Efficient pulse sequence for multisection dual-repetition time MR image acquisition

A magnetic resonance imaging pulse sequence was developed in which multisection spin-echo image data are simultaneously acquired for two repetition time (TR) intervals (TR1 and TR2) in one imaging sequence. In a conventional multisection image at a single TR, the number of sections is limited to TR/TS, where TS is the readout time. With this new sequence, the number of sections that can be imaged at both TRs in one acquisition is equal to (TR1 + TR2)/(TS1 + TS2), where TS1 and TS2 may be different for the two TRs. Imaging time is equal to that for a single image at a TR of TR1 + TR2. Clinical images were obtained with the new sequence from 15 patients and compared with images acquired at the same TR/TE by means of standard multisection single-TR methods. Relative image quality was assessed by three radiologists in 37 comparisons. In general, the dual-TR results at the long TR were judged equivalent to those from a single-TR image. Dual-TR results at the short TR had a modest reduction in contrast, but in none of 15 cases were any pathologic features missed.     

The presence of astrocytes in areas of demyelination influences remyelination following transplantation of oligodendrocyte progenitors

To date, most experiments examining the myelination potential of transplanted cells have been undertaken into either the immature nervous system or into acutely demyelinating lesions. Since these are situations where myelination or remyelination are occurring, such studies provide little information on the likely outcome of introducing myelinogenic cells into area of chronic demyelination. In an attempt to gain a greater understanding of the interaction between astrocytes and oligodendrocyte progenitors in areas of demyelination, we undertook transplantation experiments in which an identical preparation of oligodendrocyte progenitors (OPCs) was (1) transplanted directly into astrocyte-free areas of acute demyelination (3 days after induction), (2) transplanted cranial to similar areas of demyelination (20 days after induction) or (3) transplanted cranial to areas of demyelination (20 days after induction) that had been injected with astrocytes at 3 days to confront OPCs with demyelinated axons in an astrocytic environment. The acute astrocyte-free lesions were remyelinated by oligodendrocytes and Schwann cells while the delayed interaction of OPCs with demyelinating lesions resulted in only oligodendrocyte remyelination, the extent of which was reduced when the area of demyelination contained astrocytes. The results of these experiments illustrate that the introduction of OPCs into an astrocyte-free area of demyelination soon after its induction favours Schwann cell differentiation while the presence of established astrocytes in an area of demyelination has an inhibitory effect on the extent of oligodendrocyte remyelination achieved by OPCs.     

Apparent digestibility and proteic quality of the basic diet of Rio de Janeiro State complemented with multimixture

Some factors in food can influence the protein digestibility positively or negatively. The protein quality is related to the protein synthesis capacity, growth, maintenance, reproduction and reconstitution of an organism. This work aims to determine the apparent digestibility coefficient and the protein quality of the standard basic diet of Rio de Janeiro State (HERJ), complemented with 2% of the multimixture (HERJ + MM), during rats' gestation and lactation periods. The results indicated a lower apparent digestibility coefficient (P < 0.05) during the gestation and lactation periods in HERJ diets (82.4% ± 0.55; 80.64% ± 1.7) and HERJ + MM (80.9% ± 3.28; 81.7% ± 1.2), in comparison to the casein diet (91.8% ± 0.6; 93.9% ± 0.4). There was no significant difference (P < 0.05) between HERJ diet (2.75 ± 0.14) and HERJ + MM diet (2.53 ± 0.18). However, the casein diet has showed a higher lactation value (3.27 ± 0.3) in comparison with the two above mentioned groups. Therefore the use of the multimixture at 2% level neither impairs the apparent digestibility coefficient nor does it change the protein quality of the standard diet of Rio de Janeiro State.     

Early Diagnosis and Management of Gastric Lesions

An attempt is made to point out the dangers in medical treatment of gastric lesions, drawing a clear distinction between gastric and duodenal lesions as to the possibility of medical treatment. Cases are cited to emphasize different types of delay in operation on gastric lesions which help to represent the high mortality from gastric carcinoma. Some suggestions are made as to the possibility of reducing this high mortality.