Introduction to the special issue: transitions in substance use across time, gender, and culture.
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Adolescent↗
Biomedical subjects
R J Rose
Publications and source records attributed to R J Rose.
Distribution and heritability of BMI in Finnish adolescents aged 16y and 17y: a study of 4884 twins and 2509 singletons.
OBJECTIVE: 1) To estimate the heritability of body mass index (BMI) in twins aged 16y and 17y, with a special emphasis on gender-specific genetic effects and 2) to compare heights, weights, BMIs, and prevalences of 'overweight' (BMI > or = 25 kg/m2) in these twins and in singletons aged 16.5y. DESIGN: Cross-sectional and longitudinal epidemiological questionnaire study of twins at ages 16y and 17 y, and cross-sectional study of singletons at age 16.5y. MEASUREMENTS: BMI (kg/m2) was calculated from self-reported heights (m) and weights (kg). SUBJECTS: 4884 twins (2299 boys, 2585 girls) at baseline (age 16 y), 4401 twins (2002 boys, 2399 girls) at age 17 y, and 2509 singletons (1147 boys, 1362 girls) at age 16.5 y. Both twin and singleton samples are nationally representative. RESULTS: At the ages of 16y and 17y, genetic effects accounted for over 80% of the interindividual variation of BMI. The correlations for male-female pairs were smaller than for either male-male or female-female dizygotic pairs. The singletons, especially the boys, had a higher BMI than the twins. Nine percent of singleton boys, but only 4-6% of twin boys and twin and singleton girls were 'overweight' (BMI > or = 25 kg/m2). CONCLUSIONS: Among adolescents, genetic factors play a significant role in the causes of variation in BMI. The genetic modelling suggested that the sets of genes explaining the variation of BMI may differ in males and females. At this age, the twin boys, but not girls, seem to be leaner than singletons. Further follow-up will indicate whether these small differences disappear, and if not, what implications it might have to the generalizability of twin studies.
Adolescent↗
Bone marrow response to large volume blood collection in the horse.
Evaluation of erythropoietic regeneration in horses is difficult unless serial bone marrow aspirates are performed. To investigate the acute and chronic erythropoietic regenerative response of equine bone marrow following acute removal or loss of blood, sequential bone marrow aspirates over 4 weeks were taken from the sternum of five horses from which 20 ml kg(-1)of blood had been removed. We found that the total number of erythroid cells counted (expressed as a percentage of the total number of erythroid and myeloid cells counted) expanded initially by 13.7 per cent within 3 days after blood removal, the erythroid response peaking by 9 days with a further 13.5 per cent increase. This peak coincided with the lowest M:E ratio. Concomitantly, a shift from proliferative phase cells to maturing phase cells occurred, which appeared to persist beyond 31 days post collection. Thus, we found that the equine bone marrow mounted a regenerative erythropoietic response more slowly than previously determined and, also, regeneration of the erythroid compartment was incomplete 31 days after blood removal of this magnitude.
Animals↗
Histopathological findings in the medial palmar and dorsomedial intercarpal ligaments of the equine midcarpal joint.
Medial palmar intercarpal ligaments (MPICL) and dorsomedial intercarpal ligaments (DMICL) from the midcarpal joints of 11 adult horses in training were examined histopathologically. These were compared with ligaments from seven horses less than 12 months of age, and 10 grossly enlarged DMICLs of adult horses. Tearing of the MPICL was observed in 15 of 22 joints from adult horses. Collagen fibre bundles of the MPICLs generally were disorganized and poorly aligned, and there were large areas of loose connective tissue. In young horses there was more parallel alignment of collagen bundles and less loose connective tissue. Collagen bundles of adult DMICLs were well organized and showed parallel alignment, whereas in foals the structure appeared more like that of fibrous joint capsule. Grossly enlarged DMICLs in adults consistently had discrete areas of fibrovascular infiltration. Degeneration of the MPICL was associated with increasing age and could explain the high incidence of tearing of the ligament. Enlargement of the DMICL was associated with low-grade tearing and repair.
