USPIO-related T1 and T2 mapping MRI of cartilage in a rabbit model of blood-induced arthritis: a pilot study.

Ultrasmall paramagnetic iron oxide (USPIO)-enhanced MRI is promising for evaluating inflammation. The aims of this study were to investigate the effect of USPIO on cartilage T1 and T2 mapping, and to evaluate a proposed rapid vs. conventional T2 map method for imaging cartilage in a blood-induced arthritis model. Knees of nine arthritic (induction by intra-articular autologous blood injection) and six control rabbits were imaged over time (baseline, weeks 1, 5, 10) by 1.5 T MRI. All rabbits had USPIO (35-75 µmol Fe/kg)-enhanced MRI at each time point. T1 and T2 (conventional and rapid) maps and signal-to-noise ratios (SNR) were obtained pre- and post-USPIO administration. Cartilage biochemistry and histology were compared with MRI. Excellent correlations were noted between T1 map values and histologic scores at week 10 pre-USPIO (medial, r = 0.93, P = 0.0007; lateral, r = 0.87, P = 0.005) in the arthritic group, but not between T2 map and histology. Marginally and significant differences were observed between pre- and post-USPIO T2 values at weeks 5 (P = 0.06) and 10 (P = 0.02), but only with the administration of high USPIO doses in the arthritic group using the conventional method. No significant differences were noted between pre- and post-USPIO T1 values at any imaging time points. Cartilage T2 maps with short-TR and conventional protocols provided similar T2 values [(decreased trend)] (P > 0.05). Concomitant use of USPIO to T1 and T2 mapping of cartilage would not impair the identification of interval changes of T1 and T2 maps. Rapid T2 map provides similar results compared to conventional method, but its validation warrants further investigation.

Effect of corticosteroids on orthodontic tooth movement in a rabbit model.

INTRODUCTION: While there are a growing number of studies on the effects of medications on orthodontic tooth movement (OTM), only few studies have investigated the role of corticosteroids, despite their widespread use. The aim of the current study was to evaluate the effects of triamcinolone acetonide injection on OTM in a rabbit model. STUDY DESIGN: Sixteen one-month old rabbits were randomly divided into two groups: Eight rabbits had triamcinolone acetonide (1 mg/kg/day) administered IM daily for 21 days (test group) while the remaining eight rabbits received no drug (control group). The rabbits in both groups had a tube bonded to the upper central incisors and a stainless steel helical spring was inserted in tube slot to apply 50 cN distal force. After 3 weeks, the rabbits were sacrificed and the distance between mesial corners of incisors was measured The incisors are associated tissue was processed for histology and the apical and cervical area of the roots evaluated. An observer who was blind to the study groups evaluated the specimens. RESULTS: All appliance-treated incisors in test and control groups showed evidence of tooth movement. The distance between the incisors was significantly greater in the triamcinolone acetonide treated group compared to the control group (P < 0.001). Histological examination revealed an increased number of resorption lacunae and decreased number of cuboidal osteoblastic cells around the apical and cervical area of the Incisor roots in the test compared to the control group (P < 0.01). CONCLUSION: Treatment with triamcinolone acetonide is associated with increased tooth movement in rabbits via increased resorptive activity in the alveolar bone.

Herpes simplex virus type 2 and HIV infection among US military personnel: implications for health prevention programmes.

US military personnel are routinely screened for HIV infection. Herpes simplex virus type 2 (HSV-2) is a risk factor for HIV acquisition. To determine the association between HSV-2 and HIV, a matched case-control study was conducted among US Army and Air Force service members with incident HIV infections (cases) randomly matched with two HIV-uninfected service members (controls) between 2000 and 2004. HSV-2 prevalence was significantly higher among cases (30.3%, 138/456) than among controls (9.7%, 88/912, P < 0.001). HSV-2 was strongly associated with HIV in univariate (odds ratio [OR] = 4.2, 95% confidence interval [CI] = 3.1-5.8) and multiple analyses (adjusted [OR] = 3.9, 95% CI = 2.8-5.6). The population attributable risk percentage of HIV infection due to HSV-2 was 23%. Identifying HSV-2 infections may afford the opportunity to provide targeted behavioural interventions that could decrease the incidence of HIV infections in the US military population; further studies are needed.

Isolation and identification of six Pneumocystis carinii genes utilizing codon bias.

