Effect of PSC 833, a potent inhibitor of P-glycoprotein, on the growth of astrocytoma cells in vitro

Malignant astrocytomas have been found to express P-glycoprotein (Pgp, mdr1 gene product). It was hypothesized that in addition to conferring multidrug resistance, Pgp is intimately associated with the development of astrocytomas. Accordingly, we studied the effect of PSC 833 (PSC, Novartis), a potent inhibitor of Pgp, on the growth of Pgp-expressing astrocytoma cells. The results showed that in all the cell lines tested, PSC (10-60 microM) inhibited the growth as well as induced cell death. Cells exposed to PSC exhibited DNA ladder characteristic of apoptosis. PSC-induced cell death could be reversed by Z-VAD-fmk, a general caspase inhibitor, indicating that PSC-induced cell death was characteristic of caspase-mediated apoptosis. These results suggest a novel therapeutic strategy in the treatment of malignant astrocytomas by inhibitors of Pgp.

IGF-1 and insulin receptor expression in the minor salivary gland tissues of Sjögren's syndrome and mucoceles--immunohistochemical study

OBJECTIVE

To investigate the expression of IGF-1 receptors and insulin receptors on the minor salivary gland (MSG) tissues of patients diagnosed with Sjögren's syndrome (SS) and normal salivary gland tissue surrounding mucoceles.

SUBJECTS AND METHODS

Five MSG tissue sections from SS and seven from mucocele patients were stained immunohistochemically using antibody to IGF-1 receptor and insulin receptor in a horse radish peroxidase and DAB system.

RESULTS

The expression of the insulin receptor was increased in the SS sections compared with controls, while the insulin-like growth factor-1 receptor was more intensely expressed in the controls.

CONCLUSION

The presence of differential expression of receptors for IGF and insulin might suggest a possible role of these growth factors in the pathogenesis of SS.

Comparison of laser speckle and laser Doppler perfusion imaging: measurement in human skin and rabbit articular tissue

Laser Doppler perfusion imaging (LDI) is currently used in a variety of clinical applications, however, LDI instruments produce images of low resolution and have long scan times. A new optical perfusion imager using a laser speckle measurement technique and its use for in vivo blood flow measurements are described. Measurements of human skin and surgically exposed rabbit tissue made using this instrument were compared with a commercial laser Doppler perfusion imaging instrument. Results from blood flow measurements showed that the laser speckle imager measured an 11-67% decrease in blood flow under arterial occlusion. Under similar conditions, the laser Doppler imager measured blood flow decreases of 21-63%. In comparison with LDI, it was observed that the higher temporal resolution of the laser speckle imager was more sensitive to measuring the hyperaemic response immediately following occlusion. This in vivo study demonstrated some of the several advantages laser speckle imaging has over conventional LDI, making the new instrument more versatile in a clinical environment.

The assessment and management of strabismus and amblyopia: a national audit

AIMS

To determine what systems are in place within ophthalmic services for the assessment and management of children suspected of having amblyopia and strabismus. To find out what methods are used for the assessment of these children.

METHODS

A questionnaire-based study auditing 288 orthoptic departments in the UK.

RESULTS

Responses were received from 75% orthoptic departments. Most hospitals employ more than one system for the assessment of strabismus and amblyopia, which is generally dependent on route of referral. These include 'orthoptic assessment without refraction' (66%), 'combined orthoptist and ophthalmologist assessment' (66%), while 22% have an entirely orthoptist/optometric system. Ophthalmologists are involved in the initial assessment in 145 units (67%), whereas some units involve an ophthalmologist only if response to treatment is poor (15%), or if surgery is required (6%). Fourteen per cent of units reviewed all children, with discharge criteria being based on normal visual acuity (52%), accurate visual acuity (39%) and a normal orthoptic assessment (42%). Seventy-six per cent of units review some children, commonly as a result of family history (55%), parental concern (43%), poor co-operation (30%) and young age (72%). In the absence of squint or amblyopia children are discharged at the first visit, in only 8% of units. There is considerable variation in the tests used to assess visual acuity. LogMAR-based tests (eg EDTRS) are not routinely used in 75% of units.

