Ectopic Gallstone as a Cause of Gastric Outlet Obstruction

Callstone ileus is, of course, a well known cause of small bowel obstruction. A gallstone, however, is a very rare cause of gastric outlet obstruction. Three cases illustrating this phenomenon are exhibited. Radiographs were diagnostic in two of the studies. All three patients did well postoperatively.     

Presence of an amphipathic helical segment and its relationship to biological potency of calcitonin analogs

The conformational properties of a number of calcitonin analogs were studied by circular dichroism. The ability of dimyristoylphosphatidylglycerol, lyso-phosphatidycholine or sodium dodecyl sulfate to induce the formation of more highly ordered structures in these peptides was also assessed by circular dichroism. In all cases sodium dodecyl sulfate induced the largest change in the circular dichroism spectra of the peptides. Salmon calcitonin and its analogs were slightly more helical in the presence of the anionic phospholipid than in the presence of the zwitterionic detergent lysophosphatidylcholine while the reverse is true for human calcitonin and its analogs. Some of the calcitonin analogs convert turbid suspensions of phosphatidylglycerol to a clear solution from which the phospholipid is no longer readily sedimentable by centrifugation. Several of the physical properties of these peptides could be correlated with their biological activity. Generally peptides which showed no hypo-calcemic activity had the least negative mean residue ellipticities at 222 nm. Only biologically active analogs were able quantitatively to solubilize dimyristoyl-phosphatidylglycerol and in this solubilized form the peptides have a higher helical content. More active derivatives exhibit larger increases in helix content in the presence of this phospholipid. Inactive analogs had the least negative mean residue ellipticities at 222 nm in the presence of lysophosphatidylcholine or sodium dodecyl sulfate. Thus, the ability of a calcitonin analog to form structures of higher helical content in the presence of amphiphiles is a requirement for the analog to exhibit high potency in assays of biological activity.     

Clinical Assessment of Gestational Age

There is disagreement among authors as to what criteria are most reliable in assessing postnatal fetal age. A comparison–for objectivity, accuracy, and frequency of use– of specific criteria was made using three independent examiners at different educational levels: a second-year medical student, a perinatal nurse practitioner, and a pediatrics resident. It was shown that trained examiners develop favorite criteria which differ among examiners and thus sacrifice accuracy; however, accurate assessment of fetal age can be accomplished by an examiner with minimum clinical knowledge.     

Origin of Pulmonary Megakaryocytes

1. Evidence is presented which indicates that pulmonary megakaryocytesdo not originate in the lungs but elsewhere in the body and are carried tothe lungs in the venous blood.

2. Some megakaryocytes in the lungs evidently deliver platelets to theblood.

3. Surgery is a potent stimulus to megakaryocyte production; the numbersof megakaryocytes found in the lung postoperatively is significantly increased.

Submitted on July 3, 1964 Accepted on September 19, 1964     

Heinz Body Anemia: An Ultrastructural Study. II. Red Cell Sequestration and Destruction

This study reports electron microscope observations on the process of redcell sequestration and destruction in the spleen and liver of the phenylhydrazine-treated rabbit. Damaged red cells are recognized by virtue oftheir Heinz bodies, a morphologic manifestation of the oxidative injury whichthey have sustained. Sequestration, in the spleen, involves the selective accumulation of damaged cells within the vascular spaces of the Billroth cords.Erythrophagocytosis and the intracellular digestion of red cells followssequestration. More severely injured cells may undergo intravascular hemolysiswithin the splenic red pulp. In the liver, however, no evidence for the intravascular sequestration of injured red cells is observed. Damaged cells areremoved directly from the sinusoidal blood by erythrophagocytosis. Theselectivity of spleen and liver for red cells subjected to different degrees ofinjury is discussed in terms of the observed differences in the vasculararchitecture of the two organs.

Submitted on November 15, 1964 Accepted on November 22, 1964     

Oxygen and Redox-Active Drugs: Shared Toxicity Sites

Oxygen and Redox-Active Drugs: Shared Toxicity Sites. Brown,O.R. and Seither, R.L. (19S3).Fundam. Appl. Toxicol. 3:209-214.Paraquat and nitrofurantoin can accept single electrons and,under appropriate conditions in tissues and cells, can passthese electrons to oxygen, thus participating in redox cycling.Similarities in the response of the target organ (the lung)and in subsequent pathology have also been observed among animalspoisoned by oxygen and by these chemicals. We report evidenceprimarily obtained from Escherichia coli for common biochemicalsites of toxicity for these agents. Common sites for oxygenand paraquat involve biosynthesis of specific amino acids, inductionof genetic stringency via unloaded tRNAs resulting from aminoacid deficiencies, decreased thiamin content, and impaired biosynthesisof pyridine nucleotide coenzyme biosynthesis for paraquat andoxygen. Inhibition of specific amino acid biosynthesis and inductionof stringency also have been observed for nitrofurantoin. RNAand DNA biosynthesis are also impaired by oxygen; this has notbeen examined for paraquat or nitrofurantoin. There is a biochemicalbasis and preliminary data to support inhibition of NAD biosynthesisas a component of mammalian toxicity for these agents. Niacinmay act to circumvent the consequences of the biochemical lesionat quinolinate phosphori-bosyl transferase in NAD biosynthesis.     

Pelvic Dosimetry Comparison of Two Manual Afterloading Systems

Two different, manually afterloaded, gynaecological applicators for intracavitary therapy are compared in a study of the pelvic dose distribution in 114 patients. The applicators have a similar shape but the source geometry in the vaginal ovoids is significantly different. The change in the geometry accounts for a 17% reduction in the dose to the recto-vaginal septum. One of the applicators is constructed from stainless-steel, the other from polyvinyl chloride. On the average, the mid-line symmetry appeared better with the plastic applicators, but the variation between patients was greater.     

A light for anaesthetists

A new type of lighting device is incorporated into the ether screen cross-bar, enabling better illumination of the patient's face. A 12-V, DC power supply is used. The temperature, with vacuum-assisted cooling, should not cause burns to an unconscious patient. Assessment of patient colour was evaluated and found to be reliable. The lamp must not be used with flammable anaesthetic agents.