Roller traction: mobilizing patients with acetabular fractures

Patients with acetabular fractures unamenable to open reduction and internal fixation are subject to 6-12 weeks of traction and, traditionally, bed rest. Using roller traction allows the patient to be mobilized to a bedside chair and to stand without disrupting the traction. This is accomplished by slightly modifying a standard lower extremity skeletal traction setup. Roller pulleys and stopper clamps are substituted for the usual pulleys. These are attached to extra-long horizontal bars that expand the lateral space that the patient can now use around the bed. Roller traction helps prevent the common complications of prolonged bed rest, particularly deep vein thrombosis, skin breakdown, pulmonary stasis and boredom.

Human microsomal triglyceride transfer protein large subunit gene structure

Microsomal triglyceride transfer protein (MTP) is a heterodimer consisting of the multifunctional enzyme protein disulfide isomerase and a unique, large 97-kDa subunit. MTP is required for the assembly and secretion of very low density lipoproteins and chylomicrons by the liver and intestine, respectively. In vitro, MTP catalyzes the transport of triglyceride, cholesteryl ester, and phosphatidylcholine between phospholipid surfaces. We have characterized the gene encoding the large subunit of human MTP. It contains 18 exons and spans approximately 55-60 kb. Fluorescent in situ hybridization localized this gene to band 4q24 of chromosome 4. A (CA)n repeat polymorphic marker, which may be useful for investigating a link between the MTP gene and genetic defects in lipid metabolism, was identified in intron 10. Sequence analysis of the 5' flanking region of the gene revealed potential sites which may bind transcriptional factors and control MTP expression.

Secretion of apolipoprotein B-containing lipoproteins from HeLa cells is dependent on expression of the microsomal triglyceride transfer protein and is regulated by lipid availability

To elucidate the role of the microsomal triglyceride transfer protein (MTP) in lipoprotein assembly, MTP and apolipoprotein B-53 (apoB 53; the N-terminal 53% of apoB) were expressed in HeLa cells. The results showed that apoB-53 could be expressed in HeLa cells with or without expression of MTP. In contrast, efficient secretion of apoB-53 required expression of MTP. Ultracentrifugal density flotation analysis showed that apoB-53 was secreted predominantly as a particle with the density of high density lipoprotein. An essentially identical apoB-53 particle density distribution was obtained after transient expression of apoB-53 in McArdle RH-7777 rat hepatoma cells. The mass of apoB-53 secreted was greater, and the flotation density was lower, from cells fed lipid, suggesting that apoB secretion in HeLa cells was regulated by lipid availability, similar to what has been described for lipoprotein-producing cell lines. These results indicate that MTP is necessary and sufficient to direct the regulated secretion of apoB-53 in HeLa cells.

Cloning and gene defects in microsomal triglyceride transfer protein associated with abetalipoproteinaemia

The microsomal triglyceride transfer protein (MTP), which catalyses the transport of triglyceride, cholesteryl ester and phospholipid between phospholipid surfaces, is a heterodimer composed of the multifunctional protein, protein disulphide isomerase, and a unique large subunit with an apparent M(r) of 88K (refs 1-3). It is isolated as a soluble protein from the lumen of the microsomal fraction of liver and intestine. The large subunit of MTP was not detectable in four unrelated subjects with abetalipoproteinaemia, a rare autosomal recessive disease characterized by a defect in the assembly or secretion of plasma lipoproteins that contain apolipoprotein B (ref. 6). We report here the isolation and sequencing of complementary DNA encoding the large subunit of MTP. A comparison of this sequence to corresponding genomic sequences from two abetalipoproteinaemic subjects revealed a homozygous frameshift mutation in one subject and a homozygous nonsense mutation in the other. The results indicate that a defect in the gene for the large subunit of MTP is the proximal cause of abetalipoproteinaemia in these two subjects, and that MTP is required for the secretion of plasma lipoproteins that contain apolipoprotein B.

Molecular cloning of cellular genes encoding retinoblastoma-associated proteins: identification of a gene with properties of the transcription factor E2F

The retinoblastoma protein interacts with a number of cellular proteins to form complexes which are probably crucial for its normal physiological function. To identify these proteins, we isolated nine distinct clones by direct screening of cDNA expression libraries using purified RB protein as a probe. One of these clones, Ap12, is expressed predominantly at the G1-S boundary and in the S phase of the cell cycle. The nucleotide sequence of Ap12 has features characteristic of transcription factors. The C-terminal region binds to unphosphorylated RB in regions similar to those to which T antigen binds and contains a transactivation domain. A region containing a potential leucine zipper flanked by basic residues is able to bind an E2F recognition sequence specifically. Expression of Ap12 in mammalian cells significantly enhances E2F-dependent transcriptional activity. These results suggest that Ap12 encodes a protein with properties known to be characteristic of transcription factor E2F.