Aging↗
The state of implantable pain therapies in the United States: a nationwide survey of academic teaching programs.
UNLABELLED: The purpose of this questionnaire survey was to provide an overview of anesthesiology pain fellowship programs in the United States with regard to implantation of spinal cord stimulators (SCS) and opioid infusion devices. Of the 95 programs solicited, 80% responded to questions pertaining to the prevalence of use and technical considerations of implantation. Of the responding programs, 87% report implanting SCS, and 84% report implanting neuraxial infusion pumps. All programs perform a stimulation or infusion trial before implantation, although the duration varied from a trial in the operating room at the time of implantation to 25 days. Of the programs, 83% implant cylindrical leads, and 17% implant flat leads via laminectomy for their nonrevision SCS implants. Morphine, bupivacaine, hydromorphone, and baclofen are the most commonly used drugs and are used in implanted pumps by >50% of respondents. The question of industry-sponsored pain fellow education in implantable techniques is addressed. IMPLICATIONS: Of the pain teaching programs in the United States, 80% responded to a questionnaire eliciting information about the implantation of spinal cord-stimulating and opioid infusion devices. The range and diversity of responses imply a lack of agreement about implantation techniques, drugs, and protocols.
Analgesics↗
Spinal cord stimulation for intractable angina pectoris.
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Aged↗
Postoperative performance of racing horses with tearing of the medial palmar intercarpal ligament.
OBJECTIVE: To examine the relationship between medial palmar intercarpal ligament (MPICL) tearing and postoperative performance in racing horses. MATERIALS AND METHODS: The postoperative performance of 42 horses in which the midcarpal joint was examined arthroscopically was followed prospectively. Intra-articular variables examined were the severity of MPICL tearing, subchondral bone damage and articular cartilage damage. Using a scoring system based on the class of race and the position in the race, a mean score was calculated for up to five races before and after surgery. The preoperative score was subtracted from the postoperative score to give a net score. Statistical analysis was by a Mann Whitney U test and multiple linear regression. RESULTS: Thirty-two (76%) raced postoperatively, 23 (55%) won at least one race and 12 of 26 (46%) performed at the same or higher level. Horses with grades 2 to 4 MPICL tearing had significantly lower net scores than those with grade 1 or no tearing. The severity of subchondral bone damage was the only variable on its own that was significantly correlated with net score (r2 = 0.23, P < 0.05). The addition of the grade of MPICL tearing to bone damage significantly improved the prediction of postoperative performance (P < 0.05). The inclusion of articular cartilage damage had no effect on the prediction of postoperative performance. CONCLUSION: Tears involving more than one third of the MPICL as observed arthroscopically have a significant detrimental affect on postoperative performance of racing horses.
Animals↗
Comparison of bacteriology and cytology of tracheal fluid samples collected by percutaneous transtracheal aspiration or via an endoscope using a plugged, guarded catheter.
Cytological and bacteriological results from tracheal fluid samples obtained endoscopically using a telescoping, plugged catheter (TPC) were compared with results from samples collected by percutaneous transtracheal aspiration (PTA). The TPC technique and PTA were performed in random order on 9 healthy Standardbred geldings. Three weeks later the procedures were performed on the same horses in the reverse order. The presence of oropharyngeal contamination was determined by quantitative bacteriology and quantification of squamous epithelial cells (SEC)/ml sample. The relative numbers of macrophages, haemosiderophages, giant cells, neutrophils, lymphocytes and eosinophils did not differ between techniques. The number of SEC/ml was greater in samples with more colony forming units/ml indicating that quantification of SEC provides evidence of the probable degree of oropharyngeal contamination. Fifteen out of the 18 TPC samples were free of contamination, indicating that the TPC can provide adequate samples for bacteriology. The results also indicate that tracheoscopy sometimes results in oropharyngeal contamination of the trachea, but that this does not affect the results of the TPC sample.
Animals↗
Blood gas changes during incremental and sprint exercise.
