The tooth, the whole tooth and nothing but the tooth: tooth shape and ontogenetic shift dynamics in the white shark Carcharodon carcharias

Results from this study of the white shark Carcharodon carcharias include measurements obtained using a novel photographic method that reveal significant differences between the sexes in the relationship between tooth cuspidity and shark total length, and a novel ontogenetic change in male tooth shape. Males exhibit broader upper first teeth and increased distal inclination of upper third teeth with increasing length, while females do not present a consistent morphological change. Substantial individual variation, with implications for pace of life syndrome, was present in males and tooth polymorphism was suggested in females. Sexual differences and individual variation may play major roles in ontogenetic changes in tooth morphology in C. carcharias, with potential implications for their foraging biology. Such individual and sexual differences should be included in studies of ontogenetic shift dynamics in other species and systems.

Anatomical variations of the sensory nerves to the fibular osteocutaneous flap

OBJECTIVE

To describe the anatomical relationship of the sural sensory nerve complex to the posterior crural intermuscular septum (PS), the key anatomical structure for the osteoseptocutaneous fibula skin paddle.

DESIGN

Anatomical study.

SUBJECTS

Twenty-two legs from 11 cadavers (7 females and 4 males).

RESULTS

The lateral sural cutaneous (LSC) nerve, present in 20 of 22 legs, divides into lateral and medial branches near the head of the fibula. The LSC nerve and its medial branch course away from the PS, whereas the lateral branch tends to course toward the PS. The lateral branch courses nearest to the PS at a median distance of between 4 cm proximally and 3 cm distally. The medial branch of the LSC nerve terminates approximately in the middle of the leg, and the lateral branch of the LSC nerve terminates within 7 cm below the head of the fibula. The peroneal communicating branch is thicker than the LSC nerves; however, it is further from the PS in the upper leg.

CONCLUSIONS

The LSC nerve is the most consistent and accessible donor sensory nerve in the posterior leg for harvest with the osteoseptocutaneous fibula free flap. Results of this study will assist the surgeon in harvesting a sensory nerve with the osteoseptocutaneous fibula free flap, bringing this potentially sensate flap into more common use. Arch Facial Plast Surg. 2000;2:252-255

Superior cantholysis for zygomatic fracture repair

OBJECTIVE

To determine if performing a superior cantholysis eases the surgical exposure, reduction, and rigid fixation of the zygomaticofrontal suture in the open repair of zygomatic complex (ZMC) fractures.

PATIENTS AND METHODS

Fifteen superior cantholysis procedures were used in 14 patients who presented with ZMC fractures requiring open reduction and internal fixation. Follow-up ranged from 6 to 18 months. Collected data included patient demographics, cause of fracture, fracture classification, associated facial injuries, methods of fracture exposure and reduction, type and location of fixation, procedure-related complications, and postoperative outcome, including adequacy of fracture reduction.

RESULTS

Superior cantholysis opens a direct surgical route to the zygomaticofrontal suture for exposure, reduction, and rigid fixation. It also expedites exposure and assessment of the sphenozygomatic suture. No postreduction ZMC malunions or malpositions occurred during the study. There were 4 complications, none of which could be attributed to superior cantholysis. The complications related primarily to the transconjunctival and lateral canthotomy incisions.

CONCLUSIONS

Superior cantholysis eases the surgical exposure, reduction, and rigid fixation of the zygomaticofrontal suture in the open repair of ZMC fractures. The superior cantholysis added no morbidity in open ZMC fracture repair, and it simplified exposure of the lateral orbital rim, without the need for overzealous tissue retraction.

Genetic diversity and reproductive biology in Warea carteri (Brassicaceae), a narrowly endemic Florida scrub annual

Carter's mustard (Warea carteri) is an endangered, fire-stimulated annual endemic of the Lake Wales Ridge, Florida, USA. This species is characterized by seed banks and large fluctuations in plant numbers, with increases occurring in postdisturbance habitat. We investigated the mating system, patterns of isozyme variation, and effective population sizes of W. carteri to better understand its population biology and to comment on reserve designs and management proposals relevant to this species. Warea carteri is self-compatible and autogamous, and probably largely selfing. Measures of genetic variation in W. carteri were lower than values reported for species with similar ecological and life history traits (6.6% of loci polymorphic within populations, 1.87 alleles per polymorphic locus, and 0.026 and 0.018 expected and observed heterozygosity, respectively). The high average value for Nei's genetic identity (0.989) reflects the paucity of genetic diversity. Genetic variation within populations was not correlated with aboveground population size, effective population size estimates (N(e)), or recent disturbance history. Much of the diversity detected was found among populations (F(ST) = 0.304). A significant cline in allele frequencies at one locus and a significant negative correlation between geographic distance and Nei's genetic identity also point to spatial organization of genetic diversity. As a result we propose that reserve design should include the entire geographic range of W. carteri. We also recommend that the natural fire regime be mimicked.

