Preclinical studies on deoxycoformycin and deoxyadenosine as pharmacologic T cell purging tools

Deoxycoformycin (dCf) is a potent toxin to T lymphocytes in human peripheral blood and bone marrow. In the presence of deoxyadenosine (dAdo), dCf inhibits T cell function as measured by DNA synthesis induced by stimuli in the rank order of mixed lymphocyte culture greater than murine monoclonal antibody OKT3 greater than phytohemagglutinin. Approximately two logs of human bone marrow T cells were removed by 24 h of incubation with dCf and dAdo at doses that preserved colony-forming ability of the treated marrow. A semi-closed system of isolating mononuclear cells in large volumes using density gradient centrifugation was developed. Using this system, it was found that dCf and dAdo could remove about two logs of T lymphocytes after 24 h of incubation when the cells were incubated in large volumes at a relatively high concentration (10(7) cells/ml). This system appears well suited for purging T lymphocytes from human bone marrow before clinical transplantation.

Deficient neurogenic innervation of the myenteric plexus with normal submucous plexus involving the entire small and large bowel

A newborn presented with a picture of intestinal obstruction. Multiple biopsies of the small and large bowel showed an unusual neurogenic innervation. The myenteric plexus of Auerbach was severely depleted of ganglion cells and nerve fibers, while the submucous plexus of Meissner was normally innervated. An ileostomy failed to function and extended trial with experimental smooth muscle stimulant (Cisapride) was equally ineffective. The patient was finally treated by a myectomy from the duodenum to the descending colon with a sigmoid colostomy. This procedure, coupled with a Nissen fundoplication, stopped the vomiting and allowed normal defecation through the colostomy. The patient is presently taking increasing increments of oral fluids with a concomitant decrease in the volume of parenteral nutrition. The myectomy initiated marked hypertrophy of the muscularis mucosa. Could this muscular hypertrophy account for the improvement in bowel function? Possible etiology will be discussed. We caution that rectal submucosal suction biopsy alone may be misleading if normal ganglion cells and nerve fibers are found, yet the patient's clinical symptoms fail to improve. A full thickness bowel wall biopsy is then recommended.

Myoplasmic binding of fura-2 investigated by steady-state fluorescence and absorbance measurements

Binding of the fluorescent Ca2+ indicator dye fura-2 by intracellular constituents has been investigated by steady-state optical measurements. Fura-2's (a) fluorescence intensity, (b) fluorescence emission anisotropy, (c) fluorescence emission spectrum, and (d) absorbance spectra were measured in glass capillary tubes containing solutions of purified myoplasmic proteins; properties b and c were also measured in frog skeletal muscle fibers microinjected with fura-2. The results indicate that more than half, and possibly as much as 85%, of fura-2 molecules in myoplasm are in a protein-bound form, and that the binding changes many properties of the dye. For example, in vitro characterization of the Ca2+-dye reaction indicates that when fura-2 is bound to aldolase (a large and abundant myoplasmic protein), the dissociation constant of the dye for Ca2+ is three- to fourfold larger than that measured in the absence of protein. The problems raised by intracellular binding of fura-2 to cytoplasmic proteins may well apply to cells other than skeletal muscle fibers.

Immunogenic structure of the influenza virus hemagglutinin

We chemically synthesized 20 peptides corresponding to 75% of the HA1 molecule of the influenza virus. Antibodies to the majority (18) of these peptides were capable of reacting with the hemagglutinin molecule. These 18 peptides are not confined to the known antigenic determinants of the hemagglutinin molecule, but rather are scattered throughout its three-dimensional structure. In contrast, antibody raised to intact hemagglutinin did not react with any of the 20 peptides. Taken together these results suggest that the immunogenicity of an intact protein molecule is not the sum of the immunogenicity of its pieces.

Performance of automatic exposure controls when used with rare-earth intensifying screens

The performance of four phototiming systems was evaluated for use with six different intensifying screens. Phototimer response was studied as a function of patient thickness, kVp, field size, and exposure time. Each system demonstrated a sufficient range of sensitivity to produce acceptable film densities with all screens using an average-sized phantom; three systems produced overexposures of thin phantoms with almost all screens. With each phototimer, the kVp response for most screens was similar, allowing the use of a single kVp-compensating circuit. Exposure times had to be twice the minimum response time to avoid overexposure.

Nicotiana glauca-induced congenital deformities in calves: clinical and pathologic aspects

Seven calves born to 7 cows fed Nicotiana glauca during portions of the 1st trimester of gestation were deformed at birth. Deformities increased in severity as the calves aged. At birth, calves typically had arthrogryposis of the forelimbs or curvature of the spine; severity varied among calves. In 4 calves necropsied at about 15 months of age, there was general malpositioning and misalignment of the distal ends of the radius and ulna and the proximal ends of the metacarpal bones. Carpal joints were severely affected, fetlock joints were moderately affected, and pastern joints were slightly affected, with lateral rotation of forelimbs common; severity varied among calves. In 1 of the 4 calves, there was moderate torticollis and scoliosis resulting from wedging of some of the cervical and thoracic vertebrae and abnormal cranial curvature of the left thoracic ribs. Histologic changes were not noticed in muscle, brain, spinal cord, or endocrine organs of the 4 calves.

Radiation exposure to the paediatric patient from cardiac catheterization and angiocardiography

Thermoluminescent dosimetry was used to study the dose received by 50 consecutive paediatric patients. The average thyroid exposure was 7.7 R and the average gonad exposure 0.35 R. The relative contribution of both fluoroscopy and serial film radiography was calculated and over 70% of the thyroid dose comes from the use of the roll film changer. The significance of high thyroid dose is discussed and it is concluded that serial film changers no longer have a primary role in the study of congenital heart disease.