-beta 3 immunoreactivity was associated with the coronal suture remaining unossified. RT/PCR demonstrated the presence of transcripts for TGF-beta 1, beta 2, and beta 3 in dural tissues isolated from rat calvaria. These data support the notion of a role for TGF-beta s in regulating cranial suture morphogenesis and establish the in vitro model as a valid system for examining mechanisms by which growth factors regulate both suture morphogenesis and bone growth at the suture site.

Animals↗
PubMed2005

[Experimental model of laparoscopic handsewn suture in colon of dogs].

PURPOSE: Develop an experimental model of laparoscopic hand-sewn suture in colon of dogs to be specially used for surgeons' training. METHODS: Forty male dogs were operated on, weight between 15 and 20 kg, from the laboratory of the Veterinary School of the State University of Ceara. They were distributed within two groups with 20 animals each: GI--The colonic wall incision was done with an electrical scalpel followed by haemosthasia and GII--The colonic wall incision was performed with a scissors. Each group was shared in two other groups with 10 animals each, according to the abdominal approach used. A-Laparotomic approach and B-Laparoscopic approach. Under intra-venous general anesthesia, a transverse incision was performed envolving 50% of the sigmoid wall, 15 cm far from the pelvic peritoneal pouch, followed by an extra-mucosa, one layer and interrupted suture with 000 polydioxanona (PDSâ). The animals were evaluated concerning to the clinical recovery, macroscopic appearance, suture-tension test and histologic study. The animals were sacrificed on the 7th postoperative day. Fisher and Qui-square tests were used for statistical analysis. RESULTS: All the animals submitted to colotomy performed by scissor (GIIA, GIIB) and nine animals operated on with an electrical scalpel (GI), five (50.0%) by laparotomic approach (GIA) and four (40.0%) laparoscopically (GIB) had a satisfactory clinical recovery, walking and accepting oral diet on the first post-operative day. The first bowel movement occurred between 48 and 72 hours. It didn't occur diarrhea or vomits. Eleven animals from group I, five (50%) from group IA and six (60.0%) from group IB didn't accept oral diet and complained of diarrhea (3 to 5 evacuations each day), 1 to 3 episodes of vomits each day and they die between the fourth and seventh postoperative day. Comparing groups GI with GII, a statistical significant difference was observed (p<0.005). There was no difference between GIA and GIB. Colonic sutures were intact in all the animals from group II and in five from group I with statistical significant difference (p<0.005). Three (30.0%) were from group IA and two (20.0%) from group IB. The colonic suture was envolved by epiploon in four animals, two (20%) from GIA and 2 (20%) from GIB. Suture dehiscence with peritonitis occurred in eleven (55%) animals from GI (p<0.005), five (50%) from GIA and six (60%) from GIB (p>0.005). All the animals died between the fourth and seventh postoperative day. The tension suture test was performed with an average pressure of 222,1 mmHg and there was no colonic suture disruption in any animal from the group II and in five (40.0%) from the group I (p<0.005). Three (30%) animals were from GIA and two (20.0%) from GIB (P>0.005). Colonic suture rupture occurred in four (20%) dogs from group I, two from GIA and two (20%) from GIB with an average pressure of 94.0 mmHg. The histological analysis of the surgical specimens removed on the 7th postoperative day demonstrated the same level of the inflammatory process in both approach used. CONCLUSION: The handsewn laparoscopic colonic suture in dogs can be safely performed, showing the same results of the laparotomic approach. The surgical results depend specially on the adequate surgeon's training in laparoscopic surgical technique.

Animals↗
PubMed2000

The load-displacement characteristics of neonatal rat cranial sutures.

