Chest CT for the Diagnosis of Pediatric Esophageal Foreign Bodies

Foreign body ingestion is a common problem in children. Radiography is the mainstay of imaging, but many radiolucent items go undetected without further imaging by fluoroscopic esophagram. While studies in adults support the use of computed tomography (CT) for esophageal foreign body ingestion, CT has historically not been used in children given the typically higher radiation doses on CT compared with fluoroscopy. In distinction to an esophagram, CT does not require oral contrast nor presence of an onsite radiologist and can be interpreted remotely. At our institution, a dedicated CT protocol has been used for airway foreign bodies since 2015. Given the advantages of CT over esophagram, we retrospectively reviewed institutional radiation dose data from 2017 to 2020 for esophagrams, airway foreign body CT (FB-CT), and routine CT Chest to compare effective doses for each modality. For ages 1+ years, effective dose was lowest using the FB-CT protocol; esophagram mean dose showed the most variability, and was over double the dose of FB-CT for ages 5+ years. Routine CT chest doses were uniformly highest across all age ranges. Given these findings, we instituted a CT foreign body imaging protocol as the first-line imaging modality for radiolucent esophageal foreign body at our institution.

Optimization of subcritical fluid extraction of bioactive compounds using Hansen solubility parameters

Process engineering operations in food and nutraceutical industries pertaining to the design of extraction of value-added products from biomass using pressurized liquids involve a careful selection of the solvent and optimal temperature conditions to achieve maximum yield. Complex molecular structure and limited physical property data in the literature of biological solutes extracted from biomass compounds have necessitated the process modeling of such operations. In this study, we have applied the Hansen 3-dimensional solubility parameter concept to optimize the extraction of molecularly complex solutes using subcritical fluid solvents. Hansen solubility spheres characterized by the relative energy differences (RED) have been used to characterize and quantify the solute-subcritical solvent interactions as a function of temperature. The solvent power of subcritical water and compressed hydroethanolic mixtures above their boiling points has been characterized using the above-mentioned method. The use of group contribution methods in collaboration with computerized algorithms to plot the Hansen spheres provides a quantitative prediction tool for optimizing the design of extraction conditions. The method can be used to estimate conditions for solute-solvent miscibility, an optimum temperature range for conducting extractions under pressurized conditions, and approximate extraction conditions of solutes from natural matrices.

Activated T lymphocytes disappear from circulation during endotoxemia in humans

Seventeen volunteers received an intravenous bolus of endotoxin (2 ng/kg of body weight). Endotoxin-induced lymphopenia was constituted mainly by cells with an immature phenotype (CD45RA(+) CD45RO(-)) that were less likely to undergo apoptosis (CD28(+)), whereas cells with the highest rates of disappearance were characterized by an activated phenotype (CD45RA(-) CD45RO(+)) as well as a phenotype linked to apoptosis (CD95(+) CD28(-)). In conclusion, endotoxin-induced lymphopenia reflects the disappearance from the circulation of activated lymphocytes prone to undergo apoptosis.

MCF-7/VD(R): a new vitamin D resistant cell line

Several in vitro and in vivo experiments have demonstrated potent cell regulatory effects of vitamin D compounds in cancer cells. Moreover, a promising phase I study with the vitamin D analogue Seocalcitol (EB 1089) in patients with advanced breast and colon cancer has already been carried out and more clinical trials evaluating the clinical effectiveness of EB 1089 in other cancer types are in progress (Mørk Hansen et al. [2000a]). However, only little is known about the mechanisms underlying the actions of vitamin D or about the possible development of drug resistance in the patients. Therefore, in an attempt to gain more insight into these aspects, we have developed the MCF-7/VD(R) cell line, a stable subclone of the human MCF-7 breast cancer cell line, which is resistant to the growth inhibitory and apoptosis inducing effects of 1alpha,25(OH)(2)D(3). Despite this characteristic, receptor studies on the VDR have clearly demonstrated that the MCF-7/VD(R) cells contain fully functional VDRs, although in a lower number than seen with the parental MCF-7 cells. The regulation of the 24-hydroxylase enzyme appeared to be intact in the MCF-7/VD(R) cells and no differences with regard to growth rate and morphological appearance between the MCF-7/VD(R) cells and the parental MCF-7 cells were observed. Interestingly, however, the sensitivity of the MCF-7/VD(R) cells to the pure anti-estrogen ICI 182,780 was found to be increased. The MCF-7/VD(R) cell line shows characteristics different from those of previously described vitamin D resistant breast cancer cell lines but also some similarities. Together such vitamin D resistant cell lines therefore serve as a useful tool for studying the exact mechanism of action of vitamin D and the development of vitamin D resistance.

Hypotension during endotoxemia in aged humans

BACKGROUND

and objective The aim of this study was to determine possible age-associated differences in human blood pressure regulation during an immunological challenge in healthy subjects.

METHODS

Eight healthy young volunteers (median age 24 yr) and nine healthy elderly volunteers (median age 66 yr) received an intravenous bolus injection of Escherichia coli endotoxin (2 ng kg(-1)). Blood pressure, heart rate and core temperature were monitored during the first 7 h. Plasma catecholamine concentrations were measured at hourly intervals.

RESULTS

The elderly showed a significantly more pronounced decrease in mean arterial pressure 4-7 h after endotoxin administration compared with the young controls (ANOVA; age x time; P < 0.0005). This mainly reflected a decrease in the systolic blood pressure in the elderly. The heart rate of both groups increased without difference between groups. Increased plasma epinephrine concentrations were found 2-3 h after endotoxin administration in both groups. Five hours after the endotoxin challenge, the epinephrine concentration had returned to control values in the elderly group only, in spite of decreased blood pressure.

CONCLUSION

In conclusion, healthy elderly subjects fail to maintain a constant mean arterial pressure in response to the immunological challenge of endotoxemia.

