Alpha-thalassemia in two Mediterranean populations

We used restriction endonuclease analysis to determine the incidence of alpha-thalassemia in two Mediterranean islands. In a random population sample, the gene frequency of deletion-type alpha-thalassemia-2 (- alpha) was 0.18 in Sardinians and 0.07 in Greek Cypriots. All cases were the rightward crossover type. From these frequencies and the known incidence of hemoglobin-H disease in these populations, we calculated the frequency of the alpha-thalassemia-1 genotype (--) and determined that it was low. We also found that beta-thalassemia homozygotes in sardinia have a higher incidence of alpha-thalassemia than normals and beta thalassemia heterozygotes because a significantly greater number of these homozygotes are also homozygous for the alpha-thalassemia-2 lesion. These findings support the theory that coinheritance of alpha- thalassemia mitigates the severity of beta-thalassemia and suggest that the protection is most pronounced when two alpha-globin genes are deleted.     

Social perception of speech in individuals with oropharyngeal reconstruction

Oral cancer affects approximately 5% of the Canadian population every year. One option for treatment of oropharyngeal cancer includes resection of the diseased tissue with primary reconstruction of the defect using a microvascular free flap, followed by post-operative adjuvant radiation therapy. The aim of reconstructive surgery is to maintain functional speech and swallowing. While the literature provides support for the maintenance of speech intelligibility following reconstructive procedures, certain aspects of resonance may be altered when the palatal structures are involved. Little is known about the effect of such alterations on the perception of speakers who have been treated with microvascular free flap reconstruction. Social perception is a process in which we infer attributes of others, with the speech signal playing an integral part in attribution. The purpose of this study was to explore the social perceptions formed about speakers both before and after surgery for oropharyngeal cancer. The results of this study revealed that positive perceptions of speakers significantly diminished as a result of surgery and negative perceptions increased. Certain variables, such as degree of resection of the soft palate and base of tongue, and sex of the speaker, had influence on the results. This research suggests that intelligibility measurements of speech, although useful, do not provide a complete indication of the social impact of reconstructive surgery on patients with oropharyngeal resections.     

Role of prostaglandins in the pathogenesis of X-linked hypophosphatemia

X-linked hypophosphatemia is an X-linked dominant disorder resulting from a mutation in the PHEX gene. PHEX stands for phosphate-regulating gene with endopeptidase activity, which is located on the X chromosome. Patients with X-linked hypophosphatemia have hypophosphatemia due to renal phosphate wasting and low or inappropriately normal levels of 1,25-dihydroxyvitamin D. The renal phosphate wasting is not intrinsic to the kidney but likely due to an increase in serum levels of fibroblast growth factor-23 (FGF-23), and perhaps other phosphate-wasting peptides previously known as phosphatonins. Patients with X-linked hypophosphatemia have short stature, rickets, bone pain and dental abscesses. Current therapy is oral phosphate and vitamin D which effectively treats the rickets and bone pain but does not adequately improve short stature. In this review, we describe recent observations using Hyp mice; mice with the same mutation as patients with X-linked hypophosphatemia. We have recently found that Hyp mice have abnormal renal prostaglandin production, which may be an important factor in the pathogenesis of this disorder. Administration of FGF-23 in vivo results in phosphaturia and an increase in prostaglandin excretion, and FGF-23 increases proximal tubule prostaglandin production in vitro. In Hyp mice, indomethacin improves the phosphate transport defect in vitro and in vivo. Whether indomethacin has the same effect in patients with X-linked hypophosphatemia is unknown.     

Malignant blue nevus of the parotid gland: A case report

BACKGROUND: Malignant blue nevus is a highly aggressive tumor arising from a background of benign blue nevus. Extensive review of the medical literature revealed a few reported cases of this transformation from cutaneous origin. We report the first case of blue nevus of the parotid gland and its malignant transformation within this gland. METHODS: A 62-year-old woman presented to our clinic with sudden onset parotid mass. After a superficial parotidectomy, histologic examination of the specimen was performed. Features compatible with blue nevus with focal region of atypical mitotic activity were evident. The diagnosis of malignant blue nevus was confirmed by immunohistochemical studies. RESULTS: We report the first case of malignant transformation of blue nevus within the parotid gland. CONCLUSIONS: We found this lesion to be highly aggressive and to have metastasized shortly after diagnosis.     