OBJECTIVE: Recently several centers have attempted to distract the craniofacial skeleton in infants with craniosynostosis. To effectively achieve this goal, we must first understand the normal sutural response to tensile forces. The objective of this study was to determine the load-displacement characteristics of neonatal rat sutures. METHODS: Thirty cranial sutures were harvested from 1-week-old Wistar rats (10 each coronal, posterior frontal, and sagittal). The width of the harvested bone-suture-bone construct was standardized to 4 mm. The specimens, kept moist, were mounted fresh and distracted at 10 microm/sec until rupture using a Vitrodyne V1000 universal tester. Standard load-displacement curves were constructed. The stiffness, defined as tensile force/change in suture length, and the ultimate stress, defined as tensile force at suture rupture/cross sectional area, were calculated. RESULTS: These sutures demonstrated classical viscoelastic behavior. During the elastic phase, they elongated approximately 1 microm for every 1 g of force (10(4) N/m). The ultimate tensile stress was approximately 4 MN/m2. The estimated mean elastic modulus was 10 megapascals. The posterior frontal sutures were significantly less stiff than the other two sutures (Kruskal-Wallis nonparametric analysis of variance, p = .0023). The difference in the ultimate stress was also significant (p = .0201). CONCLUSIONS: This study provides data regarding the basic mechanical behavior of neonatal cranial sutures in a mammalian system.

Analysis of Variance↗
PubMed1989

[Morphological studies on the margo infraorbitalis (on the longitudinal changes of infraorbital suture)].

The purpose of this study was to obtain information on the developmental changes of the infraorbital margin and the form of infraorbital suture. 136 Indian craniums were divided into five developmental groups according to the stage of eruption of the teeth. The anterior view of the skull was observed photographically. The results are summarized as follows: 1. The infraorbital margins were divided into three types according to the shape of the infraorbital suture. Type I: Infraorbital suture was independent. Type II: Infraorbital suture and zygomatico-facial suture coincided. Type III: Infraorbital suture and zygomatico-facial suture were joined. Type I was the basic type of infraorbital suture. 2. The frequency of type I was 90% at the pre-eruption stage, 31.8% at the eruption stage, 41.7% at the deciduous dentition stage, 56.3% at the mixed dentition stage, and 62% at the permanent dentition stage. 3. On the distance between the median line and each point of the infraorbital margin the growth rate is expressed in values relative to a standard that was based on the pre-eruption stage. The growth rate was greatest at the highest point of the superior margin in the infraorbital foramen (1.79 times), the middle rate was at the position of the infraorbital suture (1.72 times) and the smallest rate was 1.63 times at the position of the zygomatico-facial suture. Each measuring point moved towards lateral side.

Cephalometry↗
PubMed1999

Outcomes of irradiated polyglactin 910 Vicryl Rapide fast-absorbing suture in oral and scalp wounds.

BACKGROUND: This study evaluated the outcome of wounds closed with irradiated polyglactin 910 (IRPG) Vicryl Rapide (Ethicon, Somerville, N.J.). METHOD: Seventy-one patients with 80 oral wounds and 42 patients with 42 scalp wounds closed with IRPG were evaluated on the day of surgery, then one, seven, 14, 28 and 90 days following surgery. The incidence of inflammation, suppuration and hypertrophic scarring was recorded, along with the timing of spontaneous suture disappearance. This suture material was compared with polytetrafluoroethylene (PTFE) sutures used in dental implant patients, traditional polyglycolic acid (PGLA) sutures used in osteotomy patients and skin staples used in patients with scalp wounds. RESULTS: In the group with intraoral wounds, there were two cases of suppuration with no inflammatory reactions or hypertrophic scarring when IRPG sutures were used, compared to three cases of suppuration with the traditional PGLA sutures. In the group with scalp wounds, there was no suppuration or hypertrophic scarring with IRPG sutures and one inflammatory reaction with skin staples. IRPG sutures never required removal, while all staples, PGLA and PTFE sutures eventually required separate removal. CONCLUSION: Irradiated polyglactin 910 Vicryl Rapide is a useful suture material with both intra- and extraoral applications in the pediatric and adult populations.

Adult↗
PubMed1976

Polyglactin 910 suture absorption and the role of cellular enzymes.