Pneumocystis carinii pneumonia (PCP) is a leading cause of death among AIDS patients in the United States. Our analysis of P. carinii protein-coding genes has revealed a significant A + T codon bias. Polymerase chain reaction (PCR) was utilized to isolate and identify the genes encoding calmodulin, beta-tubulin, DNA polymerase II, and RNA polymerases I, II and III from P. carinii. Primer pairs were designed to incorporate P. carinii codon preference to known conserved protein regions from other organisms. This strategy should be useful for a large variety of P. carinii genes and assist in the comprehensive analysis of the genomic structure of this important pathogen.

The killing of rat placental cells by rat and mouse granulated metrial gland cells in vitro.

Small round cells which migrated from explant cultures of rat metrial gland were identified as granulated metrial gland (GMG) cells. They contained large amounts of glycoprotein and displayed the leucocyte common antigen. Other cells which migrated from the explants were probably derived from the fibroblast-like stromal cells of the metrial gland. The asialo-GM1 antigen was found on rat GMG cells in culture and in cryostat sections of rat metrial gland. The rat GMG cells in culture exhibited locomotion and, when co-cultured with placental cells, made numerous contacts with the placental cells. A small number of these contacts (less than 1 per cent) were followed rapidly by the death of the placental cell. Mouse GMG cells which had migrated from explant cultures of mouse metrial gland were also co-cultured with rat placental cells. The migratory activity of the mouse GMG cells also involved numerous contacts being made with rat placental cells and a small number (less than 1 per cent) of these contacts were cytotoxic for the rat placental cells. The observations support previous suggestions that GMG cells are a type of killer cell. The cytotoxic activity of rat and mouse GMG cells against co-cultured rat placental cells is discussed in relation to the nature of the target molecule involved.

Lectin histochemistry of rat placental tissues.

Lectin binding of rat trophoblast subpopulations was examined at days 10, 12 and 15 of gestation. Biotinylated lectins, specific for a range of carbohydrates, were applied to paraffin wax embedded tissues. At day 10 of pregnancy, a wide and similar range of lectins reacted with ectoplacental cone and giant cells: chorionic lamina was relatively unreactive except with wheat germ agglutinin. At days 12 and 15, the range of lectins reacting with the placental labyrinth was relatively restricted. Spongiotrophoblast at day 12 showed lectin reactivity similar to that of ectoplacental cone cells but at day 15 the reaction pattern indicated loss of N-acetylgalactosamine residues in the large, glycogen-rich cells. Trophoblastic giant cells also showed wide lectin reactivity: some reacted only with cytoplasmic components whilst others showed pericellular reactivity. Varying lectin reactivity of giant cells in different regions of the placenta suggests functional differences. There was reduced lectin reactivity of endovascular trophoblast at day 15, compared with day 12 of pregnancy, which may reflect altered invasive potential associated with loss of sialic acid and N-acetylgalactosamine residues. The pattern of lectin reactivity suggests that ectoplacental cells, as well as giving rise to giant cells, may also contribute to spongiotrophoblast and to endovascular trophoblast.

Granulated metrial gland cells.

Granulated metrial gland (GMG) cells take their name from the metrial gland. The metrial gland is formed during pregnancy in many rodents with the appearance of GMG cells in the mesometrium at each implantation site. This paper reviews knowledge about GMG cells in rats and mice: the species most extensively studied. Granulated metrial gland cells are characterised by their cytoplasmic granules which contain glycoproteins and hydrolytic enzymes. The cytoplasm of some GMG cells contains extensive deposits of glycogen and moderate amounts of rough endoplasmic reticulum and Golgi bodies are usually present. Some GMG cells are binucleate and at certain stages of pregnancy many undergo mitosis. A few GMG cells are present in the endometrium (in mice) before implantation but in rats and mice during the week following implantation their numbers rapidly increase. During the 2nd week of gestation GMG cells are a prominent cell population in the decidua basalis and they appear in the circular layer of the myometrium and within the mesometrial triangle. By the beginning of the 3rd week of gestation they are present in the metrial gland in large numbers but they disappear and are relatively scarce at parturition. Rat and mouse GMG cells are readily distinguished by differences in the ultrastructure of their electron-dense granules. These differences have made it possible to show that GMG cells differentiate from bone marrow cell precursors by studying GMG cells in radiation-induced chimeric mice. The disappearance of GMG cells from the decidua basalis and metrial gland as pregnancy proceeds is accounted for by their death in situ and by their migration into blood vessels. Some GMG cells probably become trapped in lung capillary beds but the GMG cells in the maternal blood spaces of the placental labyrinth appear to interact with some layer 1 trophoblast cells and degeneration of the trophoblast and GMG cells occurs. Other cell types present in the uterus are described and their relationships to GMG cells considered. A close morphological relationship exists between cells in the decidua basalis and GMG cells and between fibroblast-like stromal cells in the metrial gland and GMG cells. Although initially GMG cells are closely packed between smooth muscle cells at the base of the mesometrium, the organisation of muscle cells in this region is disrupted with the formation of the metrial gland. Macrophages are considered, particularly in relationship to endocytotic activity of cells in the uterus, and it is argued that "it is not appropriate simply to dismiss GMG cells as macrophages".(ABSTRACT TRUNCATED AT 400 WORDS)

