Perfusion mapping using computed tomography allows accurate prediction of cerebral infarction in experimental brain ischemia

BACKGROUND AND PURPOSE

We have developed a dynamic CT method to measure absolute cerebral blood flow (CBF), cerebral blood volume (CBV), and mean transit time (MTT). In this study we evaluated the ability of CT-derived functional maps to detect infarction in a rabbit model of focal cerebral ischemia.

METHODS

Sequential dynamic CT studies were performed at 2 different slices in 5 control rabbits and another 8 after induction of focal cerebral ischemia. The size of critically ischemic tissue was correlated to size of infarction measured by postmortem 2,3,5-triphenyltetrazolium chloride staining. In the control rabbits, short-term variability of the parameters was assessed by ANOVA analysis.

RESULTS

In 7 of 8 animals of the ischemia group, cerebral infarction was visible on 2,3, 5-triphenyltetrazolium chloride staining, constituting 16.7+/-10.6% of the ipsilateral hemisphere. Good agreement of CBF functional maps with tissue specimens was found with respect to size and location of infarction. Best prediction of infarction was found for thresholds of CBF <10 mL/100 g per minute (mean size, 17.5+/-13.4%; r=0.95) and MTT >6 seconds (mean size, 15.6+/-13.5%; r=0.85), with regression slopes close to unity. CBV maps were less predictive of occurrence of infarction, especially in cases of small infarction. The short-term variability of CBF, CBV, and MTT in the control group was 10.9%, 15.2%, and 19.9%, respectively.

CONCLUSIONS

Functional CT measurements of absolute CBF and MTT early after onset of ischemia allow prediction of the size and location of cerebral infarction with good accuracy.

Gabapentin in the treatment of cocaine dependence: a case series

BACKGROUND

Although multiple medications have been studied for the treatment of cocaine dependence, no medication has been shown to have a robust effect on craving and use. This pilot project was designed to evaluate the safety and tolerability of gabapentin in subjects with cocaine dependence.

METHOD

Thirty cocaine-dependent subjects (DSM-IV criteria) were enrolled in an 8-week, open-label trial of 1,200 mg/day of gabapentin in divided doses. Urine drug screens, subjective measures of craving, and cocaine use interviews were conducted at each weekly visit.

RESULTS

Baseline rating of amount and frequency of craving decreased significantly by week 8 (78% vs. 25% for amount, p = .000; 74% vs. 23% for frequency, p = .004). Positive urine drug screens for cocaine decreased from 86% at baseline to 29% at weeks 4 and 8. There were no reports of significant side effects or adverse events.

CONCLUSION

This pilot study indicates that gabapentin is safe and well tolerated and may be beneficial in the treatment of cocaine dependence. A placebo-controlled trial would be of interest.

Risk factors for depression and anxiety in abstainers, moderate drinkers and heavy drinkers

AIMS

To identify risk factors for depression and anxiety that are more prevalent in abstainers than in moderate drinkers and to estimate their contribution to U-shaped relationships of depression and anxiety with alcohol consumption.

DESIGN

Cross-sectional general population sample.

SETTING

Canberra, Australia.

PARTICIPANTS

2725 subjects completed questionnaires, including 1128 men and 1258 women aged 18-59 years.

MEASUREMENTS

Consumption categories from AUDIT quantity/frequency items: (1) non-drinkers (no alcohol in the past year), (2) occasional drinkers (monthly or less), (3) lower-level drinkers (up to 14 standard drinks per week for men and seven for women), (4) higher-level drinkers (up to 28 and 14 standard drinks per week, respectively), and (5) those drinking at hazardous or harmful levels (over 28 and 14 standard drinks per week, respectively). Goldberg and DSSI/sAD depression and anxiety scales. A range of demographic, socio-economic, socio-environmental and personality factors.