Sensitization to TNF-induced apoptosis by 1,25-dihydroxy vitamin D(3) involves up-regulation of the TNF receptor 1 and cathepsin B

The active form of vitamin D(3), 1,25-dihydroxyvitamin D(3) (1,25(OH)(2)D(3)), induces caspase-independent apoptosis in MCF-7 and T47D breast cancer cells. Before the appearance of apoptotic cells at Day 4 after the addition of 1,25(OH)(2)D(3), the MCF-7 cells are sensitized to the caspase-mediated apoptosis induced by TNF. We studied the mechanism underlying the cross talk between these 2 distinct death pathways in MCF-7 and T47D cells. Whereas 1,25(OH)(2)D(3) pre-treatment enhanced TNF-induced apoptosis of TNF sensitive MCF-7 cells, it failed to render TNF resistant T47D cells sensitive to this cytokine. Opposing to an earlier report suggesting that cytosolic phospholipase A(2) (cPLA(2)) mediates the 1,25(OH)(2)D(3)-induced sensitization to TNF, we could not detect any cPLA(2) protein in MCF-7 cells and its overexpression had no effect on cellular sensitivity to 1,25(OH)(2)D(3) or the combination with TNF. The sensitization of MCF-7 cells to TNF-induced apoptosis by pre-treatment with 1,25(OH)(2)D(3) may instead be partially explained by an increased surface expression of the TNF receptor 1 (TNF-R1). In line with this, not only the TNF-induced activation of caspases and apoptosis but also that of NF-kappaB was enhanced by 1,25(OH)(2)D(3) pre-treatment. Furthermore, 1,25(OH)(2)D(3) enhanced TNF-induced NF-kappaB activation in T47D cells suggesting that it potentiates TNF signaling in general. Interestingly, the lysosomal protease cathepsin B, which expression is up-regulated by 1,25(OH)(2)D(3), was released from the lysosomes upon TNF treatment, and inhibition of its activity rescued 1,25(OH)(2)D(3) treated MCF-7 cells from TNF-induced apoptosis. In conclusion, 1,25(OH)(2)D(3) may enhance TNF-induced apoptosis by increasing the expression of both the TNF-R1 and cathepsin B.

Vitamin D and cancer: effects of 1,25(OH)2D3 and its analogs on growth control and tumorigenesis

Today, it is well established that besides playing a crucial role in the establishment and maintenance of the calcium homeostasis in the body, the active form of vitamin D, 1,25(OH)2D3, also acts an effective regulator of cell growth and differentiation in a number of different cell types, including cancer cells. This has led to an increased interest in using 1,25(OH)2D3 in the treatment or prevention of cancer patients and to a substantial number of studies investigating the effect of 1,25(OH)2D3 on cancer cells. The results are encouraging, but clearly demonstrate that the therapeutic window of 1,25(OH)2D3 is extremely narrow due to the calcemic adverse effects of this compound. Much effort has consequently been directed into identifying vitamin D analogs with potent cell regulatory effects but with weaker effects on the calcium metabolism than those of 1,25(OH)2D3. In an attempt to clarify the mechanisms implicated in the cell regulatory effects of 1,25(OH)2D3 and eventually facilitate the process of developing new specific vitamin D analogs, numerous investigations have been carried out with 1,25(OH)2D3 and its analogs. The present review will focus on the results obtained in these studies and describe some of the synthetic analogs, which have shown to be of particular interest in relation to cancer.

Assessment of vitamin B-6 status in young women consuming a controlled diet containing four levels of vitamin B-6 provides an estimated average requirement and recommended dietary allowance

The Recommended Dietary Allowance (RDA) of vitamin B-6 for young women was recently reduced from 1.6 to 1.3 mg/d based on an adequate plasma pyridoxal phosphate (PLP) concentration of 20 nmol/L. To assess vitamin B-6 requirements and suggest recommendations for intake, seven healthy young women consumed a controlled diet providing 1.2 g protein/kg body weight for a 7-d adjustment period (1.0 mg vitamin B-6/d) and three successive 14-d experimental periods (1.5, 2.1 and 2.7 mg/d, respectively). Direct and indirect vitamin B-6 status indicators were measured in plasma, erythrocytes and urine. Indicators most strongly correlated with vitamin B-6 intake [i.e., plasma and erythrocyte PLP, urinary 4-pyridoxic acid (4-PA) and total vitamin B-6] were regressed on vitamin B-6 intake and the dietary vitamin B-6 to protein ratio. Inverse prediction using adequate and baseline values estimated vitamin B-6 requirement. Adequate values were determined for plasma PLP and urinary 4-PA from baseline values of 60 previous subjects, using the statistical method suggested by Sauberlich. The current study suggests a vitamin B-6 Estimated Average Requirement (EAR) for young women of 1.1 mg/d or 0.016 mg/g protein, and a RDA of 1.5 mg/d or 0.020 mg/g protein. When results from this study are combined with data from four other recent studies, the combined data predict an EAR of 1.2 mg/d or 0.015 mg/g protein, and a RDA of 1.7 mg/d or 0.018 mg/g protein. This study suggests that the current vitamin B-6 RDA may not be adequate.

