Close linkage of Mdm-1, a gene amplified and overexpressed in a transformed 3T3 cell line, with gamma interferon (Ifg) on chromosome 10 of the mouse

The Mdm-1 gene was mapped to the distal end of Chromosome (Chr) 10. An extensive series of restriction fragment variants was identified among conventional and exotic inbred strains of mice. Mapping was carried out with recombinant inbred strains and an intersubspecific testcross. No recombinants were observed between Mdm-1 and the gamma interferon locus (Ifg). These two loci appear to be in linkage disequilibrium among inbred strains. Data from the testcross place Mdm-1 approximately 11 centimorgans distal to the steel (Sl) locus. Because of its extensive polymorphism, Mdm-1 is a useful genetic marker for distal Chr 10.

Herrmann multiple synostosis syndrome with neurological complications caused by spinal canal stenosis

A young man was found to have multiple synostosis syndrome type I after presenting with a neck injury causing a cervical spinal cord contusion. Neurological symptoms and signs suggested spinal cord compression. Magnetic resonance (MR) and computerized tomography (CT) imaging of the spine showed spinal canal stenosis with cord compression at C3-C6, a deformed spinal canal flattened in the anteroposterior dimension, vertebral fusions and deformed lateral processes of the vertebrae. He had a long broad nose with hypoplasia of the alae nasi, conductive hearing loss requiring hearing aids, muscular build, stiff spine, prominent acromia, pectus excavatum, ischial prominences, short fifth fingers, fusion at the proximal interphalangeal joints of the fifth fingers with indistinct overlying creases, and toe syndactyly. Spinal cord stenosis is a serious complication of multiple synostosis syndrome, that should be kept in mind in considering the risk of neck or back injury associated with certain sports or other activities. In both the multiple synostosis syndrome and the less severe proximal symphalangism deafness syndrome, mutations have been detected in the human homologue of the noggin gene on chromosome 17q21-q22.

Improved quality-control detection of false-negative Pap smears using the Autopap 300 QC system

Federally-mandated quality control (QC) in Papanicolaou (Pap) smear testing requires rescreening of 10% of negative smears, to include cases selected randomly as well as smears from patients that may have a higher risk for developing cervical cancer based on clinical information. FDA approval of NeoPath's AutoPap 300 QC system (NeoPath, Inc., Redmond, WA) allows practical QC rescreening of all negatives. We tested the ability of AutoPap to help increase identification of detection errors compared to random 10%/high-risk selection. From March 1-August 30, 1997, we utilized AutoPap/high-risk status to select cases for manual rescreen, and compared the rate of identification of primary screening errors to that for the preceding year using 10% random selection/high-risk status. Of 35,027 smears accessioned, 31,240 (89.1%) were screened as negative and 7,965 were selected for manual rescreen. Of these, 353 were determined to be abnormal. Most abnormals identified by this protocol were classified as atypical squamous or glandular cells of undetermined significance (ASCUS or AGUS). However, 59 low-grade squamous intraepithelial lesions (LSIL) and 13 high-grade squamous intraepithelial lesions (HSIL), many with few abnormal cells, were also identified. These results represented an increase in pickup rate of false negative due to detection errors of 2.3-, 2.8- and 5.6-fold for atypical squamous or glandular cells of undetermined significance, LSIL, and HSIL, respectively, when accounting for the volume differences over the time period measured. Our findings strongly support the conclusions drawn from clinical trials of the AutoPap that false negatives due to detection error can be significantly reduced when using AutoPap as part of a routine quality control program.

Making general practice work for young people

Adolescents have many serious health issues but tend not access GP care. This paper discusses how GPs may make their practices work for young people, and is based on the experience of Clockwork--Young People's Health Services and focus group findings.

Mothers' emotional needs and difficulties after childbirth

OBJECTIVE

To set up and evaluate weekly group sessions for mothers experiencing difficulties after childbirth.

METHOD

These sessions were held at Barwon Region Child Health Centre in Geelong, Victoria, with input from a general practitioner and a clinical psychologist.

RESULTS

Questionnaires confirmed the group sessions were effective in allaying the mothers' concerns about their babies' health, and that the mothers had low self esteem. Records of the meetings indicated that mothers were mainly concerned about their babies' health, anxiety, lifestyle changes, depression, relationship problems, their own health, the birth experience and lack of support. Social factors often predisposed mothers to these problems.

CONCLUSION

There is clearly scope for the general practitioner to be involved in the diagnosis and management of postnatal problems and group sessions are an effective way of achieving this.

