Effect of trunk exercise upon lumbar IVD height and vertebral compliance when performed supine with 1 g at the CoM compared to upright in 1 g

Background

Spinal unloading in microgravity is associated with stature increments, back pain, intervertebral disc (IVD) swelling and impaired spinal kinematics. The aim of this study was to determine the effect of lateral stabilization, trunk rotation and isometric abdominal exercise upon lumbar IVD height, and both passive and active vertebral compliance when performed supine on a short-arm human centrifuge (SAHC)—a candidate microgravity countermeasure—with 1 g at the CoM, compared to that generated with equivalent upright exercise in 1 g.

Methods

12 (8 male) healthy subjects (33.8 ± 7 years, 178.4 ± 8.2 cm, 72.1 ± 9.6 kg) gave written informed consent. Subjects performed three sets of upper body trunk exercises either when standing upright (UPRIGHT), or when being spun on the SAHC. Lumbar IVD height and vertebral compliance (active and passive) were evaluated prior to SAHC (PRE SAHC) and following the first SAHC (POST SPIN 1) and second Spin (POST SPIN 2), in addition to before (PRE UPRIGHT), and after upright trunk exercises (POST UPRIGHT).

Results

No significant effect upon IVD height (L2–S1) when performed UPRIGHT or on the SAHC was observed. Trunk muscle exercise induced significant (p < 0.05) reduction of active thoracic vertebral compliance when performed on the SAHC, but not UPRIGHT. However, no effect was observed in the cervical, lumbar or across the entire vertebral column. On passive or active vertebral compliance.

Conclusion

This study, the first of its kind demonstrates that trunk exercise were feasible and tolerable. Whilst trunk muscle exercise appears to have minor effect upon IVD height, it may be a candidate approach to mitigate—particularly active—vertebral stability on Earth, and in μg via concurrent SAHC. However, significant variability suggests larger studies including optimization of trunk exercise and SAHC prescription with MRI are warranted.

Trial Registration

North Rhine ethical committee (Number: 6000223393) and registered on 29/09/2020 in the German Clinical Trials Register (DRKS00021750).

Spring-loaded body mass equivalent horizontal reactive countermovement jump ground contact and flight times, but not peak forces, are comparable to vertical jumping

Horizontal (cylinder-based) sledge jumping has been shown to ameliorate multi-system deconditioning induced by long-term bed-rest. However, biomechanics differ from 1 g vertical jumping, in particular prolongation of ground contact times (GCT), reduction of peak force, rate of force development (RFD) (and presumably stretch shortening cycle [SSC] efficacy) and stiffness, whilst also requiring relatively complex equipment. Thus, we sought to determine if horizontal spring-loaded countermovement jumps were more analogous to vertical jumping. 9 healthy (5 female) subjects (27 ± 7yrs; 169.0 ± 5.3 cm; 63.6 ± 2.6 kg) performed 10 reactive countermovement jumps vertically, and horizontally (randomized) when lay on a spring-loaded carriage performed against loading (at lift-off) equivalent (±6%) to their body weight. Jump kinetics, kinematics and lower limb/trunk electromyographic activity were compared between conditions (paired t-tests). Mean flight and GCTs did not differ, however, peak jump height (p = 0.003; d = -0.961) was greater when jumping horizontally. In contrast, ground reaction forces (zGRF) during take-off (p < 0.001; d = 1.645) and landing (p = 0.002; d = 1.309), peak acceleration (p = 0.001; d = 1.988), leg stiffness (p = 0.001; d = 2.371) and RFD (p = 0.023; d = 1.255) were lower horizontally. Mean rectus femoris activity was lower during landing (p = 0.033; d = 0.691) when horizontal, but did not differ during either take-off or land-lift. Mean medial gastrocnemius activity was significantly (p = 0.018; d = 0.317) lower during horizontal take-off. Spring-loading (1 g at take-off) maintained short GCTs and flight times presumably maintaining muscle SSC efficacy in a manner that appears intuitive (in young active subjects), simple, robust and potentially compatible with spaceflight. Whether appropriate jump characteristics can be achieved in older subjects and in μg/hypogravity needs to be determined. However, greater jump height, lower peak zGRF, RFD and leg stiffness along with reduced lower limb and trunk muscle activity suggests that 1 g at take-off is insufficient to replicate vertical jump biomechanics. Thus, further investigation is warranted to optimize, and evaluate spring-loaded jumping as a gravity-independent multi-systems countermeasure on Earth, and in Space.

Detection of multiple hypervirulent Klebsiella pneumoniae strains in a New York City hospital through screening of virulence genes

OBJECTIVES

The 'hypervirulent' variant of Klebsiella pneumoniae (hvKp) is a predominant cause of community-acquired pyogenic liver abscess in Asia, and is an emerging pathogen in Western countries. hvKp infections have demonstrated 'metastatic' dissemination in immunocompetent hosts, an unusual mode of infection associated with severe complications. Two cases alerted us to the possible presence of hvKp at our hospital, both involving elderly Hispanic males who presented with recurrent fever, bacteraemia, epigastric pain and liver abscesses/phlegmon, thus prompting an assessment of hvKp prevalence.

METHODS

A surveillance of K. pneumoniae blood, body fluid and wound isolates was conducted using real-time PCR to detect virulence-associated genes (uni-rmpA, iucA and peg344). Positive isolates were further characterized by wzi gene sequencing to determine capsular types (K-type) and by multilocus sequence typing and pulsed-field gel electrophoresis to determine strain relatedness.

RESULTS

Four-hundred and sixty-three K. pneumoniae isolates, derived from 412 blood, 21 body fluids and 30 abdominal wound specimens, were screened over a 3-year period. Isolates included 98 multidrug-resistant strains. Eighteen isolates from 17 patients, including two from the index patient, screened positive for all three virulence genes. Sixteen of 18 positive isolates had K-types associated with hvKp, and isolates from different patients were unrelated strains, indicating likely community acquisition. Of 13 patients with significant morbidity, five died; eight patients had co-existing hepatobiliary disease, and six had diabetes mellitus.

