Orientation by taste in fish of the genus Ictalurus.

Fish of the genus Ictalurus can find distant chemical clues by means of taste alone, and they exhibit true gradient searching in the absence of a current. Neither unilateral nor bilateral deprivation of the sense of smell impaired their searching ability, but unilateral deprivation of taste receptors which are spread over body and barbels of the animals caused pro nounced circling toward the intact side. The relation of swimming paths of the fish to the chemical in the water suggested that comparisons of concentrations were made in time and space.

Chemical communication in social behavior of a fish, the yellow bullhead (Ictalurus natalis).

Studies of behavior in yellow bullheads showed that they recognized individuals of their own species by means of pheromones. After training by reward and punishment, blinded bullheads were able to discriminate between the odors of two donor fish, but they lost this ability when deprived of their sense of smell. The main source of the intraspecific chemical stimuli involved in recognition is the mucus. A change in status after fighting was chemically communicated to other bullheads.

Dysmorphophobia: symptom or disease?

Although dysmorphophobia, a subjective feeling of ugliness in a person of normal appearance, constitutes a distinctive symptom cluster occasionally seen in patients requesting cosmetic surgery, it is not included in current major psychiatric diagnostic systems. Patients with dysmorphophobia are usually young and perfectionistic and have both schizoid and narcissistic traits. The authors present two representative case histories and suggest that study of more patients with dysmorphophobia is needed to determine whether it is a symptom of an underlying disease or is itself a separate disease entity.

Fluorescein test in the prediction of viability of skin flaps on pigs.

The fluorescein test is widely used in clinical and experimental studies for prediction of the viability of skin flaps. A thorough search of the literature revealed that the accuracy of this test had never been studied. Therefore, this study was designed to evaluate the accuracy of the fluorescein test in predicting the viability of skin flaps. A total of 212 unipedicle porcine skin flaps were used in this study. Statistical analysis demonstrated that the surviving area of the flap was significant greater than the staining area of the flap. We suggest that caution be exercised when the fluorescein dye test is used to assess skin flap viability and that the test be used for an approximate indication and not for an accurate prediction of the surviving flap area.

Microsurgical techniques in free flap reconstruction.

Free flap reconstruction is discussed with emphasis on microsurgical technique utilized in union of blood vessels 1 mm in external diameter. Proper microsurgical instrumentation, magnification and small vessel suture technique are all of importance in achieving a successful microvascular anastomosis. Technical maneuvers employed in identifying and avoiding small vessel thrombosis are presented. Surgical techniques, as presented here, have allowed us to successfully use free flaps to reconstruct large oral cavity defects following ablative cancer operations.

Implantation of human keloid into athymic mice.

In the interest of developing an animal model for keloids, human keloid dermis was implanted in the subcutaneous tissues of athymic (nude) mice. Subsequent growth resulted in a lesion with histology similar to the original keloid. Fibroblasts were cultured from keloid dermis. When the fibroblasts alone were implanted in the subcutaneous tissues of nude mice, growth of a visible lesion was again produced. The fibroblasts had proliferated and deposited collagen in an abnormal fashion with the histology resembling the parent keloid. Further research could develop this into a reliable animal model to allow in vivo experimentation.

Irradiated homologous cartilage grafts. Long-term results.

The use of irradiated homologous cartilage for the restoration of facial contour defects remains a controversial issue in reconstructive surgery. Both favorable and unfavorable reports can be found in the literature. Some basic research concerning the rate and mechanism of resorption has been completed but has failed to resolve the issue of the usefulness of this material in day-to-day practice. One frequently cited reference concerning the use of irradiated homologous cartilage in reconstructive surgery was coauthored by two of the present investigators ten years ago. In an effort to place this study in a long-term perspective, we examined 42 of the original 107 patients who formed the initial population base. Sixty-two of the original 145 irradiated homologous cartilage grafts have been followed up for an average of nine years, with an average resorption rate of approximately 75%. Eighteen of 24 grafts followed up from 11 to 16 years completely resorbed. In spite of complete graft resorption, some patients have maintained satisfactory facial contour with fibrous tissue replacement of the cartilage.

Serial measurement of blood flow in expanded tissue by laser Doppler velocimetry.

This study provides additional information about changes in blood flow in expanded tissue as measured by laser Doppler. Five one-kilogram albino Hartley guinea pigs were implanted with commercially available hemispheric expanders. The expanders were inflated every 3 days on four successive occasions. Blood flow measurements were taken on each animal just before each inflation, immediately after inflation, and then at 1, 2, 3, 4, and 24 hours after expansion. Measurement of flow changes immediately after each inflation of the expander showed that, initially, blood flow in the tissue overlying the expander recovered quickly, but as the expansion process was continued, the flow did not return to baseline values so rapidly. This might be an indication that tissue expansion in patients could be carried out more rapidly during the initial inflations, with increasing recovery periods between inflations as the expansion process continued.

The relationship between lip pressure following lip repair and craniofacial growth: an experimental study in beagles.

In the present study with beagles, various states of lip pressure (decreased and increased) following surgical creation of the lip and palatal defects and subsequent lip repair were found to be significantly related to craniofacial growth aberrations and disproportions. These aberrations are discussed in terms of an imbalanced functional skeletal-soft-tissue matrix. Significantly elevated lip pressure following lip repair in group III animals was found to be more detrimental to craniofacial growth than decreased lip pressure resulting from the surgical creation of a defect left unrepaired. Results of the study present, for the first time, documented evidence of a significant relationship between lip pressure following lip repair and craniofacial growth. Caution should be employed in extending these conclusions to the clinical setting, yet the findings underscore the need for well-controlled clinical studies designed to assess the influence of cleft lip repair on craniofacial growth.

