Determination of the 243 Cm/244 Cm ratio alpha spectrometry and spectral deconvolution in environmental samples exposed to discharges from the nuclear fuel cycle

The presence of curium nuclides in irradiated nuclear fuel is well known, as is their occurrence in environmental materials exposed to liquid waste discharges from reprocessing plants and to fallout following the Chernobyl accident. Knowledge of the 242 Cm/244 Cm and 243 Cm/244 Cm atom ratios can be a useful tool for characterizing a source-term and assessing the burn-up history of nuclear fuel. Here, a practical technique, based on high-resolution alpha spectrometry and spectral deconvolution, is described by which the 243, 244 Cm multiplet can be resolved at the low activities typical of most environmental samples. The resulting 243 Cm/244 Cm ratio is then used to correct for any interference by 243 Cm in the 242 Cm window. The technique has been applied to the determination of the 243 Cm/244 Cm ratio in samples of seabed sediment collected near the Sellafield outfall, riverine sediment sampled downstream of the Mayak reprocessing plant and soil and lichen from within the Chernobyl exclusion zone. Near Sellafield, the 243 Cm/244 Cm ratio was found to be < 2%, while near Mayak and Chernobyl it was considerably higher, being approximately 6-8%.

Catquest questionnaire for use in cataract surgery care: assessment of surgical outcomes

PURPOSE

To demonstrate the outcome for patients after cataract extraction using the Catquest cataract questionnaire and discuss the models validity in assessing outcome.

SETTING

Thirty-five Swedish departments of ophthalmology.

METHODS

Patients having cataract extraction performed by surgeons from 35 Swedish departments of opthalmology participated in the study. The questionnaire was given to 2970 consecutive patients having surgery during March 1995 at the participating surgical units. The questionnaire was sent by mail to patients and completed on a voluntary basis. It focuses on visual disabilities in daily life, activity level, cataract symptoms, and degree of independence. The results form the questionnaire are interpreted using a benefit matrix that credits not only a decrease in visual disabilities and cataract symptoms but also an improvement in or maintenance of a preoperative activity level.

RESULTS

Complete surgical outcome data and completed preoperative and postoperative questionnaires were available in 1933 cases (65.1%). Benefit from surgery according to the model was achieved by 90.9% of the patients. Patients having their second cataract extraction had the highest frequency of the greatest benefit form surgery. There was good agreement between the different levels of benefit from surgery according to the model and the patient's global rating of his or her vision or achieved visual acuity after surgery, respectively. Patients with missing data (did not return postoperative questionnaire or had missing surgical result variables) were older and had a higher frequency of other diseases and handicaps.

CONCLUSION

The Catquest cataract questionnaire allowed the outcome of cataract surgery to be graded by different levels of benefit. There seemed to be good agreement between this model of assessment and the patient's global rating of his or her vision. Missing data may be a problem when a postal questionnaire is used.

Catquest questionnaire for use in cataract surgery care: description, validity, and reliability

PURPOSE

To describe and evaluate the Catquest self-assessment questionnaire for cataract patients.

SETTING

Thirty-five Swedish departments of ophthalmology.

METHODS

The Catquest is designed to be used by cataract surgeons for continuous quality control regarding appropriateness and outcome of surgery. It is administered before and after cataract surgery. The questionnaire focuses on visual disabilities in daily life, activity level, cataract symptoms, and degree of independence. The results are interpreted using a benefit matrix that credits not only a decrease in visual disabilities and cataract symptoms but also an improvement or a maintenance of a preoperative activity level. The questionnaire was used by consecutive patients having surgery during March 1995 at the participating surgical units.

RESULTS

A full range of responses was given to all questions. A strong relationship was found between patients' responses to questions about visual disabilities in daily life and their general opinion about vision (P < .001). The answers showed a high stability when test-retest reliability was evaluated and a high internal consistency when different questions about visual disabilities were compared (P < .001). The answers from cataract patients before surgery were significantly different from those of a control group that did not have cataract (P < .0001).

CONCLUSION

The Catquest had high validity and reliability when used as a disease-specific instrument testing visual disabilities in patients having cataract extraction.

Use of non-cross-linked polyacrylamide for four-color DNA sequencing by capillary electrophoresis separation of fragments up to 640 bases in length in two hours

Four-color DNA cycle sequencing was performed on an M13mp18 template using dye-labeled primers. Sequencing fragments were separated by capillary electrophoresis at 60 degrees C and at an electric field of 150 V/cm. The sieving medium was 5%T, non-cross-linked polyacrylamide in 7 M urea. The use of high temperature for the separation reduces formation of secondary structures in the sequencing fragments, generating a sequence that is free of compressions without the use of strongly denaturing gels. The use of high temperatures also increases the separation rate compared with room-temperature operation. Fragments up to 640 bases are separated in less than 2 h.

