The combination of SKY and specific loci detection with FISH or immunostaining

Spectral karyotyping (SKY) represents an effective tool to detect individual chromosomes and analyze major karyotype abnormalities within an entire genome. We have tested the feasibility of combining SKY and FISH/protein detection in order to combine SKY's unique abilities with specific loci detection. Our experimental results demonstrate that various combined protocols involving SKY, FISH and immunostaining work well when proper procedures are used. This combined approach allows the tracking of key genes or targeted chromosome regions while monitoring changes throughout the whole genome. It is particularly useful when simultaneously monitoring the behavior of both protein complexes and DNA loci within the genome. The details of this methodology are described and systematically tested in this communication.

Neuropsychological profiles of children with type 1 diabetes 6 years after disease onset

OBJECTIVE

To describe neuropsychological profiles and their relationship to metabolic control in children with type 1 diabetes 6 years after the onset of disease.

RESEARCH DESIGN AND METHODS

Children with type 1 diabetes (n = 90), aged 6-17 years, who had previously been assessed soon after diagnosis and 2 years later, were reevaluated 6 years after the onset of disease. Their neuropsychological profiles were compared with those of individuals in a community control group (n = 84), who had been assessed at similar intervals. Relationships between illness variables, such as age at the onset of disease and metabolic control history, and neuropsychological status were also examined.

RESULTS

Six years after onset of disease, children with type 1 diabetes performed more poorly than control subjects on measures of intelligence, attention, processing speed, long-term memory, and executive skills. Attention, processing speed, and executive skills were particularly affected in children with onset of disease before 4 years of age, whereas severe hypoglycemia was associated with lower verbal and full-scale intelligence quotient scores.

CONCLUSIONS

Neuropsychological profiles of children with type 1 diabetes 6 years after the onset of disease are consistent with subtle compromise of anterior and medial temporal brain regions. Severe hypoglycemia, particularly in very young children, is the most plausible explanation for neuropsychological deficits, but the contributory role of chronic hyperglycemia warrants further exploration.

Modified constraint induced therapy: a randomized feasibility and efficacy study

This case series examined the feasibility and efficacy of a modified constraint induced therapy (CIT) protocol administered on an outpatient basis. The Fugl-Meyer Assessment of Motor Recovery After Stroke (Fugl), Action Research Arm Test (ARA), Wolf Motor Function Test (WMFT), and Motor Activity Log (MAL) were administered to six patients between 2 and 6 months poststroke (CVA) exhibiting stable motor deficits and learned nonuse of the affected limb. Two patients then participated in half-hour physical and occupational therapy sessions three times/week for 10 weeks. During the same period, their unaffected arms and hands were restrained 5 days/week during 5 hours identified as times of frequent use. Two other patients received regular therapy and two control patients received no therapy. The ARA, Fugl, WMFT, and MAL were again administered after 10 weeks. Patients receiving modified CIT exhibited substantial improvements on the Fugl, ARA, and WMFT, as well as increases in amount and quality of use of the limb using the MAL. Patients receiving traditional or no therapy exhibited no improvements. Results suggest that modified CIT may be an efficacious method of improving function and use of the affected arms of patients exhibiting learned nonuse.

Management of necrotizing pancreatitis

Infection complicating pancreatic necrosis leads to persisting sepsis, multiple organ dysfunction syndrome and accounts for about half the deaths that occur following acute pancreatitis. Severe cases due to gallstones require urgent endoscopic sphincterotomy. Patients with pancreatic necrosis should be followed with serial contrast enhanced computed tomography (CE-CT) and if infection is suspected fine needle aspiration of the necrotic area for bacteriology (FNAB) should be undertaken. Treatment of sterile necrosis should initially be non-operative. In the presence of infection necrosectomy is indicated. Although traditionally this has been by open surgery, minimally invasive procedures are a promising new alternative. There are many unresolved issues in the management of pancreatic necrosis. These include, the use of antibiotic prophylaxis, the precise indications for and frequency of repeat CE-CT and FNAB, and the role of enteral feeding.

Genotypic correlates of a virologic response to stavudine after zidovudine monotherapy

Prior evidence suggests that resistance to zidovudine (ZDV) confers some degree of cross-resistance to stavudine (d4T), but no genotypic correlates of clinical d4T susceptibility and resistance exist. To identify the genotypic correlates of a virologic response to d4T, reverse transcriptase (RT) sequencing of archived plasma HIV isolates was performed on 31 subjects who received d4T monotherapy in the AIDS Clinical Trials Group 302 study, all of whom received more than 3 years of ZDV monotherapy. Baseline characteristics and all RT mutations were analyzed for impact on virologic suppression. Eight of 31 subjects (27%) achieved a virologic response of greater than 0.3 log reduction in plasma HIV RNA after 8 weeks of d4T. Responders were more likely to have lower median baseline viral loads (4.2 vs. 4.7; p =.01) and a trend toward fewer ZDV-associated mutations (median: 1 vs. 2; p =.09). No subject with greater than one ZDV mutation had a virologic response to d4T. Seven of the 8 responders had only a K70R mutation at baseline. We conclude that in patients with prior ZDV treatment, those with only one ZDV mutation, particularly at position 70, can still get reasonable virologic activity from d4T. Those with more mutations are not likely to have much benefit.

