Crystal and molecular structure of l-valyl-l-lysine hydrochloride

l -Valyl-l -lysine hydrochloride, C₁₁N₃O₃H₂₃ HCl, crystallizes in the monoclinic space group P2, with a = 5.438(5), b = 14.188(5), c = 9.521(5) Å, β= 95.38(2)° and Z = 2. The crystal structure, solved by direct methods, refined to R = 0.036, using full matrix least-squares method. The peptide exists in a zwitterionic form, with the N atom of the lysine side-chain protonated. The two γ-carbons of the valine side-chain have positional disorder, giving rise to two conformations, χ¹¹₁= -67.3 and 65.9°, one of which (65.9°) is sterically less favourable and has been found to be less popular amongst residues branching at β-C. The lysine side-chain has the geometry of g^? tgt, not seen in crystal structures of the dipeptides reported so far. Interestingly, χ³₂ (63.6°) of lysine side-chain has a gauche⁺ conformation unlike in most of the other structures, where it is trans. The neighbouring peptide molecules are hydrogen bonded in a head-to-tail fashion, a rather uncommon interaction in lysine peptide structures. The structure shows considerable similarity with that of l -Lys-l -Val HO in conformational angles and H-bond interactions [4].     

Comparative analysis of oncological morbidity in the population of an industrial city and workers of a metallurgical plant

Analytical epidemiology techniques were used to study the malignant neoplasms prevalence in the population of Magnitogorsk (400,000), and among the workers engaged in the Magnitogorsk metallurgical plant (64,000 workers). Revealed was that the malignant neoplasms related morbidity rate was 1.6 higher in men and 3.2 higher in women among the plant workers as compared with the city population in general. The cancer risk factors were predominantly occupational ones, e. i. the major industrial carcinogens--benzopyrene in tars and carbon-black; benzol, chromium and nickel in the dust; the carcinogenesis modifying substances--nitrogen oxide, sulfur dioxide, phenols, iron oxides, lead and its non-organic compounds, high temperatures. The data received can be used in further studies and elaboration of primary preventive measures.     

Indoor 222Rn levels in New York State, North Carolina, and South Carolina

Results are presented from approximately 9000 Rn measurements made in New York state, North Carolina, and South Carolina. The estimated statewide geometric mean concentrations were 28.1 Bq m-3 and 55.8 Bq m-3 for basements in New York state, 27.5 Bq m-3 for living rooms and 108.9 Bq m-3 for basements in North Carolina, and 25.0 Bq m-3 for living rooms in South Carolina.     

Lymphocyte subpopulations in the thymus, lymph nodes and spleen of iron-deficient and rehabilitated mice

Three groups of weanling female mice were fed one of two iron-deficient diets (5 and 12 mg Fe/kg diet) or a normal diet (30 mg Fe/kg diet) for 6 wk. A control pair-fed group was included. Seven mice received the 5 mg Fe/kg diet for 6 wk, then were rehabilitated using the 30 mg Fe/kg diet for 10 d. Mice fed the 5 mg Fe/kg diet were moderately iron-deficient, as shown by indices of iron status. No significant differences were observed in thymus weight or in the proportion and number of thymocyte subsets in thymuses of anemic, moderately iron-deficient and control mice. Thymus weight was decreased in pair-fed mice. No significant difference was found in lymph node subsets. In the spleen of anemic mice, the proportions and total number of Thy-1+ splenocytes, CD4-8+ and CD4+8- cells were very low compared with control (P less than 0.01) and iron-deficient (P less than 0.02) mice. The decrease was not only observed for the percentage of subsets but also for the absolute number of cell subtypes per spleen. Thy-1+ splenocyte subpopulations were normalized after rehabilitation. These quantitative modifications could explain alterations in the blastogenic response of splenic lymphocytes described by other authors.     

The transient hypercholesterolemia of major weight loss

Serum lipoproteins, body composition, and adipose cholesterol contents of six obese women were studied during and after major weight loss by very-low-calorie diets (VLCDs). Subjects started at 168 +/- 11% of ideal body weight, lost 30.3 +/- 3.7 kg in 5-7 mo, followed by 2+ mo in weight maintenance. Serum cholesterol fell from a prediet (baseline) value of 5.49 +/- 0.32 to 3.62 +/- 0.31 mmol/L (P less than 0.01) after 1-2 mo of VLCDs (nadir), after which it rose to 5.95 +/- 0.36 mmol/L (peak, P less than 0.01 compared with nadir and baseline) as weight loss continued. With weight maintenance, serum cholesterol fell to 4.92 +/- 0.34 mmol/L (P less than 0.05 compared with peak). Adipose cholesterol content did not change in peripheral (arm and leg) biopsy sites but rose significantly in abdominal adipose tissue with weight loss. We conclude that major weight loss was associated with a late rise in serum cholesterol, possibly from mobilization of adipose cholesterol stores, which resolved when weight loss ceased.