Mouse metrial gland cells do not kill Yac-1 myeloma cells.

Mouse metrial gland cell suspensions, which included granulated metrial gland cells, were assessed for their ability to lyse NK cell target Yac-1 myeloma cells in a 51chromium release cytotoxicity assay. Metrial gland cells did not kill Yac-1 cells even after in vivo stimulation of NK cytotoxicity activity by polyinosilic-cytidilic acid. The precise relationship of granulated metrial gland cells to the NK cell lineage remains to be clarified.

Immunological characterisation of surface receptors on rat metrial gland cells.

Cells from metrial glands of pregnant rats were examined for surface receptors. No E, EA mu or EAC receptors were demonstrated. Fc gamma receptors were detected by EA gamma rosette formation, using sheep red blood cells sensitised with the IgG fraction of rabbit or rat antisera. Significantly more of the metrial gland cells, and of the rat peritoneal exudate and spleen cells examined as controls, formed rosettes with red cells sensitised with rabbit IgG than with those sensitised with rat IgG. The proportion of metrial gland cells forming EA gamma rosettes decreased significantly between day 12 and day 15 of pregnancy but increased by day 19. Metrial gland cells from deciduomata formed EA gamma rosettes, and the proportions varied during pseudopregnancy. At day 13 of pregnancy a greater proportion of metrial gland cells displayed Fc gamma receptors in multiparous rats than in primigravid rats. The binding affinity of the Fc gamma receptors was characterised by inhibition studies with homologous and heterologous IgGs. Maximal inhibition occurred when the inhibitory IgG was homologous to the IgG used to sensitise the red cells. EA gamma rosette formation by cells from the metrial gland was inhibited by both monomeric and heat-aggregated IgGs.

Localisation of immunoglobulin (IgG) within the rat metrial gland.

An immunohistological method was used to assess the IgG content of the rat metrial gland at different stages of pregnancy. The result apparently varied according to the type of fixative used. Saturated alcoholic mercuric chloride was found to produce the most consistent demonstration, with the IgG located in cells which also contained diastase-fast, PAS-positive granules. Using single cell suspensions prepared from metrial glands, significantly more cells were shown to contain cytoplasmic IgG at day 13, compared to day 14 of pregnancy. However, there were no other significant differences at other stages of pregnancy examined. Surface IgG was detected on a small proportion of the cells and the findings are discussed in relation to the hypothesis of a lymphocytic origin for the granulated metrial gland cells.

Localisation of immunoglobulin (IgG) in granulated metrial gland cells of deciduomata of the pseudopregnant rat.

Using an immunoperoxidase technique, after fixation in saturated alcoholic mercuric chloride, it was possible to detect cytoplasmic immunoglobulin (IgG) in granulated metrial gland cells from deciduomata of pseudopregnancy in the rat. The extent of the reaction for IgG was variable but did not appear to be related to the day of pseudopregnancy or to the extent of the decidual reaction. Examination of single cell suspension enabled quantification of IgG-containing cells, but no significant differences were detected in the numbers of positive cells at the days of pseudopregnancy which were examined. Surface IgG was detected on a small proportion of the cells, and they were distinguished from the Fcgamma receptor-bearing cells in the metrial gland of deciduomata of pseudopregnancy.

Derivation of highly mefloquine-resistant lines from Plasmodium falciparum in vitro.

