Measurement of stellar age from uranium decay

The ages of the oldest stars in the Galaxy indicate when star formation began, and provide a minimum age for the Universe. Radioactive dating of meteoritic material and stars relies on comparing the present abundance ratios of radioactive and stable nuclear species to the theoretically predicted ratios of their production. The radioisotope 232Th (half-life 14 Gyr) has been used to date Galactic stars, but it decays by only a factor of two over the lifetime of the Universe. 238U (half-life 4.5 Gyr) is in principle a more precise age indicator, but even its strongest spectral line, from singly ionized uranium at a wavelength of 385.957 nm, has previously not been detected in stars. Here we report a measurement of this line in the very metal-poor star CS31082-001, a star which is strongly overabundant in its heavy elements. The derived uranium abundance, log(U/H) = -13.7 +/- 0.14 +/- 0.12 yields an age of 12.5 +/- 3 Gyr, though this is still model dependent. The observation of this cosmochronometer gives the most direct age determination of the Galaxy. Also, with improved theoretical and laboratory data, it will provide a highly precise lower limit to the age of the Universe.

Non-bullous congenital ichthyosiform erythroderma, with ocular albinism and Noonan syndrome

A 21-year-old woman presented with non-bullous congenital ichthyosiform erythroderma; she was born a collodion baby. Associated features were ocular albinism, anterior segment dysgenesis of both eyes and Noonan syndrome. X-linked ichthyosis (steroid sulphatase deficiency) and X-linked ocular albinism have been mapped to the Xp22.3 region and cases have been reported with both conditions due to a partial short-arm deletion of the X chromosome. The ichthyosis and ocular albinism in the present case, however, are likely to be of the autosomal recessive type - a very rare association - and the combination with Noonan syndrome has not been reported previously.

The bioceramic orbital implant: a new generation of porous implants

PURPOSE

The authors describe a new generation of porous orbital implant made of aluminum oxide (Al2O3) and compare it with the hydroxyapatite orbital implants (Bio-Eye and FCI hydroxyapatite).

METHODS

The authors examined the new implant macroscopically, with chemical analysis and microscopically with scanning electron microscopy. Animal implantation studies were performed using six adult male New Zealand albino rabbits. Implant vascularization was evaluated by means of magnetic resonance imaging and histopathologic sectioning.

RESULTS

The Bioceramic orbital implant was found to have very uniform pore structure with an average pore size of 500 microm. The implant was 99.9% aluminum oxide on x-ray diffraction. Magnetic resonance imaging in vivo vascularization studies demonstrated enhancement of the implant to its center by 4 weeks after implantation in the rabbit. Histopathologically, fibrovascularization occurred uniformly throughout the implant and was noted by 4 weeks.

CONCLUSIONS

The Bioceramic orbital implant represents a new porous orbital implant that has a very regular and extensive interconnected pore system, is as biocompatible as hydroxyapatite, is easy to manufacture, structurally strong, and free of contaminants. It is manufactured with no disruption to marine life ecosystems as may occur in the harvesting of coral for other orbital implants. It is less expensive than currently available hydroxyapatite implants and was approved by the U.S. Food and Drug Administration in April 2000.

Understanding inference as a source of knowledge: children's ability to evaluate the certainty of deduction, perception, and guessing

Three experiments investigated children's understanding of inference as a source of knowledge. Children observed a puppet make a statement about the color of one of two hidden toys after the puppet (a) looked directly at the toy (looking), (b) looked at the other toy (inference), or (c) looked at neither toy (guessing). Most 4-, 5-, and 6-year-olds did not rate the puppet as being more certain of the toy's color after the puppet looked directly at it or inferred its color than they did after the puppet guessed its color. Most 8 and 9-year-olds distinguished inference and looking from guessing. The tendency to explain the puppet's knowledge by referring to inference increased with age. Children who referred to inference in their explanations were more likely to judge deductive inference as more certain than guessing.

Contribution of the assisted reproductive technologies to fertility in males suffering spinal cord injury

This study reviews 19 couples referred between 1990 and 1997 for fertility treatment for anejaculatory infertility in the male partner following spinal injury. Using sperm obtained by assisted ejaculation procedures, 14 of the 19 patients (74%) achieved at least 1 pregnancy. Pregnancy rates per treatment cycle were 12.0% for timed intrauterine insemination, 38.9% for gamete intra-Fallopian transfer and 19.2% for intracytoplasmic sperm injection followed by uterine embryo transfer. Choice of the appropriate assisted reproduction treatment to match the available semen quality results in a high level of success in such patients.