We investigated and compared arterial blood gas and ventilatory changes during rapid acceleration sprint and during incremental treadmill exercise. Seven clinically normal racehorses completed standardised incremental exercise tests and rapid acceleration tests at speeds calculated to elicit 115% VO2max. Arterial oxygen tension decreased (P < 0.001) between 15 s (mean +/- s.d. 103.8 +/- 14.3 mmHg) and 30 s (85.0 +/- 7.7 mmHg) after the onset of rapid acceleration exercise, but did not change significantly during the remainder of the sprint. This was accompanied by an increase in PaCO2 of 5.9 mmHg (P < 0.05). Despite reductions in SaO2 during exercise, CaO2 did not change due to increases in haemoglobin concentration. Heart rate increased rapidly (P < 0.001) during the first 15 s of exercise and thereafter remained constant. The mean maximum speed during the incremental test (11.4 +/- 0.5 m/s) was not significantly different to the speed calculated to elicit 115% VO2max during the sprint test (12.2 +/- 0.8 m/s). The mean peak HR and Hb during the sprint test were significantly less than during the incremental test. However, there were no significant differences in the maximum or minimum values achieved for other variables. We conclude that rapid acceleration exercise is accompanied by rapid changes in blood gas variables, reaching steady state within 45 s. Blood gas responses during the simpler incremental test describe maximal changes during high-intensity sprint exercise.
Animals↗
Effects of phlebotomy and autologous blood transfusion on oxygen transport in the racehorse.
Because the haemoglobin concentration Hb[ during exercise may be at the upper limit of blood viscosity for effective oxygen delivery, we hypothesised that administration of blood would not further enhance oxygen delivery or exercise capacity. Six Thoroughbred geldings were used in 5 incremental treadmill exercise tests over a period of 4 weeks. The first test was performed 6 days prior to phlebotomy, which involved the removal of 20 ml/kg bwt of venous blood. Exercise tests were performed at 1, 8 and 15 days after blood removal. Six days after the 15 day post phlebotomy exercise test, blood from each horse was reinfused and the final test performed 24 h after blood reinfusion. During the 3 weeks following blood collection, the blood, collected into acid citrate dextrose, was stored at 3 degrees C. Each exercise test involved measurements of arterial and mixed venous blood gases, plasma lactate concentrations, heart rate and VO2 using an open flow system. Cardiac output was measured by direct Fick. The removal and reinfusion of blood had significant effects on packed cell volume (PCV) with the lowest PCV value during exercise of 0.57 +/- 0.04 l/l being recorded in the second post phlebotomy test and the highest value of 0.67 +/- 0.04 l/l found after blood reinfusion. There were no significant effects of phlebotomy or blood reinfusion on arterial blood gas values. However, arteriovenous oxygen content difference was significantly altered by phlebotomy and reinfusion. The maximal values during the 3 tests following phlebotomy were significantly lower (P < 0.05) by about 7% than those before phlebotomy and after blood reinfusion, mirroring the alterations in Hb[. There was no significant effect of phlebotomy or blood reinfusion on heart rate but stroke volume was significantly higher (P < 0.01) during the 3 post phlebotomy tests than for the control or blood reinfusion tests. There was no significant effect of phlebotomy or blood reinfusion on either the submaximal or maximal values for VO2. No significant effect of blood removal or reinfusion was found on the treadmill run time to fatigue. We concluded that haemodynamic adjustments following phlebotomy or blood reinfusion maintained oxygen delivery during exercise. No detrimental effects on exercise capacity were found from phlebotomy nor beneficial effects from autologous blood transfusion. However, it should be noted that the extent of change induced in Hb[ was relatively small and with the number of horses in the study, the experimental power was not great.
Animals↗
Effects of low- and moderate-intensity training on metabolic responses to exercise in thoroughbreds.
