Protein substitution to produce a processed cheese with high branched-chain amino acids of medical and genetic importance

The most important metabolic impairment in patients with advanced liver disease is characterized by low levels of circulating branched chain amino acids [BCAAs]. The etiology of such abnormal amino acid metabolism is multifactorial including protein restricted diet or inadequate nutritional intake as in protein energy malnutrition. Multiple studies report the beneficial effects of BCAAs supplementation to improve plasma amino acids imbalance, several neurologic diseases, protein energy malnutrition, and subsequently the survival rate of cirrhotic patients. In the present study we used a protein substitution technique to synthesize a new processed cheese as a dairy source rich in BCAAs, with low phenylalanine content manufactured from Ras cheese, kariesh cheese, butter oil and phenylalanine-free milk. Chemical composition, amino acids analysis, rheological properties and sensory evaluation were done to all of the cheese samples. L-Phenylalanine was selected to induce hepatic and brain affections in Begg Albino strain c [BALB/c] mice model. Effect of 2.5%, 5% and 10% protein-replacement cheese formulas was evaluated among mice groups including histopathological sections of the liver and brain; colorimetric determination for liver enzymes; serum total and differential cholesterol profile, serum albumin, globulin and total protein along with phenylalanine levels determinations. Analysis of the processed cheese sample with 10% protein substitution revealed that the protein content was 7.42 mg/g [about 50% of the content in the standard processed cheese] while fat content, acidity and moisture were nearly the same. The sensory score for all the formulas ranged from 79-88. Highest content of BCAAs along with least phenylalanine content was attained in the processed cheese with 10% protein substitution. Weight of mice fed on different substitution formulas ranged from 22.8 +/- 2.2-24.66 +/- 2.5 g compared with 17.8 +/- 1.9 g in the untreated diseased mice [P< 0.05]. Serum phenylalanine was 1.822 +/- 0.42 mg/dl in the mice fed on 10% protein substitution formula compared to 6.2 +/- 1.32 mg/dl in the untreated mice [P < 0.01]. There was a highly significant difference [P <0.01] between untreated mice and mice fed on 10% substitution cheese formula as regards the serum protein, Aspartate Transaminase [AST] and Alanine Transaminase [ALT]. The improvement in histopathological findings was more apparent in the mice fed on 10% formula cheese. The manufactured processed cheese with 10% protein substitution was proved to have a more nutritional therapeutic potential that can help in the implementation of dietary management in many medical and genetic disorders with liver and brain affections

Histopathological, lipid and protein profiles of BALB/c mice model fed with low phenylalanine skim milk formulae

The aim of the present study was to synthesize two low-phenylalanine diet formulae. These formulae were to be readily available from natural milk [skim milk] using two proteolytic purified enzymes [immobilized papain and protease XXIII]. Skim milk hydrolysate was adsorbed on either barium sulphate or on activated carbon. The formula was supplying 0.71 g phenylalanine/100 g protein and 0% free phenylalanine in the formula adsorbed on barium sulphate compared with 3.41% in the formula adsorbed on activated carbon. The effects of such two formulae on the cellular pathology, lipid and protein profiles were studied in an animal PKU model. BALB/c mice were used to induce hyperphenylalaninemia using 3% L-phenylalanine and 0.3% L-ethionine. The study concluded that skim milk hydrolysate formulae proved to be effective in reducing the blood level of phenylalanine and restoration of the cellular normal pattern as well as cellular lipids and protein profiles. These formulae may be helpful in the implementation of dietary management of PKU children and the hyperphenylalaninemia mothers, especially before conception and during pregnancy

La nueva genética / The new genetics

Actualmente, la genética moderna se considera una disciplina central en el estudio de la variabilidad y la herencia humana; ha permitido el entendimiento de muchas enfermedades de las diferentes áreas médicas y en un futuro se esperan importantes logros. El modelo de herencia mendeliana en la que rasgos dominantes y recesivos se transmiten de acuerdo a la segregación cromosómica es la base del conocimiento de las enfermedades genéticas. Sin embargo, muchos clínicos se encuentran con familias cuya historia genética no se explica fácilmente por este esquema. La genética molecular ha revelado nuevos mecanismos acerca de la herencia humana que permite explicar esta ®herencia no tradicional¼, la cual incluye principalmente: el mosaicismo, herencia mitocondrial, impronta genómica, disomía uniparental y enfermedades por trinucleótidos de repetición