Enzyme histochemical procedures for both hydrolase and oxidoreductase enzyme activity were applied to cryostat sections of polyglactin 910 suture implant sites. Sutures were implanted either solely in tissue or in a combination of in vitro incubation followed by implantation in vivo for total time periods of seven to 56 days. Suture absorption rates were also measured. It is concluded from the results that neither cellular nor enzyme activity is necessary for the degradation and absorption of polyglactin 910 sutures. This conclusion is based on similar absorption rates for sutures implanted solely in vivo and sutures treated in vitro and then implanted in tissue to give equivalent time spans. There were strong indications, however, that the products of suture hydrolysis are probably metabolized through the oxidative enzyme systems of cells adjacent to the suture. This mechanism of polyglactin 910 suture absorption is quite different from that observed and reported for catgut absorbable sutures.

Absorption↗
PubMedDate not supplied

Topographic changes that occur with 10-0 running suture removal following penetrating keratoplasty.

Twelve eyes undergoing penetrating keratoplasty with a double-running suture technique had corneal topographical analysis immediately before and one month after 10-0 suture removal. Substantial changes in astigmatism were evident following suture removal. Twenty five percent of eyes showed a decrease of 1 D, 33% of eyes showed a decrease of 3 D, 8.3% of eyes showed an increase of 1 D, 8.3% of eyes showed an increase of 2 D, 16.6% of eyes showed an increase of 3 D, and 8.3% of eyes showed an increase of 4 D of astigmatism following suture removal. The mean corneal astigmatism did not show a significant change from a mean of 5.3 D after suture removal. There was less individual variation of spherical corneal power following suture removal. Thirty three percent of eyes showed a decrease of 1 D, 33% of eyes showed a decrease of 2 D, 8.3% of eyes showed a decrease of 3 D, 18.3% of eyes showed an increase of 1 D, and 6.6% of eyes showed an increase of 2 D of spherical power following suture removal. The surface asymmetry index (SAI), a centrally weighted measure of corneal surface irregularity, decreased significantly (P less than 0.04) from a mean of 1.17 before suture removal to a mean of 0.93 after suture removal. These results suggest that surface irregularity may be decreased following the removal of a single running 10-0 nylon suture following penetrating keratoplasty.

Astigmatism↗
PubMed1981

Primary vascular anastomosis in growing pigs: comparison of polypropylene and polyglycolic acid sutures.

Stenosis remains a significant problem in vascular anastomoses performed in the growing patient. This study compares the growth of vascular anastomoses performed with either polypropylene or polyglycolic acid sutures. End-to-end infrarenal aortic anastomoses were performed in 18 piglets. Twelve were performed with polypropylene; in six all sutures were placed in a continuous fashion (Group 1A), and in the other six the posterior sutures were continuous and the anterior were interrupted (Group B). Six anastomoses were performed with polyglycolic acid sutures placed in a continuous fashion (Group 2). The animals were killed 6 months following operation. The abdominal aorta was removed, measured, burst tested, and subjected to histologic studies. All anastomoses were patent. There were no burst failures at 300 mm Hg mean pressure. All polypropylene sutures in Group 1A and the continuous portion in Group 1B had straightened without breaking. Straightening without polypropylene suture breakage resulted in stricture in three Group 1A anastomoses and one Group 1B anastomosis; there was intraluminal polypropylene suture material in two Group 1A and five Group 1B anastomoses. Bowstring formation of the straightened, continuous portion of the polypropylene suture in two Group 1A anastomoses and one Group 1B anastomosis resulted in adherent thrombus. Group 2 anastomoses were without stricture and were grossly indistinguishable from adjacent normal vessel. Histologic examination showed varying degrees of chronic inflammation in the polypropylene anastomoses but negligible inflammation in the polyglycolic acid anastomoses. These results suggest that continuous suture techniques with polypropylene in growing vessels may result in stenosis and/or thrombosis. Moreover, synthetic absorbable polyglycolic acid sutures will be of use in vascular anastomoses in growing patients and in cases in which exacting technique with minimal postsurgical inflammation may be crucial to patency.