CONCLUSION

Different systems exist for the assessment and management of squint and amblyopia across the country. While much of this variation is to be expected given their possible aetiologies, some could be reduced to produce a more cohesive service. There is also considerable scope for rationalising the tests used to screen infants and children for amblyopia and strabismus.

Distinct role of surface lymphotoxin expressed by B cells in the organization of secondary lymphoid tissues

In order to definitively ascertain the functional contribution of lymphotoxin (LT) expressed by B cells, we produced mice with the LTbeta gene deleted from B cells (B-LTbeta KO mice). In contrast to systemic LTbeta deletion, in B-LTbeta KO mice only splenic microarchitecture was affected, while lymph nodes and Peyer's patches (PP) were normal, except for PP's reduced size. Even though B-LTbeta KO spleens retained a small number of follicular dendritic cells (FDC) which appeared to be dependent on LTbeta produced by T cells, IgG responses to sheep red blood cells were markedly reduced. Thus, the organogenic function of B-LTbeta is almost entirely restricted to spleen, where it supports the correct lymphoid architecture that is critical for an effective humoral immune response.

Elastin distribution in the myometrial and vascular smooth muscle of the human uterus

Magnetic resonance imaging and transvaginal ultrasonography in women of reproductive age suggest that the myometrium consists of inner and outer layers. It was hypothesized that these structural and functional differences in the myometrium might be associated with a variation in elastin distribution. Fifty-one hysterectomy specimens representing all phases of the normal menstrual cycle were studied by immunocytochemistry, orcein staining and image analysis. Elastin was present within the outer myometrial smooth muscle, but was less widely distributed in the inner smooth muscle. Immunoreactivity and staining were observed in the myometrial arteries and arterioles and within the basal portions of endometrial arterioles. Elastin was also present in perivascular tissue, particularly near the large vessels. More extravascular (i.e. perivascular and smooth muscle) elastin was present in the outer myometrium in all cases, although no distinct layering was observed. Semi-quantitative analysis of the elastin distribution in 11 full thickness specimens demonstrated a decreasing gradient from outer to inner myometrium rather than distinct layering. Contrary to previous reports, these data suggest that the external region of the myometrium is more elastic than the inner region and that elastin is found throughout the arteriolar tree of the human uterus.

An EMG-based, muscle driven forward simulation of single support phase of gait

This paper describes the process used to generate lower limb kinematics during single limb stance phase of gait, using musculoskeletal modelling, muscle driven forward simulation and gradient based optimisation techniques (including design of experiment techniques). Initial inputs to the forward simulation process were the normalised quantified muscle activation patterns of 22 muscles, and the initial segmental configuration (both angles and angular velocity) derived from Winter (The biomechanics and motor control of human gait, 1987, University of Waterloo Press, pp. 1-72). Two distinct musculoskeletal models (one including 6 DOF, the other 7 DOF) were defined and a muscle driven forward simulation was implemented.A series of optimisation sequences then were executed to modify the muscle activation patterns and initial segmental configuration, until the system output of the forward simulation approximated the angle data reported by. The accuracy and effectiveness of the analysis sequence proposed and the model response obtained using two distinct musculoskeletal models were verified and analysed with respect to the kinesiology of normal walking.

Alteration of mood state after a single bout of noncompetitive and competitive exercise programs

This study evaluated the effects of three popular physical activities on the psychological well-being of university students. 44 students in three physical activity classes enrolled in the Fitness for Life Program at Montana State University which included circuit training, weight training, and racquetball were administered the Profile of Mood States scale 5 min. before and 5 min. after one bout of physical activity. Two of the three activities appeared to be associated positively with scores on certain subscales. The results supported positive psychological well-being of students after physical activity. Implications for research are presented.