Molecular Evaluation of Vitamin D3 Receptor Agonists Designed for Topical Treatment of Skin Diseases11The authors declared not to have conflict of interest

MC903 (calcipotriol) is a synthetic, low calcemic analog of the nuclear hormone 1alpha,25-dihydroxyvitamin D3 and used in the treatment of psoriasis. The beneficial effects of MC903 on psoriasis are based on gene regulatory events. The genomic actions of 1alpha,25-dihydroxyvitamin D3 and its analogs are primarily mediated by a complex of the vitamin D3 receptor and the retinoid X receptor bound to a 1alpha,25-dihydroxyvitamin D3 response element that can be considered as the molecular switch of 1alpha,25-dihydroxyvitamin D3 signaling. In this study, the interaction of MC903 and two new analogs, GS1500 and EB1213, with this molecular switch was compared with that of 1alpha,25-dihydroxyvitamin D3. In DNA-dependent limited protease digestion assays, ligand-dependent gel shift assays and mammalian-one-hybrid assays, all four ligands appeared to be equally sensitive VDR agonists that activated vitamin D3 receptor-retinoid X receptor-1alpha,25-dihydroxyvitamin D3 response element complexes at a concentration of approximately 0.2 nM. The analyzed VDR agonists, however, also showed individual molecular properties, such as a reduced sensitivity in HaCaT cells (MC903), a selectivity for DNA-bound vitamin D3 receptor-retinoid X receptor heterodimers (GS1500) and a long-lasting stabilization of vitamin D3 receptor-retinoid X receptor-1alpha,25-dihydroxyvitamin D3 response element complexes (EB1213). This molecular evaluation demonstrated that the sensitivity in activating the vitamin D3 receptor is already optimal for MC903, but the analog may not be ideal in keeping the receptor active and in selectively triggering 1alpha,25-dihydroxyvitamin D3 signaling pathways.

Stability of vitamin B-6-dependent aminotransferase activity in frozen packed erythrocytes is dependent on storage temperature

Pyridoxal 5'-phosphate (PLP) stimulation of erythrocyte alanine and aspartate aminotransferase (EALT, EAST) activities is a frequently used functional measure of vitamin B-6 status. Stability of enzyme activities and activity coefficients (AC, stimulated / unstimulated) was assessed in packed erythrocytes frozen at -20, -80 degrees C and under liquid nitrogen (-196 degrees C). Activities of EALT and EAST, with and without added PLP, were determined in fresh erythrocytes (d 0) and frozen samples on d 1, 7, 14, 28, 58 and 84. In -20 degrees C samples, EALT basal activity decreased 17 and 22% (P < or = 0.05 for both) by d 58 and 84, respectively, and EAST basal activity decreased 40% (P < or = 0.05) by d 58. In -80 and -196 degrees C samples, EALT and EAST basal activities did not change significantly. Activity coefficients did not differ significantly from d 0 at any storage temperature, but EAST-AC increased 9-19% (nonsignificant) in samples stored at -20 and -80 degrees C for 7 to 84 d. Additionally, EAST-AC was significantly higher in -20 than -80 and -196 degrees C samples on d 1 and 58, respectively. Erythrocytes may be frozen for 28 d at -20 degrees C and 84 d at -80 degrees C before analysis for EALT; for EAST, activity should be measured on fresh erythrocytes.

Vitamin D compounds exert anti-apoptotic effects in human osteosarcoma cells in vitro

Several studies have demonstrated that vitamin D regulates growth and differentiation in bone cells in vitro. In addition, in vivo studies have shown that vitamin D stimulates bone formation, increases the number of osteoblast precursor cells and prevents bone mineral loss. These observations indicate that vitamin D may have anabolic effects on bone, and thus therapeutic potential in the treatment of osteoporosis. However, little is known about the effects of vitamin D on apoptosis in bone cells and about the contribution of this process to the effect of vitamin D on bone mineral loss. To investigate this aspect in more detail, we studied the effect of 1alpha,25(OH)(2)D(3) and a series of analogues on apoptosis in human osteosarcoma cells. No significant induction of apoptosis was observed with any of the compounds after a 5 day treatment period. In contrast, some of the analogues showed a tendency to protect the cells from undergoing apoptosis. This anti-apoptotic effect of vitamin D was further confirmed by the ability of 1alpha,25(OH)(2)D(3) to suppress camptothecin- and staurosporin-induced DNA fragmentation in the cells. In cultures treated simultaneously with 1alpha,25(OH)(2)D(3) in combination with camptothecin or staurosporin, the level of DNA fragmentation was markedly reduced compared with cultures treated with camptothecin or staurosporin alone. On the basis of the present results, it is therefore concluded that vitamin D displays anti-apoptotic effects in human osteoblast-like osteosarcoma cells in vitro. This observation suggests that besides regulating growth and differentiation, vitamin D exerts its anabolic effects on bone by protecting osteoblastic cells from undergoing apoptosis.

Ageing is associated with a prolonged fever response in human endotoxemia

The purpose of this study was to investigate whether an age-associated impaired acute-phase response exists. Nine healthy elderly volunteers (median, 66 years; range, 61 to 69 years) and eight young controls (median, 24 years; range, 20 to 27 years) were given an intravenous bolus of endotoxin (2 ng/kg). The rectal temperature was monitored continuously, and blood samples for cytokine measurements were obtained before endotoxin administration as well as 0.5, 1, 1.5, 2, 3, 4, 8, 12, and 24 h after the injection. The elderly subjects showed a more prolonged fever response compared to the young controls. Levels of tumor necrosis factor alpha (TNF-alpha), soluble TNF receptors (sTNFR-I), interleukin-6 (IL-6), IL-8, IL-10, and IL-1 receptor antagonist (IL-1ra) in plasma increased markedly following endotoxin administration in both groups. The elderly group showed larger initial increases in TNF-alpha and sTNFR-I levels and prolonged increased levels of sTNFR-I. Monocyte concentrations decreased in both groups, with the elderly group showing a more rapid decrease and a slower subsequent increase than did the young group. Furthermore, the elderly group had a more rapid increase in C-reactive protein levels than did the young group. In conclusion, ageing is associated with an altered acute-phase response including initial hyperreactivity, prolonged inflammatory activity, and prolonged fever response.