Airway smooth muscle cell proliferation is increased in asthma

Increased airway smooth muscle (ASM) within the bronchial wall of asthmatic patients has been well documented and is likely to be the result of increased muscle proliferation. We have for the first time been able to culture ASM cells from asthmatic patients and to compare their proliferation rate with that of nonasthmatic patients. Asthmatic ASM cell cultures (n = 12) were established from explanted lungs and endobronchial biopsies. Nonasthmatic ASM cells (n = 10) were obtained from explanted tissue from patients with no airway disease, emphysema, carcinoma, and fibrosing alveolitis. Cell counts, tritiated thymidine incorporation, and cell cycle analysis were conducted over 7 d. Asthmatic ASM cell numbers at Days 3, 5, and 7 were significantly higher than corresponding values for nonasthmatic cells (p < 0.05). Tritiated thymidine incorporation was increased 3.2-fold in asthmatic cells compared with nonasthmatic cells within the first 24 h (p = 0.026). Flow cytometric analysis of DNA content on Days 1 and 2 revealed that a significantly greater percentage of asthmatic ASM cells were in the G2 + M phase (p < 0.05). This study shows for the first time that proliferation of ASM cells is increased in patients with asthma and provides evidence for an intrinsic abnormality in the ASM cell in this disease.

KEYWORDS

asthma; human airway smooth muscle; cell culture; cell proliferation; hyperplasia

Risk of psychiatric disorders among individuals reporting same-sex sexual partners in the National Comorbidity Survey

OBJECTIVES

This study examined the risk of psychiatric disorders among individuals with same-sex sexual partners.

METHODS

Data are from the National Comorbidity Survey, a nationally representative household survey. Respondents were asked the number of women and men with whom they had sexual intercourse in the past 5 years. Psychiatric disorders according to Diagnostic and Statistical Manual of Mental Disorders, Revised Third Edition (DSM-III-R) criteria were assessed with a modified version of the Composite International Diagnostic Interview.

RESULTS

A total of 2.1% of men and 1.5% of women reported 1 or more same-sex sexual partners in the past 5 years. These respondents had higher 12-month prevalences of anxiety, mood, and substance use disorders and of suicidal thoughts and plans than did respondents with opposite-sex partners only. Decomposition showed that the elevated same-sex 12-month prevalences were largely due to higher lifetime prevalences. Ages at onset and persistence of disorders did not differ between the same-sex and opposite-sex subsamples.

CONCLUSIONS

Homosexual orientation, defined as having same-sex sexual partners, is associated with a general elevation of risk for anxiety, mood, and substance use disorders and for suicidal thoughts and plans. Further research is needed to replicate and explore the causal mechanisms underlying this association.

Spectral karyotyping (SKY) of mouse meiotic chromosomes

The spectral karyotyping procedure of in situ hybridization with chromosome-specific probes assigns a unique colour code to each of the 21 mouse mitotic chromosomes. We have adapted this procedure to meiotic prophase chromosomes, and the results show that each of the pachytene or metaphase I bivalents can be identified. This technique has the potential to recognize synaptic anomalies and chromosome-specific structural and behavioural characteristics. We confirm these potentials by the recognition of the heterologous synapsis of the X and Y chromosomes and by the variances of synaptonemal complex lengths for each of the colour-coded bivalents in eight prophase nuclei.

Outcome of long-stay intensive care patients

OBJECTIVES

To assess the numbers, characteristics and outcome for patients requiring long-term intensive care.

DESIGN AND SETTING

Observational cohort study in 23 Scottish intensive care units over a 3-year period.

PATIENTS AND PARTICIPANTS

323 patients with an ICU stay of 30 days or more.

MEASUREMENTS AND RESULTS

Although representing only 1.6% of patients, those with long stays occupied 15.7% of bed-days. Hospital survival among these patients was 59.9%. With the available data it was not possible to discriminate survivors from non-survivors.

CONCLUSIONS

Since these patients have a relatively high hospital survival, resources should not be withheld from them on the basis of prolonged ICU stay alone, even in countries with limited ICU provision.

Spectral karyotyping of mouse cell line WMP2

We have evaluated the mouse cell line WMP2 using both GTG-banding analysis and spectral karyotyping to verify the reliability of using this established cell line derived from WMP/WMP mice. The WMP cell lines contain easily identifiable metacentric fusion chromosomes and are used extensively for gene mapping. Because of karyotypical changes in the WMP1 cell line, WMP2 was examined. Our results demonstrate that WMP2 is stable during culture, and the karyotype is simple and easy to use. Based on the findings discussed in this paper, we recommend the use of the WMP2 cell line for future prospective gene mapping in the mouse.

