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Biomedical subjects

D J David

Publications and source records attributed to D J David.

At least 19 recordsLinked to original sources
PubMed2006

The conservative management of facial fractures: indications and outcomes.

BACKGROUND: With little in the published literature on the conservative management of facial fractures we set out to determine whether our current criteria for treatment are valid. METHOD: Two hundred and thirty adult patients with fractures of the facial skeleton were treated conservatively by our unit between February 1997 and January 2003. Their notes were reviewed retrospectively. RESULTS: Most patients were males (76%), the average age was 38 years, and drugs or alcohol were a significant aspect of the history in 30% of the cases. The most common mechanism of injury was assault (47%), followed by falls and sporting injuries. Fifty percent of the fractures involved the orbital or orbito-zygomatic complex, and 55% had associated injuries. Average follow-up was for six weeks (range 0-44 weeks). Most patients were managed conservatively based on our current criteria of un-displaced/minimally displaced fracture (57%); or minimal/no symptoms (24%). At final review, a number had residual symptoms, but only three required corrective surgery. The other reasons for conservative management included patient non-compliance (11%), and medical contraindications (8%). CONCLUSION: Our results support current indications for the conservative management of facial fractures, but emphasise the need for ongoing follow-up of these patients.

Adolescent↗
PubMed2006

An unusual complication of mandibular distraction.

BACKGROUND: The authors present an unusual complication of mandibular distraction in a child with the curious condition of multiple pterygium syndrome is presented. CASE REPORT: The patient was a Caucasian male with severe pterygia in his neck. As a result of his limited mouth opening and restricted upper airway leading to obstruction, he underwent lengthening of his mandible by distraction, which significantly improved his breathing. During his follow-up, it was observed that an unusually elongated permanent molar was present in an abnormal position. CONCLUSION: This case highlights the need to carefully plan the sites for osteotomy and the potential for damage to the developing permanent dentition in young children.

Child, Preschool↗
PubMed2006

Three-dimensional computed tomography cephalometry of plagiocephaly: asymmetry and shape analysis.

OBJECTIVE: To investigate facial asymmetry associated with both deformational and synostotic plagiocephaly and to identify variables based on skeletal landmarks that distinguish the conditions and quantify severity. DESIGN: Retrospective, cross sectional. SETTING: Australian Craniofacial Unit, Adelaide. MAIN OUTCOME MEASURES: Proportional differences between bilateral distances and principal component (PC) analysis of the skeletal landmarks. PATIENTS: The three-dimensional positions of 78 osseous landmarks were determined from computed tomography (CT) scans of 21 patients with deformational plagiocephaly (DP), 20 patients with unilateral coronal synostosis (UCS), and 2 patients with unilateral lambdoid synostosis (ULS). RESULTS: For both DP and UCS, significant asymmetry was found for the orbital depths, mandibular lengths, maxillary depths, zygomatic arch lengths, lateral base of the parietal bone, and the angle between the anterior and the posterior cranial base projected onto the axial plane. The small sample size for ULS precluded definitive statistical statements but allowed some useful comparisons with the other conditions. The first three PC scores were able to distinguish among the three conditions and which side was affected. CONCLUSIONS: The asymmetry of the cranial base and facial structures, arising from localized abnormality or deformational forces in either the frontal or the occipital regions, can be quantified by a plethora of bilateral features or summarized by PC analysis.

Cephalometry↗
PubMed2005

Multidisciplinary management of Opitz G BBB syndrome.