CONCLUSIONS

Multiple strains of hvKp are emerging in New York City and are associated with high mortality relative to multidrug-resistant and classical Klebsiella infections. Co-existing hepatobiliary disease appears to be a potential risk factor for these infections.

MR Angiographic-Guided Percutaneous Sclerotherapy for Venous Vascular Malformations: A Radiation Dose-Reduction Strategy

We present a new technique using MRA instead of the usual DSA to provide guidance in the treatment of venous vascular malformations. When one performs this embolization procedure, appropriate needle positioning within the malformation must be confirmed before injection of the sclerosing agent to prevent untoward complications. Time-resolved imaging of contrast kinetics-MRA can accurately depict the angioarchitecture of the lesion, which substantially reduces the total radiation dose in these patients who are commonly in the pediatric age group and usually require numerous treatment episodes.

Risk stratification of pT1-3N0 patients after radical cystectomy for adjuvant chemotherapy counselling

BACKGROUND

In pT1-T3N0 urothelial carcinoma of the bladder (UCB) patients, multi-modal therapy is inconsistently recommended. The aim of the study was to develop a prognostic tool to help decision-making regarding adjuvant therapy.

METHODS

We included 2145 patients with pT1-3N0 UCB after radical cystectomy (RC), naive of neoadjuvant or adjuvant therapy. The cohort was randomly split into development cohort based on the US patients (n=1067) and validation cohort based on the Europe patients (n=1078). Predictive accuracy was quantified using the concordance index.

RESULTS

With a median follow-up of 45 months, 5-year recurrence-free and cancer-specific survival estimates were 68% and 73%, respectively. pT-stage, ge, lymphovascular invasion, and positive margin were significantly associated with both disease recurrence and cancer-specific mortality (P-values ≤ 0.005). The accuracies of the multivariable models at 2, 5, and 7 years for predicting disease recurrence were 67.4%, 65%, and 64.4%, respectively. Accuracies at 2, 5, and 7 years for predicting cancer-specific mortality were 69.3%, 66.4%, and 65.5%, respectively. We developed competing-risk, conditional probability nomograms. External validation revealed minor overestimation.

CONCLUSION

Despite RC, a significant number of patients with pT1-3N0 UCB experience disease recurrence and ultimately die of UCB. We developed and externally validated competing-risk, conditional probability post-RC nomograms for prediction of disease recurrence and cancer-specific mortality.

Wide-pulse electrical stimulation to an intrinsic foot muscle induces acute functional changes in forefoot-rearfoot coupling behaviour during walking

Interventions for strengthening intrinsic foot muscles may be beneficial for rehabilitation from overuse injuries. In this study the acute effects of high-frequency, low-intensity wide-pulse electrical stimulation (WPS) over an intrinsic muscle on subsequent foot function during walking was assessed in healthy participants. WPS was delivered to the m. abductor hallucis (m.AH) of the non-dominant foot during relaxed standing. 3-dimensional forefoot (FF)--rearfoot (RF) coordination was quantified with a vector coding technique within separate periods of the stance phase to study WPS functional effects on foot motion. 4 types of coordinative strategies between the FF and RF were interpreted and compared PRE-to-POST-WPS for both the experimental and control feet. Bilateral electromyography (EMG) from m.AH was analysed during the intervention period for evidence of acute neuromuscular adaptation. The results showed that WPS significantly modulated FF-RF coordination during mid-stance, indicative of a more stable foot. Specifically, a statistically significant increase in FF eversion with concomitant RF inversion in the frontal plane and RF-dominated adduction in the transverse plane was observed. Subject-specific increases in post-stimulus m.AH EMG activation were observed but this was not reflected in an overall group effect. It is concluded that the structural integrity of the foot during walking is enhanced following an acute session of WPS and that this mechanical effect is most likely due to stimulation induced post-tetanic potentiation of synaptic transmission.

Mineral dust exposure in young Indian adults: an effect on lung growth?

BACKGROUND/OBJECTIVE

Long-term occupational exposure to mineral dusts including quartz is known to cause pneumoconiosis but little is known about the effects of such exposure during the period of lung development in childhood. The objective of this study was to investigate the effects on young people of exposure to mineral dusts.

METHODS

We carried out a cross-sectional study of a group of 81 Indian stone crushers (average age 21) and a control group of 72 nearby slum dwellers (average age 21) in order to assess dust exposures, respiratory symptoms and lung function.

RESULTS

Stone crushers' corrected 8-hour time weighted average concentrations of total inhalable dust, respirable dust and respirable crystalline silica were 143 mg/m(3), 39.7 mg/m(3) and 2.29 mg/m(3) respectively, which are 14, 10 and 23 times the UK workplace exposure limits, respectively. Both groups also had high exposures to outdoor and general domestic particulate matter. Compared to controls, stone crushers had significantly more symptoms, lower levels of forced vital capacity (FVC) and forced expiratory time (FET) and higher levels of forced expiratory volume in one second (FEV(1))/FVC ratio and mid-expiratory flow rate (MEF). There were no differences in FEV(1) levels. Symptoms and lung function were not associated with time lived on site or time spent in job. A selection of chest radiographs showed no silicosis by International Labour Office (ILO) criteria.

CONCLUSION

Individuals exposed to mixed mineral dust in childhood and early adult life had excess symptoms and reduced vital capacity without airflow obstruction compared with control subjects. We interpret this as evidence of stunting of lung growth caused by exposure to respirable dust.

Depersonalisation/derealisation symptoms and updating orientation in patients with vestibular disease

BACKGROUND

Patients with vestibular disease have an increased rate of reporting symptoms of depersonalisation/derealisation (DD) and similar symptoms can be provoked in healthy subjects during caloric vestibular stimulation.

OBJECTIVE

To assess the relationship between DD symptoms in patients with peripheral vestibular disease and their ability to update orientation in the environment.