Audiologic aspects of the search for DFNA20: a gene causing late-onset, progressive, sensorineural hearing loss

OBJECTIVE

The purpose of this research was to identify the gene responsible for a novel form of nonsyndromic, late-onset, bilateral, progressive, sensorineural hearing loss in a Michigan family of English descent. This report describes the audiologic aspects of the search.

DESIGN

Fifty-eight members of the family served as subjects for the study. Family pedigree information was gathered from family interviews, family records, birth and death registration records and census data. Audiologic evaluation was used to describe the hearing loss (phenotype) and classify family members as affected or unaffected based on hearing status. These data then were used in a linkage analysis, a process in which the inheritance of a trait is compared with the inheritance of genetic markers and statistically significant associations are sought.

RESULTS

The team mapped the hearing loss to the long arm of chromosome 17 at band 17q25. The pattern of inheritance is autosomal dominant. The search for the gene is continuing using a candidate gene approach.

CONCLUSIONS

The hearing loss demonstrated by this mid-Michigan family is a novel form of nonsyndromic, genetic, late-onset, bilateral, progressive, sensorineural hearing loss. The locus of the gene, the 20th for autosomal dominant hearing loss, is at band 17q25 of chromosome 17.

Assessing competence to refuse medical treatment

Doctors have a duty to ensure that patients in their care who refuse medical treatment are competent to do so. Doctors who comply with an incompetent patient's refusal of treatment risk harm to the patient and are breaching their duty of care. On the other hand, doctors who treat a competent patient against the patient's will violate his or her autonomy and commit a battery. The test of competence is a legal one, with the courts being the final arbiters in cases of doubt. Assessment of competence involves a three-step process of determining whether the patient (a) can comprehend and retain relevant information, (b) believes the information, and (c) can weigh the information in the balance and arrive at a choice. Asking patients a few simple questions can help doctors assess their competence.

Hospital at home services for acute exacerbation of chronic obstructive pulmonary disease: a survey of British practice

OBJECTIVES

To identify the prevalence of and attitudes towards hospital at home services for acute exacerbation of chronic obstructive pulmonary disease (COPD) in Great Britain. To identify the models of service in existence, in particular staff numbers and the workload experienced.

DESIGN

A postal survey was used to locate existing schemes. Telephone interviews were conducted with each of the hospital at home services identified.

SUBJECTS & SETTING

A questionnaire was sent to one consultant in each of 223 respiratory departments in Great Britain. Thirty six departments were subsequently contacted by telephone.

OUTCOME MEASURES

Awareness and prevalence of hospital at home services. Perceived problems with starting a service. Details of organisation of existing services.

RESULTS

We received 186 replies to the postal questionnaire. Of these respiratory departments, 179 (96%) were aware of hospital at home services for acute exacerbation of COPD and, in November 1999, 30 (16%) were running such a service. Difficulty in obtaining funding was the main reason for not setting up a service rather than lack of evidence of benefit or unsuitability of local circumstances. Median staffing level was two nurses (range one to six) looking after a median number of new patients of five per week (range 0.5 to 12). There was wide variation in the organisation of services.

CONCLUSIONS

Despite lack of objective evidence of effectiveness, there was a high level of awareness of and interest in starting hospital at home services for acute exacerbation of COPD in British respiratory departments when assessed in November 1999.

Disseminated intravascular coagulation (DIC)

Disseminated intravascular coagulation (DIC) is a condition that is seen in critical care areas in association with a number of precipitating conditions. DIC is often described as a paradoxical disease process of concurrent haemorrhage and thrombus formation, resulting in a range of clinical manifestations related to end organ ischaemia. This article will discuss the coagulation cascade as a basis for understanding the aetiology and pathophysiology of DIC. The discourse surrounding medical treatment will be highlighted to enable bedside nurses to understand the divergent orders they may receive from physicians for different patients. Management of the patient experiencing DIC will be approached from a multidisciplinary focus, as well as highlighting the specific nursing considerations and alternatives from an independent focus.

