Purpose: To use proton magnetic resonance spectroscopy ( 1 H-MRS) to evaluate vertebral marrow fat, and to determine whether bone density correlates with fat content and fat unsaturation levels in postmenopausal women. Materials and Methods:Fifty-three women (mean age ϭ 70 years) underwent dual energy x-ray absorptiometry and 1 H-MRS, and 12 young female controls (mean age ϭ 28 years) underwent 1 H-MRS of the lumber spine. Water and lipid peak amplitudes were measured to calculate fat content and fat unsaturation index. Spearman's correlation tests and a t-test comparison of means were applied. Results:1 H-MRS was successful in 15 normal, 15 osteopenic, and 20 osteoporotic subjects, and in all controls. Marrow fat content was significantly elevated in osteoporotic (65.5% Ϯ 10%) and osteopenic (63.5% Ϯ 9.3%) subjects compared to normal subjects (56.3% Ϯ 11.2%) and young controls (29% Ϯ 9.6%). The fat unsaturation index was significantly decreased in osteoporotic (0.091 Ϯ 0.013) and osteopenic (0.097 Ϯ 0.014) subjects compared to normal subjects (0.114 Ϯ 0.016) and young controls (0.127 Ϯ 0.031). A good inverse correlation was observed between the fat content and the unsaturation index (r s ϭ -0.53, P Ͻ 0.0001). Conclusion:Osteoporosis is associated with increased marrow fat. As marrow fat increases, saturated lipids appear to increase preferentially to unsaturated lipids.

The subjects experienced a decrease in vertebral marrow maximum enhancement and enhancement slope and an increase in marrow fat content as bone density decreased. The reduction in perfusion indexes occurred only within the vertebral body and not in the paravertebral tissues supplied by the same artery.

Early intratreatment DW imaging has the potential to allow prediction of treatment response at the primary site in patients with HNSCC.

Purpose: To investigate vertebral bone marrow fat content in elderly subjects related to sex, age, and bone mineral density (BMD) and relate these findings to published data in younger subjects. Materials and Methods:A total of 259 healthy subjects (145 females, 114 males; age range, 62-90 years) underwent proton ( 1 H) MR spectroscopy of L3 vertebral body and BMD of the lumbar spine with results stratified according to age. Ninety age-and BMD-matched subjects were selected to determine sex differences in marrow fat content and BMD.Results: In females, vertebral marrow fat content rose sharply between 55 and 65 years of age while in males vertebral marrow fat content rose gradually throughout life. Vertebral marrow fat content in females more than 60 years was approximately 10% higher in females than males, i.e., a reversal of sex difference reported in marrow fat content for subjects less than 60 years. Conclusion:Marrow fat content increases sharply in female subjects between 55 and 65 years of age while male subjects continue to increase marrow fat at a more gradual steady rate. Females older than 60 years have a higher marrow fat content than males. This increased deposition in marrow fat concurs with recognized changes in extraosseous fat distribution in postmenopausal females.

Choline can be reliably detected in less than 45 minutes in large contrast-enhanced breast lesions by using a multiecho point-resolved spectroscopic protocol. The presence of water-soluble choline metabolites obtainable with (1)H MR spectroscopy could complement MR imaging findings to improve specificity and to reduce the number of unnecessary biopsies.

1. Phosphopyruvate carboxylase activity rapidly appears in the liver of prematurely delivered rats and development of activity is prevented by injection of actinomycin D just before delivery. 2. The activity is considerably decreased by puromycin and amino acid analogues and thus appears to be due to enzyme synthesis. 3. Newborn or premature animals show a transient intense phase of hypoglycaemia after delivery. 4. When the hypoglycaemic phase is prevented by glucose injection little phosphopyruvate carboxylase activity appears in the liver, but galactose, mannose and fructose, which have no effect on the blood glucose concentration, also repress enzyme development. 5. Lactate, pyruvate and glycerol injections repress the premature development of phosphopyruvate carboxylase. 6. Injections of glucagon, adrenalin and noradrenalin into the rat foetus in utero result in development of phosphopyruvate carboxylase activity. 7. These findings are discussed in relation to the mechanism of initiation of enzyme synthesis in neonatal rat liver.

1. The normal development of the key enzymes of gluconeogenesis in rat liver, glucose 6-phosphatase, hexose diphosphatase, phosphopyruvate carboxylase and pyruvate carboxylase, was measured during the neonatal period. 2. Glucose 6-phosphatase, hexose diphosphatase and pyruvate carboxylase are all present in the late foetal liver, but all the enzymes show an increase in activity after birth. 3. Phosphopyruvate carboxylase is not present in liver extracts from foetal rats, but activity appears immediately after birth and increases rapidly over the first day and then more slowly to reach its maximum at the fourth postnatal day. 4. The fluorinated synthetic glucocorticoid, triamcinolone, was administered to foetal rats at various gestation times by intraperitoneal injection in utero and the animals were killed at intervals between 4 and 48hr. later. 5. The administration of triamcinolone results in slight depression of glucose 6-phosphatase, and a more significant depression of hexose diphosphatase to about one-half its normal activity in foetal rat liver. 6. Triamcinolone injection is without effect on pyruvate carboxylase activity and does not result in premature appearance of phosphopyruvate carboxylase in foetal rat liver. 7. Pyruvate kinase and aspartate amino-transferase activities in foetal rat liver are both depressed by triamcinolone treatment, whereas phosphofructokinase activity is elevated. 8. Tyrosine amino-transferase activity in foetal rat liver is markedly elevated in animals exposed to triamcinolone for 10hr. or more, but the effect is only observed in animals close to term. 9. The results are discussed in relation to mechanisms involved in the initial synthesis of tissue-specific enzymes in developing tissues, and it is concluded that glucocorticoids do not initiate the synthesis of the gluconeogenic enzymes.

PurposeTo technically investigate the non-Gaussian diffusion of head and neck diffusion weighted imaging (DWI) at 3 Tesla and compare advanced non-Gaussian diffusion models, including diffusion kurtosis imaging (DKI), stretched-exponential model (SEM), intravoxel incoherent motion (IVIM) and statistical model in the patients with nasopharyngeal carcinoma (NPC).Materials and MethodsAfter ethics approval was granted, 16 patients with NPC were examined using DWI performed at 3T employing an extended b-value range from 0 to 1500 s/mm2. DWI signals were fitted to the mono-exponential and non-Gaussian diffusion models on primary tumor, metastatic node, spinal cord and muscle. Non-Gaussian parameter maps were generated and compared to apparent diffusion coefficient (ADC) maps in NPC.ResultsDiffusion in NPC exhibited non-Gaussian behavior at the extended b-value range. Non-Gaussian models achieved significantly better fitting of DWI signal than the mono-exponential model. Non-Gaussian diffusion coefficients were substantially different from mono-exponential ADC both in magnitude and histogram distribution.ConclusionNon-Gaussian diffusivity in head and neck tissues and NPC lesions could be assessed by using non-Gaussian diffusion models. Non-Gaussian DWI analysis may reveal additional tissue properties beyond ADC and holds potentials to be used as a complementary tool for NPC characterization.