Complications of the Low Phenylalanine Diet for Patients with Phenylketonuria and the Benefits of Increased Natural Protein.

Phenylketonuria (PKU) is an inherited disorder in which phenylalanine (Phe) is not correctly metabolized leading to an abnormally high plasma Phe concentration that causes profound neurologic damage if left untreated. The mainstay of treatment for PKU has centered around limiting natural protein in the diet while supplementing with medical foods in order to prevent neurologic injury while promoting growth. This review discusses several deleterious effects of the low Phe diet along with benefits that have been reported for patients with increased natural protein intake while maintaining plasma Phe levels within treatment guidelines.

Inequities in multi-gene hereditary cancer testing: lower diagnostic yield and higher VUS rate in individuals who identify as Hispanic, African or Asian and Pacific Islander as compared to European.

The identification of germline pathogenic/likely pathogenic (P/LP) variants in cancer predisposition genes can guide treatment and management decisions for the individual being tested and potentially at-risk relatives. Prior studies have raised concerns of racial/ethnic disparities in the detection rates of P/LP variants and variants of uncertain significance (VUSs). In 2018, Color Genomics™, a commercial laboratory, made de-identified, aggregate genetic and clinical information from 50,000 individuals who completed testing for 30 cancer predisposition genes publicly available. It is the largest publicly available database of its kind from a single laboratory. An analysis of individuals from this database with a negative personal history of cancer that identify as European (n = 31,920), Hispanic (n = 1700), African (n = 462) or Asian and Pacific Islander (n = 2602), demonstrated that the VUS rate in the hereditary breast and ovarian cancer syndrome and Lynch syndrome genes was higher for all non-European groups as compared to the European group; Hispanic (7.1% vs. 5.8%; p = 0.029), African (12.3% vs. 5.8%; p < 0.001), Asian and Pacific Islander (13.1% vs. 5.8%; p < 0.001). In the other cancer genes (OCGs), the P/LP rate was lower; Hispanic (5.1% vs. 7.6%; p < 0.001), African (2.4% vs. 7.6%; p < 0.001), and Asian and Pacific Islander (4.3% vs. 7.6%; p < 0.001). The VUS rate was also higher in the OCGs; Hispanic (16.2% vs. 12.2%; p < 0.001), African (21.6% vs. 12.2%; p < 0.001), Asian and Pacific Islander (24.4% vs. 12.2%; p < 0.001). Our study emphasizes the reality of disparities in the results of cancer genetic testing and highlights factors that propagate these inequities.

Late pathologic changes in guinea pig kidneys irradiated with conventional fractionation and hyperfractionation.

PURPOSE: The aim of this study was to determine the differences in renal damage particularly associated with the effect of a small dose per fraction with a constant total dose. METHODS AND MATERIALS: Guinea pigs, 12-week-old English Hartley females, were used. The animals were divided into five groups according to irradiation schedule: No irradiation (control group); 2.0 Gy x 1/day, 5 fraction (f)/week (wk), 40 f, total 80 Gy (Group CF-2.0 [CF = conventional fractionation]); 1.0 Gy x 2/day, 10 f/wk, 80 f, total 80 Gy (Group HF-1.0 [HF = hyperfractionation]); 3.0 Gy x 1/day, 5 f/wk, 27 f, total 81 Gy (Group CF-3.0); and 1.5 Gy x 2/day, 10 f/wk, 54 f, total 81 Gy (Group HF-1.5). Only unilateral irradiation was performed. A histologic analysis was performed before irradiation and at 6 and 12 months after the completion of irradiation. The severity and severity ratios of urinary tubule atrophy, the number of large nuclei per unit area in the renal tubules, the average diameter of the glomeruli, and the number of cells composing the glomerulus were used as parameters for evaluating renal damage. RESULTS: In Groups CF-2.0 and CF-3.0 (the conventional fractionation [CF] groups), all the renal tubules showed severe atrophy 12 months after irradiation. On the other hand, only 20% of the renal tubules showed slight atrophy in Group HF-1.0 at 12 months. In Group HF-1.5, 70% of the renal tubules were atrophic at 12 months. The number of large nuclei markedly increased in Groups HF-1.0 and HF-1.5 (the hyperfractionation [HF] groups) at 12 months, whereas the number was very low in the CF groups at 12 months. Only in Group HF-1.0 had the average diameter of glomeruli not shrunk at 12 months. The number of cells composing the glomerulus in the CF groups markedly decreased at 12 months. The number of cells in the HF groups was also reduced, however the reduction was not as severe as that observed in the CF groups. CONCLUSION: 1.0 Gy per fraction delivered by HF greatly reduces renal damage even in the 80 Gy-irradiated kidney, which is one of the most radiosensitive organs.

[Development of apoptosis induced by whole-body irradiation in murine liver].

Apoptosis is known to be induced by radiation. However, the correlation between radiation-induced apoptosis and radiation injury in tumors in vivo has been unclear. In this paper, we report the study of apoptosis induced by whole-body irradiation using an immunohistochemical technique to detect DNA fragmentation in murine liver. A dose of 7 Gy was employed as LD50/30. DNA fragmentation was observed 30 min after radiation, and it peaked between 1 and 6 hours. DNA fragmentation could be detected 48 hours after radiation in capillary endothelium. This study was able to reveal the development of radiation-induced apoptosis in the liver by detecting DNA fragmentation in situ.

[Changes in blood flow and skin reaction following radiation therapy].

Skin blood flow (SBF) during radiation therapy was measured and compared with skin reaction to examine the relationship between skin reaction and blood flow. The SBF of 50 patients including 16 with head and neck (H&N) cancer, 13 with breast cancer and eight with lung cancer were analyzed. In the H&N patients, SBF was increased according to the treated dose, while in the breast cancer patients SBF was slightly increased at 10 Gy, and did not change up to 40 Gy. In the lung cancer patients SBF was not increased until 20 Gy, and thereafter increased moderately at 30 Gy. Among H&N, breast and lung cancer patients, the most severe skin reaction was observed at the earliest time in breast cancer patients, while blood flow was only slightly increased. This must have resulted in a relatively higher skin dose than the reference point dose in breast cancer patients. Therefore, differences in the relationship between SBF and skin reaction were observed among different types of cancer patients. However, in H&N cancer patients, SBF was increased as skin dose increased. Skin blood flow could be a good indicator by which to estimate skin reaction quantitatively when the daily skin dose is around 1.6 Gy.