Cholinergic modulation of covert attention in the rat

RATIONALE

Nicotine is known to facilitate attentional processing, but its role in processing spatial and non-spatial cues is not well established in rodents.

OBJECTIVE

These experiments tested the hypothesis that nicotine facilitates the orienting of attention in space but has no effect on non-spatial cues and that the benefits are blocked by the nicotinic antagonist mecamylamine.

METHODS

Eight male rats were trained to insert their noses in an opening, which triggered the presentation of cue and target lights in a modified covert orienting task. Four types of trials were presented: valid cues (cue and target lights on the same side of the nose hole), invalid cues (cue and targets on opposite sides), double cues (both cue lights illuminated, target on either side), and no cue (cue lights omitted, targets on either side). The reaction time required to withdraw the nose from the fixation hole (RT) and the time for the rat to move to the feeder (MT) were measured.

RESULTS

Nicotine decreased all RTs in a dose-dependent manner but significantly lowered the invalid cue RTs and the validity effect (invalid-valid cue RT). Mecamylamine slowed RTs in a dose-dependent fashion and reduced the validity effect by significantly slowing the valid cue RTs. With mixtures of a fixed strength of nicotine and an increasing dose of mecamylamine, RTs showed nicotine-like effects at low doses and mecamylamine-like effects at high doses. Neither of these drugs had a major effect on non-orienting trials (double and no cue RTs), and the alerting effect (no cue RTs-double cue RTs).

CONCLUSIONS

Taken together with recent work in humans and non-human primates, these results suggest that the nicotinic cholinergic modulation of visual covert orienting is conserved across species despite different ecological niches.

Influence of antioxidants and the CYP1A1 isoleucine to valine polymorphism on the smoking--lung cancer association

To evaluate the association between CYP1A1 genotype and lung cancer risk and to assess the effect of CYP1A1 genotype and antioxidant supplementation on the smoking--lung cancer relationship we conducted a case-control study nested within a large cancer prevention trial cohort. Controls (n = 324) were matched to cases (n = 282) on age (+/- 5 years), intervention group and study clinic in a 1:1 ratio, using incidence density sampling. Genotype was determined by a PCR-based method and logistic regression was used to calculate relative risk estimates. Overall, we found no association between CYP1A1 genotype and lung cancer risk. CYP1A1 genotype did not modify the effect of smoking on lung cancer risk. However, in an examination of subgroups defined by randomized intervention assignment our findings suggest that alpha-tocopherol supplementation may reduce the risk of lung cancer associated with cumulative smoking exposure regardless of CYP1A1 genotype with the greatest effect seen among those with the variant CYP1A1 allele.

A phase II multicenter study of CAMPATH-1H antibody in previously treated patients with nonbulky non-Hodgkin's lymphoma

CAMPATH-1H is a humanized antilymphocyte monoclonal antibody (mAb) directed against the CD52 antigen expressed on normal and malignant lymphocytes. We report the results of a multicenter phase II trial using intravenous CAMPATH-1H in previously treated patients with nonbulky non-Hodgkin's lymphoma (NHL) or minimal residual NHL. Sixteen previously treated patients with nonbulky NHL and two patients with minimal residual NHL, were treated with CAMPATH-1H. Changes in peripheral blood lymphocyte subsets were analyzed by multiparameter flow cytometric techniques in eleven patients. The 18 patients enrolled in the studies received CAMPATH-1H for a median duration of 6 weeks (range, 3 to 14 weeks), and a median cumulative dose of 470 mg (range, 180 to 1185 mg). Two of the sixteen patients with nonbulky NHL achieved a complete response (CR) and one patient achieved a partial response (PR). One of the two patients with minimal residual NHL achieved a molecular CR. Infusional complications were seen with the majority of patients but were more common with initial infusions. Significant hematologic toxicity was also observed with grade (3/4) thrombocytopenia (n=10), grade (3/4) neutropenia (n=4) and grade 3 anemia (n=3). Due to excessive infectious complications observed with the patients enrolled, the trials were terminated early. Anti-tumor activity was demonstrated in a small subset of previously treated low-grade lymphoma patients with nonbulky or minimal residual disease. Future studies evaluating the effect of different drug schedules, modes of mAb administration, and concurrent use of prophylactic antibiotics/antiviral/antifungal agents to optimize anti-tumor activity and limit infectious toxicities are planned.

