Medical school and residency performances of students admitted with and without an admission interview

In 1982 the Brown University Program in Medicine eliminated the personal interview from its process of selecting applicants for admission to medical school. This study compares the 113 M.D.-program students admitted to the first three classes (entering between 1983 and 1985) without an interview with the 67 students in the previous three classes admitted with an interview. The students' characteristics were essentially the same with respect to the preadmission variables, the proportions of women and minority students, course performances, scores on Parts I and II of the National Board of Medical Examiners examinations, and evaluation scores from residency program directors. This study offers additional evidence that the selection interview, as practiced in most U.S. medical schools, does not contribute to the predictive validity of the admission process.     

Effects of 12-O-tetradecanoyl-phorbol-13-acetate on cell proliferation and Epstein-Barr virus DNA replication

The amino acid sequence at the cleavage site of the fowl plague virus hemagglutinin has been analyzed. The amino terminus of HA₂ is formed by glycine-343. The carboxy terminus of HA₁ is serine-336 to which occasionally parts of the basic intervening peptide are still attached. The data indicate that the fowl plague virus hemagglutinin like other influenza hemagglutinins is cleaved by the sequential action of a trypsin-like endopeptidase and carboxypeptidase B. There is evidence, however, that the endopeptidases involved in the cleavage of both types of hemagglutinins differ in their specificities.     

Baroreceptor control of heart rate in the conscious toad Bufo marinus

Perivascular balloons were used to elicit heart rate (HR) responses to imposed changes in mean arterial pressure (Pa) in conscious unrestrained toads (Bufo marinus). It is clear that functional baroreceptors lie in the pulmocutaneous arteries of B. marinus, and that these can elicit compensatory heart rate responses to perturbations of blood pressure. Functional baroreceptors were not present in the carotid circulation and are probably absent from the lateral aortae and conus arteriosus as well. Normalized gain of the baroreceptor-heart rate reflex (delta HR%/delta Pa) in five toads was 13%/kPa, which is considerably less than that found in other vertebrates to date.     

Mice with mutations in Mahogunin ring finger-1 (Mgrn1) exhibit abnormal patterning of the left-right axis.

Mahogunin Ring Finger 1 (Mgrn1) encodes a RING-containing protein with ubiquitin ligase activity that has been implicated in pigment-type switching. In addition to having dark fur, mice lacking MGRN1 develop adult-onset spongy degeneration of the central nervous system and have reduced embryonic viability. Observation of complete situs inversus in a small proportion of adult Mgrn1 mutant mice suggested that embryonic lethality resulted from congenital heart defects due to defective establishment and/or maintenance of the left-right (LR) axis. Here we report that Mgrn1 is expressed in a pattern consistent with a role in LR patterning during early development and that many Mgrn1 mutant embryos show abnormal expression of asymmetrically expressed genes involved in LR patterning. A range of complex heart defects was observed in 20-25% of mid-to-late gestation Mgrn1 mutant embryos and another 20% were dead. This finding was consistent with 46-60% mortality of mutants by weaning age. Our results indicate that Mgrn1 acts early in the LR signaling cascade and is likely to provide new insight into this developmental process as Nodal expression was uncoupled from expression of other Nodal-responsive genes in Mgrn1 mutant embryos. Our work identifies a novel role for MGRN1 in embryonic patterning and suggests that the ubiquitination of MGRN1 target genes is essential for the proper establishment and/or maintenance of the LR axis.     

An enzyme‐linked immunosorbent assay to detect the presence of paralytic shellfish poison using an induced crab protein marker

A purified, high molecular weight protein (referred to as saxitoxin‐induced protein, SIP), was obtained from crabs, Hemigrapsus oregonesis, by affinity chromatography prior to use in a homologous crab SIP enzyme‐linked immunosorbent assay (ELISA) procedure. The SIP measured in H. oregonesis control crabs given acute saxitoxin (SAX) challenge injections (SAX range 0–50 ng), was less than the amount of SIP present in H. oregonesis crabs exposed to a natural toxic dinoflagellate outbreak. The latter were collected from a paralytic shellfish poison (PSP) contaminated coastal area which also contained PSP toxic butterclams (2000 μg PSP per 100 g shellfish), tested by the conventional mouse lethality bioassay procedure. These ELISA results were confirmed by an immunoblotting procedure using anti‐SIP antibody. An immunoblotting procedure of purified SIP and crude SIP antiserum revealed no cross‐reactivity with control, SAX uninjected crabs, thereby indicating specificity of the assay. The method is fast and useful for the screening of antigens expressed in crabs as a consequence of PSP, and represents a procedure that will complement the standard mouse bioassay.     

Type IV Ehlers-Danlos syndrome presenting as sudden infant death

A previously healthy 5-month-old female infant presented with sudden death due to spontaneous subarachnoid hemorrhage associated with minor multifocal visceral hemorrhages. The clinical diagnosis had been sudden infant death syndrome. Although the family history was noncontributory and other features of type IV Ehlers-Danlos syndrome (EDS) were absent, the pattern of hemorrhage was consistent with this type of connective tissue disorder. The diagnosis was confirmed after postmortem analysis of skin and aorta showed less than 5% type III collagen (normal greater than 15%). Extensive literature review failed to find any other reported cases of sudden death in infancy due to intracranial hemorrhage in patients with previously unsuspected type IV EDS. The authors suggest that collagen analysis should be performed in cases of unexplained multifocal spontaneous hemorrhage in infancy so that this rare diagnosis will not be missed.     

Acute-phase proteins and the serological evaluation of experimental contact sensitivity in the mouse

The evaluation of contact reactions in previously sensitized mice is assessed conventionally by measurement of increases in ear thickness following challenge. In an attempt to develop a serological method for the investigation of contact sensitization in mice, we have examined whether analysis of changes in the concentration of acute-phase proteins in response to challenge provides a reliable alternative means of evaluating elicitation reactions. Measurement of either the relative serum haptoglobin concentration, using radial immunodiffusion, or the absolute concentration of serum amyloid A, by an enzyme-linked immunosorbent assay, has been found to correlate well with induced increases in ear thickness following challenge. Changes in the concentration of acute-phase proteins proved to be of sufficient sensitivity to reflect the specificity of contact sensitization and its inhibition by antigenic competition.