FINDINGS

Non-drinkers were more likely than lower-level drinkers to have low status occupations, poor education, current financial hardship, poor social support and recent stressful life events, and scored lower on extraversion, fun-seeking and drive. Many of these characteristics also applied to hazardous/harmful drinkers. In multivariate models, these risk factors accounted for a substantial part of the higher depression and anxiety scores of non-drinkers and occasional drinkers relative to lower-level drinkers.

CONCLUSIONS

Abstainers have a range of characteristics known to be associated with anxiety, depression and other facets of ill health, and these factors may contribute significantly to their elevated levels of depression and anxiety.

The Australian National Survey of Mental Health and Well-Being. Common psychological symptoms and disablement

BACKGROUND

The mental health of populations can be represented by case prevalence rates and by symptom scales. Scales have the advantage of identifying sub-syndromal levels of distress, which may be common and associated with considerable disability.

AIMS

To examine the distribution of common psychological symptoms and associated disablement in the Australian population.

METHOD

A household sample of 10,641 individuals representative of the adult population of Australia was interviewed using the Composite International Diagnostic Interview and completed scales measuring recent symptoms and disablement.

RESULTS

Symptom scales showed similar associations with socio-economic variables as did diagnoses, although only a small amount of variance in symptom levels was explained by these variables. Considerable disablement was associated with symptom levels indicating distress but not reaching levels for formal diagnoses of anxiety or depression.

CONCLUSIONS

Symptom scales provide parsimonious measures of psychological distress and are appropriate for use in large-scale surveys of mental health and disablement.

Gerontogenes mediate health and longevity in nematodes through increasing resistance to environmental toxins and stressors

More than 40 mutants in Caenorhabditis elegans have been demonstrated to lead to increased life span (a rigorous, operational test for being a gerontogene) of 20% or more ("Age" mutants). Age mutants alter rate-limiting determinants of longevity; moreover, important genes are identified independent of prior hypotheses as to actual mode of gene action in extending longevity and/or "slowing" aging. Age mutants define as many as nine (possibly) distinct pathways and/or modes of action, as defined by primary phenotype. Three well-studied mutants (age-1, clk-1, and spe-26) alter age-specific mortality rates in characteristic fashions; in age-1 mutants, especially, the changes in mortality rates are quite dramatic. All Age mutants (so far without exception) increase response to several (but not all) stresses, including heat, UV, and reactive oxidants. We have used directed strategies, as well as random mutagenesis, to identify novel genes increasing the worm's ability to resist stress. Two genes (daf-16 and old-1) yield over-expression strains that are stress resistant and long-lived. A variety of approaches to assess transcriptional alterations associated with increased longevity are underway. We suggest that the role of the Age genes in both longevity and stress resistance indicates that a major evolutionary determinant of longevity is the ability to respond to stress.

Passive immunotherapy of mice bearing Ehrlich ascites tumor expressing human, membrane-bound placental alkaline phosphatase

The objective of our study was to test if a tumor expressing a transgene coding for a membrane-bound protein is amenable to immunotherapy by antibodies to the same protein. To this end, we have established an Ehrlich ascites tumor (EAT) cell line, EAT-DAP, stably expressing human, membrane-bound placental alkaline phosphatase (PLAP) by infecting EAT cells (EATC) with the retroviral vector DAP and selecting neomycin-resistant cells. EATC and EAT-DAP cells grew at similar rates in vitro, and produced ascites tumor in Swiss-Webster mice with similar efficiency. We have treated mice bearing EAT-DAP ascites tumor with a mouse monoclonal antibody to human PLAP or with a monoclonal antibody to human C proteins of the heterogenous ribonucleoprotein complex (hnRNP). The average survival of mice treated with anti-hnRNP was 16.4 +/- 1.1 days (n = 8). Treatment with anti-PLAP prolonged the survival of mice; in 4 mice average survival was 23.3 +/- 5.7 days. Four animals, however, survived for 60 days when they were killed and had no visible signs of tumor. These data support the notion that passive immunotherapy using antibodies against a membrane protein, expressed in tumor cells transduced by a viral vector coding for that protein, may be effective in controlling tumor growth.

