Chondrogenesis in aggregates of embryonic limb cells grown in a rotating wall vessel

Previous studies in this lab have shown that chondrogenesis is affected in growth plates of rats exposed to microgravity, and in micromass cultures of embryonic limb mesenchyme differentiating in space. In order to provide a three dimensional aspect not seen in the micromass system, and a tissue homogeneity not possible with explants of limb or limb elements, and to alleviate certain difficulties regarding crew time and stowage, we began culturing embryonic limb cells in Rotating Wall Vessels (RWV). First, these cells were attached to beads, and grown for up to 65 days in a type of RWV known as STLV at the Johnson Space Center. During this time, the cells and beads aggregated and the aggregates continued to increase in size, and differentiated into Alcian blue staining chondrocytes. Because our intent was to use these aggregates for implanting into bony defects in addition to their use in studies of chondrogenic regulation at 1g and microgravity, aggregates of these cells without beads were grown in the commercially available version of the STLV, and their ability to ossify when subcutaneously implanted assessed.

Clinorotation inhibits chondrogenesis in micromass cultures of embryonic mouse limb cells

Studies of the response of mammalian chondrocytes to gravitational changes in vivo, in organ culture, and in cell culture show that chondrogenesis is reduced in microgravity or by unloading, and increased by low levels of excess g. To investigate the cellular responses to microgravity using a ground based model, micromass cultures were exposed to simulated weightlessness on two clinostats. For rotation on the large clinostat, cultures were set up in Rose chambers, and cells were videotaped and photographed at several time periods after rotation began. For the smaller clinostat, cultures were set up in T-flasks, and two axes of rotation for clinostated cultures were used. Stationary controls [+1 g, -1 g (upside-down), and sideways] as well as rotation controls were employed. Rotation rate was 30 rpm for both clinostatted cultures and rotation controls. Chondrocyte differentiation was assessed by cartilage specific alcian blue staining. Significantly fewer alcian blue stained nodules were present in clinostatted cultures than in stationary controls or rotation controls. Nodules that did not stain with alcian blue, probably due to unsulfated matrix were present in all cultures. The number of nodules in sideways controls was greater than in any other culture (108% of +1 g controls), probably due to ongoing stimulus of the cell via cytoskeletal components. The results show that chondrocytes in culture respond to changes in the gravity vector in a predictable manner, and that carefully controlled clinostat studies can be useful adjuncts to and predictors for spaceflight experiments.

Pregnancy and cirrhosis: management of hematemesis by Warren shunt during third trimester gestation

Considerable pathophysiologic changes accompany cirrhosis. Elevation of portal venous pressure predisposes to esophageal varices and hematemesis. The physiologic changes associated with pregnancy may exacerbate these conditions. Medical management of cirrhosis-associated problems may fail, necessitating surgical intervention. The anesthetic management of a pregnant cirrhotic patient for a Warren shunt is complicated by concerns for pre-existing hepatic dysfunction and pregnancy-induced physiologic changes as well as fetal well-being. The management of such a case is reviewed and relevant pathophysiology discussed.

Elbow flexion test in the normal population

The elbow flexion test was investigated in 204 elbows in 102 normal volunteers. The effects of various wrist and shoulder positions were also studied. In 20 elbows in 15 persons (10%) flexion tests were positive with the wrist and shoulder in neutral position. In 27 elbows in 20 persons (13%) tests were positive with wrist extension and shoulder abduction.

Vasoactive intestinal peptide and nerve regeneration

The role of vasoactive intestinal peptide (V.I.P.) in nerve regeneration was investigated by assessing the changes in immunoreactive V.I.P. levels in rat sciatic nerves following injury and repair. 60 rats were divided into three surgical groups and one control group: In group I (primary repair), sciatic nerves were divided and immediately repaired; in group II (secondary repair), sciatic nerves were divided and repaired two weeks later; in group III (no repair), sciatic nerves were divided and not repaired; and in group IV (controls), sciatic nerves were exposed but not divided. Animals were sacrificed at three days and at weekly intervals. Their sciatic nerves were extracted and assayed for V.I.P. concentrations by a specific radioimmunoassay. The mean V.I.P. concentration varied between 22 and 46 pg./mg. protein in the control nerves and between 60 and 529 pg./mg. protein in all other groups. In the three surgical groups the levels were significantly higher in proximal than in distal stumps. Following nerve injury, there was an increase in V.I.P. concentration in the injured and repaired areas. This increase was greater in injured non-repaired areas and was highest in the first 48 hours, but continued during regeneration. The accumulation of V.I.P. in divided nerves occurred in response to nerve injury.

Using comparative clinical information to understand practice patterns and affect organizational change

The University Hospital Consortium is collecting clinical, administrative and financial data from its members to develop a Clinical Information Network. The value of this collective data lies in how comparative information about peer hospitals and physicians in the same specialty can be used to influence practice. The raw data from each hospital is analyzed, classified, normalized and stored in a data repository which is easily accessible. This data becomes information when it is presented in a variety of ways, and is supported by a knowledge-base of health care rules. The "drilling down" technique to progressive levels of detail serves the needs of all levels in the organization--executives, managers, and analysts. The system combines the power of a mainframe for the data repository with the ease of use of a PC-based workstation. With an open-ended approach, the users can ask a variety of questions of the data, as well as perform statistical analysis, create graphical presentations and generate explanations of the analysis techniques.