Conservation implications of genetic variation in three rare species endemic to Florida rosemary scrub

Habitat conversion and fire suppression during the last 50 yr have greatly reduced and altered Florida scrub vegetation, resulting in threats to the persistence of its unique flora. As part of a larger conservation project, we investigated patterns of isozyme variation in three rare perennial scrub plants with overlapping ranges endemic to Florida rosemary scrub on the Lake Wales Ridge. All three species have low levels of genetic variation, comparable to or lower than those generally reported for rare plants with restricted geographic ranges. Liatris ohlingerae has more than twice the expected heterozygosity of the other two species, with little population differentiation. In contrast, Hypericum cumulicola has highly differentiated populations with little apparent interpopulation gene flow and heterozygote deficiencies indicative of inbreeding. Eryngium cuneifolium, the species with the narrowest range and fewest populations, has intermediate values for genetic parameters. Although the three species have narrow and overlapping geographic ranges and similar habitat specificity, we discuss how optimal conservation of each species differs.

Effects of vasoactive topical agents on the survival of dorsal skin flaps in rats

OBJECTIVE

To evaluate 3 vasoactive topical agents regarding their ability to improve the survival of random skin flaps in rats.

METHOD

Thirty-five adult Sprague-Dawley rats had a single 9 x 2 cm random skin flap raised with topical application of a white petroleum ointment (control group), prostaglandin E2, minoxidil, or nitroglycerin to the flap. The effect of the agents on the viability of the flaps was evaluated.

RESULTS

The control group had an average survival area of 60.8% +/- 7.9%. The nitroglycerin and minoxidil groups were not significantly different, with an average area of survival of 60.1% +/- 8.1% and 63.3% +/- 4.7%, respectively. The prostaglandin E2 group had average area of survival of 74.2% +/- 10.5% (P = 0.002).

CONCLUSION

Prostaglandin E2 demonstrated a significant increase in flap survival. Nitroglycerin ointment and minoxidil had no beneficial effects when compared with control.

Symptoms in early head and neck cancer: an inadequate indicator

Screening programs show promise in increasing the rate of early detection of head and neck cancers in high-risk populations. Prout et al (Otolaryngol Head Neck Surg 1997;116:201-8) examined the usefulness of a large-scale screening program for head and neck cancer in an inner city population by primary care physicians. Symptom assessment was based on the American Cancer Society's "Seven Warning Signs for Cancer," (Cancer manual. 8th ed. Boston: American Cancer Society, Massachusetts Division; 1990. p. 40-64) 4 of which are relevant to the head and neck. However, these signs may be insufficient for detection of early head and neck cancer. We analyzed these and other typical symptoms to determine their role in early detection. Coincident medical problems, tobacco abuse, and alcohol abuse were also analyzed. Our findings indicate that no symptom or symptom complex is strongly correlated with early head and neck cancer for any subsite except the glottis. Symptom duration is an unreliable indicator of the duration of disease. However, patients under medical supervision are more likely to have their cancers detected early, supporting the value of surveillance by the primary care physician. The absence of definite early warning signs for most head and neck cancers suggests the need to develop essential screening criteria. Defining the population that is at high risk for head and neck cancer and subjecting it to an aggressive screening protocol is essential.

Loss of heterozygosity at 11q23 in squamous cell carcinoma of the head and neck is associated with recurrent disease

Loss of heterozygosity (LOH) at chromosome 11q23 has been found in a variety of epithelial human neoplasms, suggesting that this region contains a tumor suppressor gene(s) important to tumorigenesis. We investigated whether LOH at 11q23 could be detected in squamous cell carcinoma of the head and neck (SCCHN), and whether loss at this site was associated with specific clinical parameters. Fifty-six matched blood and SCCHN tumor samples taken at the time of diagnosis were evaluated for LOH at three microsatellite markers at 11q23. Multiplex PCRs with [alpha-32P]dCTP labeling of the amplified DNA strands were performed. Clinical data were obtained from medical record review. LOH at 11q23 was found in 13 of 52 (25%) evaluable tumors. There was no association between LOH at 11q23 and amplification of the CCND1 (cyclin D1) oncogene or inactivation of the p53 gene, which had been determined previously. With a mean follow-up of 24 months, an association independent of tumor size or stage was found between LOH at 11q23 and recurrent disease (P = 0.04). Among subjects who received radiotherapy (RT) as a component of their treatment, LOH at 11q23 was associated with persistent or recurrent locoregional disease (P = 0.05). LOH at 11q23 occurs in a subset of SCCHN. It is associated with a higher likelihood of recurrent disease, perhaps related to resistance to RT. The specific gene(s) and mechanism(s) responsible remain to be identified. Until then, LOH at 11q23 might become a marker identifying patients likely to do poorly with conventional therapy.