Detection and confirmation of beta-agonists in bovine retina using LC/APCI-MS

Beta-adrenergic receptor agonists are growth-promoting drugs with the potential for illegal use in livestock, and human toxicity has resulted from consumption of contaminated meat. On-line liquid chromatography with atmospheric pressure chemical ionization mass spectrometry (LC/APCI-MS) was used for sensitive detection of several beta-agonists in retina, a tissue reported to concentrate and retain such residues for extended periods. Multiresidue extraction, separation, detection, and confirmation procedures were developed for retinal tissue and applied to eyes from cattle treated with clenbuterol (69-201 ppb) and to control eyes spiked with salbutamol (100 ppb) and terbutaline (25-100 ppb). Rapid switching of the potential difference between sampling cone and skimmer in the transport region of the API source was used to optimize acquisition of the protonated molecules and characteristic fragment ions obtained by collision-induced dissociation reactions. The respective selected ions were simultaneously acquired using a single quadrupole mass spectrometer. The accurate and precise agreement observed for diagnostic ion intensity ratios between beta-agonists in retinal samples and authentic standards suggests that LC/APCI-MS can be used for confirmation of analyte structure at trace levels and does not require the use of a triple-stage quadrupole mass analyzer.

Anomalous origin of the left circumflex coronary artery from the right aortic sinus: a familial clustering

Origin of the left circumflex coronary artery from the right sinus of Valsalva or the right coronary artery is a well-described anomaly. We report 3 cases which suggest a familial association of this anomaly. The familial clustering that we report has not been previously demonstrated.

Effect of dialysis on the clearance of Staphylococcus epidermidis from the peritoneal cavity: an experimental evaluation

Current information on the effect of peritoneal dialysis on host defenses in the peritoneal cavity is limited to in vitro studies. In the present study, clearance of Staphylococcus epidermidis from the abdominal cavity was assessed in an animal model undergoing peritoneal dialysis. In non-manipulated subjects, challenges of up to 10(8) viable microorganisms were cleared from the peritoneal cavity over a period of 24-48 hours. Cannula implantation, short- and long-term dialysis and the presence of excessive amounts of fluid in the peritoneal cavity did not affect the clearance rate. Presentation of the bacterial challenge, either as a bolus or via a slow delivery system, likewise had no effect on clearance rates. The results suggest that microbial trophism and the characteristics of the invading pathogen may be more critical determinants of the outcome of an infectious challenge to the peritoneal cavity than the status of the cellular and humoral defense systems.

The MEV mouse linkage testing stock: mapping 30 novel proviral insertions and establishment of an improved stock

Continuing efforts to improve the MEV linkage testing stock are described. The MEV stock carries multiple copies of the ecotropic murine leukemia virus genome. These proviruses are individually detectable in Southern blots, making it possible to follow the segregation of many loci simultaneously in genetic crosses. About 50 novel proviral insertions have been detected in this stock and propagated to homozygosity in a number of sublines. Many of the proviruses were first observed in individuals that were somatic and germinal mosaics. From the minimum frequency of primary transmission of proviruses to offspring, it is estimated that about 7 embryonic cells contribute to the pool of germ cells that populate the gonads. Thirty of the proviruses have been mapped to 15 different chromosomes in intercrosses between MEV sublines and the inbred Mus musculus castaneus strain CAST/Ei or in other crosses. Mapped insertions appear to be randomly distributed among chromosomes, but possibly clustered within chromosomes. Several of the mapped insertions are located such that their inclusion in improved MEV stocks would permit the screening of additional regions of the genome. An improved MEV stock that is homozygous for 12 proviruses on 11 chromosomes, including novel insertions on Chromosomes 17 and 19 is described. The stock also carries four dominant visible markers on 4 additional chromosomes. This stock is estimated to sweep approximately 68% of the autosomal genome.

Accuracy of text entries within a manually compiled anaesthetic record

We have examined the accuracy of text entries within a manually compiled anaesthetic record by comparing the record of the anaesthetist with that of an observer, present throughout the procedure but whose sole purpose was the documentation of perioperative events. Eighty-six items of information were analysed for accuracy from 197 records. The mean proportion of omissions was 35% and the mean proportion of incorrect entries was 3.4%. Where no entry should have been made, the mean proportion of unwarranted entries was 1%. Accuracy varied according to the information contained; however, omissions were common for preoperative status, fluids, tourniquet use, aspects of monitoring, local anaesthesia and intraoperative problems. The most consistently accurate information was the description of the patient and that relating to intraoperative i.v. drug use. Inaccuracy was common for the majority of sites on the record, irrespective of their reflecting on the anaesthetist's performance. We suggest, therefore, that the reason for this inaccuracy of data was not related principally to anaesthetists' defensiveness, but may reflect their attitudes to the record's value and response to inadequacies in its design. The observed deficiencies in recording accuracy may affect patient safety during future anaesthesia and has relevance to medico-legal and epidemiological research.

The management of a demanding breastfed infant

Infant crying is a common, distressing problem and the causes are multifactorial. In the management of a demanding or irritable breastfed baby, it is necessary to exclude a simple feeding problem first, even if the baby is gaining weight. Infants in this study were apparently well nourished and breastfed on demand, but the specific intervention was effective in resolving infant irritability. This was achieved by optimising breast milk taken at each feed by increasing milk supply, improving breast emptying and establishing an easier pattern of breastfeeding, which in turn helped the mothers cope better with the demands of breastfeeding.