Regulation of mOAT-mediated organic anion transport by okadaic acid and protein kinase C in LLC-PK(1) cells

Organic anion transporters in the kidney proximal tubule play an essential role in eliminating a wide range of organic anions including endogenous compounds, xenobiotics, and their metabolites, thereby preventing their potentially toxic effects within the body. We have previously cloned a cDNA encoding an organic anion transporter from mouse kidney (mOAT) (Lopez-Nieto, C. E., You, G., Bush, K. T., Barros, E. J. G., Beier, D. R., and Nigam, S. K. (1997) J. Biol. Chem. 272, 6471-6478; Kuze, K., Graves, P., Leahy, A., Wilson, P., Stuhlmann, H., and You, G. (1999) J. Biol. Chem. 274, 1519-1524). In the present study, we assessed the potential for regulation of this transporter by heterologous expression of mOAT in the pig proximal tubule-like cell line, LLC-PK(1). We report here that both protein phosphatase (PP1/PP2A) inhibitor, okadaic acid, and protein kinase C (PKC) activators down-regulate mOAT-mediated transport of para-aminohippuric acid (PAH), a prototypic organic anion, in a time- and concentrationdependent manner. However their mechanisms of action for this down-regulation are distinct. Okadaic acid modulated PAH transport, at least in part, through phosphorylation/dephosphorylation of mOAT; phosphoamino acid analysis indicated this phosphorylation occurs on serine. In contrast, PKC activation induced a decrease in the maximum transport velocity (V(max)) of PAH transport without direct phosphorylation of the transporter protein. Together these results provide the first demonstration that regulation of organic anion transport by mOAT is likely to be tightly controlled directly and indirectly by phosphatase PP1/PP2A and PKC. Our results also suggest that kinases other than PKC are involved in this process.

Australia's mental health: an overview of the general population survey

OBJECTIVES

The objectives of this study were to estimate the 1-month and 1-year prevalence of mental disorders in the Australian adult population; to determine the amount of disablement associated with this; and to determine the use of health and other services by persons with common mental disorders.

METHOD

For the Adult Survey, a household sample of 10600 persons aged 18 years and over were interviewed across Australia by experienced field staff of the Australian Bureau of Statistics. This was 78% of the target sample. The interview consisted of the composite international diagnostic interview in its automated presentation (CIDI-A) and other components to determine disablement, use of services and satisfaction with services received. The diagnostic classifications used in the analyses were both ICD-10 and DSM-IV. Only the results from ICD-10 are reported here.

RESULTS

A total of 17.7% of the sample had one or more common mental disorders, anxiety, depression, alcohol or substance abuse and neurasthenia. This morbidity was associated with considerable disablement in daily life: 3 days of impaired social role performance in the previous 4 weeks, compared with 1 day for the general population. Of all cases, 64.6% had had no contact with health services in the previous year; 29.4% had seen GPs and 7.5% had seen psychiatrists.

CONCLUSION

Australia now has its own national estimates of psychiatric morbidity. The morbidity is associated with considerable disablement, but most of it is untreated. General practitioners encounter by far the largest proportion of those reaching services.

Methanol poisoning

AIMS

This study examines clinical experience with methanol poisoning during a one-year period.

METHODS

All admissions with the diagnosis of suspected methanol toxicity were analysed and the current guidelines for the management of this problem were reviewed.

RESULTS

Twenty-four subjects were identified. Most had a history of chronic use of methylated spirits. Four died before admission to hospital and the other 20 patients had 26 admissions to hospital and form the basis for this report. Four patients died in the Intensive Care Unit. In total 11 patients were admitted to the Intensive Care Unit. Seven patients received haemodialysis. There was no correlation between the methanol level and the outcome. The strongest predictor of death or a poor outcome was a blood pH < 7.0. Some patients, in spite of potentially lethal methanol levels of up to 160 mmol/L, did not develop signs of toxicity.

