Biomechanical comparison of bi- and tricortical k-wire fixation in tension band wiring osteosynthesis

Background

Patients with a simple transversal fracture of the olecranon are often treated with a tension band wiring (TBW), because it is known as a biomechanically appropriate and cost-effective procedure. Nevertheless, the technique is in detail more challenging than thought, resulting in a considerable high rate of implant-related complications like k-wire loosening and soft tissue irritation. In the literature, a distinction is generally only made between transcortical (bi-) and intramedullary (mono-) fixation of the wires. There is the additional possibility to fix the proximal bent end of k-wire in the cortex of the bone and thus create a tricortical fixation. The present study investigates the effectiveness of bi- and tricortical k-wire fixation in a biomechanical approach.

Methods

TBW of the olecranon was performed at 10 cadaver ulnas from six donors in a usual manner and divided into two groups: In group 1, the k-wire was inserted by bicortical fixation (BC), and in group 2, a tricortical fixation (TC) was chosen. Failure behavior and maximum pullout strength were assessed and evaluated by using a Zwick machine. The statistical evaluation was descriptive and with a paired t test for the evaluation of significances between the two techniques.

Results

The average age of the used donors was 81.5 ± 11.5 (62–92) years. Three donors were female, and three were male. Ten k-wires were examined in BC group and 10 in the TC group. The mean bone density of the used proximal ulnas was on average 579 ± 186 (336–899) HU. The maximum pullout strength was 263 ± 106 (125–429) N in the BC group and increased significantly in the TC group to 325 ± 102 (144–466) N [p = .005].

Conclusion

This study confirms for the first time biomechanical superiority of tricortical k-wire fixation in the olecranon when using a TBW and may justify the clinical use of this method.

Abstract P5-03-10: Development of a novel HER2 testing strategy, using image-based cell-sorting to isolate pure cell populations from FFPE upstream of FISH

Fluorescent in Situ Hybridization (FISH) guidelines defined by American Society of Clinical Oncology (ASCO) and the College of American Pathologists for determining HER2 status are set to improve accuracy and usefulness as a diagnostic marker in breast cancer. Despite these guidelines, many factors can influence HER2 testing results such as sample preparation, assay-conditions and interpretation of test results due to heterogeneous breast cancer samples. In this multi-site study, sample preparation was carried out using the DEPArray™ to recover pure tumor cell populations from formalin-fixed, paraffin-embedded (FFPE) breast tumor samples. We then compared HER2/CEP17 ratios obtained from the DEPArray™ processed samples from each laboratory to routine FISH on tissue sections.

Methods: Eight breast FFPE tumor tissue biopsies were obtained from commercial tissue banks. From the paraffin tissue blocks, four consecutive tissue curls (each 50 microns thick) were prepared. One curl from each of the 8 patient samples was distributed to four different laboratories for analysis following DEPArray™ based sample preparation. After an initial disassociation of each curl into a single-cell suspension, intact cells were sorted and then recovered based on cytokeratin/ vimentin/DAPI staining using the DEPArray™. Cytokeratin+/Vimentin-/DAPI+ tumor (~250) and Cytokeratin-/Vimentin+/DAPI+ stromal (~250) recovered cells were then deposited onto glass slides prior to standard dual-color HER2/CEP17 FISH analysis for comparison to conventional HER2 FISH result.

Results: Serially sectioned breast tumors from 8 negative/positive cases: 7 infiltrating ductal carcinoma (IDC) and 1 metastatic carcinoma were studied. All four sites demonstrated 100% concordance between FISH results compared to the conventional HER2 FISH result. Overall, >60% of DEPArray™ isolated cells were recovered from FFPE samples that ranged from 1- 15 years of age and reported to contain 60% to 80% tumor content. The use of pure sorted cells permitted the accurate determination of HER2 amplification status in only the tumor cells while the stromal cells consistently yielded a more normalized ratio of HER2 to centromere 17.

Conclusion: The preliminary results of this multi-site study demonstrate that use of DEPArray™ for sorted pure populations is reproducible as well as reliable method for subsequent analysis of HER2 by FISH on FFPE derived tumor cells. Given that traditional FFPE-based HER2 FISH results may be influenced by the tissue sectioning procedure, tissue heterogeneity and/or the scattering of few HER2 amplified tumor cells among normal stromal cells. The DEPArray™ allows analysis of immunofluorescence images and DNA content to isolate and recover pure and intact cell populations. This isolation of pure cell populations prior to FISH analysis is attractive for achieving precise determination of HER2 status on equivocal cases. A more formal analytical validation of this approach through CLIA is currently underway.

