In vitro friction and lubrication of large bearing hip prostheses

New material combinations and designs of artificial hip implants are being introduced in an effort to improve proprioception and functional longevity. Larger joints in particular are being developed to improve joint stability, and it is thought that these larger implants will be more satisfactory for younger and more physically active patients. The study detailed here used a hip friction simulator to assess the friction and lubrication properties of large-diameter hip bearings of metal-on-metal and ceramic-on-reinforced-polymer couplings. Joints of different diameters were evaluated to determine what effect, if any, bearing diameter had on lubrication. In addition, the effects of lubricant type are considered, using carboxymethyl cellulose and bovine calf serum, and the physiological lubricant is shown to be considerably more effective at reducing friction. The frictional studies showed that the metal-on-metal joints worked under a mixed lubrication regime, producing similar friction factor values to each other. The addition of bovine calf serum (BCS) reduced the friction. The ceramic-on-reinforced-polymer samples were shown to operate with high friction factors and mixed lubrication. When tested with BCS, the larger-diameter bearings showed a decrease in friction compared with the smaller-size bearings, and the addition of BCS resulted in an increase in friction, unlike the metal-on-metal system. The study demonstrated that the component's diameter had little or no influence on the lubrication and friction of the large bearing combinations tested.

Intracranial facial nerve grafting after removal of vestibular schwannoma

OBJECTIVE

The objectives of this study were to evaluate outcomes from facial nerve (FN) cable grafting in patients who experienced FN transection during vestibular schwannoma removal and to compare the FN outcomes of patients who underwent FN grafting by using fibrin glue with those of patients who underwent FN grafting by using microsuture.

MATERIAL AND METHODS

We retrospectively evaluated a series of 33 patients in whom FN grafting was achieved either by using microsuture (8 cases) or fibrin glue (25 cases). Immediate repair of the FN was performed in all cases at the time of initial resection. The patients FN function was assessed preoperatively, in the immediate postoperative period, and at 3, 6, 9, and 12 months or more postoperatively using the House-Brackmann grading system. All patients had at least 1-year follow-up.

RESULTS

At 12 months, a House-Brackmann grade III was achieved in 75% of those who underwent cable nerve graft interposition by using microsuture and in 76% of those who underwent cable nerve graft interposition by using fibrin glue. Analysis of final FN function outcomes demonstrated no statistically significant difference in FN outcomes between the 2 groups (P = .891, Mann-Whitney U test; P = .1, Fisher exact test).

CONCLUSIONS

The functional results after FN cable grafting by using fibrin glue exclusively were equivalent to those obtained with microsuture. However, the technique of FN repair by means of fibrin glue is technically simple, less time-consuming, and imparts less trauma on the nerve than does the traditional suture method.

Decision Making for Solitary Vestibular Schwannoma and Contralateral Meniere’s Disease

The existence of dual inner ear pathology such as unilateral Meniere's disease (MD) with a contralateral vestibular schwannoma (VS) is very rare, but provides the otologist with a significant management dilemma. In this study, we present 5 cases of unilateral disabling MD with a contralateral VS in the better hearing ear. Conservative management of the VS is mandated unless there are impending complications, with management directed toward controlling the vertigo attributed to MD. If and when the VS requires intervention, or the hearing in that ear deteriorates to unserviceable levels, cochlear implant of the ear affected by MD prior to addressing the VS provides optimal management.

Outcomes in the use of intra-tympanic gentamicin in the treatment of Ménière's disease

The pathogenesis of Ménière's disease is associated with a disorder of ionic homeostasis, with the pathologic correlate being endolymphatic hydrops. Despite uncertainty as to its particular mode of action, it is accepted wisdom that intra-tympanic gentamicin has a definite therapeutic role in the control of symptoms in patients who fail to respond to medical therapy. This study reports an evaluation of the efficacy of intra-tympanic gentamicin in the treatment of Ménière's disease and also presents a simple, reliable, safe method of administering gentamicin for this purpose.