Intravenous amiodarone in intensive care. Time for a reappraisal?

Amiodarone is widely used in intensive care units for the treatment of a variety of arrhythmias. It is currently the drug of choice for supraventricular tachyarrhythmias in many units because of its combination of efficacy and safety. This review summarises the current state of knowledge regarding the short-term administration of intravenous amiodarone to control arrhythmias in perioperative, coronary care and intensive care patients. It outlines the electrophysiology, haemodynamics, pharmacokinetics and toxicity of the drug. In particular, it examines the recent concerns regarding acute pulmonary toxicity.

Consistency in the observation of features used to classify duct carcinoma in situ (DCIS) of the breast

AIM

To determine interobserver and intra-observer agreement in the assessment of cytological grade and intraduct necrosis in pure duct carcinoma in situ (DCIS) of the breast.

METHODS

Sixty unselected cases with illustrated diagnostic criteria were circulated to 19 practising histopathologists.

RESULTS

Overall agreement was moderate for cytological grade in three categories: 71% agreement; weighted kappa (kappa w), 0.36; intraduct necrosis in three categories (absent, present, extensive): 76% agreement; kappa w, 0.57; and the Van Nuys classification system: 73% agreement; kappa w, 0.48. Agreement was no better among observers participating in the National External Quality Assurance Programme. Intra-observer agreement for cytological assessment (69.6% agreement; kappa w, 0.52) and intraduct necrosis (68.3% agreement; kappa w, 0.48) was moderate, suggesting that individual variation rather than precision of criteria contributes to the lack of agreement.

CONCLUSIONS

Moderate agreement on observations can be achieved by non-specialist pathologists, with better agreement on necrosis than cytological grade. There was evidence of consistent individual bias towards over or under scoring cytological grade, which could be corrected with adequate and prompt feedback.

Virologic and CD4+ cell responses to new nucleoside regimens: switching to stavudine or adding lamivudine after prolonged zidovudine treatment of human immunodeficiency virus infection. ACTG 302 Study Team. AIDS Clinical Trials Group

Clinical benefit of zidovudine alone in the treatment of HIV infection wanes after several years, with decreasing CD4+ cell numbers and increasing HIV RNA in plasma. To develop treatment strategies following prolonged zidovudine treatment, 92 subjects from the AIDS Clinical Trials Group (ACTG) 175 study after a median of 3.6 years of zidovudine monotherapy were randomized to treatment with stavudine or zidovudine and lamivudine. Evaluation of long-term changes, the average of 40- and 48-week HIV plasma RNA, demonstrated that lamivudine and zidovudine provided significantly greater virologic suppression compared with stavudine (mean decrease 0.70 versus 0.18 1og10 copies/ml,p = 0.003). Twenty-nine percent of zidovudine plus lamivudine recipients had HIV RNA levels below 500 copies per milliliter at 48 weeks as compared with 4% of stavudine recipients (p = 0.02). Both regimens significantly increased CD4+ cell numbers, the means of weeks 40 and 48 rose to 49 and 36 CD4+ cells per cubic millimeter among zidovudine plus lamivudine and stavudine recipients, respectively. Treatments were well tolerated and only 3 of 92 subjects died or developed AIDS within 48 weeks. In zidovudine-experienced subjects, addition of lamivudine resulted in significantly decreased plasma HIV RNA levels at 48 weeks compared with treatment with stavudine alone.

Ran alters nuclear pore complex conformation

Transport across the nuclear membranes occurs through the nuclear pore complex (NPC), and is mediated by soluble transport factors including Ran, a small GTPase that is generally GDP-bound during import and GTP-bound for export. The dynamic nature of the NPC structure suggests a possible active role for it in driving translocation. Here we show that RanGTP but not RanGDP causes alterations of NPC structure when injected into the cytoplasm of Xenopus oocytes, including compaction of the NPC and extension of the cytoplasmic filaments. RanGTP caused accumulation of nucleoplasmin-gold along the length of extended cytoplasmic filaments, whereas RanGDP caused accumulation around the cytoplasmic rim of the NPC. This suggests a possible role for Ran in altering the conformation of the cytoplasmic filaments during transport.