Prolactin binding sites in rat brain and liver: effects of long-term ovariectomy and ovarian steroids

The effects of long-term ovariectomy on the levels of brain and liver lactogenic binding sites as well as plasma and liver prolactin (PRL) have been investigated in sham-operated and ovariectomized rats receiving either 17 beta estradiol (OVX-E), progesterone (OVX-P), or vehicle (OVX-V). The levels of lactogenic binding sites in the parietal and piriform cortices, amygdala, thalamus, hypothalamus, as well as in the liver were significantly decreased after long-term ovariectomy. Moreover, the levels of plasma and liver PRL were also significantly decreased. Exogenous estradiol and progesterone replacement restored the levels of lactogenic binding sites in the parietal cortex and hypothalamus as well as in the liver. However, plasma and liver PRL levels were significantly increased by estradiol but only restored by progesterone. These results suggest that ovarian steroids influence the levels of lactogenic binding sites and prolactin.

Morphine-induced prolactin release precedes a down-regulation of prolactin receptors in the male rat choroid plexus and hypothalamus

In previous studies we provided evidence for changes in prolactin (PRL) receptor levels in the male rat brain after continuously infusing morphine using subcutaneously implanted miniosmotic pumps. In this work we have studied the binding of PRL in the male rat brain following morphine administration by both subcutaneous (s.c.) and intracerebroventricular (i.c.v.) injections. The binding in the choroid plexus and the hypothalamus was measured using iodinated ovine PRL (oPRL) as a radiolabel. The results indicated that the density of the PRL-binding sites in the hypothalamus and the choroid plexus were significantly decreased 4 h and 24 h after s.c. injections, and also 30 min and 4 h after i.c.v. injections. However, no decrease in PRL-binding was observed 15 min after i.c.v. injection of morphine. The plasma levels of PRL were measured by radioimmunoassay (RIA) and were found to be significantly increased after 30 min and 4 h in all treated animals. Following i.c.v. injection a significant increase in plasma PRL was observed after just 15 min. It was suggested that the down-regulation in PRL binding to some extent at least resulted from receptor overstimulation caused by the morphine-induced elevation in the concentrations of the endogenous hormone.

Vascular permeability to growth hormone in the rat central nervous system after focal spinal cord injury. Influence of a new anti-oxidant H 290/51 and age

Vascular permeability to the growth hormone (GH) across the blood-brain barrier (BBB) is unknown. This investigation was undertaken to examine vascular permeability to 125I-labelled rat growth hormone (rGH) in the central nervous system (CNS) of normal animals. Since age and spinal cord injury influences the metabolism of GH, these factors were also included. No statistically significant difference was seen regarding rGH permeability between young (aged 19-21 weeks) and old (age 38-42 weeks) animals. A focal trauma to the cord, produced by an incision into the right dorsal horn of the T10-11 segments in young animals, increased rGH permeability in several spinal cord segments at 0.5-5.0 h after injury. This permeability increase progressed over time. Similar trauma to old rats resulted in a significantly less increase in rGH permeability in the spinal cord 5 h after the trauma. This indicates that trauma-induced increased permeability of rGH is age-dependent. Pretreatment of normal young animals with a new antioxidant (H 290/51) did not influence the rGH permeability. However the drug prevented the trauma-induced increase of rGH permeability at 5 h after injury. This indicates that inhibition of lipid peroxidation has some protective effect on trauma-induced increase in rGH permeability.

Effects of long-term ovariectomy and ovarian steroids on somatogenic binding sites in rat brain and liver

The effects of long-term ovariectomy and replacement with ovarian steroids on the levels of brain and liver somatogenic binding sites as well as plasma and liver growth hormone (GH) were studied in sham-operated (Sham) and ovariectomized female rats receiving either, 17 beta-estradiol (OVX-E), progesterone (OVX-P), or vehicle (OVX). Long-term ovariectomy decreased the levels of somatogenic binding sites in the choroid plexus and liver as well as GH in plasma and liver. The levels of these sites in the choroid plexus were partially restored only by estradiol replacement. Moreover, exogenous estradiol but not progesterone restored the levels of plasma and liver GH as well as liver somatogenic binding sites. Our results suggest that estrogens regulate the levels of somatogenic binding sites in the liver and choroid plexus.