A retrospective review of 56 patients undergoing intra-tympanic gentamicin treatment for Ménière's disease was conducted. Response to treatment was analysed using a patient survey and examination of pure-tone averages. An overall significant improvement in vertigo symptoms of 81.3 per cent was found. There was a 21.4 per cent rate of significant hearing loss, defined as greater than 10 dB, with an average loss in this group of 18.5 dB. A single dose of gentamicin applied directly to the round window resulted in a high rate of control of vertigo, with acceptably low rates of hearing loss.

Familial growth and skeletal features associated with SHOX haploinsufficiency

This study was designed to determine the intrafamilial effect of SHOX haploinsufficiency on stature, by comparing the growth and phenotype of 26 SHOX haploinsufficient individuals with 45 relatives and population standards. It confirmed that SHOX haploinsufficiency leads to growth restriction from birth to final height. Compared to unaffected siblings, the SHOX haploinsufficient cohort was 2.14 SDS (3.8 cm) shorter at birth and 2.1 SDS shorter through childhood. At final height females were 2.4 SDS (14.4 cm) shorter and males 0.8 SDS (5.3 cm) shorter than normal siblings. The family height analysis suggests that the effect of SHOX haploinsufficiency on growth may have been previously underestimated at birth and overestimated in males at final height. SHOX haploinsufficiency leads to short arms in 92%, bilateral Madelung deformity in 73% and short stature in 54%. Females were more severely affected than males. We conclude that SHOX is a major growth gene and that mutations are associated with a broad range of phenotype.

Squatting exercises in older adults: kinematic and kinetic comparisons

PURPOSES

Squatting activities may be used, within exercise programs, to preserve physical function in older adults. This study characterized the lower-extremity peak joint angles, peak moments, powers, work, impulse, and muscle recruitment patterns (electromyographic; EMG) associated with two types of squatting activities in elders.

METHODS

Twenty-two healthy, older adults (ages 70-85) performed three trials each of: 1) a squat to a self-selected depth (normal squat; SQ) and 2) a squat onto a chair with a standardized height of 43.8 cm (chair squat; CSQ). Descending and ascending phase joint kinematics and kinetics were obtained using a motion analysis system and inverse dynamics techniques. Results were averaged across the three trials. A 2 x 2 (activity x phase) ANOVA with repeated measures was used to examine the biomechanical differences among the two activities and phases. EMG temporal characteristics were qualitatively examined.

RESULTS

CSQ generated greater hip flexion angles, peak moments, power, and work, whereas SQ generated greater knee and ankle flexion angles, peak moments, power, and work. SQ generated a greater knee extensor impulse, a greater plantar flexor impulse and a greater total support impulse. The EMG temporal patterns were consistent with the kinetic data.

CONCLUSIONS

The results suggest that, with older adults, CSQ places greater demand on the hip extensors, whereas SQ places greater demand on the knee extensors and ankle plantar flexors. Clinicians may use these discriminate findings to more effectively target specific lower-extremity muscle groups when prescribing exercise for older adults.

Lower-extremity biomechanics during forward and lateral stepping activities in older adults

OBJECTIVE

To characterize the lower-extremity biomechanics associated with stepping activities in older adults.

DESIGN

Repeated-measures comparison of kinematics and kinetics associated with forward step-up and lateral step-up activities.

BACKGROUND

Biomechanical analysis may be used to assess the effectiveness of various 'in-home activities' in targeting appropriate muscle groups and preserving functional strength and power in elders.

METHODS

Data were analyzed from 21 participants (mean 74.7 yr (standard deviation, 4.4 yr)) who performed the forward and lateral step-up activities while instrumented for biomechanical analysis. Motion analysis equipment, inverse dynamics equations, and repeated measures ANOVAs were used to contrast the maximum joint angles, peak net joint moments, angular impulse, work, and power associated with the activities.