Animals↗
PubMed1995

Histologic evaluation of tissue reactivity and absorption in response to a new synthetic fluorescent pigmented polypropylene suture material in rats.

The degree and type of tissue reactivity and the absorption of a new suture material was determined by implantation within rat gluteal muscles. Amount and type of tissue inflammatory reaction was compared among the new suture material, polypropylene, and coated polyamide. Histologic evaluation of the tissues in which sutures were implanted indicated that the new suture material, polypropylene, and coated polyamide had similar amounts and types of reaction at 30 days or less after implantation, but differed after 30 days. The new suture material and polypropylene had an inflammatory reaction zone measuring less than 25% of the high-power field after 60 days, but the coated polyamide still induced reaction greater than 45% of the field at 90 days. At 60 and 90 days after implantation, the new suture material and polypropylene induced a mature fibrous reaction; the reaction to coated polyamide was either immature fibrous or granulomatous, depending on whether there was rupture of the suture coat. There was no observable absorption of the new suture material at 90 days. This study indicated that the new suture material is nonabsorbable and is minimally reactive in rat muscle. The tissue reactions induced by this suture material are similar to those of polypropylene and significantly less than those induced by coated polyamide after 30 days following implantation.

Animals↗
PubMed1995

Introduction of a new double-looped suture.

Two new sutures are introduced for laparoscopic two-handed instrument suturing and knot tying, as well as a device for making them. In the first design, a nonslipping loop is placed at each end of a straight suture; they act as anchoring devices to maintain the suture in the two-dimensional plane of focus of the laparoscopic camera. The loops provide a large surface area that facilitates grasping the suture during the rotational and pulling maneuvers employed in instrument knot tying. The double-looped suture can be used for tying off and retracting tubular structures. The second design consists of a suture ligature with a curved or straight needle at one end and a single, non-slipping loop at the other. Illustrations demonstrate tying and suturing techniques for approximating tissue with the new sutures. A device consisting of two pairs of posts, for making the looped suture in a uniform fashion, is also discussed.

Humans↗
PubMed1995

Wound breaking strength and healing after suturing noninjured tissues.

BACKGROUND: Many operative procedures involve suturing healthy, previously nontraumatized tissues. The present study was done to investigate the wound breaking strength and healing after suturing noninjured tissues. STUDY DESIGN: A new experimental model of muscluloaponeurotic suture in the mouse is described and used to investigate the scar breaking strength, the concentration of 5-hydroxyproline, the extrusion of suture material, and the histological characteristics of the repair process. Scar quality was compared at three weeks between a group of mice in which suture was done without prior tissue injury (n = 24) and three groups of mice (n = 24 each) with prior tissue injury (tight-ischemic suture, incision, and cautery). Silk (n = 8), polyglactin 910 (n = 8), and polypropylene (n = 8) sutures were used within each group. RESULTS: Scars resulting from the suturing of healthy tissues had less breaking strength than those with ischemic, incised, or cauterized wound edges (507 g compared to 590, 730, and 732 g, respectively; p < 0.001) and had a lower 5-hydroxyproline concentration (5.1 ng/mg compared to 6.09, 6.77, and 7.49 ng/mg, respectively; p < 0.01). Polypropylene sutured scars had a higher breaking strength than silk (690 compared to 608 g, p < 0.01) or polyglactin 910 (690 compared to 626 g, p < 0.01). Most of the stitches were extruded from the scar independent of the suture material. CONCLUSIONS: The quality of a scar does not seem to be as good when wound edges are healthy than when they have been previously injured.

Animals↗
PubMedDate not supplied

Why make monofilament sutures out of polyvinylidene fluoride?