CONCLUSIONS

The overall mortality was high and ethanol was given to most of the patients for up to several days. Some patients did not show any toxicity and some of those were not given ethanol. It is recommended that chronic meths drinkers, who are not acidaemic and are generally well, do not require ethanol treatment. Only the complete removal of methanol from methylated spirits will reduce the morbidity of this condition.

Focus on psychiatry in Australia

Humankind has been present on the Australian continent for at least 40 000, some say 60 000 years, remarkably adapted to the environment and having a cultural tradition appreciated by few Caucasians. White people have been here for only 200 years; and psychiatry for about half of that. We know nothing about the mental health of pre-contact indigenous peoples; but we now know a little about the ways in which mental disorders are explained and treated by traditional methods. In two centuries, the Aboriginal and Torres Strait Islands communities, which are very diverse, have been steadily reduced to become only 1.5% of the population. From settlement in 1788 until the 1950s, most non-aboriginal Australians were of Anglo-Saxon or Celtic origin. Since the Second World War, the pattern of immigration has greatly enriched Australian life, first through large numbers of people from the Mediterranean littoral, Western Europe and the Balkans, and more recently from south-east Asia. Ethnic diversity is now evident in most peoples' daily lives – whom you see in the street, whom you work alongside, who your friends are, what you eat and who you have as patients. So the present Australian population of 18 million has undergone a marked change in demography and lifestyle within only two generations. Like the people, psychiatry is also changing rapidly. Where are the changes taking place? What is it like to be a psychiatrist here at present? Where has there been success and where has there been failure? Where is there lots of action?

Cognitive abilities in children with congenital muscular dystrophy: correlation with brain MRI and merosin status

The aim of the study was to evaluate whether children with merosin-positive or merosin-deficient congenital muscular dystrophy (CMD) show any cognitive impairment and whether this is related to brain abnormalities on magnetic resonance imaging (MRI). Twenty-two patients (age range: 5.8-15.3 years) were assessed by the Wechsler Intelligence Scales. Twelve were merosin-positive and ten merosin-deficient. One child had severe mental retardation and could not be tested. The full scale IQ in the remaining 21 ranged from 51 to 134, the verbal IQ ranged from 78 to 136 and the performance from 51 to 136. Of the twelve children with normal merosin one had a mild delay (IQ < 75) and two were borderline (IQ 75-95). Of the ten children with merosin-deficiency, one showed severe mental retardation and could not be tested, one showed a mild delay and two had borderline results. While the children with merosin deficiency with the typical diffuse white matter changes on MRI had normal scores, the children who in addition had cerebellar hypoplasia had lower performance IQ. The child with cortical dysplasia had severe mental retardation. Our results suggest that the spectrum of cognitive abilities in CMD is very wide even within genetically homogeneous conditions.

Optical Contrast Variation Study of Nonaqueous Suspensions of Polymer Particles

We analyze the core-shell structure of sterically stabilized hard sphere polymer colloids by optical contrast variation. Modified polymer particles are used which have the same refractive index as the suspending solvent. At low contrast, inhomogeneities in the core-shell structure of the particles become apparent. The particle form factor is shown to be a sensitive function of the temperature due to the interplay of scattering from the core and the stabilizing layer. We explore the dependence of particle form factors on composition, radius, and temperature and rationalize our observations in terms of a simple core-shell model. By exploiting the sensitivity of the form factors we are able to independently study the two components of a binary mixture of polymer particles. Copyright 1999 Academic Press.

Cost comparison of antibacterial therapies for serious infections. A New Zealand 3-hospital study

OBJECTIVE

The first aim was to identify and determine the economic costs of the regimens currently used in 3 New Zealand hospitals in the treatment of bacterial infections in haematology patients with febrile neutropenia and in intensive care patients with severe infections. The second was to develop a spreadsheet-based decision analytic model for use by hospital decision-makers as an aid in evaluating the comparative cost of drug regimens.