Citation Format: Gerber A, Konig L, Millner L, Strotoman L, Khurana A, Kasimir-Bauer S, Moore MW, Cotter PD, Bischoff F. Development of a novel HER2 testing strategy, using image-based cell-sorting to isolate pure cell populations from FFPE upstream of FISH [abstract]. In: Proceedings of the 2016 San Antonio Breast Cancer Symposium; 2016 Dec 6-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2017;77(4 Suppl):Abstract nr P5-03-10.

Abstract P2-02-19: Somatic genetic profiling of circulating tumor cells (CTC) in metastatic breast cancer (MBC) patients

Introduction: Somatic mutations, including those in TP53, PIK3CA, and estrogen receptor alpha (ESR1), are key to the biology of cancer and response to therapy. Recently, somatic cancer-associated mutations have been identified in circulating cell free plasma tumor DNA (ptDNA). Less is known about the mutation profile of DNA extracted from CTC (CTC-DNA). Since CTC-DNA provides mutational information of single cells, we hypothesize CTC-DNA will complement ptDNA to give greater insight into tumor heterogeneity.

Methods: Patients with ER positive MBC who were enrolled in the Mi CTC-ONCOSEQ, a companion trial to Mi-ONCOSEQ (the Michigan Oncology Sequencing Program), and who had ≥5CTC/7.5 ml whole blood were included. CTC were enriched from white blood cells (WBC) with CellSearch© (CXC kit). CTC and WBC were then purified using DEPArrayTM. DNA from individual CTC and WBC was isolated and subjected to whole genomic amplification (Ampli 1TM WGA). Genetic analysis was performed on individual CTC, pooled CTC and pooled WBC DNA by multiplexed PCR based targeted next generation sequencing (NGS) using the Oncomine Comprehensive Panel (targeting ∼130 onco- and tumor suppressor genes) and the Ion Torrent Proton. All patients had exome sequencing performed on research biopsies of metastases using an Illumina HiSeq 2500 platform.

Results: This pilot study was conducted using high quality DNA from two patients assessed to date. Both patients had lobular carcinoma and as expected harbored somatic, deleterious CDH1 (E-cadherin) mutations (frameshift and non-sense) in both research biopsy and CTC-DNA. These data supported our approach. Patient #1 was TP53 wild type in her research biopsy, but multiple CTC harbored somatic TP53 frame-shift mutations (Table). Patient #2 harbored an ESR1 Y537S mutation in her research biopsy. However, only 4 of 7 CTC also harbored this somatic, heterozygous mutation.

Prioritized mutations in CTCPt#Cell Type (CTC vs WBC), numberGeneMutationVariant fraction (expected 1=homozygous; 0.5=heterozygous)Found in research biopsy?1CTC_A2CDH1p.I584fs1YES CTC_A4  1  CTC_A7  0.54  CTC_pool*  0.74  WBC_pool  0  CTC_A2TP53p.152_156del1NO CTC_A4  1  CTC_A7  0.51  CTC_pool*  0.88  WBC_pool  0 2CTC_A9ESR1p.Y537S0.52YES CTC_D1  0.34  CTC_D2  0.46  CTC_D6  0.65  CTC_pool*  0.35  WBC_pool  0  CTC_A12  0  CTC_D3  0  CTC_D7  0  CTC_A12CDH1p.Q641X1YES CTC_A9  1  CTC_D1  1  CTC_D3  1  CTC_D6  1  CTC_pool*  1  WBC_pool  0 * pool of all CTC

Conclusions: We demonstrate the ability to purify CTC, isolate, and amplify DNA of suitable quality for genetic analysis using a comprehensive targeted sequencing panel. Both known and novel alterations were identified in comparison to research biopsy specimens. This approach allows single cell analysis demonstrating heterogeneity of mutational status in different single cells. Studies of CTC-ESR1 and other genetic abnormalities in patients with known tissue mutations who participated in Mi CTC-ONCOSEQ are now underway.

Citation Format: Paoletti C, Cani AK, Aung K, Darga EP, Cannell EM, Hovelson DH, Yazdani M, Blevins AR, Tokudome N, Larios JM, Thomas DG, Brown ME, Gersch C, Schott AF, Robinson DR, Chinnaiyan AM, Bischoff F, Hayes DF, Rae JM, Tomlins SA. Somatic genetic profiling of circulating tumor cells (CTC) in metastatic breast cancer (MBC) patients. [abstract]. In: Proceedings of the Thirty-Eighth Annual CTRC-AACR San Antonio Breast Cancer Symposium: 2015 Dec 8-12; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2016;76(4 Suppl):Abstract nr P2-02-19.