The use of electron microscopy in the investigation of the ultrastructural morphology of immune thrombocytopenic purpura platelets

Ultrastructural studies have proven useful for the accurate identification and classification of certain lymphoid and hematopoietic disorders; however, the value of electron microscopy in the diagnosis and clinical management of platelet pathology is less well defined. Electron microscopy has been used to evaluate inherited platelet disorders. In these disorders, certain platelet structural defects can be characteristic. Recently, we investigated the ultrastructural morphology and immunogold localization of IgG in platelets from patients with idiopathic thrombocytopenic purpura (ITP). The accelerated platelet destruction of ITP is mediated by antiplatelet autoantibodies directed against platelet surface glycoproteins and by the functional capacity of the reticuloendothelial system. The basic dysregulation that occurs in these patients remains unexplained. Traditionally, laboratory investigation of ITP has focused on the development of serologic assays to measure the autoantibodies. As an alternative investigative approach, determination of the immunomorphologic characteristics of platelet-associated IgG (PAIgG) in ITP platelets may prove useful in the diagnosis or clinical management of patients with ITP. Our results showed that the ultrastructural morphology of ITP platelets is similar to that observed for normal platelets. No structural abnormalities are observed in ITP platelets. Immunogold labeling of IgG within alpha-granules of ITP platelets is significantly higher than that of normal platelets. Additionally, in some ITP platelets, immunogold labeling is also observed on the platelet surface and within channels of the open-cannalicular system. In comparison, immunogold labeling of these structures in normal platelets, is rare, or absent. In conclusion, electron microscopic studies should contribute to furthering our understanding of this common autoimmune disorder, and may provide possible biological explanations for the increased levels of PAIgG in platelets from patients with ITP.

Morphological analysis of microparticle generation in heparin-induced thrombocytopenia

Heparin-induced thrombocytopenia (HIT) with thrombosis is a serious complication of heparin use. HIT sera can generate platelet-derived microparticles, which are produced in a heparin-dependent manner and are hypothesized to be important initial pathological participants because they promote vascular occlusion. To date, microparticles have been studied using flow cytometric techniques. However, it is uncertain whether the small-sized material seen in flow cytometric studies represents true platelet microparticles shed from activated platelets or whether they are platelets that have contracted after releasing their internal components. This report describes a morphological investigation of platelet-derived microparticles in HIT using, among other techniques, confocal, scanning electron, and transmission electron microscopy. Following incubation with HIT sera, the existence of small membrane-bound vesicles in the milieu of activated platelets was demonstrated. A population of microparticles, expressing platelet-specific glycoproteins, was separated from platelets by centrifugation over a sucrose layer. These microparticles had identical flow cytometric profiles, size heterogeneity, and GPIb(alpha) and GPIIb/IIIa staining intensity as the microparticle population in unfractionated samples. When microparticles were generated in situ and fixed onto grids, they were demonstrated to be distinct membrane-bound vesicles that originated near the platelet body and terminal ends of pseudopods on activated platelets. These microparticles appeared to be generated by localized swelling, budding, and release. Collectively, these morphological studies document the existence of true microparticles in platelets activated by HIT sera. The microparticles may play an important role in the pathogenesis of HIT.

Video analysis of emergency medicine residents performing rapid-sequence intubations

The purpose of this study was to evaluate Emergency Medicine resident physicians' compliance with our institution's rapid sequence intubation (RSI) protocol by the use of videotape analysis. We conducted a prospective, observational study of Emergency Medicine resident physicians (EM 1,2,3) as they were videotaped performing RSI on medical and trauma patients. The videotapes were reviewed by the study investigators to assess the rates of deviation from our standard RSI protocol. Forty-four RSIs performed by 33 residents were studied. The most common deviations from our standard RSI protocol concerned proper use of the Sellick maneuver (45%) and use of the end-tidal CO(2) detector (34%). Videotape analysis provides an objective measure of Emergency Medicine resident performance of RSI.

Phytochrome regulation of phytochrome A mRNA levels in the model short-day-plant Pharbitis nil

The exposure of dark-grown Pharbitis nil seedlings to continuous R induces a rapid decrease in PHYA mRNA abundance with a half-life of about 2 h. A 5 min R pulse also induces this decline, and the effect is partially reversible by subsequent FR irradiation, confirming that the regulation of expression is mediated via the Pfr form of a phytochrome. When de-etiolated seedlings are returned to darkness after a W photoperiod, PHYA mRNA slowly reaccumulates from 20% to 50% of the dark level within 24 h. The rate of reaccumulation is greatly accelerated by the removal of Pfr with a FR pulse, resulting in reaccumulation to 100% within approximately 11 h. Without FR irradiation PHYA mRNA expression remains fully repressed for at least 11 h after the end of the photoperiod, suggesting that the controlling Pfr is highly stable.

Substrate specificity determinants of the checkpoint protein kinase Chk1

The Chk1 protein kinase plays a critical role in a DNA damage checkpoint pathway conserved between fission yeast and animals. We have developed a quantitative assay for Chk1 activity, using a peptide derived from a region of Xenopus Cdc25C containing Ser-287, a known target of Chk1. Variants of this peptide were used to determine the residues involved in substrate recognition by Chk1, revealing the phosphorylation motif Phi-X-beta-X-X-(S/T)*, where * indicates the phosphorylated residue, Phi is a hydrophobic residue (M>I>L>V), beta is a basic residue (R>K) and X is any amino acid. This motif suggests that Chk1 is a member of a group of stress-response protein kinases which phosphorylate target proteins with related specificities.