Does interference with mucoperiosteum and palatal bone affect craniofacial growth? An experimental study in beagles.

This study was designed to assess the effects of raising mucoperiosteal flaps and exposing palatal bone at the time of palatoplasty. Using 62 beagle puppies as subjects, we tested the hypothesis that raising mucoperiosteal flaps does not interfere with craniofacial growth. We further hypothesized that the size of the area of bone exposed following palatoplasty does affect subsequent craniofacial growth. The animals were divided into four groups: two control groups (unoperated and unrepaired) and two experimental groups. In the first experimental group, two-flap palatoplasty was used to close the surgically induced palatal defect, leaving narrow strips (0 to 2.5 mm) of bone exposed lateral to the flaps. In the second group, one flap was raised to close the defect, leaving a wide area (5 to 6 mm) of palatal bone exposed on one side. Thirty-four direct craniometric measurements were analyzed. Animals that had elevation of both mucoperiosteal flaps with narrow strips of denuded bone on both sides had less severe craniofacial growth aberrations than those in which the defect was left unrepaired or was repaired with one mucoperiosteal flap leaving a wider area of bare bone exposed. These findings suggest that raising mucoperiosteal flaps is less detrimental to craniofacial growth than leaving large areas of exposed palatal bone.

The influence of lip repair with and without soft-tissue undermining on facial growth in beagles.

The present study was designed to test the hypothesis that undermining of the soft tissues on the surface of the maxilla at the time of lip repair in unilateral cleft lip, alveolus, and palate results in more severe craniofacial growth aberrations than lip repair alone. Sixty-seven purebred beagles were used in this experiment. The animals were divided into four groups: two control groups (unoperated and unrepaired) and two experimental groups (lip repair without undermining and lip repair with undermining). Lip pressures were monitored in all groups. Significantly higher lip pressures were observed in animals with soft-tissue undermining. Cephalometric measurements were analyzed using univariate and multivariate techniques. The results of this study indicate that lip repair performed with soft-tissue undermining results in more severe craniofacial growth aberrations than lip repair performed alone.

The influence of two-flap palatoplasty on facial growth in beagles.

This study was designed to test the hypothesis that palate repair in beagles inhibits overall facial growth, primarily in the transversal dimension. Direct cephalometry of the skulls at 28 weeks postoperatively showed that two-flap palatoplasty did not inhibit overall facial growth in animals with surgically created cleft lip, alveolus, and palate. In many cases, facial growth in animals with palate repair was indistinguishable from that in unoperated control animals. The unexpected finding in this study was that two-flap palatoplasty seemed to stimulate intensive new bone formation in the surgically created alveolar and palatal defects. Bony remodeling may be responsible for the enhanced anteroposterior and transversal facial growth in animals with palate repair (group 3). The results of this study validate findings from our previous studies in the rabbit model; yet caution should be employed in extrapolation of these findings to the clinical setting. For the first time, evidence is presented that in normal beagles with surgically created alveolar and palatal defects, two-flap palatoplasty stimulated substantial and, significant new bone formation in the site of the defects. Studies should be designed to determine the nature and time course of bony palatal wound healing.

Late results of primary veloplasty: the Marburg Project.

Forty-five randomly selected patients with unilateral cleft lip, alveolus, and palate, all operated upon by Dr. Wolfram Schweckendiek were evaluated by three American specialists to assess the validity of primary veloplasty. Examination revealed an unusually high incidence of short palate and poor mobility of the soft palate. Facial growth was found to be highly acceptable in the majority of the patients. Unusually high incidence of velopharyngeal incompetence was found in these patients.

Simultaneous cleft lip and palate repair: an experimental study in beagles.

This study was designed to test the hypothesis that simultaneous lip and palate repair results in more severe craniofacial growth aberrations than lip repair or palate repair performed separately. Seventy-six purebred beagles were divided into five groups. Two of these groups were controls (unoperated and unrepaired animals); the three remaining groups were experimental (in one group only the lip was repaired, in another only the palate was repaired, and in the last the lip and palate were repaired simultaneously). Cephalometric measurements were analyzed using univariate and multivariate statistical techniques. In multivariate analysis, stepwise multiple regression and discrimination were applied to precisely assess the effects of the various surgical procedures. The results of this study indicate that simultaneous lip and palate repair results in more severe craniofacial growth aberrations than lip repair or palate repair performed separately.

Enhancement of tissue expansion by anticontractile agents.

To evaluate the effect of anticontractile agents on the rate of tissue expansion, guinea pig back skin was expanded while being treated with various anticontractile agents. Expansion was carried out using standard percutaneous inflatable skin expanders modified by the addition of a catheter to deliver the anticontractile agents papaverine or cytochalasin D. Expansion proceeded for 25 days with one or other of the substances being infused through the catheter; saline was used in a separate control group. Measurements of the rate and extent of expansion showed that there was a statistically significant increase in these parameters for the experimental groups as compared with saline controls. Histologic examination of the expanded tissue suggests that the cellular basis for this phenomenon may involve the relaxation or inactivation of contractile fibroblasts in the fibrous capsule surrounding the expander.