Synthesis and biodistribution of [11C]R107474, a new radiolabeled α2-adrenoceptor antagonist

R107474, 2-methyl-3-[2-(1,2,3,4-tetrahydrobenzo[4,5]furo[3,2-c]pyridin-2-yl)ethyl]-4H-pyrido[1,2-a]pyrimidin-4-one, was investigated using in vitro and in vivo receptor assays and proved to be a potent and relatively selective alpha(2)-adrenoceptor antagonist. Performed assays in vitro were inhibition of binding to a large number of neurotransmitter receptor sites, drug receptor binding sites, ion channel binding sites, peptide receptor binding sites, and the monoamine transporters in membrane preparations of brain tissue or of cells expressing the cloned human receptors. The compound has subnanomolar affinity for halpha(2A)- and halpha(2C)-adrenoceptors (K(i) = 0.13 and 0.15 nM, respectively) and showed nanomolar affinity for the halpha(2B)-adrenoceptors and 5-hydroxytryptamine(7) (h5-HT(7)) receptors (K(i) = 1 and 5 nM, respectively). R107474 interacted weakly (K(i) values ranging between 81 and 920 nM) with dopamine-hD(2L), -hD(3) and -hD(4), h5-HT(1D)-, h5-HT(1F)-, h5-HT(2A)-, h5-HT(2C)-, and h5-HT(5A) receptors. The compound, tested up to 10 microM, interacted only at micromolar concentrations or not at all with any of the other receptor or transporter binding sites tested in this study. In vivo alpha(2A)- and alpha(2C)-adrenoceptor occupancy was measured by ex vivo autoradiography 1h after subcutaneous (sc) administration of R107474. It was found that R107474 occupies the alpha(2A)- and alpha(2C)-adrenoceptors with an ED(50) (95% confidence limits) of 0.014 mg/kg sc (0.009-0.019) and 0.026 mg/kg sc (0.022-0.030), respectively. Radiolabeled 2-methyl-3-[2-([1-(11)C]-1,2,3,4-tetrahydrobenzo[4,5]furo[3,2-c]pyridin-2-yl)ethyl]-4H-pyrido[1,2-a]pyrimidin-4-one ([(11)C]R107474) was prepared and evaluated as a potential positron emission tomography (PET) ligand for studying central alpha(2)-adrenoceptors. [(11)C]R107474 was obtained via a Pictet-Spengler reaction with [(11)C]formaldehyde in 33 +/- 4% overall decay-corrected radiochemical yield. The total synthesis time was 55 min and the specific activity was 24-28 GBq/micromol. The biodistribution of [(11)C]R107474 in rats revealed that the uptake of [(11)C]R107474 after in vivo intravenous administration is very rapid; in most tissues (including the brain) it reaches maximum concentration at 5 min after tracer injection. In agreement with the known distribution of alpha(2)-adrenoceptors in the brain, highest uptake of radioactivity was observed in septum (3.54 +/- 0.52 ID/g, 5 min pi) and entorhinal cortex (1.57 +/- 0.10 ID/g, 5 min pi). Tissue/cerebellum concentration ratios for septum (5.38 +/- 0.45, 30 min pi) and entorhinal cortex (3.43+/-0.24, 30 min pi) increased with time due to rapid uptake followed by a slow washout. In vivo blocking experiments using the non-selective alpha(2)-adrenoceptor antagonist mirtazapine demonstrated specific inhibition of [(11)C]R107474 binding in selective brain areas. The receptor binding profile of mirtazapine is reported and the selectivity of inhibition of binding is discussed. These results suggest that [(11)C]R107474 deserves further investigation as a potential radioligand for studying alpha(2)-adrenoceptors using PET.

Preimplantation genetic diagnosis for a known cryptic translocation: follow-up clinical report and implication of segregation products