A comparison of two methods of breastfeeding management

This study has demonstrated that, in a small group of 58 mothers, specific advice focused on establishing easier patterns of breastfeeding resulted in more of them continuing to breastfeed their babies for a longer period post-partum, with a less intense feeding pattern and the use of fewer complementary bottles of formula or other liquids, than did those given only the standard advice about breastfeeding. Current advice might be reviewed to continue to encourage demand breastfeeding but to emphasise the establishment of easier patterns of breastfeeding that optimise the mother-infant interaction.

An experimental evaluation of the pharmacokinetics of fusidic acid in peritoneal dialysis

Fusidic acid, an antimicrobial agent with activity against coagulase-positive and coagulase-negative staphylococci, has considerable potential for the management of staphylococcal peritonitis associated with continuous ambulatory peritoneal dialysis (CAPD). Whether fusidic acid reaches therapeutic levels in the dialysate once therapeutic serum levels have been achieved is not known. An animal model of CAPD that reproduced essential features of the clinical procedure was used to investigate this issue. Although oral administration was the preferred route, fusidic acid is not absorbed from the gastrointestinal tract of laboratory rats, and a subcutaneous injection of diethanolamine fusidate was used to achieve serum levels of the agent equivalent to those achieved clinically in man. In this model, fusidic acid concentrations up to 28 times the MIC for staphylococci were found in the dialysate when therapeutic levels of the agent were reached in the serum. The data provide support for continued experimental and clinical evaluation of the role of fusidic acid in CAPD-associated peritonitis.

Characterization of an animal model of continuous peritoneal dialysis in chronic renal impairment

In this study we describe the successful development of a method of continuous ambulatory peritoneal dialysis in a rat with stable chronic uremia. The procedure involved the insertion of a permanent indwelling cannula into the peritoneal cavity through which a draining catheter was passed for each dialysis. Dialysis of uremic animal hosts over a 24-hour period removed 31% of the urea excreted in the urine by normal animals over the same interval. The effect of daily dialysis for 21 days on biochemical, hematologic and cytologic parameters was also determined. The model will allow the basic pathobiology of common problems such as CAPD-associated peritonitis to be investigated.

The murine situs inversus viscerum (iv) gene responsible for visceral asymmetry is linked tightly to the Igh-C cluster on chromosome 12

The iv gene controls left-right determination during murine organogenesis. To map this gene, we analyzed backcross progeny produced by mating (C57BL/6J X MEV/Ty)F1-iv/+heterozygotes to C57BL/6J-iv homozygotes. Hybridization of a murine ecotropic virus probe and several homeotic box gene probes coupled with analysis of dominant visible markers enabled us to exclude the iv locus from much of the mouse genome. Spurred by a recent report that mapped the iv gene to mouse chromosome 12 which was not excluded by our previous work, we used the polymerase chain reaction on our larger cohort to determine that the iv gene is indeed linked tightly to the Igh-C locus on this chromosome: we observed 0/156 recombinants between the iv and Igh-C loci. Combining data from the two studies demonstrates that the murine iv gene is close (1/201 recombinants) to the Igh-C cluster on chromosome 12.

A mouse linkage testing stock possessing multiple copies of the endogenous ecotropic murine leukemia virus genome

A new linkage testing stock of the laboratory mouse has been constructed. The stock, designated MEV (multiple ecotropic provirus), was developed by inbreeding and selection beginning with the cross of strains C58/J and AKXD-14. Eleven different murine leukemia virus (MuLV) proviruses have been fixed in the MEV/1Ty strain. Nine of these can be uniquely identified by Southern blotting of PvuII-digested DNA and probing with a cloned fragment of the ecotropic viral genome. Two proviruses had been mapped previously to chromosome 7, while single proviruses had been mapped to chromosomes 2, 9, and 11. The mapping of six additional proviruses, derived from C58/J, to chromosomes 1, 3, 5, 10, 18, and 19 is described. Another C58/J provirus was mapped to chromosome 8 and proved to be identical to the previously mapped C58v-1 virus inducibility gene of strain C58/Lw. Three dominant visible markers, hammer-toe (Hm), steel (Sl), and caracul-J (CaJ), located on chromosomes 5, 10, and 15, respectively, have been introduced onto the MEV genetic background by repeated backcrosses to provide additional linkage markers. It is estimated that approximately 50% of the genome can be screened by scoring 50 fully informative gametes from a linkage cross of the MEV-Hm, -Sl, -CaJ stock for the combination of viral and visible markers. A strategy for efficiently mapping new recessive visible mutations by pooling tissues for DNA extraction from mutant homozygotes among F2 progeny is described. Ways of further improving the MEV stock are discussed. The location of the Myb proto-oncogene is defined relative to Sl and one of the C58/J proviruses on chromosome 10.