This experiment was undertaken to determine whether there were differences in cardiorespiratory, haematological and muscular responses in horses trained at either low or moderate intensities. Ten Thoroughbred horses previously rested in paddocks for 4 months were trained 5 days/week for 9 weeks. Horses were allocated randomly into fast or slow groups and exercised the same distance each day. Training distances were 1600 m in Weeks 0 and 1 up to 4000 m in Week 9. The fast group were trained at an intensity inducing a post training blood lactate of 4-8 mmol/l. This intensity was determined for each horse each week. The slow group trained at half the speed of the fast group (blood lactate < 2 mmol/l). Horses performed a standardised exercise test prior to (Week 0) and on Weeks 1, 2, 3, 4, 7 and 9 of training. HR, VO2, VCO2 and blood lactate concentration were recorded during the last 15 s of each step. Blood samples were collected at the end of each test for determination of red cell and plasma volume. Muscle biopsies were collected from the middle gluteal muscle before training and after 4 and 9 weeks training. Training intensity had few effects on the majority of variables measured and results for both groups are combined unless otherwise stated. Bodyweight was unaffected by training. Economy of locomotion decreased from 12.0 +/- 0.4 ml/kg bwt/m prior to training to 13.8 +/- 0.6 ml/kg bwt/m at the end of training in the fast group. Run time to fatigue was not affected by training intensity. VO2max increased from 120.3 +/- 4.8 to 144.7 +/- 3.5 ml/kg bwt/min with a significant correlation between run time and VO2max. Peak HR was 221.4 +/- 2.5 beats/min prior to training and 226.5 +/- 1.7 beats/min after the first 4 weeks of training. V200 and VLa4 increased in response to training. Similarly, VLa4 increased from 7.0 +/- 0.5 to 9.2 +/- 0.2 m/s with VLa4 correlated to VO2max. Plasma volume decreased from 29.1 +/- 1.7 to 25.8 +/- 0.9 l during the last 3 weeks of training. Blood volume, red cell volume and/or red cell volume/kg were unaffected by intensity or duration of training. The activity of CS in muscle increased in the first 5 weeks of training whereas HAD activity was not affected by intensity or duration of training.
3-Hydroxyacyl CoA Dehydrogenases↗
Comparison of exercise tests in French trotters under training track, racetrack and treadmill conditions.
Standardised exercise tests were performed at 2 different tracks and on an uninclined treadmill during the same week to determine the influence of exercise surface on different measured variables such as heart rate (HR), blood lactate concentration, packed cell volume, stride frequency, stride length, gait symmetry and regularity and on different derived physiological variables such as the speed at a HR of 200 beats/min (V200), the speed at a blood lactate concentration of 4 mmol/l (V4), the speed at a maximal HR (VHRmax). Five French Trotters, age 3 years, in training for 3 months prior to the test, performed 3 exercise tests on a training track (Test 1), a racetrack (Test 2) and an uninclined treadmill (Test 3). Test 1 utilised 3 steps each of 3 min at speeds of 490, 560 and 630 m/min. Tests 2 and 3 utilised the same speeds and a fourth step in which the horse was accelerated for 30 s to speed approaching maximal. No significant differences (P < 0.05) were found for the physiological and locomotor variables between the 2 tracks. In contrast, there was a significant difference (P < 0.05) for these variables between the tracks and the treadmill, horses showing lower heart rate and blood lactate response, reduced stride frequency and increased stride length and regularity on the uninclined treadmill. We concluded that this standardised exercise test was repeatable on various tracks even when the surface and geometry vary. In contrast, both physiological and locomotor variables were different when comparing the tracks with the uninclined treadmill.
Animals↗
Maximal exercise transiently disrupts hormonal secretory patterns in standardbred geldings.