Stimulation of growth hormone secretion in children with X-linked hypophosphatemia

X-linked hypophosphatemia is characterized by low serum phosphorus, relative vitamin D deficiency and rickets. Despite adequate metabolic control with oral phosphate and vitamin D therapy, patients with X-linked hypophosphatemia have short stature. Whether growth hormone (GH) deficiency plays a role in short stature in patients with X-linked hypophosphatemia is not known. The purpose of this report was to investigate the response of GH to sequential paired pharmacological stimulation in patients with X-linked hypophosphatemia. Basal GH was 3.8±0.7 ng/ml, insulin-like growth factor-I (IGF-I) was 225±38 ng/ml and IGF binding protein-3 was 3.0±0.2 mg/l in 16 children studied with X-linked hypophosphatemia. In response tol-dopa and arginine hydrochloride stimulation, serum GH rose to above 7 mg/ml in all patients. Thus, the short stature in patients with X-linked hypophosphatemia is not due to a GH/IGF-I secretory defect.     

Use of rhGH in children with chronic kidney disease: lessons from NAPRTCS

We evaluated the utilization and potential benefits of recombinant human growth hormone (rhGH) in children with chronic kidney disease (CKD) and following renal transplantation in a large patient cohort. We queried the chronic renal insufficiency (CRI), dialysis, and transplant registries of the North American Pediatric Renal Trials and Collaborative Studies (NAPRTCS) to characterize the frequency of rhGH utilization, factors related to its usage, and the relationship between rhGH usage and catch-up growth. Data from 6,505, 5,122, and 4,478 CRI, dialysis, and transplant patients, respectively, was evaluated. Percentage utilization of rhGH 2 years after registry entry was 22%, 33%, and 3% in children with a height standard deviation score (SDS) <−1 and age <17 years (termed candidate group) in CRI, dialysis, and transplant patients, respectively. Multivariate logistic regression analysis showed that the likelihood of using rhGH was significantly correlated with age, gender, geographical region of residence and height category within the candidate group (p < 0.01). The use of rhGH was associated with catch-up growth in 27%, 11%, and 25% of candidate CRI, dialysis, and transplant patients, respectively. In the candidate group, percentage catch-up growth was highest in children who were Tanner stage 1–2, who comprised 19.4%, 7.1%, and 25.5% of the CRI, dialysis, and transplant patients, respectively. Using multiple regression analysis, the estimated impact of rhGH on final adult height (age >19 years) was 0.80, 0.50, and 0.19 SDS, in CRI, dialysis, and transplant patients, respectively. Thus, rhGH can improve height gain in some children with CKD. The use of rhGH appears to be most effective in prepubertal children with CRI.     

The long-term effectiveness of generic adult fixed-dose combination antiretroviral therapy for HIV-infected Ugandan children

Background

Access to pediatric antiretroviral formulations is increasing in resource-limited countries, however adult FDCs are still commonly used by antiretroviral therapy (ART) programs.

Objective

To describe long-term effectiveness of using adult FDC of d4T+3TC+NVP (Triomune) in children for HIV treatment.

Methods

Clinical, immunologic, and virologic outcomes of HIV-infected ART-naïve children aged six months to 12 years, were evaluated up to 96 weeks post-ART initiation.

Results

From March 2004 to June 2006, 104 children were followed with a median age of 5.4 years, median CD4 cell percent and HIV-1 RNA were 11.0% (IQR 6.7–13.9) and 348,846copies/mL (IQR 160,941–681,313) respectively at baseline. Using Kaplan-Meir estimates, 75% of children had undetectable viral loads (<400copies/mL) at 96weeks of ART. Children with a baseline CD4 cell percent >15% were 3 times more likely to achieve viral load <400copies/mL than those with baseline CD4 cell percent <5% after adjusting for baseline age {aHR = 3.03 (1.10–8.32), p=0.03}; no difference was found among those with CD4 cell percent >5–14.9% and <5%.

Conclusion

Treatment with generic adult FDC for HIV-infected Ugandan children led to sustained clinical, immunologic and virologic response during 96 weeks of ART. Early initiation of ART is key to achieving virological success.