DESIGN AND SETTING

The research utilised time and motion and microcosting techniques. The analytical perspective adopted for the study was that of a hospital administrator or clinical manager.

PATIENTS AND INTERVENTIONS

Patients were eligible for inclusion in the study if either they were treated with the imipenem/cilastatin monotherapy, or could have been treated with this regimen. The final analysis considered 360 patient-treatment days and 8 antibacterials.

MAIN OUTCOME MEASURES AND RESULTS

Drug acquisition cost ranged from 4.52 New Zealand dollars ($NZ; 1997 values) per patient-treatment day for gentamicin to $NZ104.81 for imipenem. The cost per patient-treatment day (when other cost components such as fluid additives, giving sets and needles were added) ranged from $NZ8.75 for gentamicin to $NZ129.12 for tazobactam. Drug acquisition cost, as a percentage of total drug preparation and administration cost, ranged from 52% for gentamicin to 93% for piperacillin. Giving sets and intravenous (i.v.) fluids were found to be important cost items when they were required specifically for the treatment regimen. There was a mean monitoring rate of 0.40 at a cost of $NZ6.41 per patient-treatment day for gentamicin. It was estimated that nephrotoxicity could add between $NZ23 and $NZ43 per day to the cost of aminoglycoside treatment.

CONCLUSIONS

Although the small sample sizes of the study mean that results should be regarded as indicative rather than conclusive, there were sufficient information to construct a working model and show how the total cost of an antibacterial regimen could be evaluated in practical terms. The important cost drivers were found to be drug cost, the use of fluids and giving sets, and monitoring.

Detection of Chlamydia trachomatis and Neisseria gonorrhoeae in swab specimens by the Hybrid Capture II and PACE 2 nucleic acid probe tests

BACKGROUND AND OBJECTIVES

The Digene Hybrid Capture II (HC II) CT/GC Test (Digene Corp., Beltsville, MD) is a new nucleic acid signal amplification-based test for the detection of Chlamydia trachomatis and Neisseria gonorrhoeae in specimens from the genital tract. For optimal results, the HC II CT/GC Test employs a special conical shaped brush for cervical specimen collection from nonpregnant women and swabs from pregnant women.

GOALS

To validate a protocol for HC II C. trachomatis and N. gonorrhoeae testing of specimens collected for the GenProbe PACE 2 System.

STUDY DESIGN

Specimens were collected from 1,746 patients with a swab and placed in GenProbe transport media according to the manufacturer's recommended procedure. The specimens were first tested at two clinical laboratories by the PACE 2 system, and then blindly tested by HC II CT/GC using an adjusted cutoff value. Discrepant specimens were adjudicated by polymerase chain reaction (PCR), and the result common to two of the three testing methods (HC II, PACE 2, and PCR) was defined as the consensus result.

RESULTS

Combining the data from both sites, the relative sensitivity of the HC II Test compared with the consensus result for the detection of 1,761 specimens for C. trachomatis and 1,750 specimens for N. gonorrhoeae was 100% for both organisms. The relative specificities for C. trachomatis and N. gonorrhoeae detection were 99.8% and 99.7%, respectively. The relative sensitivities of the PACE 2 CT and GC Systems were 86.5% and 87.1%, respectively, with relative specificities of 99.9% and 100%. The difference in sensitivity between HC II and PACE 2 for C. trachomatis detection was significant (P < 0.016).

CONCLUSION

The HC II CT/GC Test can be performed using specimens collected in GenProbe transport media and has a significantly greater sensitivity for C. trachomatis detection than the PACE 2 System.

Genotyping as a diagnostic aid in genetic haemochromatosis

BACKGROUND

Two mutations in a newly described gene, HFE, have been proposed as genetic markers for the inherited iron overload disease, genetic haemochromatosis.