Opitz G BBB syndrome is a rare condition characterized by the 3 major anomalies of hypertelorism, cleft lip and palate, and hypospadias, although there may be other associated anomalies. The underlying genetic causes are complex and consist of both X-linked recessive and autosomal dominant forms of the disorder. Previously, there have been publications on the underlying genetics and case reports, but there have been few reports regarding the long-term outcome. The aim in this study was to review the range of clinical presentation and evaluate outcomes of the multidisciplinary management of a cohort of patients with Opitz G BBB syndrome. In a 25-year period, 7 patients with Opitz G BBB syndrome were managed by the Australian Craniofacial Unit (ACFU), 5 male and 2 female. Most of the patients are now reaching skeletal maturity. Each one presented with a range of severity in the triad of hypertelorism, cleft lip and palate, and hypospadias anomalies. The males all exhibited the triad of anomalies, while the females both had hypertelorism, only 1 had isolated cleft palate, and neither had any genitourinary anomalies. Each patient underwent multidisciplinary assessment to make a treatment plan for staged management of different anomalies. Plan for surgical corrections of facial anomalies were performed according to the unit's protocol management of both hypertelorism and cleft lip and palate, but the presence of these coexisting anomalies required adjustment of the standard protocol of management of cleft lip and palate. In conclusion, we recommend that patients with Opitz G BBB syndrome require careful evaluation, and management of the anomalies should be in a coordinated manner by a multidisciplinary team.

Abnormalities, Multiple↗
PubMed2003

Modified costochondral graft osteotomy in hemifacial microsomia.

Hemifacial microsomia is the second most common facial clefting condition after cleft lip and palate. The deformity affects the skeleton and soft tissues in the temporal region of the affected side, although the degree of involvement is markedly variable. We describe a modification of surgical technique in a skeletally mature case who had previously undergone mandibular reconstruction with a costochondral graft.

Facial Asymmetry↗
PubMed2003

Effects of chronic paroxetine treatment on dialysate serotonin in 5-HT1B receptor knockout mice.

The role of serotonin (5-HT)1B receptors in the mechanism of action of selective serotonin re-uptake inhibitors (SSRI) was studied by using intracerebral in vivo microdialysis in conscious, freely moving wild-type and 5-HT1B receptor knockout (KO 5-HT1B) mice in order to compare the effects of chronic administration of paroxetine via osmotic minipumps (1 mg per kg per day for 14 days) on extracellular 5-HT levels ([5-HT]ext) in the medial prefrontal cortex and ventral hippocampus. Basal [5-HT]ext values in the medial prefrontal cortex and ventral hippocampus, approximately 20 h after removing the minipump, were not altered by chronic paroxetine treatment in both genotypes. On day 15, in the ventral hippocampus, an acute paroxetine challenge (1 mg/kg i.p.) induced a larger increase in [5-HT]ext in saline-pretreated mutant than in wild-type mice. This difference between the two genotypes in the effect of the paroxetine challenge persisted following chronic paroxetine treatment. Conversely, in the medial prefrontal cortex, the paroxetine challenge increased [5-HT]ext similarly in saline-pretreated mice of both genotypes. Such a challenge produced a further increase in cortical [5-HT]ext compared with that in saline-pretreated groups of both genotypes, but no differences were found between genotypes following chronic treatment. To avoid the interaction with raphe 5-HT1A autoreceptors, 1 micro m paroxetine was perfused locally through the dialysis probe implanted in the ventral hippocampus; similar increases in hippocampal [5-HT]ext were found in acutely or chronically treated wild-type mice. Systemic administration of the mixed 5-HT1B/1D receptor antagonist GR 127935 (4 mg/kg) in chronically treated wild-type mice potentiated the effect of a paroxetine challenge dose on [5-HT]ext in the ventral hippocampus, whereas systemic administration of the selective 5-HT1A receptor antagonist WAY 100635 did not. By using the zero net flux method of quantitative microdialysis in the medial prefrontal cortex and ventral hippocampus of wild-type and KO 5-HT1B mice, we found that basal [5-HT]ext and the extraction fraction of 5-HT were similar in the medial prefrontal cortex and ventral hippocampus of both genotypes, suggesting that no compensatory response to the constitutive deletion of the 5-HT1B receptor involving changes in 5-HT uptake capacity occurred in vivo. As steady-state brain concentrations of paroxetine at day 14 were similar in both genotypes, it is unlikely that differences in the effects of a paroxetine challenge on hippocampal [5-HT]ext are due to alterations of the drug's pharmacokinetic properties in mutants. These data suggest that there are differences between the ventral hippocampus and medial prefrontal cortex in activation of terminal 5-HT1B autoreceptors and their role in regulating dialysate 5-HT levels. These presynaptic receptors retain their capacity to limit 5-HT release mainly in the ventral hippocampus following chronic paroxetine treatment in mice.