Aggression Questionnaire hostility scale predicts anger in response to mistreatment

We tested the hypotheses that the hostility and anger scales of the Buss and Perry (1992) [Buss, A. H. & Perry, M. (1992). The Aggression Questionnaire. Journal of Personality and Social Psychology, 63, 452-459.] Aggression Questionnaire would predict anger in college students in response to mistreatment. We found low and high hostility groups did not differ in anger at baseline or after completing a task without provocation, but the high hostility group reported greater anger than the low group after the onset of provocation, which required all students to redo completed tasks because some students (confederates) were observed cheating. Hostility also influenced anxiety and depression, but only anger was greater as a result of the provocation in the high than in the low hostility group. The anger scale did not predict anger in response to provocation, but anger was higher in the high than the low anger group before the provocation. These findings support the construct validity of the Aggression Questionnaire hostility scale as a measure of suspicion, resentment and sensitivity to mistreatment.

Gallstone prevalence in Germany: the Ulm Gallbladder Stone Study

The Ulm Gallbladder Stone Study is the first ultrasound-based epidemiologic survey of cholecystolithiasis in the former West Germany. A study population of 1116 blood donors (656 men, age 38.0 +/- 12.0 years; 460 women, age 34.1 +/- 11.2 years) at the Central Blood Bank of the German Red Cross in Ulm was examined between April 1994 and February 1995. Based on age, subjects were assigned to one of four groups (18-30, 31-40, 41-50, and 51-65 years). Following a structured interview of each study subject, an ultrasound examination was carried out and a blood sample obtained for laboratory study. Overall, 6.0% (95% (95% CI: 4.8%-7.6%) of all study subjects (5.8% of the men and 6.3% of the women) exhibited evidence of current or past gallbladder disease (cholelithiasis or history of cholecystectomy). The prevalence of gallbladder disease correlated positively with age, reaching a maximum of 13.7% (9.5-20.0) in the 51- to 65-year-old age group, and also correlated as with body mass index (BMI). Female subjects with previous full-term pregnancies showed a higher prevalence of cholelithiasis, but this difference was not statistically significant for age-adjusted analysis. Subjects with a family history of cholelithiasis were found to suffer from gallstones in 11.5% (8.0-16.7) of cases compared with 4.6% (3.4%-6.3%) of subjects without such family history. Autopsy studies conducted in Germany have shown the prevalence of gallstones to be about 13.1% in men and 33.8% in women. Our sonographic data are relatively low in comparison. This may be due, in part, to the specific selection characteristics inherent in retrospective autopsy studies, such as age distribution and the presence of other pathologic factors associated with increased risk for cholelithiasis. The Ulm data rank in the lower third of the prevalence range reported for European sonographic studies to date. Age, positive family history, and increased BMI all correlated positively with the prevalence of gallbladder disease (P < 0.05). For the study population as a whole, there was no gender-specific increased risk for the development of gallstones.

Gallstone prevalence in relation to smoking, alcohol, coffee consumption, and nutrition. The Ulm Gallstone Study

BACKGROUND

Besides considering well-known risk factors for the development of gallbladder stones, such as age, sex, fecundity, and hereditary predisposition, efforts at prevention have focused increasingly on other factors, such as nicotine, alcohol, and caffeine consumption, as well as general nutrition, which may be modified.

METHODS

A total of 1116 blood donors were examined between April 1994 and February 1995 in the central blood bank of the German Red Cross in Ulm, Germany. Each subject received a questionnaire and underwent to an upper abdominal ultrasound examination.

RESULTS

Gallbladder stone disease (current cholecystolithiasis and history of cholecystectomy) was detailed in 5.8% of the men and 6.3% of the women. Neither regularity nor number of daily meals correlated with the frequency of gallstone disease. Vegetarians (n = 48), as a group, were not found to have gallstones. In relation to the consumption of alcohol, tobacco, or caffeine higher prevalence of cholecystolithiasis was found only in heavy drinkers of coffee (P = 0.051; odds ratio (OR), 1.083; 95% confidence interval (CI), 0.999, 1.174).