METHODS

Sixty healthy subjects and 50 patients with peripheral vestibular disease completed a DD questionnaire (Cox and Swinson, 2002) and a General Health Questionnaire (GHQ)-12 (Goldberg and Williams, 1988). This was followed by a test of updating spatial orientation in which subjects were exposed to 10 manually driven whole body rotations of 45 degrees, 90 degrees or 135 degrees in a square room, which contained distinctive features on the walls, in such a way that the features and corners subtended 45 degrees with respect to the subject. After each rotation subjects reported which wall or corner they were facing. Estimation error was calculated by subtracting the reported rotation from the actual rotation.

RESULTS

DD scores were significantly higher in vestibular patients than in healthy subjects (p<0.05, t test). In patients, the lowest symptom scores and the lowest estimation errors were found in those with a unilateral canal paresis without balance symptoms whereas the highest scores and largest estimation errors were found in those with bilateral vestibular loss (p<0.05, ANOVA). Across all patients, DD scores were related to estimation errors (adjusted r2 = 0.25, p<0.05, ANCOVA).

CONCLUSIONS

Patients with peripheral vestibular disease have a deficit in the ability to update orientation on the environment and a high prevalence of DD symptoms, which may imply a high order effect of the vestibular impairment. Derealisation symptoms in vestibular disease may be a consequence of a sensory mismatch between disordered vestibular input and other sensory signals of orientation.

Care centre visits to married people living with HIV: an indicator for measuring AIDS-related stigma & discrimination

We tested whether observation of the presence and relationship of attendants (i.e. those that accompany upon admission) and visitors to a sample of 230 (128 male, 102 female) married HIV-positive people in an HIV care centre provides an indicator of caregiving, AIDS-related stigma and discrimination. Sensitivity to gender, location (urban vs. rural), age (<35 yrs vs. >35) and source of infection (spouse vs. non-spouse) were factors considered to modulate AIDS-related stigma and assess discrimination. HIV-positive people were accompanied by their spouse (53%), mother (14%), father (7%), with only 7% attending alone. Immediate family most commonly accompanied on admission (80%), but visitors were mainly from the 'extended' family (32%) with many receiving no visitors (48%). Females (11%) were more likely than males to attend alone (11% vs. 4%; p<0.05). No effect of location, age or infector was obtained. Females were more likely to be visited by their mother (14% vs. 6%; p<0.01) and non-immediate family (39% vs. 27%; p<0.05) than males were. In contrast, fathers (0% vs. 6%; p <0.05) and spouses were less likely (3% vs. 10%; p<0.05) to visit females than males. No effect of location or age upon visitation was obtained. Non-spouse infected persons were less likely than spouse-infected to be visited by their spouse (3% vs. 10%; p<0.05) but more likely to receive 'extended' family visitation (43% vs. 24%; p<0.01). Spouse-infected persons had a higher rate of no visitors than persons not infected by their spouse (54% vs. 40%; p<0.05). Observation of the presence and relationship of attendants and visitors to HIV-positive people has potential as an indicator of caregiving AIDS-related stigma and discrimination. The measure appears particularly sensitive to the gender of the HIV-positive person. Such a measure may aid healthcare professionals to focus resources such as relational counselling upon the family and close friends of people experiencing AIDS-related stigma and discrimination, with the aim of improving the provision of care within the community.

Exposure to particulate matter on an Indian stone-crushing site

BACKGROUND/OBJECTIVES

A large number of labourers work in the stone-crushing industry in India. Many of these workers are also exposed to high levels of particulate matter in their homes from the use of biomass fuels. As part of our investigations to examine the health of these workers we characterised their exposure to respirable crystalline silica and a number of other particulate matter exposure metrics in both occupational and domestic settings.

METHODS

We used a combination of direct reading and gravimetric sampling of respirable dust, total inhalable dust and particulate matter <2.5 mum in diameter (PM(2.5)) at work (n = 19), within the general environment (n = 6) and inside the home (n = 7). We used x-ray diffraction to quantify the level of crystalline silica in the respirable dust samples.

RESULTS

After correcting for the length of the working week, the arithmetic mean 8-hour time-weighted average (TWA) total inhalable dust exposure for this group was 143 mg/m(3), the mean 8-hour TWA respirable dust exposure was 39.7 mg/m(3) and the 8-hour TWA crystalline silica exposure was 2.29 mg/m(3). Our real-time data showed peaks in exposure under certain environmental and/or working conditions. General environmental and domestic PM(2.5) exposures were also high.

CONCLUSIONS

Particulate matter exposures experienced by this group of workers and their families are likely to produce impaired lung function within a short time-frame. There is a need to introduce simple measures to reduce particulate matter exposure from both occupational sources and the use of biomass fuels in homes on this and similar sites.

Audit of nurse-led-training for epipen in a District General Hospital

BACKGROUND

A community-based study in the London Borough of Hounslow, which included patients in our District General Hospital (DGH) Paediatric Department, found that most families who had been prescribed adrenaline auto-injectors could not use them properly. This prompted the establishment of a new protocol for doctors and an Allergy Clinic where one nurse was responsible for training all patients.

AIM

This audit was done to reassess this service 3 years after the changes were made.

METHODS

68 of the 81 (83%) patients followed up in our District General Hospital Nurse led Allergy Clinic agreed to participate. They were compared with the District General Hospital sub-group of the previous study.

RESULTS

We found that most patients now reported they were trained to use the devise, had written instructions, were able to demonstrate competence on a dummy and would appropriately call an ambulance. This was significantly better than the previous situation.

CONCLUSION

The study shows that training can be improved in a DGH setting with the strategy of protocolised prescribing and a Nurse led Allergy Clinic.

Depersonalisation/derealisation symptoms in vestibular disease

BACKGROUND

Depersonalisation is a subjective experience of unreality and detachment from the self often accompanied by derealisation; the experience of the external world appearing to be strange or unreal. Feelings of unreality can be evoked by disorienting vestibular stimulation.

OBJECTIVE

To identify the prevalence of depersonalisation/derealisation symptoms in patients with peripheral vestibular disease and experimentally to induce these symptoms by vestibular stimulation.