Animals↗
PubMed2002

Blindness and severe visual impairment in facial fractures: an 11 year review.

We present an 11 year review of facial fractures treated in the Australian Craniofacial Unit and the Department of Plastic and Reconstructive Surgery at the Royal Adelaide Hospital, specifically looking at those fractures in adults that resulted in blindness or severe visual impairment. During the period 1989-2000, a total of 2516 patients with facial fractures were treated operatively. From our facial-fracture database, 317 patients were identified as having an ophthalmological complication on presentation. Of these, 19 had severe visual impairment or blindness. The exact fracture pattern and craniofacial disruption score were recorded for each of these 19 cases using the Cooter-David facial-fracture scoring system. Laterally directed forces are implied as major causative factors in these injuries. Recommendations are made based on these findings.

Adolescent↗
PubMed2001

Are there gender differences in the temperature profile of mice after acute antidepressant administration and exposure to two animal models of depression?

Numerous studies have reported gender differences in the rates of depression in humans, but few behavioural observations of antidepressant drug effects have been investigated in female mice. The forced swimming test (FST) is widely used as a predictor of antidepressant activity in rodents, as is the tail suspension test (TST), where immobility is objectively measured and in this last test, no hypothermia is induced by immersion in cold water. The present study investigated gender differences in the temperature profile of mice after acute antidepressant administration (imipramine and paroxetine) and exposure to two animal models of depression. Imipramine and paroxetine were active at 32 mg/kg in male mice in the FST, whereas they were active at 8, 16 and 32 mg/kg in female mice. In the TST, for both antidepressants immobility duration was reduced at a dose of 16 and 32 mg/kg in male mice and at 32 mg/kg in female mice. No significant difference was observed between male and female mice for immobility duration. Imipramine administration, but not paroxetine, decreased the temperature at the higher dose (32 mg/kg) in male and female mice in the FST. The body temperature was reduced in male and female mice for all treatment groups after FST challenge. Imipramine (16 and 32 mg/kg in male and 32 mg/kg in female mice), paroxetine (4, 16 and 32 mg/kg in male and 4 to 32 mg/kg in female mice) attenuated the reduction in temperature due to the FST. In the TST, imipramine tends to decrease the temperature in male and female mice, even though only imipramine at a dose of 32 mg/kg in female mice significantly decreases the temperature. Paroxetine had no effect on temperature. The TST enhanced the body temperature in male and female mice. In mice, there was no difference between the sexes after imipramine or paroxetine administration in the FST and TST. Both tests can be used to predict the activity of antidepressants as the decrease or enhancement of temperature is not correlated with a reduction in immobility duration.

Animals↗
PubMed2001

Comparison of antidepressant activity in 4- and 40-week-old male mice in the forced swimming test: involvement of 5-HT1A and 5-HT1B receptors in old mice.