In recent years some clinical reports have associated suture failures with polypropylene monofilaments. Therefore there is interest in developing an alternative suture material that is less thrombogenic than polyester and similar in handling characteristics but less prone to mechanical failure than polypropylene. To this end, Peters Laboratoire Pharmaceutique has developed a new monofilament suture material from polyvinylidene fluoride (PVDF), which has been subjected to a special treatment to modify its crystalline form and level of crystallinity. The purpose of this study was to evaluate its mechanical, chemical, and biologic properties and to compare its performance, in a peripheral vascular application, to that of a polypropylene control. A series of in vitro tests were performed to study the morphology, tensile properties, creep, surface chemistry, thermal characteristics, and resistance to iatrogenic trauma. In addition, an in vivo trial was undertaken in which vascular prostheses anastomosed with either PVDF or polypropylene sutures were implanted as a thoracoabdominal bypass for 6 months in the dog. Histologic and degradation analyses were performed on the explants. The results from the mechanical tests on 4-0, 5-0, and 6-0 PVDF and polypropylene sutures demonstrated that although both materials have similar breaking strengths, the PVDF has a higher extension at break, has less delayed extension when under tensile creep testing, and suffers less trauma than the polypropylene when compressed by a standard needle holder. While chemical analyses found evidence of surface oxidation on both types of sutures, thermal analysis confirmed that the level of crystallinity of the PVDF polymer is higher than that of the polypropylene control. During the pilot study in animals, PVDF sutures were found to have good handling and frictional characteristics that facilitated the tying of knots. Histologic analysis of the explants found no inflammatory cells in the tissue surrounding either the PVDF or polypropylene sutures, and scanning electron microscopic examination of the cleaned suture surfaces found no evidence of degradation during 6 months in vivo. Though preliminary in nature, these findings indicate that monofilament sutures made from PVDF provide an attractive alternative to those made from polypropylene for use in cardiovascular surgery. In addition to providing acceptable in vivo behavior and being easy to manipulate and more resistant to iatrogenic injury, PVDF materials can be sterilized by beta or gamma radiation and so can reduce dependence upon ethylene oxide and chlorofluorohydrocarbons.

Animals↗
PubMed1997

Evaluation of blunt suture needles in preventing percutaneous injuries among health-care workers during gynecologic surgical procedures--New York City, March 1993-June 1994.

Infections with bloodborne pathogens resulting from exposures to blood through percutaneous injuries (PIs) (e.g., needlestick injuries and cuts with sharp objects) are an occupational hazard for health-care workers (HCWs). PIs have been reported during 1% - 15% of surgical procedures, mostly associated with suturing. Most suturing is done using curved suture needles, although straight needles are used by some surgeons for suturing skin. Blunt suture needles (curved suture needles that have a relatively blunt tip) may be less likely to cause PIs because they do not easily penetrate skin. Based on small studies and anecdotal experience, blunt suture needles appear able to replace conventional curved suture needles for suturing many tissues, although they may require more pressure to penetrate the tissues. This report summarizes results of a study in which CDC collaborated with three teaching hospitals in New York City during 1993-1994 to evaluate a safety device (a blunt suture needle) in gynecologic surgery. The findings indicate that use of blunt needles was associated with statistically significant reductions in PI rates, minimal clinically apparent adverse effects on patient care, and general acceptance by gynecologic surgeons in these hospitals.

Accidents, Occupational↗
PubMedDate not supplied

Uterine closure with the endo stitch 10-mm laparoscopic suturing device--a review of 50 laparoscopic myomectomies.