RESULTS

The lateral step-up resulted in greater maximum knee flexion (P<0.001) and ankle dorsiflexion angles (P<0.01). Peak joint moments were similar between exercises. The forward step-up generated greater peak hip power (P<0.05) and total work (P<0.001); whereas, the lateral step-up generated greater impulse (P<0.05), work (P<0.01), and power (P<0.05) at the knee and ankle.

CONCLUSIONS

In older adults, the forward step-up places greater demand on the hip extensors, while lateral step-up places greater demand on the knee extensors and ankle plantar flexors.

RELEVANCE

Clinicians may use data from biomechanical analyses of in-home exercises to more effectively target specific lower-extremity muscle groups when prescribing exercise activities for older adults. The forward step-up is recommended for maintaining or improving hip extensor performance; whereas, the lateral step-up is recommended when targeting the knee extensors and ankle plantar flexors.

Optional sump: novel use of triple lumen closed drainage system

BACKGROUND

The debate over the use of drains in abdominal surgery is controversial. Selective drainage using a closed system is the method employed by most surgeons. There are, however, specific circumstances where different forms of drainage are required.

METHODS

One hundred and sixty-seven patients undergoing a mix of complex upper gastrointestinal surgery and colorectal surgery received an Axiom sump drain at the time of surgery. All side air vents were spigoted and the main lumina connected to a urine bag, with the option to convert to irrigation/suction as required.

RESULTS

Two patients required conversion to irrigation/suction, because of ongoing egress of fluid. In both cases drainage ceased without surgical intervention. The remaining cases resolved with no complications related to the drain.

CONCLUSION

The technique described allows the use of a large bore, soft, gravity-driven drain in cases where wound drainage is necessary. The closure of the ventilation ports maintains the advantage of a closed drainage system, yet allows for the conversion to a true sump system as required. This obviates the need for further drainage procedures.

CADASIL (Cerebral Autosomal Dominant Arteriopathy with Subcortical Infarcts and Leucoencephalopathy): an Australian perspective

Cerebral Autosomal Dominant Arteriopathy with Subcortical Infarcts and Leucoencephalopathy (CADASIL) is a recently described cause of stroke or stroke-like episodes. It is caused by mutations in the Notch3 gene on chromosome 19p. We sought to demonstrate mutations of the Notch3 gene in Australian patients suspected of having CADASIL. Patients from several families were referred to the study. A diagnosis was determined clinically and by neuroimaging. Those suspected of having CADASIL had sequencing of exons 3 and 4 of the Notch3 gene. Eight patients, two of whom were siblings, were suspected of having CADASIL. Five patients (including the siblings) had mutations. Because of strong clustering of Notch3 mutations in CADASIL, this has potential as a reliable test for the disease in Australian patients.

Premature calvarial synostosis and epidermal hyperplasia (Beare-Stevenson syndrome-like anomalies) resulting from a P250R missense mutation in the gene encoding fibroblast growth factor receptor 3

We report on a patient with a severe premature calvarial synostosis and epidermal hyperplasia. The phenotype was consistent with that of a mild presentation of Beare-Stevenson syndrome but molecular analysis of the IgIII-transmembrane linker region and the transmembrane domain of the gene encoding the FGFR2 receptor, revealed wild-type sequence only. Subsequently, molecular analysis of the FGFR3 receptor gene identified a heterozygous P250R missense mutation in both the proposita and her mildly affected father. This communication extends the clinical spectrum of the FGFR3 P250R mutation to encompass epidermal hyperplasia and documents the phenomenon of activated FGFR receptors stimulating common downstream developmental pathways, resulting in overlapping clinical outcomes.