CONCLUSION

Results of the present study do not show a definite relationship between nutritional factors and the consumption of alcohol, tobacco, or caffeine and an increased prevalence of gallbladder stone disease.

Complicated urinary infection in spinal injury patients: fleroxacin compared with ciprofloxacin

The efficacy and safety of fleroxacin and ciprofloxacin were evaluated in a single-centre, prospective, randomised, blinded study of patients with complicated urinary infection in a spinal injury unit. Patients were randomised to receive oral fleroxacin 400 mg once daily (n = 68) or oral ciprofloxacin 500 mg twice daily (n = 65) for 10 days. Clinical cure assessed 5-9 days after therapy was obtained in 41 of 42 (98%) assessable patients in the fleroxacin group, and in 41 of 43 (95%) of the ciprofloxacin group, and was maintained at the 6-week follow-up visit in all but 1 patient in each group. Bacteriological eradication rates 5-9 days after therapy exceeded 88% in the fleroxacin group and 86% in the ciprofloxacin group, and 69 and 65%, respectively, 6 weeks after completion of therapy. Adverse events occurred in a similarly low percentage of patients (19 and 20%) in both treatment groups, and consisted primarily of nausea. Once daily fleroxacin appears to be as safe and effective as twice daily ciprofloxacin and both represent efficacious treatment in complicated urinary infection in spinal injury patients.

Recombinant vaccinia viruses expressing hepatitis A virus structural polypeptides: detection of an anti-VP0 response in convalescent-phase sera

We have generated a number of recombinant vaccinia viruses which expressed the hepatitis A virus (HAV) structural polypeptides VP1, VP2, VP3, and VP4, either alone or in combination. The relevant sequences encoding these polypeptides were amplified from cloned cDNA by PCR and then cloned into the insertion vector pGS62. The presence of the HAV structural polypeptide-encoding sequences in the recombinant viruses was confirmed by Southern blot analysis, whilst their transcription and translation were demonstrated by Northern (RNA) blot analysis and immunodetection, respectively. Immunoprecipitation studies using these constructs have detected the presence of an anti-VP0 response in human convalescent sera following HAV infection. The significance of this finding and the usefulness of these constructs in studying cell-mediated immunity during recovery from HAV infection are discussed.

LFA-3 delta D2: a novel in vivo isoform of lymphocyte function-associated antigen 3

Lymphocyte function-associated antigen 3 (LFA-3) has previously been described as occurring as two isomers in vivo, a transmembrane (TM) form and a glycosyl phosphatidylinositol (GPI)-linked form, differing only in their membrane anchoring mechanism. A third isoform, LFA-3 delta D2, which has the cytoplasmic tail of TM LFA-3 but a truncated extracellular domain, has been identified in vitro. We report that the LFA-3 delta D2 isoform, identified by RT-PCR analysis and DNA sequencing, is also present in vivo and appears to share a signal sequence with the TM and GPI isoforms. Expression of LFA-3 delta D2 was observed in both normal and diseased human buccal mucosa and gingiva. Thus, while specific functional differences between isoforms remain to be established, our results show that LFA-3 delta D2 is constitutively expressed in vivo, along with the other, previously described, isoforms of LFA-3.

Purification and immunochemistry of a soluble matrix protein of the chicken eggshell (ovocleidin 17)

The protein components of biomineralized structures (matrix proteins) are believed to modulate crystal nucleation and growth, and thereby influence the shape and strength of the final structure. The chicken eggshell contains a complex array of distinct matrix proteins. The most abundant of these was purified to homogeneity by a combination of anionic exchange and hydroxyapatite chromatographies. Antibodies to this protein were raised in rabbit, and utilized for Western blotting and immunohistochemistry. These studies indicated that the 17 kDa antigen (ovocleidin 17, OC-17) is found in the shell gland mucosa, and that only the tubular gland cells were positive. Immunohistochemistry with decalcified shell indicated that OC-17 is uniformly distributed throughout the shell matrix, but concentrated in the mammillary bodies. Our results indicate that this protein is secreted during shell formation and becomes incorporated into this structure. It may therefore play a role in the crystallization process and influence the properties of the resulting eggshell.

