Autonomous replication in vivo and in vitro of clones spanning the region of the DHFR origin of bidirectional replication (ori beta)

Plasmids containing the origin of bidirectional replication (ori beta) of the Chinese hamster dihydrofolate reductase-encoding gene (DHFR) were tested for autonomous replication in vivo and in vitro. The results show that plasmids pX24 and pneoS13, that contain a 4.8- and a 11.5-kb fragment, respectively, spanning the ori beta region, are able to replicate autonomously in human cells and in a cell-free system that uses human cell extracts. Another plasmid, pX14, containing a 4.8-kb fragment that is immediately adjacent to the ori beta region, also replicated in these two assays.

Radiological management of renal trauma

The radiological and surgical management of renal trauma patients has changed considerably in recent years, partly because of the increasing availability of high technology facilities. This article reviews the imaging examinations employed in the assessment of patients with suspected renal trauma.

The Edinburgh Postnatal Depression Scale: validation for an Australian sample

One hundred and three post-partum women completed the Edinburgh Postnatal Depression Scale (EPDS) and were interviewed using the Diagnostic Interview Schedule. A cut-off score of 12.5 on the Edinburgh Postnatal Depression Scale identified all nine women who reached criteria for major depression. At this threshold the sensitivity (the percentage of true "cases" identified) of the EPDS was 100%, its specificity (the percentage of true "non-cases" identified as such) 95.7% and its positive predictive value (the percentage of all those tested as positive who were correctly identified as such) 69.2%. Although this study supported the validity of the EPDS, a replication of this study on a larger sample is suggested.

ors12, a mammalian autonomously replicating DNA sequence, associates with the nuclear matrix in a cell cycle-dependent manner

Origin enriched sequence ors8 and ors12, have been isolated previously by extrusion of nascent CV-1 cell DNA from replication bubbles at the onset of S-phase. Both have been shown to direct autonomous DNA replication in vivo and in vitro. Here, we have examined the association of genomic ors8 and ors12 with the nuclear matrix in asynchronous and synchronized CV-1 cells. In asynchronously growing cells, ors8 was found to be randomly distributed, while ors12 was found to be enriched on the nuclear matrix. Using an in vitro binding assay, we determined that ors12 contains two attachment sites, each located in AT-rich domains. Surprisingly, in early and mid-S-phase cells, ors12 homologous sequences were recovered mainly from the DNA loops, while in late-S the majority had shifted to positions on the nuclear matrix. In contrast, the distribution of ors8 over the matrix and loop DNA fractions did not change during the cell cycle. By bromodeoxyuridine substitution of replicating DNA, followed by immunoprecipitation with anti-bromodeoxyuridine antibodies and PCR amplification, we demonstrated that ors12 replicates almost exclusively on the matrix in early and mid-S-phase; replicating ors8 was also found to be enriched on the matrix in early S-phase. Chase experiments showed that the ors12 sequences labelled with bromodeoxyuridine in the first 2 hours of S-phase remain attached to the nuclear matrix, resulting in an accumulation of ors12 on the nuclear matrix at the end of the S period.

c-fms point mutations in acute myeloid leukemia: fact or fiction?

Point mutations in codons 12, 13, and 61 of N-ras have consistently been reported in acute myeloid leukemia (AML) and myelodysplastic syndrome (MDS) using a variety of techniques. Recently mutations in codons 301 and 969 of c-fms, preferentially involving TAT-to-TGT at codon 969, have also been identified in these disorders by allele specific oligonucleotide (ASO) hybridization. We have developed allele specific restriction analysis (ASRA) protocols for the detection of point mutations in the critical codons of these genes. ASRA involves enzymatic digestion of polymerase chain reaction (PCR)-induced restriction sites which are specific for normal but not mutant alleles. A total of 11 N-ras mutations were observed in 10 out of 46 AML patients, consistent with the reported frequency of N-ras mutations when alternative techniques of comparable sensitivity are used. In contrast, c-fms point mutations were not detected in a similar number of patients with AML, including 39 studied for mutations in both N-ras and c-fms, and this difference is statistically significant (p < 0.003). A more sensitive technique (ASRA + ASO hybridization) also failed to detect TAT-to-TGT substitutions at codon 969 in a subgroup of M4-AML patients considered to be at greatest risk of harboring c-fms mutations. This study suggests that c-fms mutations at codons 301 and 969 are not important in the pathogenesis of AML in the vast majority of patients.

Pigeon breeders' lung; IgG subclasses to pigeon intestinal mucin and IgA antigens

Sera from all symptomatics with pigeon breeders' lung and many non-symptomatic pigeon breeders react specifically with the pigeon antigens and in particular pigeon intestinal secretions and isolated pigeon intestinal mucin and IgA. In sera from all 82 precipitin-positive pigeon breeders investigated, IgG1 reacted with both IgA and mucin, while IgG2 reacted predominantly with mucin only. Sera from all 32 symptomatic patients with pigeon breeders' lung demonstrated an IgG3 reaction with mucin, but only three sera showed reactivity against IgA and this was very weak. In contrast, only three out of 27 pigeon breeders with pulmonary pathology other than pigeon breeders' lung and only three out of 23 sera from healthy pigeon breeders showed detectable IgG3 reactivity with mucin. IgG4 from eight sera only reacted with mucin (n = 7) or IgA (n = 1) and showed no consistent pattern between subject groups. Precipitin-negative sera from 30 volunteers with no previous pigeon exposure showed no IgG subclass reactivity with either the pigeon intestinal secretions or the isolated mucin and IgA antigens. These results show specific IgG2 and IgG3 subclass reactivity to pigeon intestinal mucin antigen in precipitin-positive sera from pigeon breeders. Further IgG3 subclass reactivity specific to pigeon mucin is strongly associated with sera from patients with the active pigeon breeders' lung disease.