METHODS

121 healthy subjects and 50 patients with peripheral vestibular disease participated in the study. For comparison with the patients a subgroup of 50 age matched healthy subjects was delineated. All completed (1) an in-house health screening questionnaire; (2) the General Health Questionnaire (GHQ-12); (3) the 28-item depersonalisation/derealisation inventory of Cox and Swinson (2002). Experimental verification of "vestibular induced" depersonalisation/derealisation was assessed in 20 patients and 20 controls during caloric irrigation of the labyrinths.

RESULTS

The frequency and severity of symptoms in vestibular patients was significantly higher than in controls. In controls the most common experiences were of "déjà vu" and "difficulty in concentrating/attending". In contrast, apart from dizziness, patients most frequently reported derealisation symptoms of "feel as if walking on shifting ground", "body feels strange/not being in control of self", and "feel 'spacey' or 'spaced out'". Items permitted discrimination between healthy subjects and vestibular patients in 92% of the cases. Apart from dizziness, caloric stimulation induced depersonalisation/derealisation symptoms which healthy subjects denied ever experiencing before, while patients reported that the symptoms were similar to those encountered during their disease.

CONCLUSIONS

Depersonalisation/derealisation symptoms are both different in quality and more frequent under conditions of non-physiological vestibular stimulation. In vestibular disease, frequent experiences of derealisation may occur because distorted vestibular signals mismatch with the other sensory input to create an incoherent frame of spatial reference which makes the patient feel he or she is detached or separated from the world.

Neonatal hypothermia detection by ThermoSpot in Indian urban slum dwellings

OBJECTIVE

To look at the performance of ThermoSpot liquid crystal thermometry in detecting neonatal hypothermia.

DESIGN

A comparison was made between skin temperatures taken by ThermoSpot and axillary temperatures taken by digital electric thermometry. Non-medically trained local volunteers performed daily paired recordings on infants on days 1, 2, 3, 4, 5, 6, and 7 of life.

SETTING

This is a non-hospital based study set in the homes of neonates in an underprivileged urban slum community in the developing world.

INCLUSION CRITERIA

babies born at home.

EXCLUSION CRITERIA

hospital admission; parental refusal.

INTERVENTIONS

The ThermoSpot was stuck to the neonate's abdomen over the liver area on day 1 and removed on day 7.

MAIN OUTCOME MEASURES

Fixed test properties of ThermoSpot.

RESULTS

Over 180 paired observations, the fixed test properties of ThermoSpot in the detection of hypothermia were: sensitivity 88%; specificity 97%; positive likelihood ratio 29; negative likelihood ratio 0.13.

CONCLUSIONS

ThermoSpot performed well when used by non-medically trained volunteers for the detection of neonatal hypothermia in the homes of an urban slum community.

Rapid diagnosis of bacterial meningitis using nitrite patch testing

Urine reagent strips have been used to test cerebrospinal fluid (CSF) in areas where laboratory facilities are unavailable. Protein, glucose and leukocyte esterase patches have been shown to be useful in this context. We propose that the nitrite patch also has a contribution to make: it could provide clinically useful information, at no extra cost. We tested CSF samples from 200 children with suspected meningitis. In a pragmatic approach chosen to reflect the clinical dilemma of whether or not to use parenteral antibiotics, the final laboratory diagnosis was dichotomized into either 'bacterial meningitis' or 'not bacterial meningitis'. These diagnostic categories were compared with nitrite patch results, which were either positive or negative. Nitrite patch testing of all CSF, clear CSF and bloody CSF gave positive likelihood ratios of 49, 'infinity' and 5.8, respectively.

Lung function changes in teenage carpet weavers

Lung function was measured with a Microlab 3500 Spirometer in 17 teenage carpet weavers, their 17 non weaving sisters and 13 age/sex matched controls in a carpet making community in Gwalior in late 2001. All subjects were asymptomatic. Forced expiratory volume in one second (FEV1), forced vital capacity (FVC), and mid-expiratory flow rate (MEF) were expressed as percentages of expected values for the subjects age and height using prediction equations for healthy North-Indian girls (FVC% FEV1% and MEF%). There was no significant difference in FVC% FEV1% or FEV1/FVC ratio between the 3 groups but weavers had a significantly lower mean MEF% than their sisters (p< 0.01 by paired "t" test) and the age-matched control group (p< 0.002 by "t" test). The reduction in MEF% was correlated with duration of employment (Spearmans correlation = 0.5 with p < 0.05).

Inhibition of malignant cell growth by 311, a novel iron chelator of the pyridoxal isonicotinoyl hydrazone class: effect on the R2 subunit of ribonucleotide reductase

The key roles of iron and iron proteins in cell proliferation make them potential targets for cancer therapy. However, clinical trials directed toward perturbation of tumor iron homeostasis by iron chelation have been limited to the use of deferoxamine (DFO). There is thus a need to develop agents with greater efficacy. In the present study, we investigated the mechanism of cytotoxicity of 311 (2-hydroxy-1-naphthylaldehyde benzoyl hydrazone), a novel iron chelator of the pyridoxal isonicotinoyl class. We found that 311 inhibited the growth of CCRF-CEM cells in a time- and concentration-dependent fashion with an IC(50) that was approximately 20-fold lower than that of DFO. 311 also inhibited the growth of breast, bladder, and head and neck cancer cell lines. Using electron spin resonance (ESR) spectroscopy analysis, we found that a 12-h exposure of CCRF-CEM cells to 311 inhibited the tyrosyl radical ESR signal of the R2 subunit of ribonucleotide reductase. However, overproduction of the R2 subunit in hydroxyurea-resistant CCRF-CEM cells was associated with a decrease in sensitivity of cells to 311 but not to DFO. Our studies show that 311 is a more potent cytotoxic agent than DFO, with activity against both hematopoietic and nonhematopoietic cell lines regardless of their p53 status. Furthermore, the ESR studies suggest that inhibition of the R2 subunit of ribonucleotide reductase is at least one mechanism by which 311 blocks cell proliferation.