Association of diarrhoea and upper respiratory infections with weight and height gains in Bangladeshi children aged 5 to 11 years

INTRODUCTION

The association between infection and growth delay is not well documented in school-age children in developing countries. We conducted a prospective cohort study to examine the association between infectious disease and weight and height gains among Bangladeshi children.

METHODS

A one-year follow-up study was performed to elucidate the determinants and consequences of physical growth of children under five years of age. The study included 135 households randomly selected from four villages in the Matlab area.

RESULTS

The most frequent infections were upper respiratory infections (mean = 4 episodes or 27 days per year) followed by non-dysenteric diarrhoea (mean = 2.3 episodes or 15 days per year) and dysentery (mean = 0.2 episodes or 2 days per year). The number of episodes and their duration decreased significantly with age. Over a 12-month period the mean weight gain was 1.3 kg and the mean increase in height was 2.9 cm. The total number of days when diarrhoea occurred was negatively associated with annual weight gain (regression coefficient beta = -7 g per day, P = 0.02), with adjustment for age, sex, energy and protein intake, and household land ownership. The incidence of diarrhoeal disease was significantly associated with weight gain in intermediate models but only marginally associated with it in the final multivariate model (P = 0.08). Neither the incidence nor the duration of upper respiratory infections was associated with weight gain. Height gain was not significantly associated with the duration or incidence of either category of illness. Diarrhoea was a significant correlate of retarded weight gain among children above preschool age, whereas upper respiratory infections were not.

DISCUSSION

Diarrhoeal morbidity slowed growth in children well beyond the weaning age, suggesting that increased attention should be given to the study of the continuous impact of diarrhoea in children aged over 5 years. An understanding of the determinants of growth in school-age children in developing countries would maximize the health and developmental outcomes that are the target of international child survival strategies at younger ages.

Zidovudine (AZT) versus AZT plus didanosine (ddI) versus AZT plus zalcitabine (ddC) in HIV infected adults

BACKGROUND

Zidovudine (AZT) monotherapy was the first antiretroviral drug to be tested widely. The next two drugs to be developed were didanosine (ddI) and zalcitabine (ddC).

OBJECTIVES

To assess the effects of zidovudine (AZT), zidovudine plus didanosine (ddI) and zidovudine plus zalcitabine (ddC) on HIV disease progression and survival.

SEARCH STRATEGY

Investigators and pharmaceutical companies were contacted, and MEDLINE searches were supplemented by searching conference abstracts.

SELECTION CRITERIA

Randomised controlled trials comparing any two of AZT plus ddI, AZT plus ddC or AZT alone in participants with or without AIDS which collected information on deaths and new AIDS events.

DATA COLLECTION AND ANALYSIS

Individual patient data with, wherever possible, follow-up obtained beyond that previously published were obtained and checked for internal consistency and consistency with any published reports; any apparent discrepancies were resolved with the trialists. Time to death and to disease progression (defined as a new AIDS-defining event or prior death) were analysed on an intention to treat basis, stratified to avoid direct comparisons between participants in different trials.

MAIN RESULTS

Six trials were included in the meta-analysis. During a median follow-up of 29 months, 2904 individuals progressed, of whom 1850 died. The addition of ddI to AZT delayed both progression (RR 0.74; 95% CI 0.67 to 0.82, P<0.0001) and death (RR 0.72; 95% CI 0.64 to 0.82, P<0.0001). Likewise, the addition of ddC to AZT also delayed progression (RR 0. 86; 95% CI 0.78 to 0.94, P=0.001) and death (RR 0.87; 95% CI 0.77 to 0.98, P=0.02). After 3 years the estimated percentages alive and without a new AIDS event were 53% for AZT+ddI, 49% for AZT+ddC and 44% for AZT alone; the percentages alive were 68%, 63% and 59% respectively. Five of the six trials involved randomised comparisons of AZT+ddI versus AZT+ddC: in these, the AZT+ddI regimen had greater effects on disease progression (P=0.004) and death (P=0.009).

REVIEWER'S CONCLUSIONS

The use of ddI and, to a lesser extent, ddC delayed both HIV disease progression and death, at least when added to AZT.

Immediate versus deferred zidovudine (AZT) in asymptomatic or mildly symptomatic HIV infected adults

BACKGROUND

Zidovudine (AZT) monotherapy was the first antiretroviral drug to be tested widely. Subsequent trials in asymptomatic or early symptomatic HIV infection indicated short-term delays in disease progression with AZT, but not improved survival.

OBJECTIVES

To assess the effects of immediate versus deferred zidovudine (AZT) on HIV disease progression and survival.

SEARCH STRATEGY

Investigators and pharmaceutical companies were contacted, and MEDLINE searches were supplemented by searching conference abstracts.

SELECTION CRITERIA

Randomised controlled trials comparing immediate versus deferred AZT in participants without AIDS which prospectively collected deaths and new AIDS events.

