Water in normal muscle and muscle with a tumor

The total water content, the amount of non-freezable water, and the Na⁺ and K⁺ contents in the gastrocnemius muscle of albino mice with and without a solid tumor were determined. The spin-lattice relaxation time (T₁) for the water protons in the two kinds of muscle were measured at six resonance frequencies ranging from 4.5 to 60 MHz over the temperature range +37 to −65°C. Quantitatively calculated T₁ values are given. The difference in T₁ for the two types of muscle at temperatures above −5°C is attributed to the difference in the distribution ratio of water between hydration and free states, and bears no direct relation to the concentration of Na⁺.     

The state of water in biological systems as studied by proton and deuterium relaxation.

Careful experiments on the measurement of the intensity of the deuterium NMR signal for 2-H2 O in muscle and in its distillate were performed, and they showed that all 2-H2 O muscle is "NMR visible". The spin-lattice relaxation time (T1) of the water protons in the muscle and liver of mice and in egg white has been studied at six frequencies ranging from 4.5 to 6.0 MHz over the temperature range of +37 to --70 degrees C. T1 values of deuterons in 2H2 O of gastrocnemius muscle and liver of mice have been measured at three frequencies (4.5, 9.21 and 15.35 MHz) over the temperature range of +37 to --20 degrees C. Calculations on T1 for both proton and deuteron have been made and compared with the experimental data. It is suggested that the reduction of the T1 values compared to pure water and the frequency dependence of T1 are due to water molecules in the hydration layer of the macromolecules, and that the bulk of water molecules in the biological tissues and egg white undergoes relaxation like ordinary liquid water.     

The state of water in biological systems as studied by proton and deuterium relaxation

Careful experiments on the measurement of the intensity of the deuterium NMR signal for ²H₂O in muscle and in its distillate were performed, and they showed that all ²H₂O in muscles is “NMR visible.”The spin-lattice relaxation time (T₁) of the water protons in the muscle and liver of mice and in egg white has been studied at six frequencies ranging from 4.5 to 6.0 MHz over the temperature range of +37 to −70°C. T₁ values of deuterons in ²H₂O of gastrocnemius muscle and liver of mice have been measured at three frequencies (4.5, 9.21 and 15.35 MHz) over the temperature range of +37 to −20°C. Calculations on T₁ for both proton and deuteron have been made and compared with the experimental data. It is suggested that the reduction of the T₁ values compared to pure water and the frequency dependence of T₁ are due to water molecules in the hydration layer of the macromolecules, and that the bulk of water molecules in the biological tissues and egg white undergoes relaxation like ordinary liquid water.     

LEVELS OF NOREPINEPHRINE AND DOPAMINE IN MOUSE BRAIN REGIONS FOLLOWING MICROWAVE INACTIVATION-RAPID POST-MORTEM DEGRADATION OF STRIATAL DOPAMINE IN DECAPITATED ANIMALS

—The effects of 2 methods of killing on norepinephrine and dopamine in mouse brain regions were examined. One method utilized decapitation, while the other method utilized heating with microwave irradiation concentrated on the head. The norepinephrine and dopamine contents of the cerebellum, medulla-pons, midbrain, diencephalon, hippocampus, corpus striatum, and cerebral cortex were determined by methods using liquid chromatography with electrochemical detection. Dopamine content in striatum was also quantitated by the method of gas chromatography with mass fragmentography. A significantly lower value for decapitated animals, as compared to the microwave heated group, was found only for dopamine exclusively in the striatum. Activities of the enzymes tyrosine hydroxylase, DO PA decarboxylase, monoamine oxidase, and catechol-o-methyltransferase in the striatum were also examined. These enzymes were totally inactivated by the microwave heating, except catechol-o-methyltransferase which was decreased approx 80%. These results support either (1) the existence of a substantial pool of dopamine in the striatum with a very rapid turnover rate or (2) a decapitation-related release and destruction of striatal dopamine. Measurements of 3-methoxytyramine in the striatum exhibit post-mortem increases corresponding to the decreases of dopamine. Use of the rapid tissue enzyme inactivation technique suggests that in vivo levels of this O-methylated dopamine metabolite are an order of magnitude lower than the results normally obtained after killing by decapitation.     

Longitudinal Liver Stiffness Assessment in Patients with Chronic Hepatitis C Undergoing Antiviral Therapy

Background/Aims

Liver stiffness (LS) measurement by means of transient elastography (TE) is accurate to predict fibrosis stage. The effect of antiviral treatment and virologic response on LS was assessed and compared with untreated patients with chronic hepatitis C (CHC).

Methods

TE was performed at baseline, and at weeks 24, 48, and 72 in 515 patients with CHC.

Results

323 treated (62.7%) and 192 untreated patients (37.3%) were assessed. LS experienced a significant decline in treated patients and remained stable in untreated patients at the end of study (P<0.0001). The decline was significant for patients with baseline LS ≥ 7.1 kPa (P<0.0001 and P 0.03, for LS ≥9.5 and ≥7.1 kPa vs lower values, respectively). Sustained virological responders and relapsers had a significant LS improvement whereas a trend was observed in nonresponders (mean percent change −16%, −10% and −2%, for SVR, RR and NR, respectively, P 0.03 for SVR vs NR). In multivariate analysis, high baseline LS (P<0.0001) and ALT levels, antiviral therapy and non-1 genotype were independent predictors of LS improvement.

Conclusions

LS decreases during and after antiviral treatment in patients with CHC. The decrease is significant in sustained responders and relapsers (particularly in those with high baseline LS) and suggests an improvement in liver damage.     

Specialized contacts between sarcolemma and sarcoplasmic reticulum at the ends of muscle fibers in the diaphragm of the rat

Summary An electron-microscopic study of the myotendinous portion of the diaphragm in the Wistar rat has shown that at the ends of muscle fibers, longitudinally oriented invaginations and peripheral furrows of the sarcolemma establish specialized contacts with individual sacs of the sarcoplasmic reticulum. The construction of these terminal contacts is similar to that of contacts between sarcolemmic T-tubules and terminal cisternae of the sarcoplasmic reticulum, characterized by formation of triads. The contact zones of the sac membrane are undulated and bound to the adjoining sarcolemma via electron-dense profiles of varying forms. Frequently, the terminal contacts and triads are located at the same level within the muscle fiber, at the borderline between A- and I-bands of the sarcomeres. At the ends of muscle fibers combined contacts between peripheral furrows of the sarcolemma, terminal cisternae of the sarcoplasmic reticulum, and T-tubules of the triads are also disclosed. The implications of the terminal contacts for muscle contraction are discussed.