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Biomedical subjects

S R Cohen

Publications and source records attributed to S R Cohen.

At least 91 records · Page 5Linked to original sources
PubMed1995

Histomorphologic analysis of the soft palate musculature in prenatal cleft and noncleft A/Jax mice.

The two specific aims of this study were as follows: to evaluate the appropriateness of the A/Jax mouse model in the investigation of the key cellular stages in prenatal soft palate morphogenesis and myogenesis; and to describe structural differences in the histomorphology of the soft palate anatomy from cleft and noncleft mice prior to, during, and after palatogenesis. Cleft-induced and control groups of A/Jax mouse embryos from timed pregnancies were harvested sequentially on gestational days 15 to 19. Embryos were weighed and staged for external body morphology. The heads were removed and fixed for light microscopy, sectioned serially in the frontal plane at 10 microns and stained with hematoxylin-eosin to characterize and compare the soft palate musculature. All observations were made at the head depth of the trigeminal ganglion in both age- and stage-matched embryos. The following findings were made: (1) the A/Jax mouse is a suitable animal model for the study of soft palate myogenesis; (2) there were no discernible morphologic differences between the soft palate muscles in cleft and noncleft A/Jax mice when viewed under light microscopy; (3) the soft palate and related muscles were identifiable as muscle fields, in both the cleft and noncleft fetuses, as early as gestational day 15 and as specific muscles at gestational day 18; (4) in both the cleft and noncleft A/Jax fetuses, the soft palate muscles appeared in a sequential anatomic fashion (the palatine aponeurosis appeared first, next the tensor palatini, and then the levator palatini muscles); and (5) in the cleft palate fetuses, both pterygoid plates were angulated and displaced laterally.

Analysis of Variance↗
PubMed1995

The association between pH level and corneal recovery from induced edema.

Corneal acidosis has been shown to reduce corneal hydration control (CHC) as measured by the rate, expressed as the percent recovery per hour (PRPH), at which the thickness of the cornea decreases exponentially after an increased hydration load. Since the effect of pH on corneal function is of scientific interest and may have clinical implications, we explored the relationship between pH and PRPH in greater detail by examining the effect of different stromal pH levels on corneal hydration control. Corneal edema was induced using a 90-min exposure to wearing a hypoxic contact lens (CL). Following removal of the CL, random assignment over four eye-test combinations of either 0, 3, 5, and 7% CO2 were made while pH and corneal thickness were monitored using slit lamp fluorophometry and optical pachometry to measure corneal pH and corneal thickness, respectively. From these measurements we determined the pH-dose/PRPH relationship. The average stromal pH +/- 1SD resulting from exposure to either the 0, 3, 5, and 7% CO2, was 7.65 +/- 0.11, 7.30 +/- 0.09, 7.15 +/- 0.08 and 7.04 +/- 0.07 (p < 0.001), respectively. Analysis based on a quadratic model of the dose-response relationship between PRPH and corneal pH indicates that PRPH is relatively unchanged for pH in the physiological range (pH = 7.40-7.65) and then decreases notably below the physiological range.

Acidosis↗
PubMed1995

Managed care.

Explore the source record for details and available documents.

Cleft Palate↗
PubMed1995

Piriform aperture stenosis: a rare cause of neonatal airway obstruction.

Because neonates are obligate nasal breathers, neonatal nasal obstruction may have serious consequences. Prompt diagnosis and appropriate treatment are essential to avoid severe hypoxia. Anterior inlet, piriform aperture stenosis is an extremely rare cause of neonatal nasal airway obstruction and can easily be confused with choanal atresia or stenosis. Computed tomography with direct coronal scans is the best means of establishing a definitive diagnosis. We present our experience with four neonates having nearly complete piriform aperture stenosis. Prompt surgical enlargement of the nasal inlet through an upper buccal sulcus approach is recommended.

Constriction, Pathologic↗
PubMed1995

Turribrachycephaly: a technical note.

We describe a technique for early correction of the so-called towering skull deformity, or turribrachycephaly. The technique makes use of the natural elasticity and plasticity of cranial bone, and it is best applied during the first year of life. Surgery consist of routine exposure of the cranial bone via a coronal incision. The frontal bone flap is elevated and removed. On either side, a bony osteotomy is then made, commencing low down in the temporal region and running posteriorly and superiorly toward the occiput. This approach leaves a superior bone flap, which may be left attached to the occipital bone via a flexible posterior hinge region, or completely detached by continuing the osteotomy across the midline. After the osteotomy, the bone flap is elevated up to the sagittal sinus on either side of the midline. The bone flap is not removed, but pushed down, compressing the brain along the craniocaudal axis. The lateral edge of the flap overlaps the temporal bone, and it can be fixed in the desired position by means of simple positional screws or Vicryl sutures. A standard fronto-orbital advancement is performed prior to lowering the skull vault, which permits the brain to be moved down and forward, filling the dead space in the anterior cranial fossa. The frontal bone flap is then shaped appropriately and fixed by means of plates and screws to the advanced fronto-orbital bar. Posteriorly, the frontal lobe is left "floating." To date, we have performed this technique on 5 patients, and we find it both faster and simpler than other techniques. Short-term results in terms of cranial shape are good. In older infants (> 2 years of age), this technique may not prove useful because of the loss of the loss of plasticity of the bone.