This report describes preimplantation genetic diagnosis (PGD) of a couple with a known paternally-derived balanced cryptic translocation 46,XY.ish t(2q;17q)(210E14-,B37c1+;B37c1-,210E14+) in embryos from a couple who previously had a child with severe mental retardation and was previously described in this journal [Bacino et al., 2000]. This child inherited the unbalanced product of translocation from her father: 46,XX.ish der(2)t(2q;17q)pat(210E14-,B37c1+). The couple desired a normal offspring and sought PGD to avoid clinical pregnancy termination. They were treated three times with in vitro fertilization followed by PGD. Two sequential FISH hybridizations were performed. In the first hybridization, telomeric probes to 2q and 17q and a chromosome 17 centromere probe were employed. The second hybridization screened for maternal age-related aneuploidy (X,Y,13,18,21). Of the 18 informative embryos, only 4 (22%) were normal. The remaining 12 (67%) were abnormal; most with unbalanced products (10/12) from the paternally-derived rearrangement. The most frequent mode of segregation observed for this cryptic translocation was adjacent-1 (7/18, 39%). This suggests cryptic translocations are amenable to PGD and, as are traditional translocations, demonstrate higher frequencies of unbalanced segregants than the empiric risk of 10-15% observed at amniocentesis or chorionic villus sampling. Thus, cryptic translocations presumably behave like overt translocations, in that PGD must be performed on a relatively large number of embryos to assure even 2-3 transferable embryos.

[Cause of death in patients with cirrhosis]

PURPOSE

Since 1970, the rate of death from cirrhosis has decreased progressively, in part thanks to better handling of complications (preventive and curative treatment of gastric bleeding, prevention of infections and treatment of ascitis). The goal of this study was to examine the evolution in causes of death among cirrhotics.

METHODS

We identified all of the patients who died among those cirrhotics hospitalized at the Alençon Hospital during the period covered by the study, from January 1, 1993 to December 31, 1998. We examined the age of death of these cirrhotics, their causes of death, and also studied and compared this data with causes of death cited in the literature of the 1980s. Finally, we examined the prevalence of each cause of death in relation to the age of death of each patient.

RESULTS

Our results show that 347 cirrhotics were hospitalized at the Alençon Hospital during the period covered by the study, and 186 of these patients died. These deaths resulted from hepatocarcinoma in 22% of cases, gastric bleeding in 12% of cases, and liver cell failure at a terminal stage in 21% of cases. In 31% of cases, the cause was unrelated to cirrhosis, and in 13% of cases the cause was unknown. The death rate from hepatocarcinoma increased according to the patients' age, while the death rate from gastric bleeding decreased according to age.

CONCLUSION

We have noted, in comparison with Saunders in 1981 that there was a significant increase in extrahepatic causes of death and a significant decrease in deaths from liver cell failure. Percentages of the other causes of death do not show any variation, in spite of new techniques of detection and treatment.

Synthesis and pharmacology of 3-isoxazolol amino acids as selective antagonists at group I metabotropic glutamic acid receptors

Using ibotenic acid (2) as a lead, two series of 3-isoxazolol amino acid ligands for (S)-glutamic acid (Glu, 1) receptors have been developed. Whereas analogues of (RS)-2-amino-3-(3-hydroxy-5-methyl-4-isoxazolyl)propionic acid [AMPA, (RS)-3] interact selectively with ionotropic Glu receptors (iGluRs), the few analogues of (RS)-2-amino-3-(3-hydroxy-5-isoxazolyl)propionic acid [HIBO, (RS)-4] so far known typically interact with iGluRs as well as metabotropic Glu receptors (mGluRs). We here report the synthesis and pharmacology of a series of 4-substituted analogues of HIBO. The hexyl analogue 9 was shown to be an antagonist at group I mGluRs. The effects of 9 were shown to reside exclusively in (S)-9 (K(b) = 30 microM at mGlu(1) and K(b) = 61 microM at mGlu(5)). The lower homologue of 9, compound 8, showed comparable effects at mGluRs, but 8 also was a weak agonist at the AMPA subtype of iGluRs. Like 9, the higher homologue, compound 10, did not interact with iGluRs, but 10 selectively antagonized mGlu(1) (K(b) = 160 microM) showing very weak antagonist effect at mGlu(5) (K(b) = 990 microM). The phenyl analogue 11 turned out to be an AMPA agonist and an antagonist at mGlu(1) and mGlu(5), and these effects were shown to originate in (S)-11 (EC(50) = 395 microM, K(b) = 86 and 90 microM, respectively). Compound 9, administered icv, but not sc, was shown to protect mice against convulsions induced by N-methyl-D-aspartic acid (NMDA). Compounds 9 and 11 were resolved using chiral HPLC, and the configurational assignments of the enantiomers were based on X-ray crystallographic analyses.