OBJECTIVE: To evaluate the mechanical performance of the Endo Stitch Laparoscopic Suturing Device and the clinical effectiveness of both a running, locked suture technique and a new modified suture technique for closure of uterine defects after laparoscopic removal of myomas. STUDY SUBJECTS: Fifty consecutive patients with symptomatic uterine leiomyomata. OBSERVATIONAL METHOD: Retrospective chart review. MAIN FINDINGS: The endometrial cavity was entered and sutured laparoscopically, in two layers, in 22 patients. In 28 patients, only the myometrium was sutured. A two-layered closure of the endometrium and myometrium was completed in an average time of 10 minutes. Mechanical problems with the Endo Stitch occurred in 11 cases. In all patients with second-look laparoscopies, the fallopian tubes were patent bilaterally without adhesions. No uterine fistulas were present in any patients with second-look laparoscopies. Posterior myomas were removed and sutured without adhesion formation. Grade 3 adhesions, to the uterine surface, were associated with transverse incisions of the uterus and over-treatment with GnRH analogs. CONCLUSIONS: The Endo Stitch Laparoscopic Suturing Device in combination with a running, locked suture technique achieves a rapid, hemostatic, clinically secure closure of the endometrium and myometrium. The Endo Stitch and our modified suture technique were not associated with adhesions or blockage of the fallopian tubes or uterine fistulas following laparoscopic myomectomies. The initial mechanical problems with the Endo Stitch were resolved. In our experience, currently the Endo Stitch is the best instrument for laparoscopic suture closure of uterine defects.

Adult↗
PubMed2004

A comparison of the precision of seeds deposited as loose seeds versus suture embedded seeds: a randomized trial.

PURPOSE: Brachytherapy for prostate cancer with permanent low-dose-rate seeds has been shown to be an effective treatment for early stage prostate cancer. Due to the rapid falloff of dose, accurate seed placement is critical for optimal dosimetry. One approach to achieve optimal dosimetry is the use of seeds embedded in suture material. Seeds embedded in suture may not move after implantation as much as loose seeds. This would improve implant dosimetry. To evaluate this hypothesis a formal study was conducted in which half the gland was implanted with seeds embedded in suture and half with loose seeds. Final dosimetry is compared between both halves of the prostate. METHODS AND MATERIALS: Patients entered this Investigational Review Board approved prospective trial after completion of informed consent. At time of implant, the side of the gland to be implanted with loose as opposed to suture embedded seeds was randomly assigned. The patients then underwent intraoperative preplanned implantation. None of the preplans directed seed locations outside the prostate. Both the seeds embedded in suture and the loose seeds were implanted using needles with stylettes. At 4-6 weeks post implant, seed location was determined with CT. Both sides of the gland on CT were contoured and used for final dosimetric calculations. A cost function analysis was used to determine individual seed position deviation from intended to actual seed location. RESULTS: Eight patients were enrolled in the study. A total of 549 seeds were implanted; 240 seeds embedded in suture and 309 loose seeds. Prostate volumes ranged from 24.0-45.5 cc with a mean of 38.6 cc. The average radial deviation of the loose seeds from planned position was determined to be 3.1 mm compared with the average radial deviation of the suture embedded seeds of 3.7 mm. There was no improvement in the final dosimetry when suture embedded seeds where used. The D90 and V100 values for the half of the prostate implanted with suture embedded seeds were 71-140 (mean, 92.1) and 80.2-99.5 (mean, 89.6), respectively, for the half of the prostate implanted with loose seeds. (All D90, V100 values are % of prescription dose.) CONCLUSION: Seeds embedded in suture material do not lead to superior precision in seed deposition when compared with loose seeds, when implanted inside the prostate.

Brachytherapy↗
PubMed1987

A technique for rapid non-suture vascular anastomosis.

In an attempt to overcome some of the difficulties inherent in vascular anastomosis using standard suture methods, we have developed a technique that allows for rapid non-suture anastomosis of blood vessels. The technique has been used in over 400 anastomoses, including interposition vein grafts in rat, rabbit and dog vessels ranging in size from 0.7 mm to 3 mm in diameter. Animals have been followed for over 1 year postoperatively with serial angiography and histological evaluation including scanning electron microscopy. Stress studies have compared the biomechanical properties of both non-suture and suture anastomosis. The overall patency rate in non-suture end-to-end anastomoses using an interposition vein graft was 85% at 1 year follow up. Histological evaluation revealed a healing pattern that was temporally similar to that of the suture technique. Stress tests revealed no significant difference between suture and non-suture technique. These studies reveal that the non-suture technique compares favourably with the suture technique, and demonstrate the feasibility of applying this technique to man.