Six-year follow-up after Helicobacter pylori eradication in peptic ulcer disease

BACKGROUND

The longterm outlook after Helicobacter pylori (H. pylori) eradication in peptic ulcer disease is unclear.

AIM

This study documents H. pylori recurrence, dyspeptic symptoms and anti-secretory therapy in peptic ulcer patients six years or more after H. pylori eradication.

METHODS

Peptic ulcer patients with H. pylori eradication between 1990 and 1992 were included. Infection recurrence was diagnosed by 13-carbon urea breath test (UBT). Dyspeptic symptoms and anti-secretory therapy use were assessed by questionnaire.

RESULTS

Sixty-one patients completed the study protocol. Mean follow-up after eradication was 6.1 years (range 4.8-8.3). Four patients had a positive UBT. H. pylori recurrence rate was 6.6% or 0.02% per patient per year. Forty-two patients (69%) had dyspeptic symptoms. Heartburn and belching were more common than pain (p<0.001). All four patients with H. pylori recurrence had symptoms compared with 38 of 57 H. pylori-negative patients (p>0.05). Ten of 61 patients (16.4%) were taking anti-secretory therapy and their dyspepsia scores were higher.

CONCLUSIONS

Despite a low H. pylori recurrence rate, longterm dyspeptic symptoms were common in peptic ulcer patients after H. pylori eradication. The symptoms are mainly reflux in type and require anti-secretory therapy in only a minority of patients.

The influence of spirituality on substance use of college students

OBJECTIVES

The issue of substance use and the problems resulting from that use has become a major concern in the United States. The past decade has seen several new trends in substance use by college students and an increase in the effort to try and determine factors that may ameliorate the problem. Spirituality is one possible factor that may have some role in the phenomenon. Some research has been conducted on the relationship of spirituality to substance use but the results are mostly descriptive and concerned with religiosity rather than spirituality. The purpose of this study was to explore the relationship between a student's spiritual and religious beliefs and the impact of those beliefs on the decision to use substances.

METHOD

A sample of 337 university students was surveyed using the CORE Alcohol and Drug Survey and several supplemental questions.

RESULTS

In general, spirituality had a moderate buffering effect upon the decision to use alcohol and marijuana. This general protective effect exists for both alcohol use and binge drinking but dissipated as the students reached upper-class levels.

CONCLUSION

Spirituality may play a significant role in the decision of college students to use substances. Further research should focus on this important factor. Also, implementation of spiritual aspects into university prevention and treatment programs may help boost efficacy rates.

Activation of MHC class I, II, and CD40 gene expression by histone deacetylase inhibitors

Epigenetic mechanisms are involved in regulating chromatin structure and gene expression through repression. In this study, we show that histone deacetylase inhibitors (DAIs) that alter the acetylation of histones in chromatin enhance the expression of several genes on tumor cells including: MHC class I, II, and the costimulatory molecule CD40. Enhanced transcription results in a significant increase in protein expression on the tumor cell surface, and expression can be elicited on some tumors that are unresponsive to IFN-gamma. The magnitude of induction of these genes cannot be explained by the effect of DAIs on the cell cycle or enhanced apoptosis. Induction of class II genes by DAIs was accompanied by activation of a repressed class II transactivator gene in a plasma cell tumor but, in several other tumor cell lines, class II was induced in the apparent absence of class II transactivator transcripts. These findings also suggest that the abnormalities observed in some tumors in the expression of genes critical to tumor immunity may result from epigenetic alterations in chromatin and gene regulation in addition to well-established mutational mechanisms.