Localization of AtROP4 and AtROP6 and interaction with the guanine nucleotide dissociation inhibitor AtRhoGDI1 from Arabidopsis

The small GTPases of the Rho family play a key role in actin cytoskeletal organization. In plants, a novel Rho subfamily, called ROP (Rho of plants), has been found. In Arabidopsis, 12 ROP GTPases have been identified which differ mainly at their C-termini. To test the localization of two members of this subfamily (AtROP4 and AtROP6), we have generated translational fusions with the green fluorescent protein (GFP). Microscopic analysis of transiently transfected BY2 cells revealed a predominant localization of AtROP4 in the perinuclear region, while AtROP6 was localized almost exclusively to the plasma membrane. Swapping of the AtROP4 and AtROP6 C-termini produced a change in localization. As RhoGDIs are known to bind to the C-terminus of GTPases of the Rho family, we searched for Arabidopsis RhoGDI genes. We identified the AtRhoGDI1 gene and mapped it to chromosome 3. AtRhoGDI1 encodes a 22.5 kDa protein which contains highly conserved amino acids in the isoprene binding pocket and exhibits 29% to 37% similarity to known mammalian RhoGDI homologues. The AtRhoGDI1 gene was expressed in all tissues studied. Using the yeast two-hybrid system, we showed specific interaction of AtRhoGDI1 with both AtROP4 and AtROP6 as well as with their GTP-locked mutants, but not with a GTPase of the RAB family. Recombinant GST-AtRhoGDI1 could bind GFP-AtROP4 from transgenic tobacco BY2 cell extracts, confirming the interaction observed with the two-hybrid system.

GTP-binding proteins in plants

GTP-binding proteins are found in all organisms. They are important switches that cycle between an active and an inactive state, ensuring vectorial flow of information on the expense of guanosine triphosphate (GTP). In this review, we discuss current progress in the molecular characterization and functional analysis of plant genes encoding heterotrimeric and small GTPases. An up-to-date list including all cloned plant GTPase genes is given and a systematic classification is proposed.

At-GDI1 from Arabidopsis thaliana encodes a rab-specific GDP dissociation inhibitor that complements the sec19 mutation of Saccharomyces cerevisiae

Rab GTPases play a central role in the control of vesicular membrane traffic. These proteins cycle between cytosolic and membrane-bound compartments in a guanine nucleotide-dependent manner, a process that is regulated by several accessory proteins. Of particular interest are the Rab guanosine nucleotide diphosphate dissociation inhibitor proteins (Rab-GDI) which bind to prenylated Rab GTPases, slow the rate of GDP dissociation and escort GDP bound Rab proteins to their target membranes and retrieve them after completion of their catalytic cycle. We have cloned from Arabidopsis thaliana a cDNA coding for the Rab guanosine diphosphate dissociation inhibitor (AtGDI1) by functional complementation of the Saccharomyces cerevisiae sec19-1 mutant. The Arabidopsis cDNA potentially encodes a 49850 Da protein which is homologous to yeast GDI (49%) and to other members of the Rab-GDI family (49-63%). Northern blot analysis indicates that the mRNA is expressed in all tissues examined. The existence of a plant homologue of the Rab-GDI family indicates that the basic vesicle traffic control machinery may be highly conserved in plants as it is in yeast and mammals.

[Detection of fetal cells in maternal blood: towards a noninvasive prenatal diagnosis]

Fetal cells exist in maternal blood and can be utilized for prenatal genetic diagnosis. These cells are present during the first and second trimesters, with frequency increasing as gestation advances. Enrichment of erythroblasts by various density gradient techniques and either magnetic activated or flow sorting techniques can be followed by FISH with chromosome-specific DNA probes. This approach has allowed detection of trisomy 21, trisomy 18, Klinefelter syndrome 47,XXY and 47,XYY. Polymerase chain reaction (PCR) analysis of maternal blood has enabled the detection of fetal sex, certain Mendelian disorders (e.g. beta-globin mutations), HLA polymorphisms, and fetal Rhesus (D) blood type. The fetal cell types receiving the most attention has been nucleated erythrocyte (erythroblast) and the trophoblast. Lymphocytes and granulocytes are also present in maternal blood; however, lymphocytes are considered the cell type most likely to persist after pregnancy. A large scale collaborative is now underway in the U.S. that will allow determine whether sensitivity and specificity of this technique provide a noninvasive alternative to conventional methods of prenatal cytogenetic diagnosis.

