Biomedical subjects
Publications and source records attributed to D Meier.
We report two cases of leptomeningeal carcinomatosis in which CSF-positive cytologic features were present but other CSF measurements were normal--a most unusual combination. In both cases, the results of the cytologic examination led to substantial therapeutic alterations. Cytologic examination of the CSF should be performed in any case with unexplained CNS symptoms or signs, regardless of the character of the CSF.
Sixteen children below the age of 12 were operated on for blunt injury to the pancreas during a ten-year period. Unless there was an associated injury, signs and symptoms did not immediately develop. Common to the delayed manifestation of an injury to the pancreas was history of an impaling force to the upper abdomen, abdominal tenderness, and an elevated serum amylase level. The postoperative morbidity for contusion of the pancreas was unpredictable, and a prolonged period without oral alimentation should be anticipated.
Cochleo-vestibular lesions may result from decompression accidents and barotrauma. The etiology of both clinical syndromes as well as their therapy is discussed on the basis of seven personal observations.
Cell-free preparations from encapsulated Artemia salina embryos readily translate poly(U), but there is no endogenous protein synthesis or translation of added natural mRNA until development resumes upon incubation in saline. High-salt-washed 80S ribosomes and highspeed supernatant (cytosol) were prepared from undeveloped eggs and from eggs allowed to develop to a stage prior to hatching. Endogenous protein synthesis occurs only with ribosomes from developed embryos, whether with undeveloped or developed cytosol. This is mainly elongation of preformed polypeptide chains, for it is largely resistant to edeine, an inhibitor of chain initiation. Edeinesensitive translation of added natural mRNA occurs with both developed and undeveloped ribosomes but requires developed cytosol. Translation of brome mosaic virus RNA is not much, if at all, further stimulated by high-saltwash of developed ribosomes, but that of globin mRNA is markedly enhanced. Levels of the chain initiation factor EIF-1 are the same before and after development. These results are consistent with the view that resumption of developemtn is triggered by transcription, with ensuing translation of the resulting messengers to yield, among other proteins, mRNA-recognizing initiation factors of the IF-3 type which are partly free in the cytosol and partly ribosome-bound. The data also suggest that different factors may be involved in the translation of brome mosaic virus RNA and globin mRNA by this system.
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To analyze the flow patterns of the left blood chamber of the Baylor total artificial heart (TAH) and to evaluate influences of the inflow valve angle to the flow patterns, flow visualization studies were performed. The inflow valve angle of the left housing was changed by 20 degrees orthogonal to the inflow tube, and comparison studies of the modified and unmodified models were made. For evaluating sectional flow patterns, a laser light was used, the clear transparent housing was scanned segmentally, and flow patterns were recorded on high contrast film for measuring flow velocities. A signal was used that synchronized the timing of the camera shutter to the pusher-plate movement signal. With the modified 20 degree inflow valve direction, there were better closing characteristics of the inflow valve leaflets. At the same time, we could successfully reduce the vortex formation at the inflow port, which may cause thrombus formation. We also have improved the washout during the diastolic phase in not only the bottom area, but in the entire pumping chamber. This flow visualization setup is simple and inexpensive. It is useful not only for validation of global flow patterns, but also for validation of local flow velocities of various blood pumps.
To evaluate the feasibility of magnetic resonance (MR) imaging in patients with nonferromagnetic metallic implants, we imaged implants in vitro and in 15 patients. Image artifacts both in vitro and in vivo occurred only locally and consisted of image distortions, areas of total signal loss, and lines of high signal intensity. The artifacts were most prominent in areas where the implants exhibited edges or points, but overall image quality was good except for regions lying very close to the implants. The implants themselves appeared as structures without signal in all patients. We conclude that in patients with femoral head prostheses or osteosynthetic plates that are nonferromagnetic MR may be preferable to CT, where beam hardening artifacts usually degrade image quality severely in the entire field of view.
Sera of successive littermates of mothers producing anti-allotype antibodies (Ab) were analysed for altered a locus or b locus allotype expression. We measured the allotype concentration in sera of 66 individuals (17 litters) of seven mothers producing anti-a1 Ab, and 63 individuals (15 litters) of seven mothers producing anti-b4 Ab, in an enzyme-linked immunosorbent assay (ELISA). We confirmed that the ability to induce allotype suppression in utero increases with the number of antigen boosts applied to the mother, even though the Ab titre in the maternal serum may be decreased. All individuals of a litter expressed the allotype in about equal concentration. This contrasts the results we obtained when newborn rabbits were injected with anti-allotype antiserum. Injection of the same amount of anti-allotype antiserum into nine offspring of two mothers caused allotype suppression in only five individuals, showing no effect in the others. No suppression was observed when IgG-depleted antiserum was injected into newborn rabbits. As expected, maternal antibodies to a paternal allotype do not affect the Mendelian distribution of the progeny phenotypes.
Allotypes of rabbit Ig provide a useful tool for the study of quantitative expression of alternative allelic forms. In the rabbit, maternal Ig is transmitted to the foetus and protects the immunologically immature newborn during several of the first weeks of life. Induced maternal antibodies directed towards a paternally inherited allotype of the offspring can influence the expression of that allotype drastically. Normal Ig level in heterozygous allotype suppressed animals is provided by increased expression of the alternative allele. On the other hand, allotype suppression in homozygous animals leads to increased expression of non-allelic alternative gene products. We quantitatively analysed the expression of bas, a marker on the kappa 2 light chain isotype of the mutant strain Basilea, in homozygous bas/bas rabbits which had been fostered in utero of b4/b6 mothers producing anti-bas. All of the offspring studied expressed the kappa 2 isotype at a very low level at two months of age, and, in some individuals, bas was hardly expressed after 6 to 12 months. A suppressed rabbit, which was immunized to produce auto-antibodies against bas, continued to do so for at least 2.5 years. The long duration of homozygous bas suppression contrasts with homozygous suppression of other allotypes (CL kappa 1 and VHa) which generally lasts for a much shorter period.
In the presented light microscope study, the question was examined of whether the size of the nucleus and nucleolus, respectively the nuclear:cytoplasmic ratio of pinealocytes, are changed in different human age groups. We investigated the pineals of 30 to 40-year-old men in comparison with those from patients who were older than 70 years. The investigation was performed with smears of the pineal gland which were stained according to Pappenheim (May-Grünwald and Giemsa method). The results show that the nuclear size of the pinealocytes of the younger men (30 to 40-year-olds) is 92 micron 2 and is significantly larger than in the older patients; in this age group the nuclear area is only 75 micron 2. The cell size of the pinealocytes shows no differences between both age groups. From these data a nuclear:cytoplasmic ratio of 1:1.77 was calculated for the 30 to 40-year-old men. In the age group of the over 70-year-olds, this ratio is significantly decreased to 1:2.13. Concerning the nucleoli in the 30 to 40-year-old men a value of 10.1 micron 2 was measured, which is significantly different from the 7.8 micron 2 for the over 70-year-old patients. On the basis of well-known criteria of nuclear size and nuclear:cytoplasmic ratio, our study underlines the higher functional significance of the pineal gland in the younger decades of life.