French multicenter study involving eight test sites for radiometric determination of activities of 10 antimicrobial agents against Mycobacterium avium complex

The radiometric BACTEC 460-TB methodology has filled an increased need in the screening of a wide range of antimicrobial agents against Mycobacterium avium (MAC) isolates on a patient-to-patient basis. In this context, a multicenter study involving eight test sites across France was performed to determine the MICs of 10 antimicrobial agents for MAC organisms. The aim of the investigation was to compare the in vitro activities of D-cycloserine, ethambutol, ethionamide, rifampin, amikacin, streptomycin, ciprofloxacin, sparfloxacin, clofazimine, and clarithromycin against MAC isolates. All of the test sites received the same clinical isolates of MAC, and the MICs were determined by a common protocol. The overall interlaboratory reproducibility of the MICs within +/- 1 dilution of the modal MICs varied from 79.70 to 100% (mean, 95.2% +/- 2.1%), whereas overall agreement of the MICs among the test sites varied from a mean of 91% +/- 4.1% to a mean of 98 +/- 1.3%. We confirmed that the proposed methodology is easy, accurate, and sufficiently reproducible to be used routinely in a clinical laboratory. Despite variations in the MICs of the same drug among strains, no link between the origin of MAC isolates (from human immunodeficiency virus-positive or -negative patients) and their drug susceptibilities was established. On the basis of the MICs that inhibited 50 and 90% of isolates tested for the drugs used, clarithromycin, clofazimine, ethambutol, and streptomycin were the most uniformly active against MAC; this was followed by amikacin, rifampin, and sparfloxacin. On the other hand, ciprofloxacin, D-cycloserine, and ethionamide showed only marginal in vitro activities.

Decreased binding of growth hormone in the rat hypothalamus and choroid plexus following morphine treatment

Male Sprague-Dawley rats were continuously infused with morphine through subcutaneously implanted mini-osmotic pumps over a period of 5 days. The binding of rat growth hormone (rGH) to specific sites in choroid plexus, cortex, hypothalamus, hippocampus and striatum was determined. It was found that in the acute phase of morphine administration the density of growth hormone-binding sites was significantly decreased in choroid plexus and in hypothalamus, but not in any other of the tissues studied. When tolerance to morphine was developed, the level of growth hormone-binding was restored to control level. In the acute phase, the plasma levels of GH, as measured by radioimmunoassay, correlated negatively with the density of the binding sites in choroid plexus and hypothalamus. The decrease in growth hormone-binding in these regions of the rat brain was also confirmed by SDS-polyacrylamide gel electrophoresis of cross-linked complexes of the binding entities to 125I-labelled rGH as visualized by autoradiography. In experiments, where morphine was administrated by intermittent injections, a similar decrease in rGH-binding was observed. However, the time-course of this decrease seemed to be dependent upon the route of administration. Following intracerebroventricular (i.c.v.) injections, the binding of the hormone was already affected after 30 min, whereas the binding of rGH in brain areas after subcutaneous (s.c.) injections was affected at a later stage.

Characterization of growth hormone binding sites in rat brain

The binding of 125I-labelled rat growth hormone (GH) to different areas in the brain was studied in male Sprague-Dawley rats. A high density of GH binding was found in the choroid plexus, hypothalamus, hippocampus, pituitary and spinal cord, whereas a lower binding density was observed in the cortex. Binding of the hormone to the various brain regions was age dependent. Binding was also dependent on time, pH and protein concentration. The binding affinity of the labelled hormone to choroid plexus was 4.3 per nmol/l and the binding capacity was 33.4 nmol/mg protein. The corresponding figures for binding of 125I-labelled GH to hypothalamus were 5.6 per nmol/l and 21.6 nmol/mg protein. By sodium dodecyl sulphate electrophoresis of the cross-linked hormone-receptor complexes, molecular weights of 60,000 and 61,000 were determined for the binding units in the choroid plexus and hypothalamus, respectively. It was further indicated that the binding unit for rat GH was distinct from that for prolactin.