METHODS

We assessed the frequency of both mutations in a cohort of genetic haemochromatosis patients and compared these with a control population. The patients were genetic haemochromatosis patients from Western Australia whose diagnosis met strict criteria for phenotypic expression. Control patients had other liver disease where iron overload was excluded.

RESULTS

Genomic DNA of 72 genetic haemochromatosis patients and 69 controls was examined for the C282Y and H63D mutations of the HFE gene using polymerase chain reaction amplification and restriction enzyme digestion. In genetic haemochromatosis patients, the C282Y mutation was homozygous in 64 of 72, giving a sensitivity of 89% (95% confidence interval 82-96%), heterozygous in five (7%) and absent in another three (4%), whereas none of the control subjects were homozygous. The H63D mutation was present in one genetic haemochromatosis patient and was not useful as a diagnostic marker. In this cohort of Western Australian patients with phenotypic expression of genetic haemochromatosis, the specificity of a homozygous C282Y mutation for genetic haemochromatosis was 100%.

CONCLUSIONS

The results indicate that genotyping for the C282Y mutation is a useful test for the diagnosis of genetic haemochromatosis in clinical practice.

Frames of reference utilized in the rehabilitation of individuals with eating disorders

An occupational therapist's role with clients diagnosed with eating disorders, both anorexia nervosa and bulimia nervosa, has been described throughout the literature. However, the frames of reference and treatment approaches that occupational therapists implement have not been clearly established or validated. This paper outlines the symptomatology of anorexia nervosa and bulimia nervosa, and critically reviews the current literature concerning the frames of reference and treatment approaches used by occupational therapists when intervening with this population. The literature reviewed indicates that therapists are using a variety of frames of reference and treatment approaches. There appears to be an emphasis on the psychoanalytical and cognitive-behavioural frames of reference, although there is a lack of empirical evidence in regards to all frames of reference and treatment approaches. Reasons for the lack of current research with this population, and possible future areas of research are suggested.

Attitudes towards people with a mental disorder: a survey of the Australian public and health professionals

OBJECTIVE

The aim of this paper was to compare the Australian public's attitudes towards people who have been treated for a mental disorder with the attitudes of general practitioners, psychiatrists and clinical psychologists.

METHOD

The study involved a household survey of 2031 members of the Australian public and a postal survey of 872 general practitioners, 1128 psychiatrists and 454 clinical psychologists. Survey participants were presented with a vignette describing a person with schizophrenia or one with depression. They were asked opinions about the person's long-term outcome in various areas of life after receiving treatment. Participants were also asked whether they thought the person described would be discriminated against by others.

RESULTS

Both the public and professionals rated outcomes as poorer and discrimination as more likely for the person with schizophrenia than for the one with depression. The professionals made more negative ratings than the public, although the clinical psychologists had similar attitudes to the public about depression.

CONCLUSIONS

Compared to the public, health professionals rate long-term outcomes more negatively and discrimination as more likely. It is possible that these more negative attitudes are realistic, being based on greater knowledge of mental disorders. However, professional attitudes may be biased by greater contact with patients who have chronic or recurrent disorders. Either way, health professionals need to be aware of the effects that their negative attitudes might have on patients and the public.

Congenital hemiplegia in children at school age: assessment of hand function in the non-hemiplegic hand and correlation with MRI

The aim of this study was to evaluate whether children with congenital hemiplegia show abnormal hand function on the non-hemiplegic side and whether this, if present, can be related to the type and extent of brain lesions on MRI. Twenty-two children with congenital hemiplegia of age ranging between 4.8 and 12.3 years, were assessed with a clinical and MRI assessment. Clinical assessment included a structured neurological examination, assessment of hand grips and the Movement Assessment Battery for Children which also includes one item assessing speed and accuracy in each hand. The results showed that 64% of the children studied showed some degree of functional impairment of the non-hemiplegic hand. Manual dexterity 1 from the Movement ABC was, in our experience, a more sensitive tool to detect minor functional abnormalities than the evaluation of hand grips. The severity of the impairment on the non-hemiplegic side was not significantly related to the severity of impairment in the hemiplegic hand (p > 0.05). In contrast, a significant association was found with the site of lesions as hand function in the non-hemiplegic hand was always normal in children with unilateral lesion and abnormal in the ones with bilateral parenchymal lesions (p < 0.05). Children with predominantly unilateral lesions but with bilateral ventricular dilatation or periventricular changes showed more variable results.

