Preparation of monoclonal antibodies against the spindle checkpoint kinase Bub1

The Bub1 kinase is a critical component of the spindle checkpoint involved in monitoring the separation of sister chromatids at mitosis. The viral oncoprotein Simian virus 40 large T antigen (LT) can bind and perturb the spindle checkpoint function of Bub1. We have developed three highly specific monoclonal antibodies against the Bub1 protein and have demonstrated that they can all detect Bub1 via Western blotting and immunofluorescence, in addition to their ability to immunoprecipitate Bub1.

Simian virus 40 large T antigen targets the spindle assembly checkpoint protein Bub1

The mitotic spindle checkpoint protein Bub1 has been found to be mutated at low frequency in certain human cancers characterized by aneuploidy. Simian virus 40 large T antigen efficiently immortalizes rodent cells and occasionally transforms them to tumorigenicity. T antigen can also cause genomic instability, inducing chromosomal aberrations and aneuploidy. Here, we report an interaction between Bub1 and T antigen. T antigen coimmunoprecipitates with endogenous Bub1 and Bub3, another component of the spindle checkpoint complex. Genetic analysis demonstrates that the interaction of T antigen with Bub1 is not required for immortalization but is closely correlated with transformation. T antigen induces an override of the spindle checkpoint dependent on Bub1 binding. This interaction with proteins of the spindle checkpoint machinery suggests another role for T antigen and provides insight into its ability to cause chromosomal aberrations, aneuploidy, and transformation.

Cardiorespiratory effects of premedication for children

Cardiovascular and respiratory effects of pediatric preanesthetic premedication have received only minimal attention, probably because most children tolerate such drugs without apparent ill effect. In children with congenital heart disease or other serious illness, there is often reluctance to use premedication. We sought to determine whether different premedication regimens produced significant cardiorespiratory effect. A randomized prospective study of the cardiovascular and respiratory effects of different oral, nasal, and rectal premedication regimens was conducted. Fifty-eight young children (average age 2.7 yr) were studied. Oral meperidine (3 mg/kg) with pentobarbital (4 mg/kg) decreased heart rate, mean arterial pressure, cardiac index, respiratory rate, and oxygen saturation. Stroke volume was maintained. Nasal ketamine (5 mg/kg) with midazolam (0.2 mg/kg) produced no significant cardiovascular or respiratory effects. Rectal methohexital (30 mg/kg) increased heart rate with a coincident decrease in stroke volume but had no other positive or negative cardiac or respiratory effect. This information documents disparate cardiorespiratory effects of different preanesthetic medications in normal children.

Cardiovascular effects of rectal methohexital in children

STUDY OBJECTIVE

To define the cardiovascular effects of rectal methohexital in children with normal cardiac function.

DESIGN

Cardiovascular evaluation of each patient was performed before and after medication. Each patient's predrug results were used as control measurements for comparison with measurements made after methohexital administration.

SETTING

Inpatient operating room induction area in a privately endowed philanthropic children's hospital.

PATIENTS

Forty-seven children age 35 +/- 22 months (mean +/- SD) scheduled for elective orthopedic or plastic surgery, free of cardiac or pulmonary disease, and receiving no medication with central nervous system activity.

INTERVENTIONS

Control measurements of heart rate (HR), blood pressure (BP), and echocardiographic evaluations were obtained on the day before scheduled surgery. Repeat measurements were performed after the onset of methohexital-induced sleep. The time span of the measurements was designed to include the period of peak plasma methohexital concentration. In the preoperative holding area, 30 mg/kg of a 10% methohexital solution was administered rectally. If sleep did not occur in 15 minutes, an additional 15 mg/kg was given.

MEASUREMENTS AND MAIN RESULTS

HR increased markedly after rectal methohexital [126 +/- 23 beats per minute (bpm) to 144 +/- 21 bpm, p less than 0.001], and stroke volume (SV) decreased (24 +/- 9 ml to 21 +/- 8 ml, p less than 0.01). There were no significant changes in BP or cardiac index. The shortening fraction and ejection fraction remained within the normal range for this age-group.

CONCLUSIONS

Rectal methohexital induces sleep in healthy pediatric patients with minimal cardiovascular side effects. The primary effects are increased HR and decreased SV.

Contralateral tension pneumo/hemothorax resulting from left subclavian vein cannulation under general anesthesia

A patient had a subclavian vein catheter placed under general endotracheal anesthesia with positive pressure ventilation. During placement, the superior vena cava, pleura, and pulmonary tissue were punctured, resulting in a tension pneumo/hemothorax, the detection of which was complicated by its slow onset and unusual location. The lesion required an emergent thoracotomy for repair.

Cartilage sulfation inhibitor from rat liver curtails growth of embryonic chicken cartilage in vitro

We studied the effect of high MW cartilage sulfation (somatomedin) inhibitors from rat liver on cartilage growth in vitro. Pelvic rudiments from 11-day-old chicken embryos (5.70 mg average weight) were incubated in an organ-culture system with defined tissue-culture medium; after two days (T0-2), media were changed and incubation continued for another three days (T2-5). Normal rat serum (10% vol/vol) stimulated cartilage growth (weight change + 1.33 +/- 0.16 mg, mean +/- SEM T0-2 and + 1.33 +/- 0.27 mg, T2-5). Partially purified cartilage sulfation inhibitors (CSI) caused a weight decrease (-1.09 +/- 0.17 mg T0-2 and -0.44 +/- 0.06 mg T2-5). Adding inhibitors to cartilage incubations containing normal serum abolished the growth-promoting effect of serum (-0.79 +/- 0.07 mg T0-2 and -0.40 +/- 0.08 mg T2-5). The growth-curtailing effect of CSI was reversible; after preincubating cartilage with CSI for two days (-0.62 +/- 0.11 mg T0-2), subsequently exposing it to normal serum allowed cartilage growth to resume (+1.02 +/- 0.21 mg T2-5). Cartilages incubated with normal serum and various concentrations of inhibitor exhibited a dose-dependent inhibition of serum-stimulated growth. Cartilage Length was not altered by the inhibitor; cartilage dry:wet weight ratio or protein concentration (microgram/mg wet weight) did not differ among groups. Triodothyronine (T3) stimulated cartilage growth in a dose-dependent manner as expected. Adding CSI to cartilage incubations containing T3 (1.5 nmol/l or 15 nmol/L) completely abolished the growth-stimulating effect of T3.(ABSTRACT TRUNCATED AT 250 WORDS)