RATIONALE: A recent study suggested that selective serotonin reuptake inhibitors were inactive in 40-week-old male mice in the mouse forced swimming test, possibly because of alteration of 5-HT1 receptors. OBJECTIVES: The present study was aimed at investigating the action of various antidepressant drugs in 4- and 40-week-old male mice using the mouse forced swimming test and determining the involvement of 5-HT1A and 5-HT1B receptors mediating the effects. METHODS: Different classes of antidepressants [imipramine (tricyclic), maprotiline (noradrenline reuptake inhibitor), venlafaxine (mixed serotonin and noradrenaline reuptake inhibitors), fluvoxamine and sertraline (selective serotonin reuptake inhibitor)] were tested in the same randomised experimental session, alone and in combination with 5-HT1A and 5-HT1B receptor agonists [buspirone (partial 5-HT1A agonist), anpirtoline (5-HT1B agonist)] in the mouse forced swimming test. RESULTS: All antidepressants were found to be active in the mouse forced swimming test in 4-week-old mice and 40-week-old mice, with the exception of fluvoxamine in the 40-week-old mice. The anti-immobility effect after antidepressant administration was higher in 4-week-old male mice than in 40-week-old male mice. Venlafaxine is the most active antidepressant drug in 40-week-old mice. Prior administration of buspirone (0.06 mg/kg, i.p.) or anpirtoline (1 mg/kg, i.p.) enhanced the antidepressant-like effects in 4-week-old mice (except in the case of sertraline, 8 mg/kg). In elderly mice, only prior administration of buspirone enhanced the antidepressant-like effects of fluvoxamine. A neurochemical study showed that significantly higher serotonin and dopamine concentrations were found in 40-week-old control mice brains than 4-week-old control mice brains but that the noradrenaline concentration is higher in 4-week-old mice. CONCLUSION: Tricyclic, noradrenaline reuptake inhibitors and serotonin reuptake inhibitors are more active in 4-week-old mice than 40-week-old mice. Our results suggested that 5-HT1B receptors may be more altered than 5-HT1A receptors in 40-week-old mice.

Aging↗
PubMed2001

Oblique facial clefting associated with unicoronal synostosis.

Oblique facial clefts are said to account for 0.25% of all clefts. Craniosynostosis is not known to be associated with oblique facial clefting, although craniofrontonasal dysplasia is well described. Craniosynostosis and oblique facial clefting presenting together in the same patient is a rare event. We present such a case, and detail the treatment plan to allow simultaneous correction of both deformities.

Child, Preschool↗
PubMed2000

Occipital plagiocephaly.

The diagnosis of occipital plagiocephaly has remained a complex and controversial issue in the field of craniofacial surgery. Over the past 30 years, numerous studies have been published describing the management and treatment for 'posterior plagiocephaly', 'plagiocephaly without synostosis', 'deformational plagiocephaly' and 'occipital plagiocephaly', with surgical 'correction' being chosen as the primary modality of treatment irrespective of the patency status of the lambdoid sutures. Two hundred and four patients with unilateral occipital plagiocephaly have been seen at the Australian Craniofacial Unit over the past 16 years. Each patient was evaluated by a craniofacial surgeon, paediatric neurosurgeon and paediatric geneticist. All children underwent plain radiographs of the skull to define the sutural anatomy. In those patients where the sutural anatomy was equivocal, 2-D and 3-D CT scans were performed. Only two of the 204 patients (approximately 1%) manifested the clinical, radiographic and pathological features of true unilambdoid synostosis. There was radiographic evidence of sutural fusion on plain films, 2-D and 3-D CT scans. Pathology specimens showed bony sutural fusion. Two hundred and two patients presented with unilateral occipital deformities and patent sutures on radiography. These patients with occipital plagiocephaly in the absence of true synostosis were initially managed conservatively (head positioning, and physiotherapy in those patients with torticollis). Those patients who underwent surgical correction in infancy (21/204) included patients with severe plagiocephaly not responding to conservative therapy (19/204) and the two patients with true unilambdoid synostosis (2/204).One hundred and ninety-one of the total patients (94%) were noted by their parents to have acceptable improvement in their head shape. Thirteen patients were seen within the past year and are too early to assess. Two surgical patients (one fronto-orbital advancement, one occipital craniectomy) and one patient followed conservatively were judged by their parents to be without notable improvement. In our series it is apparent that the majority of cases of occipital plagiocephaly are not secondary to true synostosis and can be managed by conservative positional measures.

Cranial Sutures↗
PubMed2000

CT-determined intracranial volume for a normal population.