Histopathological analysis of Leri-Weill dyschondrosteosis: disordered growth plate

Leri-Weill syndrome (LWS) is a dominant (pseudoautosomal) skeletal dysplasia with mesomelic short stature and bilateral Madelung deformity, due to dyschondrosteosis of the distal radius. It results from the loss of one copy of the Short Stature Homeobox Gene (SHOX) from the tip of the short arm of the X or Y chromosome. SHOX molecular testing enabled us to evaluate the histopathology of the radial physis in LWS patients with a documented SHOX abnormality. A widespread disorganisation of physeal anatomy was revealed with disruption of the normal parallel columnar arrangement of chondrocytes. Tandem stacking of maturing chondrocytes within columns was replaced by a side-by-side arrangement. The presence of hypertrophic osteoid with micro-enchondromata in the radial metaphysis suggests abnormal endochondral ossification. The Vickers' ligament was confirmed to blend with the triangular fibrocartilage complex (TFCC). This histopathological study demonstrates that the zone of dyschondrosteosis in LWS is characterised by marked disruption of normal physeal chondrocyte processes and that a generalised physeal abnormality is present.

Human Dermo-1 has attributes similar to twist in early bone development

Basic helix-loop-helix (bHLH) transcription factors are implicated in cell lineage determination and differentiation. Dermo-1 encodes a bHLH transcription factor that shares extensive homology with another bHLH transcription factor, Twist. We have cloned and characterized human Dermo-1 from two different bone cytoplasmic DNA (cDNA) libraries. Dermo-1 mRNA and protein expression were examined in human embryo and adult tissue sections. Dermo-1 is expressed in a subset of mesodermally and ectodermally derived tissues. We further examined expression of Dermo-1/Twist in human tissues and cell lines. In addition, we observed Dermo-1 expression in response to basic fibroblast growth factor in osteoblastic cell lines. To evaluate the functionality of the human Dermo-1 transcription factor in osteoblast metabolism, we made stable osteoblastic cell lines that over- and underexpress human Dermo-1. These cell lines were analyzed and compared with previously published data of similar cell lines transfected with Twist. Our results demonstrate that Dermo-1 caused changes similar to Twist in the osteogenic properties of osteoblastic cells, such as morphology, bone marker gene expression, and biochemical response to cytokines. However, Dermo-1 expression also has unique effects in regulating the mechanism of proliferation, on alkaline phosphatase enzyme activity, and in temporal expression patterns. We speculate that expression of Twist and Dermo-1 maintains cells in an osteoprogenitor or preosteoblast-like state, respectively, and prevents premature or ectopic osteoblast differentiation. Therefore, Twist and Dermo-1 must be sequentially downregulated in order to initiate the cascade of events responsible for osteogenic cell differentiation. These results indicate that, during osteoblast development, Dermo-1 may inhibit osteoblast maturation and maintain cells in a preosteoblast phenotype by utilizing mechanisms similar but not identical to those utilized by Twist.

Clinical findings in a patient with FGFR1 P252R mutation and comparison with the literature

We report on a patient with the skeletal findings of Jackson-Weiss syndrome, who manifests only mild craniofacial anomalies. Molecular analysis of her fibroblast growth factor receptor 1 gene (FGFR1) identified a heterozygous P252R missense mutation, previously only reported with FGFR1-Pfeiffer syndrome like manifestations. Mutations in the immunoglobulin-like, II-III (IgII-III) linker region of FGFR1 and FGFR3 molecules may present as a skeletal dysplasia affecting the appendicular skeleton including, brachydactyly, short broad middle phalanges, phalangeal epiphyseal coning and broad halluces. This communication is a further example of the phenomenon of an activated FGFR molecule resulting in overlapping manifestations in FGFR syndromes.

The backpack run test: a model for a fair and occupationally relevant military fitness test

Our purpose in this investigation was to develop and validate a theoretical model for a backpack run test based on how fast one can run 2 miles while wearing a backpack. Using actual unloaded (no backpack) 2-mile-run test data from 59 male service academy cadets, we calculated the average oxygen cost during the run, the equivalent cost if wearing additional weight, and the corresponding estimated run time with the backpack. The correlations between body weight and loaded (backpack weight = 30 kg) run times (r = 0.55 [p < 0.05] and r = 0.12 [p > 0.05], respectively) demonstrate that the bias against heavier runners is eliminated with the backpack run. Given that the backpack run test requires only standard-issue equipment, demonstrates clear occupational and health-related fitness relevance, predicts no apparent body-size bias, and measures work- and health-related components of fitness, we recommend that the military services consider the present data when developing or modifying tests of physical fitness.