Cyanoguanidine CHS 828 induces programmed cell death with apoptotic features in human breast cancer cells in vitro

The cyanoguanidine CHS 828 was recently shown to possess potent anti-tumour effects both in vitro and in vivo. The exact mechanism of action of CHS 828 is not known, but recent results have indicated that induction of programmed cell death may be one mechanism by which CHS 828 exerts its anti-tumour effects. To investigate this aspect in more detail, we studied the effect of CHS 828 and the reference compound Taxol beta on programmed cell death in human breast cancer cells in vitro. Both compounds were found to induce DNA fragmentation in the cells. However, microscopic examination of the cells demonstrated that CHS 828 and Taxol triggered different types of cell death. In the CHS 828-treated cultures most cells were found to be Annexin-V positive, indicating that these cells were early apoptotic cells, while no morphological characteristics of classical apoptosis were seen. In contrast, the cells in the Taxol-treated cultures displayed morphological features characteristic of classical apoptotic cells, but no Annexin-V positive cells could be observed. These findings together with the previously reported potent effects of CHS 828 on tumour cells, makes CHS 828 a promising new agent for the treatment of cancer patients.

Expression of a novel factor, com1, is regulated by 1,25-dihydroxyvitamin D3 in breast cancer cells

Tumor cells and their surrounding microenvironment produce a variety of factors that promote tumor growth and metastasis. We recently identified a nuclear factor, termed com1, that is up-regulated in human breast carcinoma cells on formation of experimental metastatic tumors and is assumed to act as a growth-promoting factor in breast cancer. 1,25-Dihydroxyvitamin D3 [1,25(OH)2D3] is a potent inhibitor of growth in breast cancer both in vitro and in vivo. We compared the growth-regulatory mechanisms of nontumorigenic and estrogen-dependent MCF-7 cells with those of the tumorigenic and tamoxifen-resistant subline MCF7/ LCC2 in the presence of 1,25(OH)2D3. Proliferation of MCF7/LCC2 cells, which revealed constitutive com1 expression, was inhibited by 1,25(OH)2D3 (10(-7) M). This was strongly associated with cell cycle arrest in G1 phase, consistent with accumulation of the hypophosphorylated form of the retinoblastoma protein as well as the induction of the cyclin-dependent kinase inhibitor p21. These cell cycle events were preceded by a transient up-regulation (5-8-fold) of com1 mRNA. Furthermore, clonal growth of the MCF7/LCC2 cells was also inhibited by 1,25(OH)2D3 (10(-7) M), and when the com1-negative MCF-7 cells were stably transfected with com1, the resulting MCF7/com1 cells showed a significant decrease in colony formation. These results seem to indicate that rather than promoting growth, com1 may participate in the regulatory pathway involved in cellular growth inhibition when recruited by inhibitory signals.

Seocalcitol (EB 1089): a vitamin D analogue of anti-cancer potential. Background, design, synthesis, pre-clinical and clinical evaluation

It is well established that the metabolically active form of vitamin D, 1alpha,25-dihydroxyvitamin D3 (1alpha,25(OH)2D3) plays a key role in the establishment and maintenance of the calcium metabolism in the body. In addition to this classic effect of 1alpha,25(OH)2D3, substantial evidence has emerged demonstrating that 1alpha,25(OH)2D3 is able to regulate cell growth and differentiation in a number of different cell types, including cancer cells. However, the clinical usefulness of 1alpha,25(OH)2D3 is limited by its tendency to cause hypercalcaemia. Much effort has therefore been directed to identifying new vitamin D analogues with potent cell regulatory effects, but with weaker effects on the calcium metabolism than those of 1alpha,25(OH)2D3. One of these new synthetic analogues is Seocalcitol (EB 1089). Despite being 50-200 times more potent than 1alpha,25(OH)2D3 with respect to regulation of cell growth and differentiation in vitro as well as in vivo, EB 1089 displays a reduced calcaemic activity in vivo compared to that of 1alpha, 25(OH)2D3. These characteristics make EB 1089 a potentially useful compound for the treatment of cancer. Recent clinical evaluation of EB 1089 has focused mainly on establishing a maximum tolerated dose in cancer patients. Early results confirm that the low calcaemic activity observed in animals can be reproduced in the clinic. Furthermore, EB 1089 has been shown to induce regression of tumours, especially in hepatocellular carcinoma where complete remission has been obtained. In conclusion, the development of EB 1089 as an anti-cancer drug holds promise. However, its final evaluation must await the completion of ongoing controlled clinical trials.

Application of the bootstrap procedure provides an alternative to standard statistical procedures in the estimation of the vitamin B-6 requirement

The bootstrap procedure is a versatile statistical tool for the estimation of standard errors and confidence intervals. It is useful when standard statistical methods are not available or are poorly behaved, e.g., for nonlinear functions or when assumptions of a statistical model have been violated. Inverse regression estimation is an example of a statistical tool with a wide application in human nutrition. In a recent study, inverse regression was used to estimate the vitamin B-6 requirement of young women. In the present statistical application, both standard statistical methods and the bootstrap technique were used to estimate the mean vitamin B-6 requirement, standard errors and 95% confidence intervals for the mean. The bootstrap procedure produced standard error estimates and confidence intervals that were similar to those calculated by using standard statistical estimators. In a Monte Carlo simulation exploring the behavior of the inverse regression estimators, bootstrap standard errors were found to be nearly unbiased, even when the basic assumptions of the regression model were violated. On the other hand, the standard asymptotic estimator was found to behave well when the assumptions of the regression model were met, but behaved poorly when the assumptions were violated. In human metabolic studies, which are often restricted to small sample sizes, or when statistical methods are not available or are poorly behaved, bootstrap estimates for calculating standard errors and confidence intervals may be preferred. Investigators in human nutrition may find that the bootstrap procedure is superior to standard statistical procedures in cases similar to the examples presented in this paper.