Sleep fragmentation and ventilatory responsiveness to hypercapnia

It has been postulated that sleep disruption may change ventilatory chemoresponsiveness to hypercapnia and hypoxia and thereby contribute to the development of respiratory failure in some patients with obstructive sleep apnea syndrome (OSAS) or with other respiratory disorders. Some studies have demonstrated a reduction in ventilatory chemoresponsiveness in normal subjects after one night of total sleep deprivation. However, sleep fragmentation rather than total sleep deprivation is usual in patients. In this study, therefore, we measured hypercapnic ventilatory responsiveness (HCVR) and spirometry in 13 healthy male subjects (18 to 30 yr of age) after two consecutive nights of severe sleep fragmentation (arousal to an auditory stimulus after each minute of sleep) and compared the results with those obtained in the same subjects after normal sleep. Sleep fragmentation and normal sleep were separated by a week, and the order of intervention was randomized from patient to patient. No significant differences were observed in the slope or position of the HCVR curve after sleep fragmentation or in forced expiratory volumes. Although it is possible that a more prolonged period of sleep fragmentation than that used in this study may have an effect on HCVR, the results suggest that sleep fragmentation is an unlikely cause of progressive respiratory failure in patients with OSAS or with other respiratory disorders.

Breast screening: a subject for debate

The National Health Service Breast Screening Programme was instituted in 1988 following the recommendations of the Forrest report in 1986. From the beginning it has been controversial. Is breast cancer screening efficacious? Can the efficacy produced in trials be reproduced nationwide in the UK? Do the benefits of screening outweigh the adverse effects? Answers to all these questions are not yet available but in the light of current evidence, breast screening does appear to offer a realistic opportunity to reduce the mortality from a disease which constitutes a major public health problem in the UK. The role of the general practitioner and the primary care team is considered in the light of the experience gained in the first phase of the screening programme.

Biochemical and cytochemical responses of Stylosanthes guianensis to infection by Colletotrichum gloeosporioides: association of callose deposition with resistance

Biochemical and cytochemical responses of leaves of the tropical pasture legume Stylosanthes guianensis cv. Graham to infection by a compatible and incompatible race of Colletotrichum gloeosporioides have been investigated. No evidence for the synthesis of phytoalexins and induction of the enzyme phenylalanine ammonia-lyase was obtained. Peroxidase was induced but with little difference between the two interactions. Cytochemical staining and radiolabelling with [14C]cinnamic acid indicated that infection was not associated with cell-wall lignification. In the compatible interaction, several pathogenesis-related proteins and chitinase were induced at 4 days after inoculation, but these proteins were not induced in the incompatible interaction. The deposition of callose in host cells associated with fungal appressoria was monitored by staining with aniline blue. The appressoria of the incompatible race were associated with a greater number of host callose deposits than those of the compatible race between 1 and 3 days after inoculation. In addition, the aniline blue staining deposits associated with the appressoria of the incompatible race showed a greater intensity of fluorescence when compared with those of the compatible race. Histological studies showed low levels of penetration (1–6%) for both interactions. In the incompatible interaction, fungal development did not extend past vesicle formation in the penetrated cell, whereas in compatible interactions the fungus had extended to greater than 20 cells by 96 h. Thus, among a number of possible host responses to infection, the deposition of callose associates most closely with race-specific resistance. Key words: anthracnose, phytoalexins, peroxidase, papillae, chitinase.

Managing the difficult patient: practical suggestions from a study day

A study day for general practitioners was arranged on the subject of managing the difficult patient. Participants were asked to supply written details of their most difficult patient and the problems they associated with him or her. The issues raised were addressed in a number of formal presentations and formed the basis for discussion in workshops. This paper focuses on the underlying similarities between the patients and discusses a practical approach to their management.

Searching health education literature. Bibliographic and indexing tools

The first two articles in this series looked in different ways at relationships between libraries and health education units. We now look at a selection of bibliographic and indexing tools that can be used to identify journal articles, books and other materials of interest to health educators. Audio-visual items are not covered.

Paraneoplastic subacute necrotic myelopathy

A 79 year old male acutely developed a Brown-Sequard syndrome two weeks following resection of renal cell carcinoma. The subsequent clinical course was marked by subacute progression of spinal cord signs. Pathologic studies showed extensive multifocal spinal cord necrosis that could not be attributed to vascular occlusion or to vasculitis. This case appears to be a rare example of paraneoplastic subacute necrotic myelopathy.

Effects of erythromycin and gentamicin in experimental peritonitis

Erythromycin and gentamicin were used to analyse the concept of bacterial synergy in an experimental model of acute appendicitis. Erythromycin given orally suppressed the aerobic flora other than the Enterobacteriaceae. When given by injection, a notable reduction in the counts of bacteroides and other anaerobic Gram-negative bacteria was also achieved. The addition of gentamicin, itself inactive against bacteroides, resulted in their total suppression. The implications of these findings are discussed.