Basal concentrations of cortisol (CORT), beta-endorphin (beta EP), growth hormone (GH) and testosterone (T) and their disruption during 32 h of recovery after treadmill exercise were investigated in 4 geldings. Blood samples were collected from resting horses every 20 min between 0600-1000 and 1500-1900 h, and hourly between 1000-1500 h on 3 consecutive days. Treadmill exercise tests comprising 2 min intervals at 30, 50, and 70% VO2max then to fatigue at 100% VO2max were conducted between 1020-1130 h on Day 2. Blood was collected before, during and 15, 30, 60 and 90 min after exercise. Mean (Cav), peak (Cmax) and total (i.e. integrated) (Ctot) concentrations were calculated for CORT, beta EP and GH during the 20 min sampling sessions, and for CORT, beta EP, GH and T between 1000-1300 h on Days 1-3 (incorporating the samples during exercise on Day 2) and 1300-1900 h on Days 1-3. Cav, Cmax and Ctot for CORT, beta EP, GH and T were greater during exercise and recovery than in the same period on Day 1. Cav and Ctot values for plasma T during the 1300-1900 h period were significantly elevated on Day 2 and compared to Day 1 (P < 0.05), but there were no differences between Days 1 and 3 values for these variables. We concluded that plasma T concentration increases in response to maximal exercise in geldings, as does plasma CORT, beta EP and GH. Furthermore, maximal exercise disrupts basal plasma concentrations of CORT, beta EP and GH for up to 24 h and T for 26-32 h post exercise in geldings, therefore reflecting the minimum recovery periods required before evaluating normal, resting levels of these hormones in horses undergoing training.
Animals↗
Haematological and biochemical responses to training and overtraining.
We sought a physiological marker of overtraining in horses, using commonly practised field and laboratory tests to allow early prediction and treatment of the syndrome. Thirteen Standardbred horses were trained as follows: phase 1 (endurance, 7 weeks), phase 2 (high intensity, 9 weeks) and phase 3 (overload, 18 weeks). In phase 3 the horses were divided into 2 groups: overload training (OLT) and control (C). The OLT group exercised at greater intensities, frequencies and durations than the C group. Overtraining occurred after 31 weeks and was defined as a significant decrease in treadmill run time to fatigue (RT) in response to a standardised exercise test (SET). Variables measured included: feed intake, bodyweight (BWT), resting haematology and plasma biochemistry and treadmill SETs to measure RT. The OLT group had a decrease in BWT after week 28 (P < 0.05) without a reduction in feed intake and a reduction in RT during the SET after 31 weeks. Signs persisted after 2 weeks of a reduced training load confirming overtraining. Haematology and biochemistry failed to detect any markers of overtraining. Although no physiological markers of overtraining were identified, empirical observations revealed that the behaviour of horses in the OLT group was different from those in the C group during the period of overtraining. This study reflects that a model of overtraining has been developed based on measurement of a reduction in performance; however, there were no consistent changes in haematology or serum biochemical values in association with the decrement in performance capacity.
Animals↗
Peers, teachers and parents as assessors of the behavioural and emotional problems of twins and their adjustment: the Multidimensional Peer Nomination Inventory.
A multidimensional peer nomination inventory (MPNI; 30 items) and parallel versions--MPNI-Teacher and MPNI-Parental Rating Forms (37 items each)--were developed during a major new Finnish study of families with twins. The twins (477 girls and 467 boys) were 12 years old, representing subsets of three nationwide Finnish twin cohorts (b. 1983-1985). They were enrolled in 503 school classes, and the total number of children participating in peer nominations was 12,937. Three main factors were extracted from peer nominations and teacher and parental assessments. Intercorrelating sub-components were found, especially in parental assessments. Scales were formed, accordingly, for Behavioral Problems (including Hyperactivity-Impulsivity, Aggression, and Inattention), Emotional Problems (including Depression and Social Anxiety), and Adjustment (including Constructiveness, Compliance, and Social Activity). A framework for the development of the multidimensional inventory was a model of emotional and behavioural regulation. Peer nominations were most reliable, while parental assessments, although mostly satisfactory, were least reliable. Results provided evidence of concurrent validity of peer-referenced assessment, using teacher assessments as criteria; correlations between assessments of peers and parents were lower. The inventory has discriminative validity. Intra-pair correlations of monozygotic co-twins were higher than correlations of same-sex (SS) and opposite-sex (OS) dizygotic (DZ) co-twins for all scales across all three assessors, and peer nominations of both SS and OSDZ co-twins yielded correlations significantly greater than zero for all scales. All scales, except Depression and Social Anxiety, differentiated boys from girls.
Anxiety↗
Individual differences in adolescent religiosity in Finland: familial effects are modified by sex and region of residence.