Somatogenic and lactogenic binding sites in rat brain and liver: quantitative autoradiographic localization

The distribution of somatogenic and lactogenic binding sites in female and male rat brain as well as in liver was studied by quantitative receptor autoradiography using 125I-human growth hormone (125I-hGH) as a ligand. Quantitative measurement of binding sites for 125I-hGH showed differences in the levels of these sites in the female and male brain and liver. Moreover, regional differences in the brain were also observed in each sex. In the female brain high levels of 125I-hGH binding sites were found in the choroid plexus. Intermediate levels were observed in the striatum, the hypothalamus and the hippocampus, whereas low levels of these sites were found in the central gray, the temporal, the piriform and the entorhinal cortices. In the male brain high levels of 125I-hGH binding sites were detected in the choroid plexus. Intermediate levels were observed in the parietal cortex, the hypothalamus and the hippocampus, whereas low levels were found in the tegmentum, the temporal cortex and the striatum. Quantification of 125I-hGH binding sites in the liver revealed higher levels in the female than in the male liver. In general, higher levels of binding sites (16%-77%) were observed in the female than in the male tissues. The quantification of rat growth hormone (rGH) by radioimmunoassay was also performed in this study. Varying amounts of rGH immunoreactivity were detected in the different brain regions, with the highest levels of rGH-like material being found in the midbrain and cortex of both sexes. Moreover, higher levels of rGH-like material were observed in the female than in the male brain.(ABSTRACT TRUNCATED AT 250 WORDS)

Nickel-63 in Baltic fish and sediments

The determination of 63Ni was carried out on fish samples of cod (Gadus morhua), herring (Clupea harengus), sprat (Sprattus Sprattus) and samples of sediment core from the Gdańsk Bay. In contrast to stable nickel, 63Ni is non-uniformly distributed within the fish. More than 95% of total 63Ni content in cod and herring is located in fillet with skin and scale. Our data suggesting, that mechanism for uptake of 63Ni in cod and herring is by passive adsorption onto the surface of skin and scale mucus. The concentration of 63Ni in analysed sediment lies within the range from 0.5 to 3.8 mBq.g-1 dry wt, while values of its specific activity ranged between 10 and 70 Bq.g-1.

Sex differences in binding of human growth hormone to rat brain

The binding of 125I-human growth hormone (125I-hGH) to membranes from female and male rat brain was studied. The binding was time-, pH- and protein concentration-dependent. The binding capacities calculated for the hormone were higher in the female brain (12.1 fmol/mg protein) than in the male brain (4.5 fmol/mg protein). In the female brain, saturation isotherms yielded dissociation constants (Kd) of 6.2 x 10(-10) and 4.5 x 10(-8) M and maximal binding (Bmax) of 2.9 and 8.4 fmol/mg protein for the high and low affinity binding sites, respectively, and in the male brain a Kd of 2.3 x 10(-9) M and a Bmax of 3.5 fmol/mg protein. Displacement studies indicated that in the female brain the binding of 125I-hGH was inhibited in a dose-dependent manner more potently by lactogenic than by somatogenic hormones. The rank order of potencies of these hormones to inhibit the binding of 125I-hGH was hGH > hPRL > rPRL > oGH > rGH. However, in the male brain the inhibition of 125I-hGH binding was found to be most pronounced by somatogenic hormones with the rank order of hGH > oGH > rGH > hPRL > rPRL. These findings indicate the presence of specific binding sites for hGH in the rat brain. The level as well as the properties of these sites vary in the two sexes, with higher levels in the female brain as compared to the male brain. Moreover, these sites display predominantly lactogenic characteristics in the female brain and almost exclusively somatogenic characteristics in the male brain.

Effects of morphine on prolactin receptors in the rat brain

The effect of chronically given morphine on the binding of ovine prolactin (oPRL) to specific areas in the male rat brain was studied. The drug was delivered through subcutaneously implanted miniosmotic pumps. The results indicated that the density of prolactin binding sites in the hypothalamus and the choroid plexus was significantly decreased in the acute phase of morphine administration but restored to control levels when tolerance to morphine was developed. The decrease in prolactin binding was contrasted by elevated plasma levels of the hormone. A negative correlation was found between the hormone concentration in plasma and the density of its binding sites in the hypothalamus and choroid plexus. The hormone-binding sites in these two regions were further characterized with regard to binding constants and molecular sizes. The relevance of the present results with respect to the hypothalamic control of prolactin secretion is discussed.

