Thirty-five millimeter versus digital photography: comparison of photographic quality and clinical evaluation

The objective of this article is to assess the quality of digital images versus standard 35-mm photodocumentation and to undertake a comparative assessment of 35-mm and digital photography in a clinical setting in facial plastic surgery. For evaluation of image quality, 10 subjects had images captured via a conventional 35-mm single lens reflex (SLR) camera and a digital camera under identical lighting conditions. The digital images were transferred to computer hard drive and processed for production of slides. Direct side-by-side comparison of projected images was performed by the authors. The standard photographic slides were of slightly finer detail and crispness than the computer-generated images. In a clinical setting, the quality of both the 35-mm and digital photographs enables complete preoperative evaluation and assessment of postsurgical outcome.

Retropharyngeal aberrant thymus

INTRODUCTION

Upper airway obstruction from a retropharyngeal mass requires urgent evaluation. In children, the differential diagnosis includes infection, trauma, neoplasm, and congenital abnormalities. Aberrant cervical thymic tissue, although occasionally observed on autopsy examination, is rarely clinically significant. We present the case of an infant with respiratory distress attributed to aberrant thymic tissue located in the retropharyngeal space.

CASE

A 6-week-old infant was brought to the emergency department for evaluation of stridor associated with periodic episodes of cyanosis. Lateral neck radiograph revealed widening of the retropharyngeal soft tissues. The patient's symptoms did not improve with intravenous ampicillin-sulbactam. Magnetic resonance imaging (MRI) performed on the seventh day of hospitalization revealed a retropharyngeal mass that extended to the carotid space. The mass was easily resected using an intraoral approach. Microscopic examination demonstrated thymic tissue. A normal thymus was also observed in the anterior mediastinum on MRI. The patient recovered uneventfully and had no further episodes of stridor or cyanosis.

DISCUSSION

Aberrant cervical thymic tissue may be cystic or solid. Cystic cervical thymus is more common, and 6% of these patients present with symptoms of dyspnea or dysphagia. Aberrant solid cervical thymus usually presents as an asymptomatic anterior neck mass. This case is unusual in that solid thymic tissue was located in the retropharynx, a finding not previously reported in the English literature. Additionally, the patient presented in acute respiratory distress, and the diagnosis was confounded by the presence of mild laryngomalacia. In retrospect, our patient likely had symptoms of intermittent upper airway obstruction since birth. The acute respiratory distress at presentation was likely the result of laryngomalacia exacerbated by the presence of aberrant thymic tissue and a superimposed viral infection. Aberrantly located thymic tissue arises as a consequence of migrational defects during thymic embryogenesis. The thymus is a paired organ derived from the third and, to a lesser extent, fourth pharyngeal pouches. After its appearance during the sixth week of fetal life, it descends to a final position in the anterior mediastinum, adjacent to the parietal pericardium. Aberrant thymic tissue results when this tissue breaks free from the thymus as it migrates caudally. Therefore, aberrant thymic tissue may be found in any position along a line from the angle of the mandible to the sternal notch, and in the anterior mediastinum to the level of the diaphragm. In an autopsy study of 3236 children, abnormally positioned thymic tissue was found in 34 cases (1%). The aberrant thymus was most often located near the thyroid gland (n = 19 cases) but was also detected lower in the anterior neck (n = 6 cases), higher in the anterior neck (n = 8 cases), and at the left base of the skull (n = 1 case). The presence of thymic tissue in the retropharyngeal space in our patient is more unusual given the typical embryologic origin and descent of the thymus in the anterior neck to the mediastinum. Children with aberrant thymus may have associated anomalies. Twenty-four of 34 children (71%) with aberrant thymus detected at autopsy had features consistent with DiGeorge syndrome, and only 5 of the remaining 10 patients had a normal mediastinal thymus present. Our patient had normal serum calcium levels after excision and a mediastinal thymus was visualized on MRI. Biospy is required for diagnosis of cervical thymus and should also be considered to exclude other causes. MRI is helpful in delineating the presence, position, and extent of thymic tissue. Immunologic sequelae or recurrence after resection of an aberrant cervical thymus has not been reported.

Traumatic perilymphatic fistulas in children: etiology, diagnosis and management

Post-traumatic perilymphatic fistulas have been described following ear and temporal bone injury, particularly in the setting of temporal bone fractures. However, indications for exploratory surgery in cases of trauma without temporal bone fracture are vague and not well described. We describe three children who presented with symptoms suggestive of perilymphatic fistula (PLF) without an associated temporal bone fracture: two with penetrating tympanic membrane injuries and one with blunt temporal bone trauma. All had symptoms of hearing loss and vestibular disturbance. Two of the children cooperated with ear-specific audiologic assessment, which demonstrated sensorineural hearing loss (SNHL) on the traumatized side. The third child showed audiometric evidence of a SNHL on the injured side, but due to his age, the degree of severity of the SNHL was unable to be appropriately addressed prior to the patient being surgically managed. All three children underwent exploratory surgery and were found to have bony defects in the region of the oval window. All were repaired with fascial grafts to the oval and round windows with complete resolution of vestibular symptoms. However, two of the three patients with documented post-operative audiograms suffered from persistent SNHL on the injured side. We conclude that exploratory middle ear surgery is indicated in patients suffering from blunt or penetrating temporal bone or middle ear trauma who demonstrate persistent vestibular symptoms, sensorineural hearing loss or radiographic evidence of oval window pathology. As this is a limited number of patients, a larger series may be warranted to study the actual incidence of post-traumatic PLF in the child with persistent hearing loss and vertigo after head or ear trauma.