Serial passage of a multidrug-resistant clone of Plasmodium falciparum in concentrations of mefloquine hydrochloride ranging from 30 to 2,400 ng/ml resulted in the derivation of increasingly resistant parasite lines in vitro. Parasite lines isolated in mefloquine concentrations greater than 300 ng/ml demonstrated increased vacuolization, enhanced pigment production, and increased growth rates as compared with the progenitor clone, W2-mef. Although microdilution incorporation assays demonstrated that the 50% inhibitory concentration (IC50) of mefloquine were similar for all lines, the IC90, IC95, and IC99 levels were significantly increased. Growth rate assays performed in 5% hematocrit suspensions demonstrated different levels of mefloquine resistance among these lines. Under these conditions the most resistant line, Mef 2.4, grew efficiently in approximately 10-fold higher concentrations of mefloquine than the progenitor clone W2-mef. Analysis of drug susceptibility profiles to mefloquine hydrochloride, chloroquine diphosphate, quinine sulfate, and halofantrine hydrochloride indicated that selection for high levels of mefloquine resistance had resulted in significant increases in resistance to halofantrine and increased sensitivity to chloroquine. The phenotypic changes demonstrated in the most resistant line, Mef 2.4, reflect a multidrug resistant-like phenotype, and appear to mimic changes recently reported in drug susceptibility profiles of recrudescent isolates following mefloquine treatment failures in Thailand.

A strong association between mefloquine and halofantrine resistance and amplification, overexpression, and mutation in the P-glycoprotein gene homolog (pfmdr) of Plasmodium falciparum in vitro.

Stepwise selection for increased mefloquine resistance in a line of Plasmodium falciparum in vitro resulted in increased resistance to halofantrine and quinine, increased sensitivity to chloroquine, and amplification and overexpression of the P-glycoprotein gene homolog (pfmdr1). A point mutation (tyrosine to phenylalanine) noted at amino acid 86 in pfmdr1 in the mefloquine-resistant line W2mef was amplified in more resistant lines derived from it by in vitro selection pressure with mefloquine. Conversely, lines selected for increased chloroquine resistance exhibited a revertant phenotype that was sensitive to mefloquine and halofantrine. These lines also demonstrated increased sensitivity to quinine, loss of amplification of pfmdr1, loss of the mefloquine/halofantrine phenylalanine-86 mutation, and selection for a tyrosine-86 mutation previously associated with chloroquine resistance. These findings provide strong evidence for pfmdr1 mediating cross-resistance to halofantrine and mefloquine in P. falciparum in vitro.

Effect of smoking and transdermal nicotine on colonic nicotinic acetylcholine receptors in ulcerative colitis.

BACKGROUND: Ulcerative colitis (UC) is a disease largely of non-smokers, in which nicotine is of therapeutic value. The mode of action is unknown, but may involve nicotinic acetylcholine receptors (nAChRs) in the bowel wall. AIM: To investigate the presence of nAChRs in rectal mucosa, and the effect of smoking and nicotine on their expression. DESIGN: Prospective case-control study. METHODS: In situ hybridization (ISH) and immunocytochemistry (ICC) were used to show alpha3 nAChRs in colonic mucosa. Rectal mucosa was examined from controls (n=55) and patients with inactive UC (n=62), both smokers and non-smokers, by ICC, using two antibodies to show the density and distribution of receptors in the mucosa. Non-smokers with UC (n=43) were given transdermal nicotine or placebo patches for 6 months, and rectal biopsies, taken before and after treatment, were examined by ICC to show nAChRs. RESULTS: In normal colon, ISH and ICC showed alpha3 subunit in a wide variety of cells, including mucosal epithelium. In rectal biopsies, neither smoking nor nicotine influenced the expression of alpha3 immunoreactivity in epithelium, either in controls or UC. However, controls had a significantly greater density of immunodetectable mucosal epithelium alpha3 subunit, compared with UC patients. DISCUSSION: The presence of nAChRs in colonic epithelium may be pertinent to the beneficial effect of nicotine in UC, but since neither smoking nor nicotine treatment is associated with any change in the expression of epithelial alpha3 nAChRs, the effect may be due to functional changes in the receptor. The decreased number of alpha3 nAChRs in UC compared with controls may be related to an increased cell turnover in UC.

Granulated metrial gland cells at implantation sites of the pregnant mouse uterus.

A study has been made of the distribution of, and synthesis of DNA by, granulated metrial gland cells at implantation sites in the pregnant mouse uterus. Granulated cells were found in small numbers randomly distributed throughout the endometrium on day 4 1/2 of pregnancy. Subsequently cells of this type were lost from the antimesometrial and lateral decidua but increased dramatically in number in the developing decidua basalis. From day 7 1/2 granulated cells populated the mesometrial triangle to form the metrial gland. A high proportion of granulated cells was found to incorporate tritiated thymidine and the distribution of such cells is described. However, no granulated cells were found to incorporate tritiated thymidine at or after day 12 of pregnancy. In addition the loss of granulated metrial gland cells from the implantation site is described and is accounted for by degeneration in situ and also by migration via vascular channels. It is suggested that this latter route could be of functional significance.