Data from 16-year-old Finnish twin pairs were used to estimate familial effects on religiosity and the modification of those effects by sex and residential region. The sample of 2265 twin boys and 2521 twin girls formed 779 monozygotic and 1614 dizygotic pairs, 785 of the same sex and 829 of opposite sex. We compared religiosity scores of twins living in more rural and traditional northern Finland with those living in the more urban and secular southern region. Girls had higher religiosity scores than did boys, and twins living in northern Finland had higher religiosity scores than those resident in southern Finland. Correlations for monozygotic twins were slightly higher than those for dizygotic twins, and covariance modeling found modest heritability of religiosity [11% (95% CI 0-24) for girls; 22% (95% CI 6-38) for boys], and substantial shared environmental effects [60% (95% CI 49-69) and 45% (95% CI 31-57)] among girls and boys, respectively. The correlation between shared environmental effects in boys and girls was estimated to be 0.84 (95% CI 0.73-0.99). In analyses distinguishing region of residence, girls living in southern Finland were found to have significantly higher unshared environmental effects than girls in northern Finland, while boys living in the urban south appeared to have lower shared environmental effects, and higher additive genetic effects, than boys living in the rural north.
Adolescent↗
Familial and socioregional environmental effects on abstinence from alcohol at age sixteen.
OBJECTIVE: This study identifies, in genetically informative data, familial and socioregional environmental influences on abstinence from alcohol at age 16. METHOD: Data are from FinnTwin 16, a population-based study of five consecutive birth cohorts of Finnish twins (N = 5,747 twin individuals), yielding 2,711 pairs of known zygosity. Measures of alcohol use, embedded into a health-habits questionnaire, were taken from earlier epidemiological research with nontwin Finnish adolescents. The questionnaire was administered sequentially to all twins as they reached age 16. Separate questionnaires, including measures of alcohol use and screening questions for alcohol problems, were received from 5,243 of the twins' parents. RESULTS: Abstinence from alcohol to age 16 exhibits very significant familial aggregation, largely due to nongenetic influences. Abstinence rates are influenced by socioregional variation, sibling interaction effects and parental drinking patterns. Sibling and parental influences are greater in some regional environments than in others: the relative likelihood that a twin abstains, given that the co-twin does, or that both parents do, is shown to be modulated by socioregional variation. CONCLUSION: Environmental contexts affect the likelihood of maintaining abstinence from alcohol to midadolescence, and socioregional variation modulates influences of siblings and parents. The results illustrate how genetically informative data can inform prevention research by identifying target variables for intervention efforts.
Adolescent↗
Effects of muscle glycogen depletion on some metabolic and physiological responses to submaximal treadmill exercise.
The aim of this study was to investigate the effects of reduced muscle glycogen concentration on some physiological and metabolic responses during moderate intensity treadmill exercise in horses. Six Thoroughbred geldings were randomly allocated to 2 treatments (protocols A and B) or control in a 3 x 3 replicated Latin square design. In protocol A, horses performed low intensity exercise while horses in protocol B performed short bursts of high intensity exercise. Protocol A was designed to induce glycogen depletion mainly of slow twitch muscle fibers while protocol B aimed to deplete mainly fast twitch muscle fibers. Horses in the control group did not undergo exercise prior to the exercise test. Five hours after glycogen depletion, horses performed treadmill exercise at 60% VO2max at a treadmill slope of 10% until fatigue (20-30 min). The induced glycogen depletion prior to exercise had no significant effect on plasma glucose, insulin, or lactate concentrations during the exercise test, and there was no effect on glycogen utilization rate, although respiratory exchange ratios were lower in the glycogen-depleted groups. The VO2, heart rate and central blood temperature did not vary significantly between the protocols A and B and control throughout the exercise test. It was concluded that 20-30% depletion of glycogen concentration in the middle gluteal muscle resulted in a shift towards fat metabolism, but does not significantly affect heart rate, oxygen uptake, or concentrations of plasma glucose and lactate during moderate intensity exercise.
Animals↗