DATA COLLECTION AND ANALYSIS

Individual patient data with, wherever possible, follow-up obtained beyond that previously published was obtained and checked for internal consistency and consistency with any published reports; any apparent discrepancies were resolved with the trialists. Time to death and to disease progression (defined as a new AIDS-defining event or prior death) were analysed on an intention to treat basis, stratified to avoid direct comparisons between participants in different trials.

MAIN RESULTS

Nine trials were included in the meta-analysis. During a median follow-up of 50 months, 1908 individuals developed disease progression, of whom 1351 died. In the deferred group, 61% started antiretroviral therapy (median time to therapy 28 months, which was AZT monotherapy in 94%). During the first year of follow-up immediate AZT halved the rate of disease progression (P<0.0001), increasing the probability of AIDS-free survival at one year from 96% to 98%, but this early benefit did not persist: after 6 years AIDS-free survival was 54% in both groups, and at no time was there any difference in overall survival, which at 6 years was 64% with immediate and 65% with deferred AZT (rate ratio [RR] 1.04, 95% confidence interval [CI] 0. 94 to 1.15).

REVIEWER'S CONCLUSIONS

Although immediate use of AZT halved disease progression during the first year, this effect was not sustained, and there was no improvement in survival in the short or long term.

Effects of the exposure of roots of Alnus glutinosa to light on flavonoids and nodulation

Exposure of the roots of Alnus glutinosa (L.) Gaertn. to white light stimulated within 5 days a substantial increase in the content of quercetin and kaempferol, two major flavonols in acid hydrolysates of both roots and root exudates. Both compounds were detected also in hydrolysates of root extracts of Myrica gale and Casuarina equisetifolia, the latter a species not nodulated by Frankia strains effective on Alnus. A 7-fold reduction in nodulation of seedlings 12 days after inoculation with Frankia preincubated for 24 h with kaempferol supported the possibility that flavonols might be involved in the regulation of nodulation. Nodulation of seedling roots that were inoculated with Frankia and then exposed to light was inhibited by 50% after 11 days compared with seedlings with darkened roots. This effect of light treatment was preceded by a 30-fold increase in quercetin and kaempferol. The inhibitory effects on nodulation of preincubation of Frankia with kaempferol persisted for 18 days after inoculation, but there was no significant effect on nodulation after prolonging exposure of the root system to light for 40 days. The data support indirectly the suggestion that the balance between stimulatory and inhibitory flavonoids in roots and root exudates may contribute to the regulation of nodulation of actinorhizal plants.Key words: Alnus glutinosa, flavonoids, Frankia, kaempferol, nodulation, roots.

Cerebral lateralization: relationship of language and ideomotor praxis

OBJECTIVE

To determine the relationship of language lateralization and hand preference to praxis performance following left and right hemispheric amobarbital-induced inactivations.

BACKGROUND

Patients who are aphasic from left cerebral dysfunction also frequently exhibit ideomotor apraxia in which they make temporal, spatial, and postural errors of learned skilled movements. However, hemispheric lateralization of the systems mediating ideomotor praxis in patients with atypical cerebral language dominance (i.e., bilateral or right hemispheric language function) remains uncertain.

METHODS

Subjects included 90 patients with intractable seizures who were undergoing the intracarotid amobarbital procedure (IAP) as part of their preoperative evaluation for epilepsy surgery. Hand preference was determined by the Benton Handedness Questionnaire. Praxis was assessed by the subject's performance when pantomiming the use of four pictured tools.

RESULTS

During left IAP, patients with typical language dominance made more ideomotor apraxic errors than did patients with atypical language dominance. During right IAP, patients with atypical language dominance made more ideomotor apraxic errors than did patients with typical language dominance. Overall, patients with atypical language dominance made fewer ideomotor apraxic errors than did patients with typical language dominance. These relationships were present irrespective of hand preference.

CONCLUSIONS

Language dominance is more closely associated with the laterality of temporal and spatial movement representations (i.e., ideomotor praxis dominance) than is hand preference. Patients with atypical language dominance exhibit more bilateral cerebral distribution of both language and praxis function.

Successful preimplantation genetic diagnosis for sex Link Lesch--Nyhan Syndrome using specific diagnosis

Lesch-Nyhan syndrome (LN) is a severe X-linked recessive disorder caused by a deficiency of the enzyme hypoxanthine phosphoribosyl transferase (HRT). Clinical features displayed by affected boys are particularly severe and disturbing and include hyperuricaemia, Characteristic neurological features including self-mutilation, choreothetosis, spasticity and mental retardation. A couple with a boy diagnosed with LN and a history of pregnancy termination was referred to the Hammersmith Hospital. Their affected son was born in 1982 after an uncomplicated pregnancy and vaginal delivery. Eight subsequent pregnancies had been unsuccessful. There were five therapeutic terminations and three spontaneous abortions, one at least directly caused by the sampling procedure during amniocentesis. From 1989 to 1991 two unsuccessful preimplantation genetic diagnosis (PGD) cycles by sexing were performed by DNA amplification. The mutation was characterized and a nested PCR protocol was designed which allowed the efficient amplification of the affected loci followed by the detection of the mutant allele by restriction digestion. Three PGD cycles were performed using this specific diagnostic test before a successful pregnancy was achieved resulting in the birth of a healthy unaffected baby girl.