Structural variants of the vitamin D analogue EB1089 reduce its ligand sensitivity and promoter selectivity

The nuclear hormone 1alpha,25-dihydroxyvitamin D3 (VD) has important cell-regulatory functions but also a strong calcemic effect. Therefore, various VD analogues have been synthesized and screened for their biological profile. In order to gain more insight into the molecular basis of the high antiproliferative but low calcemic action of the VD analogue EB1089, we characterized this compound in comparison to five structurally related VD analogues. The activities of the six VD analogues in in vitro assays (limited protease digestion assays for determining interaction with monomeric vitamin D receptor (VDR), ligand-dependent gel shift assays for showing the increase of DNA binding of VDR-retinoid X receptor (RXR) heterodimers, and reporter gene assays on different types of VD response elements for demonstrating the efficacy in nuclear VD signalling) were found to represent their biological potency (antiproliferative effect on different malignant cell lines). In this series, EB1089 proved to be the most potent VD analogue; that is, every structural modification (20-epi configuration, cis-configuration at position C24, or changes at the ethyl groups at position C25) appeared to reduce the determined activities mediated through the VDR of these analogues. Moreover, the modifications of EB1089 resulted in a loss of VD response element selectivity, suggesting that this parameter is very critical for the biological profile of this VD analogue.

New 1 alpha,25-dihydroxy vitamin D3 analogues with side chains attached to C-18: synthesis and biological activity

A new class of analogues of 1 alpha,25-dihydroxy vitamin D3 has been synthesised, in which the side chain (C-23 to C-27) has been removed and where new hydroxylated side chains have been attached to the C-18 methyl group. These analogues show antiproliferative activity in U937 and HaCaT cells comparable to that of 1 alpha,25-dihydroxy vitamin D3. Lack of calcemic activity makes these analogues potentially useful in the treatment of proliferative diseases.

Frequency of the "push-pull effect" in U.S. Air Force fighter operations

BACKGROUND

Recent investigation into the push-pull effect (PPE), the reduction of +Gz tolerance when preceded by less than +1 Gz, has focused on centrifuge studies to demonstrate the presence of adverse cardiovascular responses. Maneuvers found to cause the Push-Pull Effect (PPEM) have not been studied previously in U.S. Air Force (USAF) fighter aircraft. The frequency of and extent to which PPEMs are performed in fighter aircraft are unknown.

METHODS

Head-up display (HUD) videotapes from F-15 and F-16 air combat training missions were reviewed for the presence of PPEMs. The frequency of engagements containing PPEMs and the magnitude of the Gz profiles were noted.

RESULTS

PPEMs were found in 11 to 67%, of engagements reviewed, depending on the nature of the training mission, with an overall average of 32%. The PPEMs that were observed contained segments of less than +1 Gz, ranging on average from 0.0 to 0.5 Gz for an average of 3.5 to 5 s duration.

CONCLUSIONS

PPEMs are present in air combat training missions performed by today's USAF fighter aircraft and represent an operationally significant source of risk for accidents. These findings support continued research into the physiologic response to PPE and the development of countermeasures.

Sequence analysis of porcine reproductive and respiratory syndrome virus of the American type collected from Danish swine herds

Vaccine-like viruses of American type of porcine reproductive and respiratory syndrome virus (PRRSV) were detected in serum samples by RT-PCR. The viruses were analysed by nucleotide sequencing of the genomic region encoding open reading frames 2 to 7. During the ongoing study of Danish isolates of PRRSV by means of nucleotide sequencing, RT-PCR reactions and subsequent nucleotide sequencing showed the presence of American type PRRSV in Danish breeding herds. Most likely, these atypical viruses originated from boars vaccinated with live vaccine of American type (MLV RespPRRS), which were taken to artificial insemination centres and there brought together with unvaccinated boars already at the centres. The nucleotide sequences of three Danish viruses of American type PRRSV were compared to those of known PRRSV isolates. The nucleotide sequence identities of the atypical Danish isolates were between 99.2-99.5% to the vaccine virus RespPRRS and 99.0-99.3% to VR2332 which are the parental virus to the vaccine virus. Phylogenetic analysis including field isolates of American type supports the conclusion that the introduction of American type PRRSV in Denmark was due to spread of vaccine virus.

[Severely traumatized patients admitted to Aarhus Community Hospital 1994-1995]

In Denmark, only few studies have addressed the problem of severe trauma. In relation to establishing a trauma manual at our hospital we studied trauma patients requiring immediate anaesthesiological assistance. Patients from the preceeding years, 1994-1995 were identified. The injuries were scored according to the Abbreviated Injury Scale (AIS), and Injury Severity Scores (ISS) were calculated. Two hundred and fifty-eight trauma patients were identified, 132 of these were severely injured, defined as having ISS > or = 15. Of these, 75 patients were multitraumatised, defined as AIS > or = 3 in at least two regions. None of the patients with ISS < or = 15 died. Mortality was 49% among severely injured but not multitraumatised patients, while mortality was 56% among the multitraumatised patients. Head injuries were the most frequently found severe injury (AIS > or = 3), followed by injuries to the thorax and extremities. The anaesthesiologist and the orthopaedic surgeon were involved in initial diagnosis and treatment in all patients, and beyond these a variety of medical specialties were involved. In the light of this study we have revised our procedures and registration concerning severe trauma patients.

Studies on the interaction between the vitamin D receptor and the radiolabelled 20-epi vitamin D analogue GS 1500

Previous studies have shown that the binding affinity of a vitamin D analogue for the vitamin D receptor (VDR) does not correlate with the biological potency of the compound. In the present investigation the vitamin D analogue GS 1500, which is characterised by an altered stereochemistry at carbon C-20 (20-epi) and an aromatic ring in the side chain, was studied with respect to its interaction with the VDR. Using [3H]-GS 1500 as tracer, the receptor binding properties of GS 1500 were investigated and compared to those of 1,25(OH)2D3. The binding studies did not reveal a different binding site for GS 1500 than the one already established, and the binding affinity was in accordance with previously found values. At the level of VDR interaction with the vitamin D responsive element, GS 1500 did induce a binding complex at a lower concentration than 1,25(OH)2D3, which may help explain the difference in potency.