Haemolytic uraemic syndrome: prognostic factors

Haemolytic uraemic syndrome (HUS) associated with Escherichia coli O157:H7 is the commonest cause of acute renal failure (ARF) in childhood. Production of verotoxin by the organism is pivotal in the pathogenesis of the disease. Verotoxin binds to a receptor on blood and endothelial cells, expressed as the P1 blood group antigen on red blood cells. A protective effect of the P1 phenotype has been proposed in this disease. This study investigates prognostic factors and the relationship between outcome and P1 phenotype in 27 cases of diarrhoea-associated HUS. A poor outcome as defined by the presence of chronic renal failure (CRF), hypertension or proteinuria on 6 month follow-up was associated with the age of the patient at presentation and with the following clinical markers: maximum WBC and duration of raised WBC, duration of anuria and duration of need for dialysis. None of these outcome measures or prognostic factors, and no extra-renal manifestations of the disease were associated with P1 phenotype.

The effect of deprivation on child health in Bro Taf

Infant mortality rate (IMR) and disability indices were compared in 16 y birth cohorts (1979-1994) inclusive) from two neighbouring but contrasting boroughs in Bro Taf. The comparison was extended to children with mild learning difficulties. Children with and without learning problems were compared for birth weight (BW). Further data on infant mortality by cause of death, BW and maternal age were analysed for 6 y within this period (all births from 1979-1984 inclusive). The more deprived area had a higher IMR and a greater number of deaths attributed to low birth weight. It had a higher rate of childhood disability which was due to a higher rate of moderate learning disabilities. There was also a higher rate of mild learning difficulty. Learning problems were associated with low birth weight. The more deprived area had a greater proportion of low birth weight and very low birth weight babies and more mothers who were in their teens and early teens.

Dimercaptosuccinic acid distribution in renal tubular acidosis

A 99Tcm dimercaptosuccinic acid (DMSA) scan performed after a urinary tract infection demonstrated an unusual pattern of isotope uptake, promoting further investigations leading to a diagnosis of renal tubular acidosis secondary to nephropathic cystinosis. This is known to affect isotope imaging but a unique feature in this undiagnosed case was the uncorrected metabolic acidosis, which had further altered the distribution of the DMSA. It is noteworthy because other patients referred for imaging with renal disease may also have abnormalities of acid base balance.

Overlooked spine injuries associated with lumbar transverse process fractures

Transverse process fractures of the lumbar spine often are considered benign fractures related to direct trauma or psoas muscle avulsion. Treatment of these usually stable injuries is primarily administered when the patient becomes symptomatic. However, significant force often is required to cause these injuries, and other injuries may occur concomitantly. For this study, all patients who presented with identified lumbar transverse process fractures were further evaluated radiographically with computed tomography for the detection of other possible spine injuries. Medical and radiology records of 28 consecutive patients who had plain radiographs and computed tomography scans taken of their lumbar spine were reviewed retrospectively; these patients presented with lumbar spine transverse process fractures between January 1, 1989 and June 30, 1992. Three of the 28 patients (11%) had a lumbar spine fracture that was identified by computed tomography but overlooked on plain radiographs. Approximately 11% of patients with major injuries may be misdiagnosed if only plain radiographs are used in the evaluation of transverse process fractures. Computed tomography scanning of all lumbar spine transverse process fractures resulting from acute trauma should be considered because this diagnostic measure decreases the risk of overlooking potentially serious injuries.

Analog measurement of scattered optical fluctuations

Astatistical model that describes the analog measurement of a fluctuating light intensity that arises from a non-Gaussian scattering process is developed. The higher-order statistical moments are derived for a p-i-n diode receiver model and gamma-distributed intensity fluctuations. Criteria for the accurate measurement of the scattering fluctuations are found, and these are used to analyze data derived from an on-line scatterometer system. Implications for future on-line measurement technology are discussed.

Analysis of TGF-beta 1 gene expression in contused rat spinal cord using quantitative RT-PCR

We have used northern blot analysis and quantitative reverse transcription polymerase chain reaction (RT-PCR) to determine the postinjury expression profile of the transforming growth factor-beta 1 (TGF-beta 1) gene in the contused rat spinal cord. Spectrophotometric estimates of total sample RNA and quantitative analyses of cyclophilin mRNA using RT-PCR served as controls for comparisons between samples. No changes in cyclophilin gene expression were found at any postinjury survival times. The results of the TGF-beta 1 analyses, which were carried out on spinal cord samples taken at postinjury intervals ranging from 6 h to 10 days, show that the amount of TGF-beta 1 mRNA present in spinal cord increases rapidly following injury, reaching maximum levels 7 days postinjury. Unoperated control samples contained approximately 2 x 10(8) molecules of TGF-beta 1 mRNA/0.5 microgram total RNA. By 1 day postinjury, the amount of TGF-beta 1 mRNA in the cord had increased by a factor of 2.5 to 5 x 10(8) molecules/0.5 microgram total RNA. At 7 days postinjury, there were approximately 15 x 10(8) molecules of TGF-beta 1 mRNA/0.5 microgram total RNA. By 10 days postinjury the amount of TGF-beta 1 mRNA present in the spinal cord had declined to 8 x 10(8) molecules of TGF-beta 1 mRNA/0.5 microgram total RNA, a value similar to that observed at 3 days postinjury. The roles that TGF-beta 1 might play in modifying cellular responses in injured spinal cord are discussed.

Canadian immigration policy: the effectiveness of the point system and other instruments

"This paper examines the effects of changes in Canadian immigration policy on the occupational composition of immigration. We focus on 1967 changes that created a regulatory system, including the point system, that still forms the framework of Canadian immigration policy. We find that the point system provides some control over occupational composition but that its effectiveness in fine tuning is limited by the large number of other characteristics it seeks to control. We also find that entry class and source country composition of inflow have impacts that have swamped the effects of the point system in the last two decades." (SUMMARY IN FRE)

Molecular and biochemical analyses of iodopsin in rd chick retina

PURPOSE

The results of previous immunocytochemical and electrophysiological studies of retinas of rd (retinal degeneration) chicks suggest that the iodopsin cone visual pigment may be defective in this mutant. The goal of this study was to determine if the primary structure and synthesis of this protein is normal in this animal model of inherited retinal degeneration.