An allelic variant at the ATM locus is implicated in breast cancer susceptibility

We have tested a simple procedure, disease association by locus stratification, for identifying breast cancer patients with pathogenetic allelic variants at several candidate loci. The strategy was based on the assumption of epistatic interactions of the candidates. We analyzed 66 independent cases from sib pairs affected with breast cancer that had previously been collected during an investigation of pathogenetic-allele-sharing at the HRAS1 mini-satellite locus. An exon 24 polymorphism of ATM, substituting arginine for proline was associated with breast cancer in these cases with an overall odds ratio of 4.5 (95% confidence interval, 1.2-20.5, nominal p = 0.02, 2-tail Fisher exact test). In the presence of a rare HRAS1 allele, the odds ratio increased to 6.9 (95% CI, 1.2-38.3, p = 0.03). Thus, our procedure identified at least one allelic variant of ATM associated with breast cancer, and indicated that the ATM locus may interact with HRAS1.

Subjective and external assessments of quality of life in schizophrenia: relationship to insight

OBJECTIVE

This study assessed the manner in which insight influenced schizophrenic patients' evaluation of their objective life conditions and the concurrent validity between patients' and clinicians' assessments of patients' global quality of life.

METHOD

Forty out-patients who fulfilled DSM-III-R criteria for schizophrenia were independently interviewed using the Lancashire Quality of Life Profile and the Standard of Living Interview. Insight was assessed using a self-report questionnaire, the Insight Scale.

RESULTS

For insightful patients there was a significant but modest correlation between objective and subjective indicators of quality of life. Likewise, a significant correlation between subjective and external evaluations of global quality of life was limited to those individuals who had good insight.

CONCLUSION

Diminished insight may limit the usefulness of the self-report methodology for assessing quality of life for some individuals with schizophrenia.

Physiatric management of mild traumatic brain injury

Mild traumatic brain injury (MTBI) is a common condition, afflicting as many as 1.5 million Americans yearly. Most individuals sustain MTBI as a result of motor vehicle collisions, but it may also occur as a result of falls, physical assault or sporting accidents. Problems related to MTBI include various pain syndromes, cognitive impairments, disorders of affect, cranial nerve dysfunction, and vertigo, arising from injury to the brain, head, or cervical spine. Symptoms are usually transient, although a small percentage of afflicted individuals develop long-lasting problems, often preventing them from leading productive lives. Recognition of these problems as arising from MTBI is difficult due to the frequent lack of abnormal findings on diagnostic tests and failure to identify a history of head trauma. The American Congress of Rehabilitation Medicine has defined MTBI, an important first step in identifying individuals who need treatment. Diagnosis is usually made by directed questions regarding trauma history and careful procurement and interpretation of appropriate tests. Once a diagnosis is made, proper care can be prescribed in order to lead patients toward more productive lives.

The Palliative Care Education Group for Gloucestershire (PEGG): an integrated model of multidisciplinary education in palliative care

Multidisciplinary teamwork is an essential part of palliative care. Traditionally, in the UK, education of health care professionals has been carried out within single professional disciplines. The Palliative Care Education Group (PEGG) for Gloucestershire, a county in the south-west region of England, UK, is a multidisciplinary group, which promotes and integrates palliative care education across the county. This report describes the evolution of the group, its aims and objectives and the methods used to evaluate its impact on clinical practice. PEGG is a practical model of multidisciplinary education, which could be adopted in other areas.

Parathyroid hormone suppression in spinal cord injury patients is associated with the degree of neurologic impairment and not the level of injury

OBJECTIVE

To demonstrate that after spinal cord injury (SCI) suppression of the parathyroid-vitamin D axis is associated with the degree of neurologic impairment and not the level of injury.