Down-regulation of laminin-binding integrins by 1 alpha,25-dihydroxyvitamin D3 in human melanoma cells in vitro

In the present investigation the effect of 1 alpha,25(OH)2D3 on the expression of the integrin laminin receptor on the melanoma cell line SK-MEL-28 has been examined. The SK-MEL-28 cells were shown to contain high-affinity receptors for 1 alpha,25(OH)2D3 and cell proliferation was found to be inhibited in a dose-dependent manner in response to the hormone. Using monoclonal antibodies against the alpha 6-sub-unit of the integrin laminin receptor, immunocytochemistry demonstrated that exposure of cells to 1 alpha,25(OH)2D3 for 5 days caused a reduced staining intensity. This observation was further confirmed by dot blot analysis, where a dose-dependent decline of alpha 6 expression was obtained after treatment of the cells with 1 alpha,25(OH)2D3 for 6 days. FACS-analysis was performed in order to quantify this decline, and it was found that the level of alpha 6-subunits on the cell surface was reduced by more than 40%. Additional investigations including Northern blot analyses of poly(A)+RNA extracts also showed a dose-dependent reduction of alpha 6 mRNA. Interestingly, the decrease of alpha 6 expression on the surface of SK-MEL-28 melanoma cells was accompanied by a reduced ability of the cells to adhere to an artificial basement membrane. In conclusion, the present investigation shows that besides having an antiproliferative effect on the SK-MEL-28 melanoma cells, 1 alpha,25(OH)2D3 is also able to inhibit the surface expression of the alpha 6-subunit of the integrin laminin receptor. Moreover, the results strongly indicate that 1 alpha,25(OH)2D3 exerts its regulatory effect on the alpha 6-subunit at the transcriptional level rather than at the protein level.

EB 1089, a novel vitamin D analog with strong antiproliferative and differentiation-inducing effects on target cells

The physiologically active form of vitamin D, 1alpha,25-dihydroxyvitamin D3, plays an important role not only in the establishment and maintenance of calcium metabolism, but also in regulating cell growth and differentiation. As the clinical usefulness of 1alpha,25-dihydroxyvitamin D3 is limited by its tendency to cause hypercalcemia, new analogs with a better therapeutic profile have been synthesized. One of these new synthetic vitamin D analogs is EB 1089, which is characterized by an altered side chain structure featuring 26,27-dimethyl groups and two double bonds. This analog has been shown to be more potent than 1,25-dihydroxyvitamin D3 in inhibiting proliferation, stimulating differentiation, and inducing apoptosis in a number of different cell types, including cancer cells. Despite being more potent than 1alpha,25-dihydroxyvitamin D3 with respect to its cell regulatory effects, EB 1089 displays weaker calcemic side-effects. These characteristics make EB 1089 a potentially useful compound for the treatment of a diversity of clinical disorders, including cancer and metabolic bone diseases. A promising phase I study with EB 1089 in patients with advanced breast and colon cancer has already been carried out, and more clinical trials evaluating the clinical effectiveness of EB 1089 in other types of cancer are in progress.

Changes in vitamin B-6 status indicators of women fed a constant protein diet with varying levels of vitamin B-6

Changes in vitamin B-6 status indicators were evaluated in vitamin B-6-replete subjects. Ten young women consumed diets providing 85 g protein/d and 1.03, 1.33, 1.73, and 2.39 mg vitamin B-6/d for 12 or 15 d during four successive diet periods; in a second study, six women were fed diets providing 85 g protein/d and 0.84, 1.14, and 2.34 mg vitamin B-6/d for 10 or 12 d during three successive diet periods. Vitamin B-6 status indicators showing significant differences among intakes included urinary excretion of 4-pyridoxic acid and total vitamin B-6, pyridoxal 5'-phosphate and total vitamin B-6 in plasma, and xanthurenic acid excretion after a 2-g L-tryptophan load. Significant correlations were found between vitamin B-6 intake and 4-pyridoxic acid, total vitamin B-6, plasma pyridoxal 5'-phosphate, plasma total vitamin B-6, erythrocyte alanine aminotransferase percentage stimulation and postload excretion of xanthurenic acid and volatile amines (kynurenine plus acetylkynurenine). Depending on the indicator, between 20% and 70% of the subjects had inadequate values for 4-pyridoxic acid, total vitamin B-6, plasma pyridoxal 5'-phosphate, and erythrocyte alanine aminotransferase percentage stimulation at a vitamin B-6 intake of 1.33 mg/d (0.016 mg vitamin B-6/g protein). A ratio of dietary vitamin B-6 to protein > 0.016 mg/g is required for adequate vitamin B-6 status in women.