METHODS

Northern cDNA sequence and western analyses were used to study rd/rd iodopsin. cDNAs encoding rd/rd iodopsin were obtained by screening an rd/rd cDNA retinal expression library and by reverse transcription PCR. Western blots were probed with either R4 or COS-1, two different monoclonal antibodies that have been shown to specifically recognize chicken iodopsin.

RESULTS

Hybridization of the +/+, +/rd, and rd/rd poly(A)+ RNA with an iodopsin cDNA probe revealed the presence of a single 1.5 kb band in each of the samples, all of which were labeled with equal intensity. No significant differences were found between the published nucleic acid sequences for normal chicken iodopsin cDNA and that determined for rd/rd iodopsin cDNA. Antibody-dependent differences in the staining intensity of the 34 kDa band containing iodopsin were observed on western blots of +/+, +/rd, and rd/rd retinal protein. R4 stained the 34 kDa band in each sample with equal intensity. COS-1 labeling of the 34 kDa band in the rd/rd sample was less intense than that observed in the +/+ and +/rd samples.

CONCLUSIONS

Based on the results of the cDNA sequence and northern blot experiments, the authors conclude that the gene encoding iodopsin and transcription of this gene are normal in the rd mutant. The results of the western blot analyses of rd/rd iodopsin suggest that post-translational processing of iodopsin may be abnormal in this mutant.

Estradiol-17 beta effects on lipid metabolism of adipose tissue in nutritionally induced lean and obese ovariectomized ewes

Nutritionally manipulated lean (68 kg) and obese (87 kg) ovariectomized ewes were administered estradiol-17 beta (E2) or sham implants. Ewes individually had ad libitum access to corn silage. Rates of de novo lipogenesis, palmitate esterification, and glycerol and fatty acid release were determined with slices of subcutaneous adipose tissue at 0, 5, and 30 d after implantation. Condition and E2 interacted over time (linear, P less than .12; quadratic, P less than .05) to affect intake. Lean ewes implanted with E2 decreased intake initially after implantation, whereas obese ewes implanted with E2 decreased intake later after implantation. The linear effect of time x condition x E2 interacted (P less than .02) for lipogenesis. Lipogenesis was inhibited in both the lean and obese ewes implanted with E2. Lean compared with obese ewes without E2 had increased lipogenesis at a faster rate over time. Esterification increased (linear, P less than .01) in the lean ewes and decreased (quadratic, P less than .01) in the obese ewes over time. A time x E2 interaction occurred for esterification (P less than .02). Glycerol and fatty acid release were variable over time within condition and E2. A 48-h adipose tissue culture determined the effect of E2 on lipid metabolism. Estradiol-17 beta decreased (P less than .05) lipogenesis, decreased (P less than .08) esterification, and maintained fatty acid and glycerol release. Data in vivo and in culture indicated that E2 acted to decrease de novo lipogenesis and palmitate esterification and had little or no effect on lipolysis.

Anxiolytic effects of nitrous oxide in mice in the light-dark and holeboard exploratory tests

To investigate anxiolytic effects of nitrous oxide (N2O), male mice were tested in two exploratory models--a two-chambered light-dark (L-D) unit and a holeboard. Tests were conducted inside a glovebag through which one of three mixtures of N2O and oxygen (25, 50 and 75% N2O) or room air (RA) was circulated at a flow rate of 10 l/min. The principal findings in the L-D unit were a concentration-related increase in number of interdepartmental transitions and a generalized increase in time spent on the light side. Nitrous oxide effectively elevated transitions in the L-D unit at a lower concentration (25% N2O) than was required to increase locomotor activity in an open field (50% N2O), suggesting that these two measures are at least partially independent; transitions might reflect a specific exploratory component of locomotor behavior. In the holeboard test, a concentration-related increase in number of head dips was observed. Pretreatment with naltrexone-HCl or saline vehicle revealed a contribution by an endogenous opioid-linked locomotor stimulant effect in some measures. A dose-related reversal by flumazenil of 50% N2O-induced shifts in number of head dips and time spent head-dipping implicates a benzodiazepine receptor. Both paradigms, in particular the holeboard, should prove useful in future N2O research.

Flexion-distraction injuries to the lumbar spine associated with abdominal injuries

Flexion-distraction injuries to the lumbar spine frequently occur with concomitant abdominal viscus injury. We encountered 16 patients with flexion-distraction lumbar spine injuries. Half of them also suffered abdominal viscus rupture. Lap safety belts were most frequently associated with these injuries; however, the incorrect, underarm use of the shoulder harness was common in our series. The diagnosis of the spinal injury was frequently delayed when abdominal viscus injury occurred together with a flexion-distraction spinal injury. Thorough physical and radiographic examination of the spine as well as a detailed history, including seat belt use, is necessary to diagnose these injuries properly.

Herniated intervertebral discs associated with unstable spinal injuries

To examine the occurrence of traumatic herniated intervertebral discs associated with unstable spinal injuries, the authors reviewed the records of all patients with spinal cord level unstable spine injuries managed at their institution over a 26-month period. Ninety-three patients were identified. All patients had roentgenographic and computed tomographic (CT) evaluation. Magnetic resonance imaging was performed in 48 patients, and revealed the presence of a herniated intervertebral disc in 16, with the highest incidence being in the cervical spine. In the patients who had only plain film and CT scans, no disc pathology was identified. Magnetic resonance imaging provides a noninvasive means of examining intervertebral disc damage in unstable spinal injuries that might otherwise be unidentified and result in spinal cord injury at the time of surgery.