DESIGN

A retrospective analysis of clinical and biochemical data obtained from hospital records of patients with SCI compared to a control group of patients with traumatic brain injury (TBI).

SETTING

The inpatient rehabilitation unit of a tertiary care hospital.

SUBJECTS

The medical records of 82 consecutive admissions to the rehabilitation unit with a diagnosis of SCI or TBI were reviewed. Patients with SCI were classified by the American Spinal Injury Association (ASIA) impairment scale and then grouped based on the completeness and level of injury.

MAIN OUTCOME MEASURE

Comparisons of serum parathyroid hormone (PTH), 25-hydroxyvitamin D, and 1,25-dihydroxyvitamin D (1,25-D) were planned. Multiple comparisons were performed for total and ionized serum calcium levels, serum phosphorus levels, and 24-hour urinary calcium excretion rates to reflect changes in mineral homeostasis. Multiple comparisons were also performed for serum albumin, prolactin, thyroid function tests, and AM cortisol levels, as well as 24-hour urinary urea nitrogen and cortisol excretion rates to reflect metabolic responses to stress.

RESULTS

Patients with SCI had significant suppression in PTH (p < .000009) and 1,25-D (p < .02) levels with elevated phosphorus (p < 0.03) and prolactin (p < .03) levels compared to patients with TBI. Also, more patients with SCI were hypoalbuminemic (p < .003) than patients with TBI. Patients with complete SCI (ASIA A) had more suppressed PTH (p < .03) and higher urinary urea nitrogen (p < .05) levels than SCI patients with incomplete injuries (ASIA B-D). Patients with complete, but not incomplete, SCI had lower albumin levels than patients with TBI (p < .05). These differences were not found between patients with tetraplegic and paraplegic SCI. ASIA motor scores did not correlate with any of the measured parameters but when used as a covariate did abolish differences in PTH and 1,25-D among the study groups by ANOVA.

CONCLUSION

In patients with SCI, the degree of neurologic impairment, and not the level of injury, is associated with PTH suppression and markers of metabolic stress.

Evaluating social skills following traumatic brain injury: the BRISS as a clinical tool

Deficits in social behaviour are a major obstacle to the reintegration into the community of traumatically brain-injured (TBI) individuals. Recognition of the importance of social skill remediation has highlighted the need for a suitable assessment tool. The TBI population presents particular requirements with respect to the special nature of deficits which commonly occur as a result of frontal lobe impairment. The Behaviorally Referenced Rating System of Intermediate Social Skills (the BRISS) has been shown to have good psychometric properties with a TBI population. It also provides a measure of particular social skills associated with frontal lobe functioning. This study examines the ability of the verbal scales of the BRISS to identify social skill deficits at the individual client level and to detect significant changes in skills following an intervention programme involving five chronic TBI males. In the case of one client, who demonstrated significant clinical improvement in social behaviour, the BRISS was found to identify specific areas of apparent change. The difficulty of using the BRISS as a sole measure of social skills is discussed in the light of relatively large pre-intervention within-subject variability which was found with respect to some behaviours.

Disease-activated transcription factor: allergic reactions in human skin cause nuclear translocation of STAT-91 and induce synthesis of keratin K17

Epidermal keratinocytes have important immunologic functions, which is apparent during wound healing, in psoriasis, and in allergic and inflammatory reactions. In these processes, keratinocytes not only produce cytokines and growth factors that attract and affect lymphocytes but also respond to the polypeptide factors produced by the lymphocytes. Gamma interferon (IFN-gamma) is one such signaling polypeptide. Its primary molecular effect is activation of specific transcription factors that regulate gene expression in target cells. In this work, we present a molecular mechanism of lymphocyte-keratinocyte signaling in the epidermis. We have induced cutaneous delayed-type hypersensitivity reactions that are associated with an accumulation of lymphocytes. These resulted in activation and nuclear translocation of STAT-91, the IFN-gamma-activated transcription factor, in keratinocytes in vivo and subsequent induction of transcription of keratin K17. Within the promoter of the K17 keratin gene, we have identified and characterized a site that confers the responsiveness to IFN-gamma and that binds the transcription factor STAT-91. Other keratin gene promoters tested were not induced by IFN-gamma. These results characterize at the molecular level a signaling pathway produced by the infiltration of lymphocytes in skin and resulting in the specific alteration of gene expression in keratinocytes.