The pharmacology of LY290324 in the guinea-pig: an orally active, potent and selective cysteinyl leukotriene receptor antagonist

This study describes the evaluation of LY290324 as a leukotriene D4 (LTD4) receptor antagonist in guinea-pigs. In vitro, LY290324 was a potent and persistent antagonist of the contractile responses to LTD4 and LTE4 with pA2 values of 9.1 +/- 0.2 and 8.9 +/- 0.17 respectively. The antagonism appeared competitive and selective for LTD4/E4, as LY290324 (10(-6) M) had no effects on contraction elicited by LTC4, prostaglandin F2 alpha (PGF2 alpha), histamine and acetylcholine. In vivo the compound was highly effective in a dose-dependent manner by the intravenous, oral and inhaled routes in preventing LTD4-induced bronchospasm. Administered i.v. LY290324 prevented the development (ED50 = 3.4 micrograms/kg) of an LTD4-induced bronchospasm and readily reversed an established bronchospasm, but failed to prevent the bronchospasm to either histamine or platelet activating factor (PAF). Oral studies demonstrated efficacy for at least 12 h. Administered orally 6 h previously, LY290324 reduced LTC4, LTD4 and LTE4-induced bronchospasm with ED50s of 0.3, 0.28 and 0.37 mg/kg respectively. Relatively low inhaled levels (2 micrograms/kg) also significantly reduced (72.5%, P < 0.001) LTD4-induced bronchospasm. Finally the compound administered orally was effective in reducing antigen-induced bronchospasm in immunologically sensitised animals.

Pigeon breeders' lung: pigeon intestinal mucin, an antigen distinct from pigeon IgA

Antigens identified by indirect immunofluorescence staining and specific for sera from patients with pigeon breeders' lung or healthy pigeon breeders, have been isolated from pigeon intestinal mucus. Two antigenic peaks, one pigeon intestinal mucin and the other IgA, were separated by equilibrium centrifugation of water-soluble mucus in a caesium chloride density gradient. Antigenic positive material was identified by a modified double-sandwich ELISA, by inhibition of haemagglutination of turkey erythrocytes and by gel diffusion. Antigenic-positive material co-fractionated on gel-filtration with purified intact and papain digested pigeon mucin, both free of IgA. These studies demonstrate antibodies to two quite different antigens are associated specifically with sera from pigeon breeders, a novel antigen pigeon intestinal mucin and the previously documented pigeon IgA.

Acute traumatic lateral patellar dislocation

An unusual case of acute extra-articular patellar dislocation is described in which the patella dislocated laterally, rotated 90 degrees about its vertical axis, and wedged against the lateral femoral condyle. Closed reduction in the emergency department failed and operative intervention was required.

The transfer of zinc across the term dually perfused human placental lobule

Net zinc transfer between fetal and maternal circulation has been described in the in vitro perfused lobule of the human term placenta. The transfer results in a 3 microM differential between fetal and maternal perfusates which is comparable to estimated values in vivo. Tissue zinc concentration is more than 10 times perfusate concentration and is correlated with zinc flux across the fetal borders of the lobule. Open-circuit studies on net transport of zinc, and upon flow of 65Zn relative to tritiated water (3H2O), indicate these fluxes depend upon the non-protein-bound (free) zinc gradient across the fetal-facing membranes. On the other hand movement across the maternal surface is not related to diffusion gradients of free zinc and is either independent of, or inversely related to, the level of tissue zinc. It is concluded that the uptake of zinc from the maternal perfusate may be coupled to metabolism, whereas its transfer to fetal circulation is linked to the level of free zinc in the tissue.

Amebic infections in asymptomatic homosexual men, lack of evidence of invasive disease

A survey for enteric infections in 140 asymptomatic homosexual men who attended a community clinic revealed a high prevalence of infection with Entamoeba histolytica (27.1 per cent) and Giardia lamblia (15.7 per cent). In contrast, the prevalence of elevated indirect hemagglutination (IHA) titers (greater than or equal to 1:128), which indicate invasive amebiasis, was low (5.7 per cent). Our findings suggest that only a limited amount of invasive amebic disease is occurring in this group of homosexual men.

Acute lymphoblastic leukaemia with t(4;11) follows neuroblastoma: a late effect of treatment?

The case presented is of a 7-year-old girl who developed acute lymphoblastic leukaemia (ALL) with t(4;11)(q21;q23) 5 years after the onset of neuroblastoma and 4 months after completing treatment for a first relapse. Consideration is given to the relative importance in this case of genetic factors and chemotherapeutic drugs in the etiology of ALL.

Fibre size distribution in the elbow joint nerve of the cat

The elbow joint nerve, a small branch of the musculocutaneous nerve in the cat, was investigated with low power transmission electron microscopy. By taking a series of overlapping photographs a montage was constructed of the cross section appearance of the complete nerve. Thus, a complete count of the number and sizes of myelinated and unmyelinated fibres was obtained. Two peaks in the distribution of myelinated fibres were consistently found, one at 2-5 micrometers and the other at 8-11 micrometers. The number of unmyelinated fibres was much larger than the number of myelinated fibres, with an average ratio of 4.4:1. This proportion of unmyelinated fibres is higher than that found by earlier workers, but is comparable with that in other peripheral nerves.

Antianaphylactic agents. 1. 2-(Acylamino)oxazoles

The synthesis and biological properties of 35 2-(acylamino)oxazoles are described. The majority of the compounds inhibit the release of slow-reacting substance of anaphylaxis (SRS-A) in vitro from sensitized guinea pig chopped lung. In addition, several of the compounds inhibited the release of SRS-A from passively sensitized human chopped lung and protected guinea pigs from the effects of anaphylaxis in a modified Herxheimer test.