Excitatory amino acid receptor ligands: asymmetric synthesis, absolute stereochemistry and pharmacology of (R)- and (S)-homoibotenic acid

The (R)- and (S)-forms of 2-amino-3-(3-hydroxyisoxazol-5-yl)propionic acid (homoibotenic acid, HIBO) were synthesized, using (S)-BOC-phenylalanine as a chiral auxiliary and their absolute stereochemistry correlated with that of (R)-Br-HIBO. The enantiomeric excesses for (R)-HIBO (1) (> 99.5%) and (S)-HIBO (2) (99.5%) were determined using chiral HPLC. Whereas compounds 1 and 2 were equipotent inhibitors of the binding of [3H]glutamic acid in the presence of calcium chloride, 2 showed AMPA agonist activity and 1 very weak NMDA agonist activity.

Tissue reaction to and fate of parenterally administered titanium dioxide. I. The intraperitoneal site in male Marsh-Buffalo mice

In 32 male Marsh-Buffalo mice each receiving a saline suspension of 25 mg TiO2 intraperitoneally, four neoplasms appeared over the 18-month experimental period. During this time, four neoplasms appeared in 30 control mice receiving isotonic saline by the same injection route. A nonsignificant association of tumorigenesis with experimental treatment indicated a lack of carcinogenic potential for TiO2 and is discussed in terms of the local tissue reaction in the mice that received the TiO2. Focal deposits of dose material rather than a diffuse distribution were found on the intraperitoneal wall and muscles as well as the gut. In some instances, TiO2 had migrated from the initial injection site. For the most part, no foreign-body reaction to TiO2 involving the presence of macrophages or characteristic capsular connective tissue formation was demonstrated, although a dose deposit attached to the peritoneum by a transparent membrane was observed. In one mouse, chronic myositis developed in muscle tissue containing a large amount of dose material.

Long-term estrogenization in mammals. IV. Body, adrenal, and testes weights; polydipsia; food intake; vasopressin administration; and serum corticosterone levels in estrogenized male Evans rats

In three experiments, the initial body weight losses after estrogenization were maintained or lagged the weight gains of the controls by the same amount over 61, 138, and 336 days, respectively. The mean serum corticosterone level of the controls was 56% that of the estrogenized rats 341 days after estrogenization. Water consumption (mg/kg b.w.) approximated 150% that of the controls several weeks following estrogenization, remaining elevated until the end of the experiment. Estrogen treatment produced a higher level of water intake in a few rats similar to that previously observed for mice. During the experimental period for water measurement, food consumption (g/kg b.w.) approximated 115% that of the controls. Gnawing and food-spilling behavior was observed in some of the estrogenized rats. Following vasopressin administration, food intake was lowered the first and second days in one estrogenized group; water intake was lowered the first day in the three control and estrogenized groups. In contrast to studies with Marsh mice, estrogenization did not produce bladder damage in Evans rats, but two showed tubular calcification in the kidneys.

Long-term estrogenization in mammals. III. Vasopressin and calcitonin in the regulation of water intake in estrogenized Marsh mice

During the increasing polydipsia following estrogenization, vasopressin administration produced increasing antidiuretic effects demonstrating that renal receptor sites remained functional. The antidiuretic effect in the controls was less than in the estrogenized mice. An antidiuretic effect with calcitonin was demonstrated in the controls and in one experiment in the estrogenized mice but not in another with a high standard error for water intake. A decrease in food intake for the estrogenized mice the first day after vasopressin administration was of doubtful significance. A significant decrease in food intake in the control and estrogenized mice was demonstrated for calcitonin. The effects of the vehicles used for hormone administration on water and food intake necessitated a correction in some instances. As previously observed in estrogenized mice, bladder pathology preceded kidney pathology in additional experiments.

Long-term estrogenization in mammals. II. Environmental influences of housing conditions upon estrogen-induced polydipsia and food intake in Marsh mice

Estrogen-induced polydipsia was influenced by environmental conditions in which Marsh mice were housed in plastic cages with bedding or in metal cages having grilled floors and no bedding. Increases in this polydipsia with metal-cage housing were reversed upon return to plastic. The increases over controls as ml/kg body weight ranged from 40 to 250%. After an initial fall in food consumption following estrogenization, controls and estrogenized mice consumed nearly the same amount of food/mouse but 10% more for the estrogenized mice on a g/kg body-weight basis. Increased food consumption for controls and estrogenized mice following the change from plastic to metal cages was attributed to compensation for increased loss of body heat. Whether in plastic or metal cages, core temperatures of controls were higher than those of estrogenized mice; both groups had relatively higher temperatures in the metal cages. The older mice in metal cages developed a gnawing pattern wasting food. In five experiments with males, body-weight losses following estrogenization were maintained 43 to 70 days but recovered in 2 of 4 experiments with females under comparable conditions.

