[GrS Montreal: A private hospital specializing in gender-affirming surgery in Canada]

Gender dysphoria refers to the suffering an individual experiences when his or her sex at birth does not correspond to the expression of his or her gender. Gender-affirmation surgery is a procedure that can alleviate this suffering. For 20 years, GrS Montreal has been Canada's only center dedicated exclusively to this type of surgery. Thanks to its expertise, quality of care, state-of-the-art infrastructure and convalescent home, GrS Montreal receives patients from all over the world. This article describes the particularities of this center and puts into perspective the evolution of this type of surgery.

Spontaneous resolution of a giant keratoacanthoma penetrating through the nose

Although keratoacanthomas are common and spontaneous resolution well recognized, case reports with photographic documentation of resolution are few. The subtype of giant keratoacanthoma (GKA) can give rise to severe cosmetic destruction because of their size and their predilection for cosmetically sensitive areas (nose and eyelids). Spontaneous resolution of GKAs has not been widely reported. We present an impressive series of clinical photographs documenting the spontaneous resolution of a GKS on the nose of a 56-year-old patient.

Morphometric X-ray absorptiometry and morphometric radiography of the spine: a comparison of analysis precision in normal and osteoporotic subjects

Morphometric techniques, which use conventional lateral spine radiographs to quantify vertebral body shape (morphometric radiography, MRX), have proved a useful tool in the identification and evaluation of osteoporotic vertebral deformities. Recently a new method of acquiring the images required for vertebral morphometry using dual-energy X-ray absorptiometry scanners (morphometric X-ray absorptiometry, MXA) has been developed. In this study we compare repeat analysis precision of vertebral height measurement using MXA and MRX. Twenty-four postmenopausal women were recruited (mean age 67 +/- 5.8 years): 12 normal subjects and 12 with osteoporosis and vertebral deformities. Each subject had a MXA scan and lateral thoracic and lumbar radiographs at a single appointment, which were each analyzed quantitatively in a masked fashion, using a standard 6-point method, twice by one observer and once by a second observer. Anterior (Ha), mid (Hm) and posterior (Hp) vertebral heights were measured and wedge (Ha/Hp) and mid-wedge (Hm/Hp) ratios calculated for each vertebral body. Intra- and interobserver precision were consistently poorer in MXA compared with MRX in both normal subjects and those with vertebral deformities, with MXA CV% generally at least 50% higher than corresponding values for MRX. For both MXA and MRX interobserver precision was clearly poorer than intraobserver precision, a problem associated with any morphometric technique. MXA intra- and interobserver precision were significantly poorer for subjects with vertebral deformities compared with those without, with a CV% for deformity subjects up to twice that of normal subjects. Conversely, MRX showed little or no obvious worsening of intra- or interobserver precision for deformity subjects. Comparison of MXA precision in the normal and deformed vertebrae of the deformity subjects demonstrated that the poorer precision in these subjects compared with normal subjects was the result of increased variability in point placement on the deformed vertebrae themselves. However, the precision for normal vertebrae in these subjects was also somewhat poorer than the precision in normal subjects. We conclude that MXA precision is generally poorer than that of MRX and that the presence of vertebral deformities has a more pronounced effect on MXA precision than on MRX precision.

Morphometric X-ray absorptiometry: reference data for vertebral dimensions

Vertebral fractures are a common and important consequence of osteoporosis and are often identified via morphometric analysis of conventional lateral spine radiographs (morphometric radiography or MRX). A new method of performing vertebral morphometry using images acquired on dual-energy X-ray absorptiometry (DXA) scanners (morphometric X-ray absorptiometry or MXA) has recently been developed. In this study, we derive reference data for vertebral heights and height ratios using MXA scans as the data source and compare the results with previously published MRX studies. One thousand and nineteen Caucasian women (mean age 63 years, range 33-86) were recruited. An MXA scan, covering 13 vertebrae from L4 to T4, was acquired for each subject on one of four DXA systems located at three centers in the U.K. Analysis of variance found statistically significant but relatively small differences among centers, machines, and scan modes, and therefore data were pooled for reference range calculations. Three vertebral heights (anterior, mid, and posterior) were measured and four ratios (wedge, mid-wedge, and two crush) calculated. These data sets were trimmed using an iterative algorithm to remove extreme values assumed to represent deformed vertebrae, then mean and SD values were calculated using the remaining data. When the data were split by age, a small but statistically significant decrease in vertebral height between the sixth and eighth decades was found, but this was not replicated for the vertebral height ratios. Marked differences were observed between MXA data and MRX, but were comparable to those between different MRX studies. These may result from differences in image quality and point placement protocols, population differences, differences in radiographic technique, and differences in the derivation of a group of "normal" vertebrae. This study suggests that reference data of vertebral dimensions should be specific to the technique which uses those data as a reference, i.e., MXA.

Heavy metal effects on Proteus mirabilis superoxide dismutase production

Proteus mirabilis expressed three superoxide dismutase activities, which depended on the level of soluble iron and dioxygen in the culture medium. Cadmium and lead decreased production of super oxide dismutase in liquid culture and on solid medium. A fourth super oxide dismutase activity appeared in extracts from cells grown in the presence of cadmium. These results support the idea of an interaction between toxic metal ions and putative iron- and redox-dependent regulatory systems.

Diurnal and longitudinal variations in human milk sodium and potassium: implication for nutrition and physiology

Human milk sodium ([Nal]) and potassium ([K)] concentrations were measured every 4 h for 24 h in 28 subjects 3.5 to 32 wk postpartum. A diurnal variation in milk Na was seen, which was reciprocal to K. Significant negative correlations between Na and K were seen in these periods: 3.5 to 6; 8 to 18, 20 to 32 wk postpartum (p less than 0.01 for each). The mean 24 h milk sodium concentrations (x(Na)) decreased between 3.5 and 18 wk postpartum (p less than 0.005 by paired t test). Changes in mean potassium (-XK) were not statistically significant. Diet apparently does not affect milk Na. Administration of a low Na diet: 10.8 +/- .9 (SD) mEq Na/day and 60 to 100 mEq K/day for 2 days did not change x(Na). But urinary Na decreased 7-fold as aldosterone increased 5-fold. No significant correlation was seen between 24 h Na excretion in urine and x(Na) in milk (n = 51). A significant positive correlation was seen between urinary K and -XK in milk (r = 0.36), p less than 0.001).

Modular Formula: an approach to management of infants with specific or complex food intolerances

Modular Formula is a dietary preparation for use in treating infants with complex malabsorptive disorders and for weaning infants from total parenteral nutrition. With this formula the physician can alter the quality of the various nutrients normally fed to infants as well as concentrations of those nutrients. Infants who cannot tolerate existing proprietary formulas will often thrive with the judicious use of this flexible formula. Modular Formula provides the clinician with a useful aid in the diagnosis and treatment of chronic diarrhea of infancy.