Blunted growth hormone response to intravenous arginine in subjects with a spinal cord injury

The influence of the activities of daily living on human growth hormone (hGH) release and plasma insulin-like growth factor (IGF-I) levels is not known. Individuals with spinal cord injury (SCI) and paralysis generally have reduced levels of activity compared with ambulatory subjects. We studied sixteen subjects with SCI and sixteen nonSCI subjects matched for age, gender and body mass index (BMI) as controls. After an intravenous infusion of arginine hydrochloride (30 g/subject over 30 minutes), mean plasma hGH values at 30 and 60 minutes were significantly lower in the group with SCI compared with the control group (3.4 +/- 0.7 versus 10.7 +/- 2.5 ng/ml, p < 0.01; and 5.2 +/- 1.5 versus 12.5 +/- 2.7 ng/ml, p < 0.05). Also, peak and sum hGH responses were significantly lower in the group with SCI than in the control group (5.8 +/- 1.5 versus 14.1 +/- 2.8 ng/ml, p < 0.01; and 15.2 +/- 3.1 versus 34.8 +/- 7.2 ng/ml, p < 0.02). Controlling for age and BMI, the results remained significant. However, the mean plasma IGF-I level was significantly lower in SCI subjects younger than 45 years old than in the similar subgroup of age-restricted controls (202 +/- 19 versus 324 +/- 27 ng/ml, p < 0.05), whereas, a comparison of subgroups of subjects 45 years or older did not reveal a significant difference. These findings support the hypothesis that decreased daily physical activity results in depression of the hGH/IGF-I axis in younger individuals with SCI and may be considered to be a state of premature aging.(ABSTRACT TRUNCATED AT 250 WORDS)

Molecular effects of T lymphocytes on the regulation of keratin gene expression

The interactions between lymphocytes and the epidermis are very important in autoimmune skin diseases. Mutual interaction between keratinocytes and T cells is effected both by soluble peptides and by direct cell-to-cell contact. We investigated the possibility that direct cell-to-cell contact with T cells may also play a role in the regulation of keratin gene expression. We have transfected human epidermal keratinocytes with the constructs containing promoters of keratin genes and then cocultured them with the HUT78 strain of human T cells. We found that T cells induce transcription of K5, K6, K14 and K16 genes, as well as the RSV viral promoter, but not K17, K10 or the SV40 viral promoter controls.

Heat stress regulates the human 70-kDa heat-shock gene through the 3'-untranslated region

Cells respond to a variety of stresses by synthesizing a family of proteins termed heat-shock proteins (HSP). Recently, the 3'-untranslated regions (UTRs) of some mRNAs have been shown to be important in the posttranscriptional regulation of protein production. Therefore, we hypothesized that heat could regulate HSP70 production through the HSP70 3'-UTR, in addition to its known effects on transcription. To test this hypothesis, cells were transfected with either a plasmid containing sequences encoding the human HSP70 or beta-globin 3'-untranslated region placed downstream of a chloramphenicol acetyltransferase (CAT) reporter gene. In both plasmids, the CAT gene was driven by an SV40 promoter. Following heat stress, cells transfected with the CAT construct containing the HSP70 3'-UTR showed increased CAT activity relative to the beta-globin 3'-UTR construct. This effect paralleled increases in HSP70 mRNA and levels of the inducible HSP70 protein by Western blot. These studies identify a heat-induced mechanism of posttranscriptional control of HSP70 synthesis utilizing the HSP70 3'-UTR, which may be important in the cells ability to regulate the heat-shock response.