Suxamethonium and critical illness polyneuropathy

Administration of suxamethonium to patients with critical illness polyneuropathy may produce life-threatening hyperkalaemia. A questionnaire to assess the awareness of this problem was sent to all UK intensive care units. A clinical scenario suggestive of critical illness polyneuropathy was accompanied by a list of possible drugs used to facilitate endotracheal intubation. Most respondents (68.7%) chose suxamethonium while 20.4% avoided any muscle relaxant. This result suggests a worrying lack of appreciation of the dangers of suxamethonium use in critical illness polyneuropathy.

Endurance training reduces the rate of diaphragm fatigue in vitro

PURPOSE

The present study examined the effects of endurance training on the contractile and biochemical properties of the rat costal diaphragm in vitro.

METHODS

Sixty-four rats were divided into two groups: exercise trained (T) and control (C). Training consisted of treadmill running 5 d x wk(-1), 60 min x d(-1) at approximately 70% of VO2max, over a 10-wk period.

RESULTS

Control diaphragm strips produced an average of 12% less force from minute 15 to 50 of a 60-min in vitro fatigue protocol, compared with the T diaphragm strips (P < 0.01). T diaphragms had 10.1% higher citrate synthase (CS) and 12.1% higher superoxide dismutase (SOD) activities compared with the C (P < 0.05). Despite a significant decrease (P < 0.05) in Type IIb myosin heavy chains (MHC) and an increase (P < 0.05) in Type I MHC in T diaphragms, maximal shortening velocity (Vmax) in the diaphragm was not different between T and C animals. No differences were observed in specific force or the relative proportions of myosin light chains between groups.

CONCLUSIONS

These findings suggest that endurance training reduces the rate of diaphragm fatigue in vitro but has no effect on Vmax or specific force.

Nursing workload: an unquantifiable entity

BACKGROUND

In the increasingly prominent drives towards cost containment and efficiency nursing is under pressure to justify its value to healthcare. On the surface nursing workload assessment methods would appear to offer a means to quantify the nursing input to patient care.

AIMS

To examine the validity of nursing workload methods with respect to nursing practice and nursing knowledge.

FINDINGS

Previous studies and the conclusions of subject reviews have cast doubt on the reliability and validity of most methods and indicate that they have no clear theoretical base.

CONCLUSION

It appears that nursing is more concerned with knowledge processing and nurses' intentions than just with the activities of caring. It is suggested that patients control the time element of nursing care. The need for nursing workload information, despite its validity problems, is discussed and a pragmatic solution is suggested.

Measurement of endogenous and exogenous alpha-granular platelet proteins in patients with immune and nonimmune thrombocytopenia

Idiopathic thrombocytopenic purpura (ITP) is caused by antiplatelet antibodies and is characterized by increased platelet destruction and elevated levels of IgG (platelet-associated IgG, PAIgG). Nonimmune thrombocytopenic patients also have elevated levels of PAIgG. In this study we investigated two possible biological explanations for the increased levels of PAIgG in these patients. The first hypothesis suggests that a thrombocytopenic stress causes increased thrombocytopoiesis with increased numbers and content of the platelet alpha granules. The second hypothesis is that for uncertain reasons (immunological or cytokine) there is increased absorption of plasma proteins by either megakaryocytes or by the platelets themselves. To address this issue, we compared the level of megakaryocyte synthesized alpha granular proteins [platelet factor 4 (PF4) and beta-thromboglobulin (beta-TG)] to plasma-absorbed alpha granular proteins (albumin, IgG and fibrinogen) in patients with immune (n = 39) and nonimmune (n = 60) thrombocytopenias. Plasma-absorbed alpha-granular proteins were elevated in both immune and nonimmune thrombocytopenia with no increase in megakaryocyte synthesized alpha-granular proteins. These plasma-derived protein elevations were not attributable to elevated mean platelet volumes or elevated plasma concentrations of the respective protein. We hypothesize that the increased IgG in these platelets is not the result of production of larger platelets, but reflects a selective increase in the endocytosis of plasma-absorbed alpha-granular proteins at the megakaryocyte and/or platelet level.