Animals↗
PubMed1999

Mitochondria of rat lenses: distribution near and at the sutures.

PURPOSE: This study is part of an effort to clarify mitochondrial distribution in the lens in order to better understand lens metabolic function. This study of the rat lens involves: 1) Using confocal microscopy, Rhodamine-123 and Calcium Green fluorescent dyes, to characterise the distribution of mitochondria and calcium in whole rat lenses of different ages in epithelial and superficial cortical fibre cells approaching sutures and 2) Using a scanning laser system to measure the optical quality at the sutures. METHODS: Lenses of rats from age 1 week to 22 months were pre-incubated for 24 hrs in 1.5 ml medium 199 (M199). Those exhibiting damage, as evaluated by protein leakage or visual opacities, were discarded. Lenses were labelled with 50 microg/ml Calcium Green for 45 min and/or 14 microM Rhodamine-123 for 25 min and embedded in 1% agarose in M199 for inverted laser scanning confocal microscopy with a 40 x water immersion lens. The lens optical properties were determined with a scanning laser system. RESULTS: Lens focal length variability significantly increased at the sutures of 13 month-old lenses, the only age investigated. An absence of both mitochondria and calcium was observed at the sutures in rat lenses of all ages. Elongated (up to 108 mm) mitochondria were present in superficial cortical fibre cells approaching the sutures of 16 month-old lenses. Calcium Green fluorescent staining was seen closer to the border of the suture, where mitochondria were absent. Along the axis, 1 week-old lenses showed a mitochondria free zone (MFZ) starting 177 microm below the lens surface, whereas in 22 month-old lenses the MFZ started only 29 microm below the surface. In the equatorial fibre cells, mitochondria were seen to a depth of 220 microm. CONCLUSIONS: Optical quality near and at the suture decreased in 13 month-old lenses despite the reduction in light scattering that should be associated with absence of mitochondria at the sutures. This suggests that mitochondrial loss in superficial cortical fibre cells may originate at the sutures and may compensate for loss of optical quality at the sutures.

Animals↗
PubMedDate not supplied

Cranial suture obliteration is induced by removal of transforming growth factor (TGF)-beta 3 activity and prevented by removal of TGF-beta 2 activity from fetal rat calvaria in vitro.

Cranial suture morphogenesis requires soluble, heparin-binding factors secreted by the dura mater to resist premature osseous obliteration. Elevated levels of transforming growth factor (TGF)-beta 1, TGF-beta 2, and TGF-beta 3 have previously been noted in cranial sutures undergoing normal and premature sutural obliteration. To examine the role of TGF-beta s in regulating cranial suture morphogenesis, an established in vitro, serum-free, calvarial culture system was used. In this system, fetal rat coronal sutures undergo apparently normal suture morphogenesis in the presence of dura mater, but undergo osseous obliteration in the absence of dura mater. Neutralizing polyclonal antibodies to TGF-beta 1, TGF-beta 2, or TGF-beta 3 were added to cultures of fetal day 19 rat calvaria, which were harvested at 3, 4, or 5 days, processed for histology, sectioned, and examined. Coronal sutures from calvaria cultured in the presence of dura mater resisted obliteration, either alone or in the presence of TGF-beta 1 or TGF-beta 2 neutralizing antibodies. However, sutures from calvaria cultured in the presence of TGF-beta 3 neutralizing antibodies became obliterated. Conversely, sutures from calvaria cultured in the absence of dura mater became obliterated by bone, either alone or in the presence of neutralizing antibodies to TGF-beta 1 or TGF-beta 3. However, those sutures cultured in the presence of neutralizing antibodies to TGF-beta 2 were rescued from osseous obliteration.

Animals↗