The development of a spinal injuries unit in Armenia

A severe earthquake in December 1988 in Armenia, resulted in a large number of spinal cord injuries. A rehabilitation facility was urgently established in Yerevan by the Red Cross with volunteers from various countries outside the then Soviet Union. A programme of training of Armenian doctors, nurses and therapists was established, and a new purpose built spinal unit planned. The new unit was opened in August 1992 and should serve as a model for similar units throughout the Commonwealth of Independent States.

Plasma thromboxane and pulmonary artery pressure in neonates treated with extracorporeal membrane oxygenation

To examine whether neonates with persistent pulmonary hypertension are subject to a thromboxane-mediated exacerbation of their pulmonary hypertension during extracorporeal membrane oxygenator therapy (a form of partial cardiopulmonary bypass), we performed serial measurements of plasma thromboxane B2 and pulmonary artery pressure before, during, and after extracorporeal membrane oxygenation. Pulmonary artery pressure was high before extracorporeal membrane oxygenation, did not increase after the start of this therapy, but began to decrease after 48 hours of extracorporeal membrane oxygenation. During the course of extracorporeal membrane oxygenation, mean pulmonary artery pressure decreased by 50% and mean plasma thromboxane B2 levels decreased by 70%. In addition, serial plasma thromboxane B2 levels were significantly correlated with pulmonary artery pressures in individual infants with a primary diagnosis of meconium aspiration (r = 0.965 to 0.723). We speculate that the decrease in pulmonary artery pressure and plasma thromboxane B2 levels over time may reflect resolution of acute lung injury and that thromboxane B2 may play a role in regulating pulmonary artery pressure in infants with meconium aspiration.

Clean intermittent self-catheterisation for quadriplegic patients--a five year follow-up

We present the findings of clean intermittent self-catheterisation (CISC) as a long term method of bladder management for 36 quadriplegic spinal cord injured patients, primarily at C6/C7 level, who were taught CISC between 1983 and 1987. Success in CISC was assessed by a mail survey, a telephone interview, and current sterile urine status. Twenty nine (81%) of 36 patients continued to use CISC after a mean discharge period of 2.9 years (p less than 0.001) with high levels of acceptance. Rao's V discriminant analysis showed success in CISC was affected by the interval between injury and initial self-catheterisation (Canonical Correlation Co-efficient = 1.34). Results of urinalysis for patients continuing CISC were obtained for 18 (62%) patients, 16 (88%) of whom had sterile urine. Implications of these and other findings along with reasons for cessation of CISC are discussed.

Plasma prostanoids in neonates with pulmonary hypertension treated with conventional therapy and with extracorporeal membrane oxygenation

Thromboxane may be a mediator of pulmonary hypertension in the neonate. Acute thromboxane-mediated pulmonary hypertension has been described in sheep receiving extracorporeal membrane oxygenation, which raises concerns about a potential thromboxane-mediated exacerbation of pulmonary hypertension in human neonates with severe pulmonary hypertension who are treated with extracorporeal membrane oxygenation. We measured plasma levels of thromboxane, prostaglandin F2 alpha, and 6-keto-prostaglandin F1 alpha in infants with pulmonary hypertension, some of whom were treated medically and some of whom were treated with extracorporeal membrane oxygenation. Plasma levels of all three prostanoids were elevated in infants with pulmonary hypertension and decreased with time, whether the neonates were treated with extracorporeal membrane oxygenation or with medical management alone. In infants treated with extracorporeal membrane oxygenation, we collected samples simultaneously from preoxygenator sites, postoxygenator sites, and umbilical artery catheter. We could demonstrate no significant difference in plasma prostanoid levels across the oxygenator. In two patients, plasma thromboxane and prostaglandin F2 alpha levels measured shortly after a platelet transfusion were distinctly higher in the umbilical artery catheter than in venous samples.