Smoking and mental health: results from a community survey

OBJECTIVE

To assess the relationship of smoking with depression and anxiety symptoms and with risk factors for depression.

DESIGN AND SETTING

A community survey conducted in Canberra in 1997.

PARTICIPANTS

2725 persons aged 18-79 sampled from the electoral roll.

MAIN OUTCOME MEASURES

Smoking was investigated in relation to psychiatric symptoms (anxiety, depression, alcohol misuse), sociodemographic characteristics (age, sex, education, occupational status), social stressors (divorce, unemployment, financial difficulties, negative life events, childhood adversity), personality (extraversion, neuroticism, psychoticism), and social support (family and friends).

RESULTS

Smokers had more depression and anxiety symptoms, more stressors and lower socioeconomic status compared with non-smokers. The association between smoking and psychiatric symptoms persisted even when stressors, socioeconomic characteristics and other factors were statistically controlled.

CONCLUSIONS

Smoking is associated with poorer mental health. In helping patients to give up smoking, doctors need to be aware that some may have underlying mental health problems that require attention.

Motor and perceptual-motor competence in children with Down syndrome: variation in performance with age

The aim of this study was to determine whether perceptual-motor competence in school-age children with Down syndrome was generally delayed or varied as a function of type of action. Twenty-two children with Down syndrome (13 males, 9 females), aged between 4.5 and 14 years were assessed on two standardized tests, the Movement Assessment Battery for Children (Movement ABC), a test of motor competence assessing gross and fine motor coordination, and on the Developmental Test of Visual-Motor Integration, a test focusing on shape copying. In order to obtain a profile of each child's performance on the different items contained in the Movement ABC, the test was used in its extended form. This involves testing any child who failed an item appropriate for his/her level, at progressively lower levels until a base-line measure was obtained. All the children obtained scores below the 5th percentile for their age on both tests. However, superimposed on this delay, we found distinct variation as a function of task. Whereas some aspects of gross motor function showed age development with delayed but regular acquisitions, all the aspects of fine motor skills assessed were more severely impaired and showed little development with age. Accuracy and timing of tasks requiring bimanual coordination were most impaired in our sample while balance and ball skills showed more variability. These results suggest that intervention in the motor domain should be varied according to each child's particular profile of performance.

Distinct mutants of retrograde intraflagellar transport (IFT) share similar morphological and molecular defects

A microtubule-based transport of protein complexes, which is bidirectional and occurs between the space surrounding the basal bodies and the distal part of Chlamydomonas flagella, is referred to as intraflagellar transport (IFT). The IFT involves molecular motors and particles that consist of 17S protein complexes. To identify the function of different components of the IFT machinery, we isolated and characterized four temperature-sensitive (ts) mutants of flagellar assembly that represent the loci FLA15, FLA16, and FLA17. These mutants were selected among other ts mutants of flagellar assembly because they displayed a characteristic bulge of the flagellar membrane as a nonconditional phenotype. Each of these mutants was significantly defective for the retrograde velocity of particles and the frequency of bidirectional transport but not for the anterograde velocity of particles, as revealed by a novel method of analysis of IFT that allows tracking of single particles in a sequence of video images. Furthermore, each mutant was defective for the same four subunits of a 17S complex that was identified earlier as the IFT complex A. The occurrence of the same set of phenotypes, as the result of a mutation in any one of three loci, suggests the hypothesis that complex A is a portion of the IFT particles specifically involved in retrograde intraflagellar movement.