High molecular weight growth hormone (> 160 kD) in human serum characterized with monoclonal antibodies

Human growth hormone (hGH) was analyzed by six monoclonal antibodies (Mabs) and a polyclonal antiserum (Pas) before and after molecular sieve chromatography of sera from healthy subjects. Their hGH levels were between < 0.2 and 0.4 ng/ml as determined with Pas. The six Mabs reacted with five distinct epitopes and bound to a hGH fragment corresponding to the amino acid sequence 15-125. Two of the Mabs showed reduced binding to 20-kD hGH. The binding of Mabs to dimeric forms of hGH varied. Human GH levels in unfractionated sera as determined with Mabs were < 3.1-390 ng/ml. After molecular sieve chromatography of the sera, one peak of hGH-immunoreactive material of high molecular weight (> 160 kD) and one at the elution volume of monomeric hGH were determined with Pas and Mabs. The major part of the high molecular weight hGH (> 160 kD) seemed to consist of 22-kD hGH molecules, since Pas and all Mabs detected the hGH immunoreactivity (> 160 kD) in a similar manner. This high molecular weight hGH (> 160 kD) was distinguishable from the identified, receptor-like hGH-binding protein in serum.

Possible existence of a CYP3A protein in liver microsomes from female rats

CYP3A proteins are P450 monooxygenases involved in the metabolism of steroids, retinoic acid and several important drugs. In rats, the number of CYP3A genes and proteins, and therefore important aspects of their inducibility, developmental regulation and sex specificity are not known for certain. Using triacetyloleandomycin-metabolite complex formation, testosterone hydroxylase assays and immunoblots from peptide maps, we obtained results suggesting that in liver microsomes from mature rats, at least three, possibly four CYP3A proteins are expressed: one is present in females, another is male-specific, and one or two additional CYP3A proteins are inducible by phenobarbital, steroids, and triacetyloleandomycin.

Age-related reduction of human growth hormone-binding sites in the human brain

Previous studies have shown that alterations in various neuroendocrine functions occur with increasing age. We here report a study of growth hormone (GH)-binding sites in different areas of post-mortem human brains collected from individual males and females of different age. The results indicate that there exists a significant negative correlation between the density of GH-binding sites and increasing age. This phenomenon was observed in both sexes in brain areas such as choroid plexus, hippocampus, hypothalamus, pituitary and putamen but not in e.g. thalamus. In all tissues (except for choroid plexus), the GH binding was significantly higher in those originating from females than those from males. This discrepancy was found likely to be associated with the affinity of GH to lactogenic rather than to somatogenic sites as no pronounced sex difference in binding was observed in the presence of excessive amounts of human prolactin. Data also indicate that the putative GH receptors in the various brain regions differ with regard to binding constants and to the estimated molecular size of the hormone-binding units. The loss of GH receptors in brain of elderly people may have consequences in several physiological courses. The decrease in GH binding at hypothalamic and pituitary levels may be of importance for the mechanisms behind the release or secretion of the hormone.

Reversible 3-D decorrelation of medical images

Two methods, namely, differential pulse code modulation (DPCM) and hierarchical interpolation (HINT), are considered. It is shown that HINT cannot be extended straightforwardly to 3-D images as contrasted with DPCM. A 3-D HINT is therefore proposed which is based on a combination of 2-D and 3-D filters. Both decorrelation methods were applied to three-dimensional computed tomography (CT), magnetic resonance (MR), and single-photon-emission CT (SPECT) images. It was found that a 3-D approach is optimal for some studies, while for other studies 2-D or even 1-D decorrelation performs better. The optimal dimensionality of DPCM is related to the magnitudes of the local correlation coefficients (CCs). However, the nonlocal nature of HINT makes the local correlation coefficients useless as indicators of the dimensionality; a better candidate is the image voxel size. For images with cubic or nearly cubic voxels 3-D HINT is generally optimal. For images in which the slice thickness is large compared to the pixel size a 2-D (intraslice) HINT is best. In general, the increase in efficiency obtained by extending 2-D decorrelation method to 3-D is small.

Expression of functional growth hormone receptors in human granulosa cells

Both clinical and experimental evidence suggest that growth hormone may be of importance for ovarian function. The present study investigated whether growth hormone receptors are expressed in human granulosa cells. Granulosa cells were isolated either from natural cycles or from stimulated cycles in the course of in-vitro fertilization. Total RNA hybridized with a 32P-labelled rat growth hormone receptor cRNA probe revealed one major transcript with an estimated size of 4.5 kb and one minor transcript with an estimated size of 1.3 kb. Biotinylated growth hormone was used to analyse growth hormone binding. Competitive growth hormone binding was detected in freshly isolated granulosa cells, as well as in cultured cells. Growth hormone augmented basal and/or follicle stimulating hormone-stimulated steroidogenesis in granulosa cells obtained from patients with natural cycles, but the response to growth hormone stimulation showed considerable variation. We conclude that functional growth hormone receptors are present in human granulosa cells and that growth hormone, therefore, may have an important role in ovarian function.