Sensitive induction of apoptosis in breast cancer cells by a novel 1,25-dihydroxyvitamin D3 analogue shows relation to promoter selectivity

The biologically active form of vitamin D3, the nuclear hormone 1 alpha,25-dihydroxyvitamin D3 (VD), is an important regulator of cellular growth, differentiation, and death. The hormone mediates its action through the activation of the transcription factor VDR, which is a member of the superfamily of nuclear receptors. In most cases the ligand-activated VDR is found in complex with the retinoid X receptor (RXR) and stimulates gene transcription mainly from VD response elements (VDREs) that are formed by two hexameric core binding motifs and are arranged either as a direct repeat spaced by three nucleotides (DR3) or as an inverted palindrome spaced by nine nucleotides (1P9). The two VD analogues CB1093 and EB1089 are both very potent inhibitors of the proliferation of MCF-7 cultured breast cancer cells displaying approximately 100-fold lower IC50 values (0.1 nM) than the natural hormone. In addition, CB1093 is even more potent in vivo than EB1089 in producing regression of experimental mammary tumors. Moreover, both VD analogues induce apoptosis in MCF-7 cells, but CB1093 is effective at concentrations approximately 10-fold lower than EB1089. In accordance, the reduction of Bcl-2 protein expression showed CB1093 to be more potent than EB1089. This suggests that the antiproliferative effect of CB1093 may be related mainly to its apoptosis inducing effect, whereas EB1089 may preferentially have effects on growth arrest. EB1089 is known to result in a selectivity for the activation of IP9-type VDREs, whereas CB1093 shows a preference for the activation of DR3-type VDREs. This promoter selectivity suggests that the effects of VD and its analogues on growth arrest and the induction of apoptosis may be mediated by different primary VD responding genes. In conclusion, CB1093 was found to be a potent inhibitor of rat mammary tumor growth in vivo. CB1093 also displayed a high potency in vitro in the induction of apoptosis, a process that may be linked to a promoter selectivity for DR3-type VDREs.

Vitamin B-6 status indicators decrease in women consuming a diet high in pyridoxine glucoside

Previous research has shown that the pyridoxine glucoside (PNG) form of vitamin B-6 has a reduced bioavailability compared with pyridoxine, but its effect on vitamin B-6 status has not been assessed. Following an 8-d adjustment period, nine women consumed diets containing a high or low amount of PNG for 18 d each, in a crossover design. The high and low PNG diets provided 1.52 mg/d (8.98 micromol/d) and 1.44 mg/d (8.57 micromol/d) of vitamin B-6, of which 27% and 9% was PNG, respectively. The dietary vitamin B-6 to protein ratio of both diets was 0.017 mg/g. Urinary excretions of 4-pyridoxic acid and total vitamin B-6 were significantly lower (P < 0.05) during the high PNG diet period than when the low PNG diet was consumed. Urinary PNG excretion was equal to about 9% of the total PNG intake during both periods. Plasma total vitamin B-6 (P < 0.01) and red blood cell pyridoxal 5'-phosphate (PLP) (P < 0.05) were significantly lower when the high PNG diet was consumed than during the low PNG diet period. Fecal total vitamin B-6 excretion was significantly higher (P < 0.001) when the high PNG diet was consumed. Women consuming a diet containing a higher percentage of the total vitamin B-6 intake as PNG exhibited a decrease in vitamin B-6 status indicators, consistent with the reduced bioavailability of PNG demonstrated in other studies, equal to a loss of 15-18% of the total vitamin B-6 intake. During the determination of Recommended Dietary Allowances, the reduced bioavailability of PNG and its presence in higher amounts in some diets should be considered.

Vitamin B-6 status of women with a constant intake of vitamin B-6 changes with three levels of dietary protein

To determine the effect of varying levels of dietary protein with a constant intake of vitamin B-6 (B-6) on B-6 status, nine women were fed diets providing daily intakes of 1.25 mg B-6 and 0.5, 1.0 and 2.0 g protein/kg body weight. After an 8-d adjustment period, the women consumed each level of dietary protein for 14 d in a Latin-square design. Several direct and indirect B-6 status indicators were measured in blood and urine. Significant differences among protein levels were found for urinary 4-pyridoxic acid (4-PA) excretion (P < 0.01), plasma pyridoxal 5'-phosphate (PLP) concentration (P < 0.05), and urinary excretion of volatile amines (VA, kynurenine plus acetylkynurenine) after a 2-g L-tryptophan load (P < 0.05). Nitrogen intake was significantly negatively correlated with urinary 4-PA excretion (r = -0.619, P < 0.001) and plasma PLP concentration (r = -0.549, P < 0.01), and positively correlated with erythrocyte alanine aminotransferase percentage stimulation (r = 0.418, P < 0.05) and urinary post-tryptophan load excretion of xanthurenic acid (r = 0.535, P < 0.05), kynurenic acid (r = 0.563, P < 0.05) and VA (r = 0.626, P < 0.01). Compared with men consuming diets with similar B-6 to protein ratios In a previous study, the women excreted a greater percentage of the B-6 intake as 4-PA, had lower plasma PLP concentrations and excreted greater amounts of postload urinary tryptophan metabolites at all three protein levels. If the Recommended Dietary Allowance (RDA) of vitamin B-6 is to be based on the dietary B-6 to protein ratio, gender differences in response to varying protein intakes should be considered. For the levels of protein intake used in this study and a B-6 intake of 1.25 mg/d, a B-6 to protein ratio of greater than 0.020 mg/g is required for adequate vitamin B-6 status in women.

The anti-proliferative and differentiation-inducing effects of vitamin D analogs are not determined by the binding affinity for the vitamin D receptor alone

Calcipotriol, a synthetic analog of 1 alpha,25-dihydroxyvitamin D3 (1 alpha,25[OH]2D3), is used in the treatment of psoriasis. In this investigation, the biological profile of calcipotriol and of two new vitamin D analogs, EB 1213 and GS 1500, has been studied and compared with the profile of 1 alpha,25(OH)2D3. Despite the fact that the affinity for the intracellular vitamin D receptor of the three analogs is comparable (EB 1213) or lower (GS 1500, calcipotriol) than that of 1 alpha,25(OH)2D3, they were all found to be more potent in inhibiting human skin cell proliferation in vitro. The anti-proliferative effect was accompanied by a change in the cytokeratin pattern of the skin cells, indicating a differentiation-inducing effect of the compounds similar to that of 1 alpha,25(OH)2D3. Further investigations including ligand-induced vitamin D receptor transcription studies in chloramphenicol acetyl transferase assays showed that EB 1213 and GS 1500 were more efficient than 1 alpha,25(OH)2D3 in inducing vitamin D receptor transcription. This strongly indicates that not only the binding affinity for the receptor, but more importantly, the ability of the compounds to induce vitamin D receptor transcription, is a determinant of the biological activity of the compounds.