CD8 positive T cells influence antigen-specific immune responses through the expression of chemokines

The potential roles of CD8(+) T-cell-induced chemokines in the expansion of immune responses were examined using DNA immunogen constructs as model antigens. We coimmunized cDNA expression cassettes encoding the alpha-chemokines IL-8 and SDF-1alpha and the beta-chemokines MIP-1alpha, RANTES, and MCP-1 along with DNA immunogens and analyzed the resulting antigen-specific immune responses. In a manner more similar to the traditional immune modulatory role of CD4(+) T cells via the expression of Th1 or Th2 cytokines, CD8(+) T cells appeared to play an important role in immune expansion and effector function by producing chemokines. For instance, IL-8 was a strong inducer of CD4(+) T cells, indicated by strong T helper proliferative responses as well as an enhancement of antibody responses. MIP-1alpha had a dramatic effect on antibody responses and modulated the shift of immune responses to a Th2-type response. RANTES coimmunization enhanced the levels of antigen-specific Th1 and cytotoxic T lymphocyte (CTL) responses. Among the chemokines examined, MCP-1 was the most potent activator of CD8(+) CTL activity. The enhanced CTL results are supported by the increased expression of Th1 cytokines IFN-gamma and TNF-alpha and the reduction of IgG1/IgG2a ratio. Our results support that CD8(+) T cells may expand both humoral and cellular responses in vivo through the elaboration of specific chemokines at the peripheral site of infection during the effector stage of the immune response.

Morphometric changes in the chick nucleus magnocellularis following acoustic overstimulation

The present investigation considered the effects of cochlear damage caused by exposure to intense sound on the nucleus magnocellularis of the chick. Neonatal chicks exposed to intense sound were separated into four groups with post-exposure recovery durations of 0, 15, 27, and 43 days. Four age-matched, non-exposed control groups were also formed. At each recovery interval, the control and exposed birds were sacrificed and their brains prepared for paraffin embedding. The brain stem region containing the nucleus magnocellularis (NM) was serially sectioned in the coronal plane. All sections containing NM cells were identified and then coded in terms of their percentile distance from the most caudolateral section. Sections along the nucleus at the 15th, 30th, 50th, 65th, 80th, and 95th percentile positions were selected for evaluation, and the cross-sectional areas of individual NM cells in these sections were then measured. Cell areas were corrected for the bias introduced by eccentricity of the nucleus. The number of NM cells per 1,000 microm2 was also calculated at the 50th and 65th percentile positions. These procedures were repeated for the age-matched, non-exposed control animals. The cross-sectional cell area in exposed animals, immediately after the exposure, was reduced significantly at all positions, but returned to near normal by 43 days of recovery. However, the coronal area of NM in the sections at the 50th and 65th percentile position, as well as NM cell density, were unaffected by the exposure at all recovery intervals. The observation of structural recovery in NM cells at 43 days post-exposure was remarkable because it occurred at least 4 weeks after complete functional restoration of single-cell activity in the NM. The shrinkage in NM cell size throughout the nucleus may be due to a general reduction in spontaneous activity in the cochlear nerve fibers caused by the acoustic injury to the chick basilar papilla.

Engineering of in vivo immune responses to DNA immunization via codelivery of costimulatory molecule genes

Nucleic acid immunization is a novel vaccination technique to induce antigen-specific immune responses. We have developed expression cassettes for cell surface markers CD80 and CD86, two functionally related costimulatory molecules that play an important role in the induction of T cell-mediated immune responses. Coimmunization of these expression plasmids, along with plasmid DNA encoding for HIV-1 antigens, did not result in any significant change in the humoral response; however, we observed a dramatic increase in cytotoxic T-lymphocyte (CTL) induction as well as T-helper cell proliferation after the coadministration of CD86 genes. In contrast, coimmunization with a CD80 expression cassette resulted in a minor, but positive increase in T-helper cell or CTL responses. This strategy may be of value for the generation of rationally designed vaccines and immune therapeutics.

Effect of flicker on macular blood flow assessed by the blue field simulation technique

PURPOSE

To determine the effect of diffuse luminance flicker on the motion of leukocytes in the retinal macular capillaries of normal subjects.

METHODS

Using the blue field simulation technique, subjects were asked to match the motion of simulated leukocytes displayed on a video monitor to that of their own entoptically seen white blood cells (WBCs). The changes in velocity and density of the WBCs were recorded after stimulation with diffuse luminance flicker of various durations (0 to 16 seconds), either immediately or at various delays (2, 4, 8 seconds) after cessation of the stimulus.

RESULTS

White blood cell velocity increased as flicker duration increased from 0 to 16 seconds. After cessation of flicker, leukocyte motion decreased to baseline within 15 seconds.

CONCLUSIONS

The authors' findings suggest a coupling between retinal neural activity and blood flow in the macular region of the retina. The rapidity of both the flicker-induced increase in WBC motion and the disappearance of the effect after flicker cessation resembles the time course of blood flow changes previously observed in the microcirculation of the cat optic nerve.