Short- and long-term effects of graduated doses of DL-6-OH-DOPA upon marsh mice

The lethal effects in Marsh mice for a range of DL-6-OH-DOPA levels were ascertained and exceeded those previously reported for 6-OH-DA under comparable conditions. The addition of vitamin "C" to the 6-OH-DOPA solution given intraperitoneally increased the lethal effect, as did the intraperitionel route of injection over that of the subcutaneous. Increased water consumption developed the fourth day for those surviving toxic levels of 6-OH-DOPA given subcutaneously as compared with controls. For all mice initially surviving administration of 6-OH-DOPA, tumorigenesis and long-term survival were of the same order as that of the controls. The toxicity of 6-OH-DOPA relating to ferric heme formation more likely involves metmyoglobin than methemoglobin. The combination of direct damage to sympathetic adrenergic cardiac innervation and metmyoglobin formation appears sufficient to account for the lethal effects of 6-OH-DOPA.

Long-term estrogenization in mammals. I. Histopathology of kidney, bladder, adrenals, and gonads; polydipsia; body weight; and serum levels of corticosterone and testosterone in estrogenized Marsh mice

Single, sublethal, long-acting doses of estrone or estradiol cypionate produced the following histologic, behavioral, and blood chemistry effects in Marsh mice: (a) Bladder pathology developed following estrogen-induced polydipsia but was not consistently associated with kidney damage. (b) This polydipsia was more intense (a maximum of 250% over control intake) when the housing was in metal cages with floor screens than in plastic cages with bedding. Water intake of control mice was unaffected by housing changes. (c) Comparing litter-mate 2.5-month-old males and females, body weight loss following estrogen administration was transient with the females. With males, initial weight losses as compared with weight gains in the controls were demonstrated over a 20-week period. (d) Estrogenization markedly increased corticosterone and decreased testosterone serum levels with a significant negative correlation for these levels in the estrogenized mice. A significant positive correlation was also observed between testosterone levels and testis weights in the estrogenized mice.

Species differences in blood serum reserves for cholesterol solubilization

The capacity of male human, rat, and guinea pig sera to solubilize cholesterol was measured by in vitro equilibration. Evaporation, adsorption by filter paper and/or cholesterol, and protein denaturation were controlled by measuring serum protein and albumin along with cholesterol contents. The uptake of cholesterol for the above groups was 23.1 +/- 1.2, 18.9 +/- 1.8, and 10.7 +/- 0.8 mg/100 ml, respectively. The percentage increases over initial serum cholesterol were 11.9 +/- 0.9, 18.7 +/- 2.0, and 35.1 +/- 2.7%, respectively. The uptake of cholesterol by serum per se without involvement of either releasing or target tissues appears to be an irreversible and protective solubility phenomenon; no cholesterol plates were deposited upon the undissolved solute or precipitated on addition of triglyceride to cholesterol-saturated serum. The omnivorous human and rat had a greater absolute reserve for solubilizing cholesterol, but the herbivorous guinea pig a greatly enhanced relative (% increase) reserve.

Intraperitoneal foreign body reaction in rodents

In five experiments with female Marsh mice and male and female Evans rats, open-end cylinders of tin were implanted intraperitoneally with litter mates serving as surgical controls. The experiments were terminated 18-24 months later. The long-term local intraperitoneal foreign-body reaction with some cylinders remaining unanchored, frequent failure to develop a fibrous capsule at the outside of the tin cylinder, and a degree of lympho-histiocytic involvement and adenomatous hyperplasia in the fibrosis within the tin cylinder differed from the foreign-body reaction at the subcutaneous site characterized by avascular, cell-poor fibrosis with fibroblasts. In all the implanted rat series, a significant number of local sarcomas, 30-50% of which metastasized, developed with none in the corresponding controls. The incidences of spontaneous lymphoid tumors were decreased or not increased for the tin-implant series as compared with controls. This indicated that the local solid-state carcinogenic process was only partially, if at all, dependent upon the cell type (lymphocyte) that demonstrated a spontaneous inherently malignant potential.

Short- and long-term effects of a massive dose of 6-OH-DA upon marsh mice

Single, sublethal subcutaneous doses of 6-hydroxydopamine (6-OH-DA) were given to young adult male and female Marsh mice. The ability of 6/8 males to sire 15 or more days later was not abolished. Of 10 females dosed during pregnancy, 6 failed to deliver and lost substantially in body weight. Of the 4 that delivered, 2 cannabalized their young. The offspring of the 6-OH-DA-dosed fathers and mothers showed no gross anatomical defects nor lessened survival rates. Confrontation of 6-OH-DA-dosed males with control males as pairs demonstrated increased anal sniffing as compared with control-pair confrontation. In a long-term series with males, liver anomalies including tumor development were demonstrated for 6-OH-DA. Lymphoid tumor induction was not affected. However, 3 local fibrosarcomas and 1 intrasorbital giant cell sarcoma arose. A sublethal dose of L-dopa had no lasting effect on male mouse aggression nor on other behavioral manifestations that would implicate 6-OH-DA formation as a metabolic route.