Permeability of commercial solvents through living human skin

A procedure has been developed for measuring the steady state rate of permeation of commercial solvents through living human skin. To get the most consistent results, it was necessary with some solvents to normalize the solvent permeation rate of a given skin sample with its [3H]water permeation rate. For other solvents this was not necessary, so the un-normalized data were used. High [3H]water permeation rate also was used as a criterion for "defective" skin samples that gave erroneous permeability rates, especially for solvents having slow permeability. The linearity of the steady state data was characterized by calculation of the "percent error of the slope." The following permeability rates (g/m2h) of single solvents were measured: dimethyl sulfoxide (DMSO), 176; N-methyl-2-pyrrolidone, 171; dimethyl acetamide, 107; methyl ethyl ketone, 53; methylene chloride, 24; [3H]water, 14.8; ethanol, 11.3; butyl acetate, 1.6; gamma-butyrolactone, 1.1; toluene, 0.8; propylene carbonate, 0.7; and sulfolane, 0.2. The effect of [3H]water saturation on the shape of the presteady state portion of the permeation curve was determined and found to be very dependent on the solvent. The permeability of mixtures of DMSO and octyl acetate were measured. No octyl acetate was detected and the permeability of DMSO was proportional to its mole fraction in the mixture. The effect of two hours of solvent exposure on the viability of skin (based on DNA synthesis) was measured and found to be very dependent on the solvent.

1 alpha,25-Dihydroxyvitamin D3 inhibits the invasive potential of human breast cancer cells in vitro

Using the Boyden chamber invasion assay, the effect of 1 alpha,25-dihydroxyvitamin D3 [1 apha,25(OH)2D3] on the invasiveness of the highly invasive, oestrogen receptor-negative human breast cancer cell line MDA-MB-231 was examined. The MDA-MB-231 cells were shown to contain high-affinity receptors for 1 alpha,25(OH)2D3 with a Kd of 1.5 x 10(-11) M. When the cells were treated with 1 alpha,25(OH)2D3 for 4 days before the assay was performed, a dose-dependent inhibition of their invasive potential was demonstrated. Fifty per cent inhibition of invasion was obtained with a concentration of 13 pM of 1 alpha,25(OH)2D3. However, when the cells were treated for only 6 h during the assay, no inhibitory effect was seen. The process of migration was also affected by treatment with 1 alpha,25(OH)2D3 for 4 days, although the inhibition was not of the same magnitude as seen for the invasion. Fifty per cent inhibition of migration occurred at a concentration of 3.2 nM of 1 alpha,25(OH)2D3 (250 times higher than in the invasion assay). Inhibition of invasion and migration was not due to the known anti-proliferative effect of 1 alpha,25(OH)2D3, as no growth reduction could be demonstrated with treatment up to 5 days. Based on the present investigation it can therefore be concluded that 1 alpha,25(OH)2D3 is able to inhibit tumour cell invasiveness by a mechanism which is not exclusively based on its anti-proliferative and anti-migrative effects.

Child abuse presenting as a thoracolumbar spinal fracture dislocation: a case report

A child sustained a traumatic thoracolumbar spinal fracture--dislocation with cord compression. A court confirmed the diagnosis of child abuse. There was no history of trauma, and the diagnosis of child abuse was missed by the physicians who first saw the child. Spinal injuries in child abuse are uncommon. They may be symptomatic or asymptomatic, stable or unstable, or occur with or without bony changes on the x-rays. Injuries without a history of trauma may be overlooked if asymptomatic. Radiologic skeletal surveys in suspected abuse should include a minimum of two views of the spine even if the child has no symptoms referrable to the spine. Conversely, a traumatic cause should be considered whenever there is spinal cord injury without vertebral injury. Having a high index of suspicion for abuse while remembering that pediatric spinal injuries may occur in the context of normal x-rays will decrease the likelihood of missed diagnosis, repeated abuse, or complications from delayed immobilization of unstable injuries.

The affinities of organic solvents in biological systems

The affinities of organic solvents in biological systems are described using solubility parameter techniques. Materials studied include lard, water, blood serum, sucrose, urea, keratin and lignin. The tendency for organic solvents to collect in fatty material, swell (penetrate) the skin, absorb into wood, or preferentially transfer to aqueous media, for example, can be estimated rapidly for any of the solvents for which solubility parameters are available.

Child health problems and programmes in two underdeveloped areas of the USA

There are areas in the USA where the health problems of children a similar to those of children in some developing countries. Traditional US health programmes have contributed to an improvement in the health status of many of these children but there remains much more to be done.

Effects on pregnant adolescents of attending a special school

Data on nutrient intakes and blood vitamin levels were obtained for twenty-nine pregnant adolescents attending a special school for pregnant school-age girls in New Brunswick, New Jersey. Except for calcium and iron, mean intakes were equal to or greater than the Recommended Dietary Allowances. Food eaten at school contributed 35 to 43% of the total nutrient intake. Mean blood vitamin levels were normal to high, although about a fourth of the girls had low levels of vitamin B6 and folate. All except one delivered normal, full-term infants. It was concluded that attendance at such a special school contributes to normal pregnancy outcome among teen-age mothers.

The pediatrician and family planning in a very poor community. An appraisal of experiences in the Tufts Delta Health Center, Bolivar County, Mississippi

Family planning services should be of prime interest to all pediatricians because of their direct relationship to the health and well-being of mothers and children. Maternal and Child Health Services offer a natural starting place for introduc tion of family planning services. However, family planning should be a part of total family health care for better acceptance, rather than merely a categorical program.