Interobserver agreement among sleep scorers from different centers in a large dataset

STUDY OBJECTIVES

To evaluate epoch by epoch agreement in sleep stage assignment between scorers from different laboratories.

DESIGN

N/A.

METHODS

62 NPSGs were selected for analysis from 3 sleep centers (38 diagnostic studies for sleep disordered breathing [SDB], 10 studies during CPAP titration, and 14 studies in subjects with no sleep related complaints or sleep pathology). The sleep recording montage consisted of at least 2 EEG leads, left and right EOG and a submental EMG. Scoring was performed manually by 5 experienced sleep technologists. No scorer had knowledge of any other scorers' results. Agreement was tabulated both for sleep stage distribution and on an epoch by epoch basis for the entire data set and the normal and SDB subsets.

MEASUREMENTS AND RESULTS

The mean epoch by epoch agreement between scorers for all records was 73% (range 67-82%). Agreements were higher in the normal subset (mean 76%, range 65-85%) than in the SDB subset (mean 71%, range 65-78%). There was significant variability in agreement between records and between pairs of scorers. Overall, 75% of epochs had at least 4 of the 5 scorers in agreement on the sleep stage and 96% of epochs had agreement of at least 3 of the 5 scorers.

CONCLUSIONS

The level of agreement in sleep stage assignment varies between scorers, by diagnosis, and by record. The level of agreement between laboratories is lower than what can be maintained between scorers within the same laboratory. This warrants caution when comparing data scored in separate laboratories. The lower agreement in SDB patients supports the generally held view that sleep fragmentation makes application of the R&K rules less reliable.

Early discharge for patients with exacerbations of chronic obstructive pulmonary disease: a randomized controlled trial

BACKGROUND

We have previously reported the use of a hospital based respiratory nurse service (Acute Respiratory Assessment Service, ARAS) to support home treatment of patients with exacerbations of chronic obstructive pulmonary disease (COPD). A controlled trial was undertaken to compare early discharge with home treatment supported by respiratory nurses with conventional hospital management of patients admitted with exacerbations of COPD.

METHODS

Patients with COPD admitted as emergencies were identified the next working day. They were eligible for inclusion in the study if the differential diagnosis included an exacerbation of COPD, but were excluded if other medical conditions or acidotic respiratory failure required inpatient investigation or management. Of 360 patients reviewed, 209 were being assessed for other active medical problems and were excluded, 33 potential participants were already involved in research studies and so were ineligible, and 37 did not wish to participate in the study. Eighty one patients were randomised to receive conventional inpatient care (n=40) or to planned early discharge the next working day (n=41). Those discharged early continued treatment at home under the supervision of specialist respiratory nurses. Outcome measures were readmission, additional hospital days, and deaths within 60 days of initial admission. Process measures included number of visits, duration of follow up by the respiratory nurse, and additional treatment provided to support early discharge.

RESULTS

On an intention to treat basis, a policy of early discharge reduced inpatient stay from a mean of 6.1 (range 1-13) days with conventional management to 3.2 (1-16) days with an early discharge policy. Twelve patients (30% conventional management, 29.3% early discharge) were readmitted in each group giving a mean difference in readmission of 0.7% (95% CI of the difference -19.2 to 20.6). In the conventional management group readmitted patients spent a mean of 8.75 additional days in hospital compared with 7.83 days in the early discharge group, giving a mean difference of 0.92 days (95% CI of the difference -6.5 to 8.3). There were two deaths (5%) in the conventional management group and one (2.4%) in the early discharge group, a mean difference of 2.6% (95% CI of the difference -5.7 to 10.8).

CONCLUSIONS

Patients with acute exacerbations of COPD uncomplicated by acidotic respiratory failure or other medical problems can be discharged home earlier than is current practice with support by visiting respiratory nurses. No difference was found in the subsequent need for readmission.