Cephalometry↗
PubMed1994

Phototherapy in the treatment of depression in the terminally ill.

Research in affective disorders has shown that there is a clear link between mood and light exposure, and that exposure to bright wide-spectrum light (phototherapy) may be an effective antidepressant treatment in some clinical situations. Cancer patients, especially those in the terminal phase of illness, have a high incidence of depression. Furthermore, their mobility is often severely reduced, resulting in little exposure to direct sunlight. We report the use of phototherapy in three terminally ill patients to alleviate symptoms of depression.

Aged↗
PubMed1994

Surgical correction of severe scaphocephalic deformities.

Sagittal synostosis may result in severe skull deformities. Characteristic components of the deformity include extreme elongation, frontal and occipital bossing, temporal pinching, and angulatory apical skull deformation. Conventional strip craniectomy often fails to correct these complex problems completely in severe early or late cases of sagittal synostosis. Techniques for total calvarial vault reconstruction have previously been reported, but a single large series has not been presented. Eighteen consecutive patients ranging in age from 3 months to 5 years (mean = 12 months) with severe early and late scaphocephalic skull deformities underwent total calvarial vault reshaping. All children required transfusions ranging from 250 to 1,100 mL. Operative times averaged 6 hours, and hospital stay ranged from 4 to 7 days. There was no perioperative mortality. Two patients experienced transient syndrome of inappropriate secretion of antidiuretic hormone, which responded to fluid restriction. One patient was noted to have a 2-cm parietal craniectomy defect 9 months after operation. Microscrews, which were used in all 18 patients, had to be removed in 2 patients when they became palpable. Excellent aesthetic results were noted in all 18 patients up to 36 months of follow-up.

Child, Preschool↗
PubMed1994

Patterns of abnormal myogenesis in human cleft palates.

To test the hypothesis that soft palate muscles are abnormal in cleft palate, we compared soft palate morphogenesis in fetuses with cleft palate (n = 4) to age-matched (n = 3) and nonmatched (n = 1) control specimens. The morphologic status of all soft palate and masticatory structures were classified into one of six stages based on the level of histogenesis. At 54 mm crown-rump length (CRL), the levator veli palatini (L), palatopharyngeus (PP), and palatoglossus (PG) in cleft subjects demonstrated mesenchymal condensation into myoblastic fields, lagging behind the control specimens (97 mm CRL), which displayed definitive fields of myoblasts and myotube formation. In the 175 mm and 225 mm cleft and the 170 mm and 192 mm control specimens, muscular morphology was similar and had reached its postnatal appearance for the tensor veli palatini (175 m only) and L, PP, PG (225 mm only). Muscle fiber directions were, however, disoriented and disorganized, especially close to the medial epithelial edge of the cleft. The levator veli palatini, could not be distinguished as a discrete muscle in the cleft specimens, and what we believed to be the PP and PG seemed "normal" at the level of light microscopy, but malpositioned in a superior direction. This preliminary study demonstrates for the first time that early myogenesis in cleft palates differs from normal.

Case-Control Studies↗
PubMed1994

Metopic synostosis: evaluation of aesthetic results.

Analysis of intermediate- and long-term results of surgical treatment of metopic synostosis is lacking. We therefore retrospectively studied 23 patients with metopic synostosis (14 males, 9 females) who have been followed from 3 months to 8.1 years (mean 42.5 months) after operation. Age at first operation ranged from 2 to 56 months (mean 8.2 months), with 15 patients operated on before 6 months and 8 after 7 months. Fronto-orbital remodeling and calvarial vault reshaping with floating forehead techniques were carried out in all patients. Stabilization of bony segments was accomplished with microplates and screws in 7 patients (30 percent), wires in 15 (65 percent), and absorbable sutures in 1. Complications included minor wound dehiscence (n = 1), seizures (n = 1), and increased intracranial pressure (n = 1). Postoperative photographic documentation of surgical results was available in 17 of the 23 patients. Aesthetic outcome in these 17 patients was graded (I = none or minor contour irregularities; II = moderate; and III = severe) by one of the authors (Cohen) and by a lay panel (n = 3) according to the degree of residual cranio-orbital deformity. Judged by the surgeon, grade I results were present in 53 percent, grade II in 35 percent, and grade III in 12 percent. To date, total reoperation (reoperative fronto-orbital remodeling and calvarial vault reshaping) was necessary in 2 patients (9 percent), one of whom had signs of increased intracranial pressure 3 years after the original craniofacial procedure, while partial reoperation (temporal cranioplasty) was carried out (n = 2) or recommended (n = 3) in another 5 patients.(ABSTRACT TRUNCATED AT 250 WORDS)

Child↗
PubMed1993

The habenula and pain: repeated electrical stimulation produces prolonged analgesia but lesions have no effect on formalin pain or morphine analgesia.