Fibrochondrogenesis in male twins at 24 weeks gestation

Fibrochondrogenesis is a rare lethal chondrodysplasia. Only 5 cases have been reported. We report on a pair of affected twins diagnosed at 24 weeks of gestation. Occurrence in sibs and consanguinity in the parents in a previous report support autosomal recessive transmission.

Effect of sleep state and position on the incidence of obstructive and central apnea in infants

Sixty-four infants with a history of apnea were studied to determine the effects of sleeping position and sleep state (rapid eye movement [REM]) v (non-rapid eye movement [NREM]) on the occurrence of central and obstructive apneas. All-night polysomnographic studies were conducted on each infant, and the spontaneous occurrence of central and obstructive apneic events was determined in the prone, supine, and side positions. Sleeping position did not significantly affect the rate or duration of central or obstructive apneas. Furthermore, neither central nor obstructive apneic episodes were significantly altered by sleep state. These data suggest that, in spite of an ostensible predisposition to upper airway obstruction in the supine position and during rapid eye movement sleep, neither sleeping position nor sleep state appears to affect the rate of duration of apneic events.

Interaction of anti-kojibiose antibody with the lipoteichoic acids from Streptococcus faecalis and Streptococcus faecium

Antisera prepared in rabbits by immunization with p-aminophenyl beta-kojibioside conjugated to bovine serum albumin (antikojibiose sera), readily agglutinated whole cells of Streptococcus faecalis or Streptococcus faecium, and showed specific reactions with the lipoteichoic acids (LTAs) of these streptococci by passive hemagglutination, microscale enzyme-linked immunosorbent assay, and crossed immunoelectrophoresis. The interaction of the antikojibiose sera with the LTAs was inhibited best by kojibiose [alpha-D-glucopyranosyl-(1----2)-D-glucose], somewhat less by the dextran from which the kojibiose was prepared, and not measurably by maltose [alpha-D-glucopyranosyl-(1----4)-D-glucose]. The sera reacted only minimally in only the most sensitive assay (microscale enzyme-linked immunosorbent assay) with LTA from group A streptococci (this LTA contains a single kojibiosyl residue as part of the glycolipid moiety of the molecule and failed to react with the Lactobacillus fermentum LTA which is substituted with alpha-D-galactopyranosyl-(1----2)-D -glucosyl units.

The role of lipopolysaccharide structure in the recipient cell during plasmid-mediated bacterial conjugation

The role of the lipopolysaccharide (LPS) structure in the recipient cell during bacterial conjugation was studied using a series of well-defined LPS mutations in Salmonella minnesota. The plasmids Flac (IncFI) and R1drd19 (IncFII) transferred at a high frequency to the smooth S218 parent strain and the rough LPS mutants. However, R64drd1 1 (IncI alpha) transferred poorly to the LPS mutants compared with transfer to the smooth LPS parent strain. The decrease in R64drd1 1 transfer frequency correlated with the extent of the defect in LPS structure, suggesting that intact LPS on the recipient is a major requirement for R64drd1 1 mating. Transfer of the P-group plasmid, RK2, was not affected by changes in LPS structure. These results show that plasmids use different cell surface structures during conjugation, and that LPS is particularly important for R64drd1 1 transfer.

Multiple dose extraamniotic prostaglandin gel for second trimester termination of pregnancy

Multiple doses of PGF2 alpha gel were administered into the extraamniotic space in 30 patients to induce mid-trimester termination of pregnancy. In 18 of these patients, repeat doses of gel were given only in the absence of uterine contractions and in 12 patients the gel was administered every 4 hours, irrespective of uterine activity. The mean time to abortion in all patients was 13.9 hours; no benefit seemed to accrue from using routine 4-hourly doses and it is recommended that repeat doses are given only when contractions are absent. The latter technique compares favourably with the use of other natural prostaglandins and prostaglandin analogues.

Cell adhesion and chondrogenesis in brachypod mouse limb mesenchyme: fragment fusion studies

This study is a continuing investigation of the effect of the brachypod mouse mutation on cell interactions and chondrogenesis during early limb development. In this report, cell adhesiveness was assessed in fused fragments of brachypod and normal limb-bud mesenchyme. Examination of the interface of fused distal postaxial limb fragments show brachypod limb mesenchyme to be more adhesive than normal limb mesenchyme. Chondrogenesis within brachypod fragments is delayed and less extensive than in normal fragments. In addition, chondrogenesis within normal fragments is not affected by the juxtaposition of the brachypod fragment, and vice versa.

Reciprocal reactivities of specific thiols when actin binds to myosin

We report measurements of the reactivity (degree of labeling, as mole of ligand per mole of protein, at constant exposure time) of the reactive thiol, "SH1", of a subfragment of myosin (S-1), and of Cys-10 of F-actin under various conditions, using N-iodo-[3H]acetyl-N-(1-sulfo-5-naphthyl)ethylenediamine, a fluorescent radioactive iodoacetamide analog. When either ADP or adenyloyl imidodiphosphate (simulating unhydrolyzed ATP) is bound to the enzymatic site of S-1, the reactivity of "SH1" is slightly enhanced, but when active ATPase is going on, reactivity is reduced by about a third, presumably due to the species, (S-1) ADP,Pi. The reactivity of Cys-10 alone is very low. When the complex, (S-1)-F-actin, is formed, the reactivity of SH1 is strongly decreased, and the reactivity of Cys-10 is strongly increased. The foregoing results explain our further observation (on glycerol-treated rabbit psoas fibers) that when fibers labeled in relaxation solution are compared with fibers labeled in rigor solution, myosin is more reactive and actin is less reactive, in the former case; alpha-actinin and C-protein are also less reactive in the former case.