Inactivation of p53 and amplification of cyclin D1 correlate with clinical outcome in head and neck cancer

The authors have investigated whether genetic abnormalities in two genes, loss of heterozygosity (LOH) of p53 and amplification of the cyclin D1 gene, correlate with clinical outcome in 56 matched pairs of blood and tumor from patients with squamous cell carcinoma of the head and neck (SCCHN). Frequency of p53 LOH was 47.4%, of cyclin D1 amplification 33.9%, and of both abnormalities together 23.7%. p53 LOH was associated with T4 (P = 0.003) and stage IV (P = 0.015) tumors. Cyclin D1 amplification was associated with recurrences and/or metachronous tumors (P = 0.007). The total number of p53 and cyclin D1 abnormalities (scored as zero, one, and two) show a pattern that seems to be additive; the increase in the number of these abnormalities is associated with a proportional increase in the frequency of T4, stage IV, presence of recurrences and/or metachronous tumors, and possibly a proportional decrease in the disease-free interval in the sample. The association of the markers with recurrences and/or metachronous tumors persists if the tumor stage effect is mathematically removed. The combined analysis of the p53 and cyclin D1 abnormalities seems to be more informative than either of them individually and may have predictive value in SCCHN.

Acute lingual tonsillitis

A 45-year-old woman presented to the emergency department (ED) with a 3-day history of fever, progressive sore throat, dysphagia, and difficulty speaking. She was diagnosed with acute lingual tonsillitis. The ED physician must consider this rarely discussed disorder when presented with the previously mentioned signs and symptoms. This will allow for prompt diagnosis and treatment of acute lingual tonsillitis and may help to avoid potential airway compromise.

Reducing ischemia-reperfusion injury in rat island groin flaps by dexamethasone and BW755C

Despite the known effectiveness of anti-inflammatory therapy in reducing reperfusion injury, no studies to date involve the use of anti-inflammatory therapy in reducing ischemia-reperfusion injury in fasciocutaneous flaps. Dexamethasone (a phospholipase A2 inhibitor) and specific cyclooxygenase and lipoxygenase inhibitors (indomethacin and BW755C) were administered to rats with ischemic island groin (fasciocutaneous) flaps. Significant improvement in ischemic flap survival was found with dexamethasone and BW755C. The mode of action of dexamethasone was not specifically investigated in our study; however, it may suppress neutrophil function and reduce ischemia-reperfusion injury in its shared ability with BW755C to reduce the formation of leukotrienes. Dexamethasone could be applied in the clinical setting to reduce ischemic flap loss by attenuating the systemic inflammatory response to reperfused ischemic-damaged tissue.

Diagnosis and treatment of intracranial complications of paranasal sinus infections

Complications and local extension of paranasal sinus infections most often involve the orbit and periorbita. Because of the widespread use of antibiotics since World War II, intracranial extension of maxillofacial sinusitis is rarely seen today. Nevertheless, the clinician must be aware of the potential for these complications, because late recognition of this condition and delays in treatment can increase morbidity and mortality rates. A comprehensive, current review of sinogenic intracranial complications is presented, with illustrative cases of brain abscess, subdural empyema, meningitis, cavernous sinus thrombosis, epidural abscess, and osteomyelitis. The mechanisms and potential for intracranial spread of infection from the frontal, sphenoid, and ethmoid sinuses are discussed in detail. The management of each type of complication is outlined, including the use of computed tomography and magnetic resonance imaging, and the role of surgical drainage.

Reducing ischemia-reperfusion injury in rat island groin flaps using dexamethasone

Reducing reperfusion injury is effective in reducing flap loss after prolonged ischemia. Anti-inflammatory therapy reduces reperfusion injury in canine cardiac muscle and ex vivo rat cremaster muscle; however, to date, there are no studies involving the use of anti-inflammatory agents in ischemic skin flaps. This study was designed to assess the effects of dexamethasone and indomethacin on the viability of rat island groin flaps subjected to 10 hours of ischemia. The ischemic control and the treatment group flaps were subjected to 10 hours of ischemia by clamping the inferior epigastric vascular pedicle. The treatment groups received either intravenous dexamethasone or intravenous indomethacin after the flap vascular pedicles were clamped. Our results showed significant improvement (p < 0.05, Fisher's exact test) in ischemic flap survival using dexamethasone. The specific mode of action of dexamethasone was not investigated; however, its anti-inflammatory effects were most likely responsible for the improvement of flap survival by suppressing the circulating neutrophil and decreasing reperfusion injury. Dexamethasone is easily available for clinical use, and its use should be considered in cases of prolonged ischemia in skin flaps.

Improved reflow and viability in reperfused ischemic rat island groin flaps using dexamethasone

Reperfusion injury and the no-reflow phenomenon are manifestations of a complex series of events that culminate in an acute inflammatory reaction within reperfused tissue. Antiinflammatory therapy attenuates ischemia-reperfusion injury. The purpose of this study is to evaluate the effects of dexamethasone on blood flow and viability of ischemic rat island groin flaps. Thirty-three mature male Sprague-Dawley rats were divided into 3 groups. The flaps were subjected to 8 hr of ischemia in the control and treatment groups. Fluorescein studies were performed, and flap viability was assessed. Twenty-four hour fluorescence (after reperfusion) correlated very closely with the percentage of eventual flap viability. The blood flow and viability of the treatment group flaps were significantly better than those in the ischemic control group. Dexamethasone significantly improved ischemic flap survival in the rat 8 hr ischemic island groin flap model in our study.