Insulin receptor dephosphorylation in permeabilized adipocytes is inhibitable by manganese and independent of receptor kinase activity

Autophosphorylation of insulin receptors in digitonin-permeabilized rat adipocytes increased progressively as manganese concentrations were increased. In contrast, the percent dephosphorylation of insulin receptors, when examined by chasing the [gamma-32P]ATP with unlabeled ATP, decreased at the higher manganese concentrations. Removing manganese with EGTA increased the extent of dephosphorylation by 50 to 75%. When added only at the chase, manganese but not insulin (10(-7) M) inhibited dephosphorylation. Removal of both magnesium and manganese with EDTA completely inhibited receptor autophosphorylation. However, EDTA potentiated dephosphorylation similar to EGTA when added after 2 min of phosphorylation. Thus, a dephosphorylation reaction involving the membrane-associated insulin receptor is inhibited by manganese and is independent of the receptor kinase activity. This work suggests that manganese increases net autophosphorylation of the receptor not only by enhancing kinase activity but by inhibiting receptor dephosphorylation.

Energy value of corn wet milling by-product feeds for finishing ruminants

Five trials were conducted to evaluate the energy value of corn wet milling by-products in finishing diets. In trials 1 (45 finishing lambs, 34 kg) and 2 (70 digestion wethers, 32 kg), Rambouillet X Suffolk lambs fed corn gained faster (P less than .10), more efficiently (P less than .10) and had higher (P less than .01) digestibilities of neutral and acid detergent fiber (NDF, ADF) and starch than lambs fed dry corn gluten feed (DCGF). Lambs fed wet corn gluten feed (WCGF) consumed less feed (trial 1, P less than .05; trial 2, P less than .01), were more efficient (P less than .01) NDF and ADF digestibilities than lambs fed DCGF. Starch, NDF and ADF digestion were higher (P less than .01) for lambs fed WCGF vs wet corn bran (WCB). Lambs fed WCGF gained faster (P less than .10) and consumed more (trial 1, P = .12; trial 2, P less than .10) feed than lambs fed WCB. Dried corn bran increased (trial 1, P less than .05; trial 2, P less than .01) intake and increased (P less than .01) dry matter digestion (DMD) compared with WCB. In trial 3, rates of in vitro dry matter and NDF disappearance were similar among by-product feeds. In trial 4 (50 individually fed Shorthorn-Hereford-Angus steers, 316 kg), steers fed WCGF tended to consume more (P = .14) feed than steers fed DCGF. Corn gluten feed (CGF) replacing 0 to 46% corn decreased gain (linear, P less than .05) and DMD (linear, P less than .10), while starch digestion was highest for 23% CGF (quadratic, P less than .01). A level X CGF type interaction (P = .15) occurred for efficiency due to the lower gain of steers fed 46% DCGF. The efficiency of CGF utilization was 97% that of corn when WCGF replaced 23 or 46% corn or DCGF replaced 23% corn. Dry CGF replacing 46% corn had 87% the value of corn. In trial 5 (186 Hereford-Angus cattle, 310 kg), DCGF replacing 25 and 50% corn had 97 to 100% the efficiency of corn, while intake and gain were not affected. Dry CGF replacing 25 and 50% corn silage increased (linear, P less than .05) intake 11.3% and gain 13.8%. In ruminants, CGF is highly digestible and feed efficiency is similar to corn when WCGF is fed up to 50% of the grain component or when DCGF is fed up to 25% of the grain component.

Direct determination of uracil in [32P,uracil-3H]poly(dA.dT) and bisulfite-treated phage PM2 DNA

A simple but effective technique for determining the presence of uracil existing as either A:U base pairs or G:U base pairs in DNA was developed. DNA is degraded to deoxynucleoside 3'-monophosphates by a combination of micrococcal nuclease and spleen phosphodiesterase. The monophosphates are converted to 5'-end-labeled 32P-labeled diphosphates in a reaction catalyzed by T4 polynucleotide kinase. The resultant product is then converted to 5'-end-labeled deoxynucleoside monophosphates by P1 nuclease digestion, which specifically removes 3'-phosphates. Successful separation of labeled dUMP from conventional bases in DNA is achieved by two-dimensional polyethyleneimine chromatography, with its detection determined by autoradiography and liquid scintillation counting. The sensitivity of the technique described can detect a minimum 1 X 10(-16) mol of dUMP in DNA. Additionally, the detection of 5-methylcytosine in placental DNA demonstrates the flexibility of the technique for the analysis of modified bases in DNA.

Repair of alkylated DNA: Drosophila have DNA methyltransferases but not DNA glycosylases

DNA methyltransferase activity has been identified in crude extracts of Drosophila melanogaster pupae for the removal of methyl groups from O-6 methylguanine appearing in alkylated DNA. Additionally, N-7 methylguanine and 3 methyladenine appear to be uniquely susceptible to methyltransferase activity that resides in Drosophila pupae. Consistent with this, tests to detect DNA glycosylase activity for the repair of the latter two modified bases was unsuccessful, even though a substantial loss of methyl groups from these bases was observed. Conversely, the repair of methylated purines was not detected in extracts of Drosophila embryos. The removal of methyl groups from methylated purines was dependent upon incubation temperature and was proportional to the amount of protein added to reaction mixtures. Results indicate that the methyl group is attached to protein during the repair of methylated DNA, suggesting that it is similar to the O6-methylguanine-DNA methyltransferase identified in other organisms. Although other explanations are possible, the inability to detect DNA glycosylase activity suggests that Drosophila may not rely on base excision repair for the removal of modified or nonconventional basis in DNA.

The development of children's mental tracking strategies on a rotation task

In two experiments, 5- to 13-year-old children were required to mentally track the rotation of a pointer around a circular backdrop, and to indicate the pointer's imagined position on the backdrop at the sound of a signal. In Experiment 1, children imagined the pointer rotate around its end point. In Experiment 2, children imagined the pointer rotate around its midpoint, and indicated the position of one of its two ends at the time of the signal. The end to be indicated was not specified by the experimenter until the time of the signal. Thus, children were required to use an imaging strategy that could keep track of the changing positions of both ends of the pointer. In both experiments, children older than 8 years of age generated linear distance X time functions indicating mental tracking, but younger children did not. In Experiment 2, the proportions of children at each grade level using holistic or part-to-part strategies to mentally track the pointer were comparable, as were mental tracking rates. The results were discussed in relation to both recent research on children's counting, and Piagetian and information-processing views of mental imagery development.