A mobile traction device for MR and CT imaging

The development of a spinal traction device for use in Magnetic Resonance Imaging (MRI) and Computed Tomography (CT) imaging is described. Such a device has arisen from the need to apply continuous traction to patients having suffered acute cervical spine trauma. Previous traction techniques have proven unsuitable for use in the MRI scanner, particularly as they lack stability, are awkward to implement and prove quite cumbersome to manage. Traction may be applied to a patient for periods of time in excess of 1 hour with a minimum of discomfort. Materials are used which have a negligible proton density and a low atomic number, yielding no detectable magnetic resonance and very small x-ray cross sections respectively. Calibrated traction may be applied to patients via tongs or a head harness, the latter rendering the device suitable for general transport of injured patients with traction applied. The device is compact, light and strong and contains no ferrometallic parts. Thus far in excess of 40 patients have been scanned, most in a FONAR beta-3000M .3 Tesla electromagnetic MR imager and some also in a GE 9800 Quickscan CT scanner. No artefact has been demonstrated in any of the images to date for any of the MR pulse sequences or CT kVp. Modifications likely include refinement of the tensioning mechanism, inclusion of x-ray cassette facilities and improvement of aesthetic design.

Lipoxygenase and cyclooxygenase blockade by BW755C does not prevent the secondary phase of septic pulmonary hypertension

The infusion of Group B beta hemolytic streptococci (GBS) in newborn animals generates a dual phase pulmonary hypertensive response. The initial, acute phase responds to cyclooxygenase or thromboxane inhibition, and appears to be thromboxane mediated. The second phase is characterized by a more moderate rise in pulmonary vascular resistance, accompanied by an increase in microvascular permeability. It has been speculated that this phase may be leukotriene mediated. In an attempt to clarify this, we have studied and compared the effects of the thromboxane synthetase inhibitor, Dazmegrel (DAZ), and the combined cyclooxygenase/lipoxygenase inhibitor, BW755C, on the cardiopulmonary hemodynamics of the secondary phase of GBS induced pulmonary hypertension in newborn piglets. Ten piglets were infused with GBS, and all animals developed a significant increase in pulmonary artery pressure (to 39 +/- 5 and 36 +/- 5 mmHg for DAZ and BW755C animals respectively). After one hour of GBS, either DAZ or BW755C was administered. Data were collected for another two hours following drug administration. GBS infusion was continued throughout. Both DAZ and BW755C were associated with transient, acute reductions in pulmonary artery pressure (to 22 +/- 5 and 22 +/- 8 mmHg, respectively). However, after 60 minutes, PAP again began to rise in both groups (PAP 30 +/- 5 and 30 +/- 11 mmHg respectively by 240 minutes). There were no differences between the groups at any time. These data do not support a significant role for lipoxygenase products in mediating the secondary phase of septic pulmonary hypertension.

Intravenous lipids in newborn lungs: thromboxane-mediated effects

Lipid infusions can interfere with oxygenation and cause pulmonary hypertension. We studied the effects of iv lipid infusions on pulmonary hemodynamics and oxygen transport to investigate whether the vasoconstrictor, thromboxane (Tx), mediates resulting changes. Newborn piglets were instrumented to observe cardiopulmonary hemodynamics, blood gases, and oxygen contents. Oxygen delivery (DO2), oxygen consumption, and extraction ratios were calculated. All piglets received continuous 1-g/kg.h iv lipid infusions. After one hour, and as the lipid infusion continued, six piglets were given placebo (PL) and six others were given the Tx antagonist SQ 29548 (SQ). Pulmonary vasoconstriction occurred in both groups after one hour of lipid infusion (pulmonary artery pressure [PAP] 28 +/- 6 mm Hg in the PL piglets and to 31 +/- 13 mm Hg in the SQ piglets. After intervention, PAP remained elevated only in the PL group (32 +/- 2 vs. 23 +/- 8 mm Hg) (p less than .02). PaO2 and DO2 fell significantly with iv lipid and improved after intervention in SQ animals only (p less than .02). TxB2 increased in all animals with iv lipid (276 +/- 295 to 1481 +/- 716 in PL; 228 +/- 110 to 1402 +/- 580 in SQ), and fell with intervention in the SQ animals only (2632 +/- 1236 vs. 964 +/- 305, respectively; p less than .02). In conclusion, interference with DO2 associated with pulmonary hypertension and increased TxB2 occurred with iv lipid infusion in piglets. Tx antagonism ameliorated these changes.