Nurses' attitudes to and use of patient hoists in hospital

A questionnaire on patient hoists was circulated to all 220 qualified nurses working in a geriatric department. A survey of the provision and state of repair of the hoists was carried out on the unit. Despite being aware of the value of hoists, 41 % of the 134 nurses who responded to the questionnaire never or rarely used them. An important reason for this was inadequate instruction in hoist use, 65% of nurses feeling that their instruction had been inadequate. Instruction in hoist use had rarely been given by occupational therapists or physiotherapists. Thirty-five per cent of nurses were unaware of any of the basic safety factors in hoist operation. Those who considered their instruction to have been inadequate were more likely to have unfavourable impressions of hoists (p < 0.01) and more likely to be unaware of safety factors (p < 0.01). There was a nonsignficant trend to a greater prevalence of previous back injury in nurses who never or rarely used hoists. The hoists themselves were generally in reasonable working order, although minor faults were found in 60% of the 22 hoists surveyed. They were generally used (with rigid seats) as bath hoists only, and the provision of appropriate slings might greatly increase their usefulness at minimal extra expense.

Mutated and hypermutated genes of persistent measles viruses which caused lethal human brain diseases

Persistent measles viruses (MVs) causing lethal human brain diseases are defective, and the structure of several mutated matrix genes has been elucidated previously. The present study of four persistent MVs revealed a high number of differences from a consensus sequence also in other genes. Amino acid changes accumulated in the carboxyl terminus of the nucleocapsid protein and in the amino terminus of the phosphoprotein, but did not significantly alter these products, which are implicated in viral replication and transcription. The contrary is true for the envelope glycoproteins: In three of four cases, mutations caused partial deletion of the short intracellular domain of the fusion protein, most likely compromising efficient viral budding. Moreover, in the hemagglutinin gene of a strain showing strongly reduced hemadsorption, 20 clustered A to G mutations, resulting in 16 amino acid changes, were detected. This hypermutation might be due to unwinding modification of a part of the MV RNA genome accidentally present in a double-stranded form. Finally, we classified four lytic and seven persistent MV strains on the basis of their sequences. Surprisingly, the four lytic viruses considered belong to the same class. The persistent viruses form more loosely defined groups, which all differ from the vaccine strain Edmonston.

Muscarinic cholinergic receptor binding: in vivo depiction using single photon emission computed tomography and radioiodinated quinuclidinyl benzilate

An attempt was made to characterize, in vivo, specific binding to the muscarinic cholinergic receptor in the calf using the radioiodinated ligand quinuclidinyl benzilate (123I-OH-QNB) and single photon detection emission computed tomography (SPECT). The supratentorial brain activity was significantly increased after the intravenous infusion of 123I-OH-QNB as compared to free 123I. Scopolamine, a muscarinic cholinergic receptor antagonist, decreased the measured brain activity when infused prior to 123I-OH-QNB consistent with pharmacologic blockade of specific receptor binding. Quantitative in vitro tissue distribution studies obtained following SPECT imaging were consistent with regionally distinct specific receptor binding in the striatum and cortical gray matter, nonspecific binding in the cerebellum, and pharmacologic blockade of specific binding sites with scopolamine. Although 123I-OH-QNB is not the ideal radioligand, our limited success will hopefully encourage the development of improved binding probes for SPECT imaging and quantitation.

Malaria in Cape Town. A report of 3 cases and a review of current therapy and prophylaxis

Three cases of malaria seen within 1 week at the Somerset Hospital in Cape Town are reported. One of these patients developed cerebral malaria and severe brain damage. The management of acute malaria and its complications, as well as the prophylaxis, is briefly reviewed. In view of the difficulty in obtaining intravenous quinine in Cape Town, it is strongly recommended that small supplies of intravenous quinine be maintained at centres throughout the country. This may decrease the incidence of cerebral malaria, the potentially fatal complication of Plasmodium falciparum infections.