Recent studies have found that electrical stimulation of the habenula or microinjection of morphine into it reduces pain in several pain tests. The present study explored additional properties of the habenula. Expt. 1 examined the influence of the duration of stimulation on the duration of poststimulation analgesia in the formalin test. Expt. 2 was carried out to determine whether destruction of the habenula would affect either baseline pain levels or analgesia produced by morphine administered systemically in the formalin test. The results showed that the duration of analgesia is related to the duration of electrical stimulation. However, habenular lesions did not affect baseline pain levels or morphine analgesia. These studies support earlier evidence that manipulation of the habenula can produce analgesia, but suggest that it is not tonically active in modulating pain or necessary for the analgesic effects of systemically administered morphine.

Animals↗
PubMed1993

Analyses of craniofacial and dental morphology in monozygotic twins discordant for cleft lip and unilateral cleft lip and palate.

The Michigan Cleft Twin Sample data was analyzed in order to investigate dental arch and craniofacial morphology. The present study consisted of 12 monozygotic twins discordant for either cleft lip or unilateral cleft lip and palate. Individuals having CL (repaired) alone did not differ from their unaffected counterparts in dental arch and skeletal morphology. Repaired UCLP subjects were characterized by having a shorter and more posteriorly positioned maxilla. Although reduction of dental arch width as a result of scar contraction following surgery was evident, the effects of scar tissue pull did not affect maxillary basal width.

Cephalometry↗
PubMed1993

Acrylic splints for dental alignment in complex facial injuries.

Twenty-four patients with complex facial injuries were managed by wide subperiosteal exposure, precise anatomical reduction, rigid internal fixation, and immediate bone grafting when indicated, in conjunction with dental impressions, model surgery, and fabrication of dental splints to establish proper preinjury occlusion. The study population consisted of 18 men and 6 women, whose ages ranged from 18 to 49 years (mean, 30.7 yr) at the time of injury. High velocity motor vehicle accidents were responsible for facial injuries in 18 patients, gunshot wounds in 2, low velocity blunt trauma in 3, and falls in 1. All facial fractures involved the occlusion, and unstable and/or comminuted palatal/maxillary and mandibular fractures, often with edentulous segments, were the major indications for fabrication of acrylic splints. Depending on the nature of the fracture pattern, model surgery was performed on the maxillary and/or mandibular models and segmented along fracture lines. These fragments were then repositioned according to dental wear facets and preinjury occlusion. When possible, preinjury occlusal records were obtained before splint fabrication. Models were mounted on a Galetti articulator and palatal, lingual, and/or occlusal splints were fabricated. Edentulous segments were compensated for by local buildup of the splints to produce an occlusal stop. Arch bars were fixed directly to the splint with acrylic. Twenty-six splints were used in the 24 patients to establish proper occlusal relationships before internal fixation of fractures. The types of splints were palatal (n = 8), palatal-occlusal (n = 6), lingual (n = 8), lingual-occlusal (n = 1), and occlusal (n = 3).(ABSTRACT TRUNCATED AT 250 WORDS)

Acrylic Resins↗
PubMed1993

Surgical techniques of cranial vault expansion for increases in intracranial pressure in older children.

Standard craniofacial techniques to expand the cranial vault were successful in treating elevations of intracranial pressure (ICP) in 7 older children. Of the 7 patients, a diagnosis of craniosynostosis was made in 6 and deformational head deformity with slit ventricle syndrome in 1. There were 5 boys and 2 girls, whose ages ranged from 3 1/2 to 8 years (mean, 5.2 yr). Three patients had previously undergone surgical treatment of craniosynostosis. One patient presented with visual changes and papilledema. Another with a deformational skull deformity was shunt-dependent and was diagnosed with slit ventricle syndrome. This patient had undergone several temporal craniectomies to control recurrent symptoms of increased ICP. The remaining 2 patients appeared to have craniosynostosis as an explanation for reduced cranial vault size and elevated ICP, but the specific sites of sutural fusion could not be identified. Total follow-up ranged from 3 to 18 months, and evidence of resolution of signs and symptoms of increased ICP was achieved in each of the 7 patients. Plastic surgeons involved in caring for children with craniosynostosis should be particularly aware of the possibility of increased ICP developing or recurring following craniofacial surgery.

Cerebral Ventricles↗
PubMed1993

A modification of the transcoronal flap that enhances orbital exposure and cosmesis.

The transcoronal surgical approach for the treatment of orbital disease has become increasingly popular since it affords excellent surgical exposure through a cosmetically acceptable incision. Exposure of the inferior orbit, however, can be difficult due to limited flap mobility in the frontal plane. Increased inferior exposure may be obtained by extending the incision inferiorly in preauricular skin. In children and young adults without excess preauricular skin folds or wrinkling, however, the wound may be quite apparent, compromising cosmesis. To overcome this drawback, we demonstrate a modified transcoronal incision that redirects the inferior limbs into the postauricular sulcus. This incision not only results in superior cosmesis, but avoids important preauricular neurovascular structures and enhances orbital exposure.

Humans↗