Toxicologic studies of tin needles at the intrathoracic site of mice

Male Marsh mice which received a single intrathoracic injection of 4 mg of tin needles at 3 months of age were compared with controls given isotonic saline. The form and size of most of the tin needles were similar to those of asbestos needles which produced mesotheliomas and lung neoplasms in rodents. Water and food intake was markedly reduced for 24 hrs after the injection of tin. Survival rates (followed for 19 months), pathology of the bladder, liver, and kidney, as well as local and general cancer development were not adversely associated with the tin treatment as compared with the tin treatment as compared with controls. The local reaction to the tin included giant cell phagocytosis, nodular fibroplasia, and capillary formation. The failure of the tin needles to induce local neoplasms may relate to their high density as compared with silicates and/or their lack of the unique potential of the silicate particles to stimulate avascular fibrosis.

Cholesterol plate deposition in a pathological transport environment

Triglycerides separated from human serum lipoprotein or triolein converted cholesterol needles to plates on equilibration in isotonic saline. Cholesterol needles equilibrated with human clear or lipemic plasma or serum were not converted to plates unless olive oil or triolein was added. Plasma phospholipid permitted and sodium lauryl sulfate (0.1-10%) prevented formation of plates from cholesterol needle-saturated olive oil in water at 38 degrees C. Cholesterol liquid crystals, formed from needles dispersed in aqueous plasma phospholipid, changed to plates on dilution with water. The cholesterol content of lipemic and high-, normal-, or low-cholesterol sera, equilibrated with cholesterol plates at 38 degrees C, was not significantly altered. In rats and mice the mobilization of injected cholesterol needles at the intrathoracic site manifested a sex-species difference. In the pathological deposition of cholesterol plates, a breakdown of a defense mechanism in plasma involving noncovalent binding of triglyceride with phospholipid and protein is indicated.

Male mouse aggression as a pharmacologic model

At 5 to 8 months of age the fighting and tail-rattling of male Marsh mice during paired confrontations was significantly greater for isolated than for mice prehoused in groups of males or in groups of one male with females. The differences were not significant for treatment effects tested in a similar manner with mice 11 to 12 months of age. At 5 months of age, mounting behavior of pregrouped males on paired confrontation was significantly less than that of isolated males. Paper towels instead of pine shavings for bedding abolished test-fighting for isolated mice. In any model with randomly sampled groups, an inherently highly aggressive mouse (killer) required to be eliminated from the grouped series, is not detected in the isolated series. These considerations challenge the use of isolated male mice as a pharmacologic model for evaluating behavior-modifying drugs. A four-fold difference in the area of prehousing cages of isolated males did not influence aggressive behavior. Fights correlated with tail-rattling; r equals 0.93 over the 14 series studied.

Special requirements for plastic devices

The safety testing for polymers in contraceptive devices already in use, at the human pilot test stage, or proposed is appraised. At the subcutaneous and intraperitoneal sites in the rat, polyethylene did not demonstrate chemical carcinogenicity; in the uterine horn endometritis was a prelude to epidermoid carcinoma development. In rodents, polyvinyl chloride copolymer, vinyl chloride, liquid silicone, and other polymers may respond as chemical carcinogens. A polyvinyl chloride resin produced local uterine squamous cell carcinomas in rats and leiomyosarcomas in mice. Intrauterine implants produce a characteristic foreign-body reaction in all species studied, including man, and secondary infection in rats and mice. Solid-state carcinogenesis can no longer be regarded as a phenomenon exclusive for rodents. Because it depends upon a minimum implant period in situ and a long latent period, its appearance in humans should occur only after many years and only if the implant has resided more than temporarily.

When safety testing fails because of differences in response between species and/or anatomical test sites, evaluation of the effects of polymers already used for other purposes in humans and over long periods of time may be a necessary recourse. The tendency of the silicone prosthesis to mechanically erode its way through body tissues and to absorb lipids suggest general lack of biological inertness.

The development of a fibrous capsule around parenteral implants may decrease metabolic exchange and limit the use of polymer-hormone depots.