Intracranial volume comparisons of patients with craniosynostosis and normal have been contrary to expectations, leading to questioning of the validity of the current normal reference material. Computed tomography-determined intracranial volume is presented for a white normal population. Specifically, intracranial volumes for 157 subjects (82 female and 75 male) were measured from computed tomography data using the Cavalieri estimator: volume determination was based on measuring the area in each computed tomography section. Monomolecular and Gompertz models were applied to find curves of best fit to the intracranial volume as a function of the age. The best fit was obtained using the monomolecular model when the response variable was the logarithmically transformed intracranial volume, and the independent variable was the logarithm of the age from conception. For example, the mean (standard deviation) for male subjects at 1 year and 20 years were 1,125.6 (89.6) ml and 1,472.9 (117.2) ml, respectively, and for female subjects 1,024.9 (84.0) ml and 1,321.7 (108.3) ml, respectively. Although the shape and rate of increase of the female and male curves is similar, the female mean is 1.3 standard deviations below the male mean at 20 years. These curves were compared with the commonly referenced curves of Blinkov (1941), Lichtenberg (1960), and Dekaban (1977). Our male curve is substantially higher than these curves in the age range 8 months to 4 years. Our female curve, however, is approximately 1 standard deviation below Lichtenberg's curve from birth to 7 months. There are then only minor differences between our female curve and Lichtenberg's curve until his curve crosses ours at 41 months, where they significantly diverge from approximately 4.5 years. Our curves indicate that 95% of the final intracranial volume has been attained by 42 months for girls and 46 months for boys.

Adolescent↗
PubMed1999

Outcome measurement of the treatment of maxillary fractures: a prospective analysis of 100 consecutive cases.

We performed a prospective study of 100 consecutive patients presenting to our unit with complex maxillary fractures. Fracture severity was assessed according to the alpha-numeric scoring system of Cooter and David and correlated with outcome. Regional maxillary and total fracture scores demonstrated a positive correlation with complication rates, with correlation coefficients of 0.89 and 0.98 respectively. Ocular and orbital complications were most commonly seen with these complex injuries, but occlusal problems were much less common. Despite close consultant-led supervision in a specialised centre, these injuries frequently result in long term problems.

Adolescent↗
PubMed1999

Tissue expansion in the reconstruction of Tessier craniofacial clefts: a series of 17 patients.

Tessier craniofacial clefts are among the most surgically challenging examples of craniofacial dysmorphology. These clefts are characterized by hypoplasia of soft-tissue and skeletal elements throughout the three-dimensional extent of the cleft. Whereas bone grafting and craniofacial osteotomies have been successful toward correcting the underlying skeletal abnormalities, the ultimate success of these reconstructions has been limited by the deficiency of skin and soft tissue. This deficiency demands reconstruction ideally with tissue of like texture, consistency, and, especially in the face, color. Craniofacial tissue expansion was used toward reconstructing these facial clefts with like-quality tissue, allowing for tension-free reconstruction after osteotomy and bone grafting. Seventeen patients with Tessier craniofacial clefts underwent preoperative craniofacial soft-tissue expansion in the surgical management of their clefts. Tissue expansion was used in the primary correction of facial clefts in eight patients, with nine patients undergoing expansion before secondary surgery. In this series, tissue expansion has evolved as an important element in overcoming the skin and soft-tissue deficiency associated with these clefts, allowing for tension-free closure and improved aesthetic results in these surgically challenging patients.

Adolescent↗
PubMed1998

Nicotine-evoked nitric oxide release in the rat hippocampal slice.

The effects of cholinergic agonists on nitric oxide (NO) release in hippocampal slices from male Sprague-Dawley rats were investigated using electrochemical recording procedures using Nafion and O-phenylenediamine-treated carbon fiber microelectrodes. These microelectrodes are highly selective for NO versus other interferents. Acetylcholine (Ach) with neostigmine, or nicotine was delivered by pressure ejection from pipettes placed within 300 microm of the NO sensors. Both Ach and nicotine produced NO signals ranging from 0.04 to 2.14 microM in the CA1, CA3, and dentate gyrus of the rat hippocampus that lasted for 2-5 min. The Ach responses were not antagonized by the muscarinic antagonist atropine. However, nicotine-evoked responses were partially antagonized by alpha-bungarotoxin, a finding consistent with alpha7-nicotinic cholinergic receptors being involved with the effects of nicotine. These data support the hypothesis that nicotine is capable of evoking long lasting NO release in the hippocampus.

Acetylcholine↗