Changes in the metrial gland of the rat uterus following ovariectomy on day 10 of pregnancy.

Rats were subjected to ovariectomy or a control operation on day 10 of pregnancy and light and electron microscope studies carried out to examine the cells of the decidua basalis and the mesometrial triangle. Degeneration of the decidua basalis was rapid but proliferation in the mesometrial triangle and differentiation of the typical granulated cells continued for some time, and resulted in the formation of a metrial gland. The earliest effect noted in the metrial gland was the appearance of inclusions in the fibroblast-like stromal cells one day after ovariectomy. During the next four days many stromal cells became packed with a variety of inclusions and it is suggested that some of these may represent phagocytosed cellular debris. Some debris appeared to be in intercellular spaces and was probably derived from granulated cells. Some granulated cells appeared to develop apparently empty vacuoles and this may be a preliminary stage in degeneration. Although granulated cells decreased to become very few in number five days after ovariectomy, the precise mechanism of their loss and the relationship of this to the hormonal environment could not be established.

Ultrastructural changes in the rat metrial gland in the latter half of pregnancy.

The ultrastructural changes occurring in the metrial gland in the latter half of pregnancy in the rat have been studied. Typical palely stained granulated cells are present in the metrial gland up to day 20 but many granulated cells show variations in appearance which may be associated with degeneration. In some the cytoplasm is more darkly stained and such cells often have apparently empty areas of cytoplasm adjacent to the granules. From day 14 onwards many areas of the gland show cellular debris, apparently resulting from lysis of the granulated cells. However, occasionally normal granulated cells are present in blood vessels and have been observed apparently penetrating the vascular endothelium. A variety of changes was also noted in the stromal cell population. Inclusions became apparent in many of these cells; some of these consisted of lipid while others resembled granules from the typical granulated cells. Other cells with numerous inclusions appeared to be macrophages. Lysis of granulated cells in situ is compatible with suggestions that the metrial gland produces a holocrine secretion, though some normal granulated cells enter blood vessels. The stromal cells may have a phagocytic role in late pregnancy but evidence for this was inconclusive.

Studies into the mechanism for MHV transcription.

Previous studies have demonstrated that the MHV genome is divided into seven transcriptional units which are transcribed from highly conserved intergenic start sites (UCU/CAAAC) into mRNA containing a common leader RNA at the 5' end and a coterminal 3' end. In this manuscript, we provide evidence that an additional transcriptional unit is encoded at the 3' end of the MHV genome and is transcribed from a perfect intergenic region into a leader-containing approximately 800 nt mRNA. This mRNA could potentially encode a small 17-18 kDa protein which is identical to the C-terminal third of the nucleocapsid gene.

Biochemical analysis of the response in rat bone marrow cell cultures to mechanical stimulation.

Bone marrow cells obtained from rat femora were subjected to primary culture with 15% fetal bovine serum in the presence of 10(-8) M dexamethasone, and following trypsin treatment 5 days later were seeded on Petriperm dishes which have a flexible bottom. After a 2-day subculture, a cyclic stress consisting of a 1 s stretch (0.3% strain. 0.5 Hz) and a 1 s relaxation for 30 min every day was started. Culture tissue was removed on day 2 of the subculture (immediately prior to start of stimulation), and then on days 5 and 8 (3 and 6 days after the start of stimulation, respectively), at which times dry weight, DNA, alkaline phosphatase (ALP) activity, and bone Gla protein (BGP, osteocalcin) were measured. Both the dry weight and DNA showed a significant increase in the stimulated group by day 8, while the ALP activity showed a significant increase by day 5. The BGP began to increase in the stimulated group on day 5 in contrast to the control group in which it only increased on day 8. These results support the contention that mechanical stimulation promotes the differentiation of osteogenic cells and enhances bone formation. Since in this experimental model the acceleration of bone formation by mechanical stimulation can be reproduced in vitro, it is extremely useful for investigating the mechanisms underlying mechanical stimulation.

Sport-related fractures and dislocations in the hand.

The long-term prognosis regarding any sport-related injury should remain guarded. Although optimism may be expressed by the physician regarding a specific injury, the athlete must be adequately informed of the natural history of his or her injury. The hand surgeon's management efforts must always be exact and appropriate, but the athlete must understand from the outset that the final functional and cosmetic result may depend more on the nature of the specific injury than on the treatment provided.