Fatty acid metabolism in adipose tissue of aging mice after direct tracer injection into fat pads

We have examined previously reported age-related defects in triglyceride synthesis from [1-14C]palmitate in adipose tissue of mice. Three techniques were used: in vitro, using adipocytes isolated from epididymal fat pads of young and old mice; and in vivo, using two new methods to measure free fatty acid (FFA) esterification by adipose tissue (direct injection of labeled palmitate-albumin complexes in large or small volumes into the extracellular spaces of the epididymal or inguinal fat pads of young and old mice). When the entire fat pad was filled with tracer we no longer observed heterogeneous labeling of adipocytes in epididymal fat pads that occurred in an earlier study in which an in vivo-in vitro method has been used. Free fatty acids were converted to triacyglycerol faster by adipocytes of large cells from older animal than by those of small cells from young mice; when the cell sizes of young and old mice were approximately equal, then the rates of FFA esterification were the same in young and old adipocytes. When FFA was injected as a small bolus the fractional rates of FFA disappearance and of FFA incorporation into triacylglycerol in the different fat pads, observed during a 60-min period, were the same (about 5 min or less) regardless of the region of the fat pad studied (distal or proximal epididymal fat pad), the type of fat pad (epididymal or inguinal), or the age of the mice (12-92 weeks). Other potential applications of the direct injection technique for studying FFA metabolism and structure-function in adipose tissue in vivo are discussed. Our findings, coupled with the earlier study in which labeled FFA was added to the outside of fat pads, indicate that, in adipose tissue of old mice, there exist barriers comprising mesothelial cells, collagenous structures, and/or the outer layer of adipocytes in fat pads, that interfere in the transport of FFA to the interior adipocytes when FFA is added outside the fat pad. This age-related defect may be circumvented by injecting tracer directly into the interstitial fluid compartment.

Heterogeneous labeling of adipocytes during in vivo-in vitro incubation of epididymal fat pads of aging mice with [1-14C] palmitate

We have hypothesized that the in vivo-in vitro technique of Stein and Stein for studying free fatty acid incorporation into adipose tissue triglycerides and phospholipids may introduce artifacts due to diffusion barriers such as collagenous membranes, especially in fat pads of old animals. By using this technique in young and old mice and peeling the external cells, either physically or by collagenase treatment, we were able to show that the outer adipocytes are preferentially labeled. However, this pattern of heterogeneous labeling occurred in fat pads of both young (10-14 weeks) and old (80 weeks) mice. Fat pads are known to develop thicker, collagenous outer membranes during aging. Therefore, it seems likely to us that the marked decrease in free fatty acid esterification in fat pads of old mice, using the in vivo-in vitro method that we have described previously and confirmed here, could have been due to greater diffusion barriers in the tissues of the older mice.

The use of in vivo-in vitro labeling techniques to study phospholipid fatty acid turnover and fatty acid esterification into triglycerides in adipose tissue of aging mice

We are interested in membrane phospholipid and triglyceride synthesis and turnover in aging cells. As a preliminary, short-term feasibility study we have used an established in vivo-in vitro technique to estimate the initial rates of [1-14C] palmitate (complexed to albumin) esterification to triglycerides and phospholipids in adipocytes and non-adipocytes in the epididymal fat pads of aging mice (8-92 weeks). We have expressed our data in terms of unit cell, unit triglyceride mass and unit (membrane) phospholipid mass. Fat pad and adipocyte size, cell surface area, and adipocyte volume changes were measured and found to follow the same relations as reported in the literature, with some exceptions in very old mice (retired breeders). Rates of fatty acid esterification to triglycerides were about 100 times faster than those to phospholipids in adipocytes. Aging caused a marked fall in the rates of triglyceride fatty acid formation from added palmitate; thus, the rate of fatty acid esterification to triglycerides fell from 0.75 to 0.13 nequiv. fatty acid per min per fat pad (youngest most active group, cf. oldest group). Esterification of fatty acids into phospholipids in adipocytes of the oldest mice was significantly lower than in those of the young and middle-aged groups. Contamination of adipocytes by non-adipocytes was observed in fat pads from old, but not from young, mice. The non-adipocytes accounted for about half of the phospholipid fatty acid esterification. The rate of phospholipid esterification was so slow in adipocytes (all ages) and so relatively fast in non-adipocytes that further studies of phospholipid fatty acid turnover in adipocytes using this system are not considered feasible, especially as a means for studying removal rates of autoxidized fatty acids from membrane phospholipids in vivo during aging.