Photoaffinity labeling of the beta-adrenergic receptor from cultured lymphoma cells with [125I]iodoazidobenzylpindolol: loss of the label with desensitization

The beta-adrenergic antagonist [125I]iodoazidobenzylpindolol ( [125I]IABP) specifically photolabeled two polypeptides in membrane preparations from wild-type (WT) and coupling protein-deficient cyc- cultured lymphoma cells. The molecular weights of the two polypeptides determined by sodium dodecyl sulfate/polyacrylamide gel electrophoresis were 65,000 and 55,000. They were labeled in a ratio of approximately 1:1. Pretreatment of intact WT or cyc- cells with 1.0 microM epinephrine for 15 min (desensitization) resulted in a greater loss of the 55,000 Mr polypeptide (40-60%) relative to the 65,000 Mr peptide (10-30% loss). An 18- to 24-hr pretreatment of WT cells with terbutaline (down-regulation) led to a greater than 90% reduction of the photolabeling of both polypeptides, whereas a similar pretreatment of cyc- cells resulted in no further loss of labeled receptor than that observed after only a 15-min pretreatment with epinephrine. There was no indication of a change in the electrophoretic mobility of the [125I]IABP-labeled receptors after either short- or long-term agonist pretreatment. These data provide direct evidence for heterogeneity of the beta-adrenergic receptor in lymphoma cells. The differential loss of the [125I]IABP labeling in the two polypeptides suggests a functional heterogeneity as well.

Differences in the forskolin activation of adenylate cyclases in wild-type and variant lymphoma cells

The ability of the diterpene forskolin to stimulate cyclic AMP accumulation in intact cell and membrane preparations of wild-type S49 lymphoma cells (WT) and a number of variants has been confirmed. Additionally, a number of salient new findings have emerged: (a) A time delay in forskolin stimulation of cyclic AMP accumulation and adenylate cyclase (t 1/2 approximately equal to 1.5 min) occurred in all hormone-sensitive WT and variant cell and membrane preparations tested. (b) The time delay was missing in the adenylate cyclase-deficient variant (cyc-) of the S49 lymphoma cell, which also lacks functional adenylate cyclase-coupling proteins. (c) The simultaneous addition of epinephrine and forskolin to WT cells or to membrane preparations eliminated the time delay. (d) Forskolin stimulation of intact WT cells did not appear to desensitize adenylate cyclase. (e) The activation of WT adenylate cyclase by forskolin was biphasic with respect to concentration, with both high- and low-affinity components being apparent. In cyc-, only the low-affinity component was detected.

Specific muscarinic-cholinergic desensitization in the neuroblastoma-glioma hybrid NG108-15

The cholinergic agonist carbachol, epinephrine, and the opiate morphine all inhibit prostaglandin E1 (PGE1)-stimulated adenylate cyclase in homogenates from the neuroblastoma-glioma hybrid NG108-15. Pretreatment of the hybrid with 100 microM carbachol resulted in the rapid loss (desensitization) of the carbachol inhibition of adenylate cyclase (t1/2 less than 3 min). The desensitization of the carbachol inhibition was blocked by 0.1 microM atropine. Pretreatment with carbachol (1-24 h) did not significantly affect the inhibition of adenylate cyclase by either epinephrine or morphine, nor did it alter the PGE1-stimulated activity, that is, no supersensitization was observed. Cholate extracts of the particulate fraction from either carbachol-desensitized or of control NG108-15 were able to reconstitute adenylate cyclase activities of the coupling proteins (G/F)-deficient cyc- lymphoma cell membranes with equal efficacy. These results suggested that the coupling proteins of the adenylate cyclase were not altered by the carbachol pretreatment and that desensitization occurs at the receptor or at a receptor-associated level. However, the possibility remained that specific domains of the G/F, which interact only with muscarinic receptors, were altered.

Adenylate cyclase coupling proteins are not essential for agonist-specific desensitization of lymphoma cells

Epinephrine or prostaglandin E1 pretreatment of intact S-49 lymphoma cells specifically desensitized adenylate cyclase activity. Cholate extracts of membranes from these desensitized cells showed no difference from controls in their reconstitution of hormone-stimulated adenylate cyclase activity in the adenylate cyclase-deficient variant (cyc-) of the lymphoma cell line. Adenylate cyclase in the cyc- variant was also specifically desensitized by epinephrine in prostaglandin E1. The desensitization was assessed by reconstituting the cyc- adenylate cyclase with cholate extracts of the wild type lymphoma cells. Since the cyc- has been shown to lack the coupling or G/F proteins of the adenylate cyclase complex, and these proteins are restored by cholate extracts from wild type cells, we conclude that the G/F proteins are not altered or necessary for specific desensitization of the lymphoma cell lines.

Hydrolysis of soybean trypsin inhibitor by the gamma subunit of 7SNGF and EGF-BP

Although soybean trypsin inhibitor (STI) does not inhibit the esterase activity of either epidermal growth factor binding protein (EGF BP) or the gamma subunit of 7SNGF, it does behave as a substrate for proteolysis. Cleavage of the active site peptide bond of STI does occur when incubated in the presence of either EGF-BP or the gamma subunit of 7SNGF. The hydrolysis id pH dependent with maximum proteolysis at pH 6.0-7.0. the newly formed C-terminal arginine residue in modified STI can be released by carboxypeptidase B digestion. Both enzymes are inhibited by low concentrations (2-4 microgram/ml) of the microbial protease inhibitors leupeptin and antipain. These inhibitors are specific for trypsin-like proteases. Since both enzymes can be found as part of high molecular weight complexes with growth factors these results confirm the hypothesis that they are involved during a postranslational modification event.