Generation of influenza A viruses entirely from cloned cDNAs

We describe a new reverse-genetics system that allows one to efficiently generate influenza A viruses entirely from cloned cDNAs. Human embryonic kidney cells (293T) were transfected with eight plasmids, each encoding a viral RNA of the A/WSN/33 (H1N1) or A/PR/8/34 (H1N1) virus, flanked by the human RNA polymerase I promoter and the mouse RNA polymerase I terminator-together with plasmids encoding viral nucleoprotein and the PB2, PB1, and PA viral polymerases. This strategy yielded >1 x 10(3) plaque-forming units (pfu) of virus per ml of supernatant at 48 hr posttransfection. The addition of plasmids expressing all of the remaining viral structural proteins led to a substantial increase in virus production, 3 x 10(4)-5 x 10(7) pfu/ml. We also used reverse genetics to generate a reassortant virus containing the PB1 gene of the A/PR/8/34 virus, with all other genes representing A/WSN/33. Additional viruses produced by this method had mutations in the PA gene or possessed a foreign epitope in the head of the neuraminidase protein. This efficient system, which does not require helper virus infection, should be useful in viral mutagenesis studies and in the production of vaccines and gene therapy vectors.

Efficacy and safety of delavirdine mesylate with zidovudine and didanosine compared with two-drug combinations of these agents in persons with HIV disease with CD4 counts of 100 to 500 cells/mm3 (ACTG 261). ACTG 261 Team

To evaluate the antiretroviral activity of delavirdine mesylate, a non-nucleoside reverse transcriptase inhibitor of HIV-1, we performed a phase II, randomized, double-blind, multicenter trial comparing the three-drug combination of delavirdine with zidovudine and didanosine to two-drug combinations of these drugs. Patients with CD4 cell counts between 100 and 500 cells/mm3 without prior or <6 months of monotherapy with zidovudine or didanosine were randomized to one of four arms and observed on a follow-up basis for 48 weeks. In total, 544 patients were evaluated. In those assigned to the three-drug regimen, mean short-term (weeks 4-12) and long-term (weeks 40-48) change in CD4 cells from baseline were 49.3+/-8.1 and 65.4+/-13.4 cells/mm3, respectively; mean short-term and long-term HIV-1 RNA changes from baseline were -1.13 log10+/-0.12 and -0.73+/-0.12 copies/ml, respectively. These responses in CD4 cell counts and HIV-1 RNA levels were better in comparisons with each of the two-drug arms at all study points; however, differences were not consistently significant. Gastrointestinal side effects were experienced by 33% of patients (178 of 544), and 30% (121 of 407) receiving delavirdine experienced rash, only one case of which was severe. In this study, therapy with delavirdine + zidovudine + didanosine was safe and showed modest, but not always significant, antiviral activity and CD4 cell count benefit compared with two-drug regimens with these agents. Key

Ran-GTP stabilises microtubule asters and inhibits nuclear assembly in Xenopus egg extracts

Ran is an abundant GTPase of the Ras superfamily that is highly conserved in eukaryotes. In interphase cells, Ran is mainly nuclear and thought to be predominantly GTP-bound, but it is also present in the cytoplasm, probably GDP-bound. This asymmetric distribution plays an important role in directing nucleocytoplasmic transport. Ran has also been implicated in cell cycle control, including the transition from mitosis to interphase when the compartmentalisation of the nucleus is established. Here, we have examined the role of Ran in this transition using a cell-free system of Xenopus egg extracts supplemented with sperm heads that provides a model for microtubule aster formation and post-M phase nuclear assembly. Ran-GTP, added as wild-type protein, a mutant defective in GTPase activity (Q69L), or generated by addition of the specific nucleotide exchange factor RCC1, stabilises large microtubule asters nucleated at the sperm centrosome, prevents the redistribution of NuMA from the aster to the nucleus and blocks chromatin decondensation. In contrast, Ran GDP does not stabilise microtubules or inhibit nuclear assembly. RanT24N and RanBP1, which oppose the generation of Ran-GTP by RCC1, arrest nuclear growth after disappearance of the aster. Ran associates with microtubule asters in egg extracts and with mitotic spindles in somatic Xenopus cells, suggesting that it may affect microtubule stability directly. These results show that Ran has a novel function in the control of microtubule stability that is clearly distinct from nucleocytoplasmic transport. The Ran GDP/GTP switch may play a role in co-ordinating changes in the structure of microtubules and the assembly of the nucleus associated with the transition from mitosis to interphase.

Characteristics of maternal directiveness and responsiveness with young children with visual impairments

The purpose of this study was to investigate the relation between maternal responsive and directive behaviours and the development of young children with visual impairments. The participants were 17 mother-child dyads, and the children's ages ranged from 20 to 36 months of age. The amount, quality, and appropriateness of four maternal behaviours were rated during a free play session between mother and child and compared with a developmental outcome measure designed for young children with visual impairments. In general, the results showed that the quality of maternal control and appropriateness of directiveness were positively related to children's language development; whereas, the amount of these same behaviours was negatively related to language development. The findings also indicated that both the quality and amount of maternal goal-setting behaviours, and the quality of responsiveness were positively related to children's language skills, exploration of the environment and sensorimotor development. The findings are discussed in terms of maternal influence on child development.