In vivo human triceps surae and quadriceps femoris muscle function in a squat jump and counter movement jump

An optic fibre method was used to measure in humans in vivo Achilles (ATF) and patellar tendon forces (PTF) during submaximal squat jumps (SJ) and counter movement jumps (CMJ). Normal two-legged jumps on a force plate and one-legged jumps on a sledge apparatus were made by four volunteers. Kinetics, kinematics, and muscle activity from seven muscles were recorded. The loading patterns of the tendomuscular system differed among the jumping conditions, but were similar when the jumping height was varied. Peak PTF were greater than ATF in each condition. In contrast to earlier simulation studies it was observed that tendomuscular force could continue to increase during the shortening of muscle-tendon unit in CMJ. The concentric tendomuscular output was related to the force at the end of the stretching phase while the enhancement of the output in CMJ compared to SJ could not be explained by increases in muscle activity. The stretching phase in CMJ was characterised by little or no electromyogram activity. Therefore, the role of active stretch in creating beneficial conditions for the utilisation of elastic energy in muscle was only minor in these submaximal performances. The modelling, as used in the present study, showed, however, that tendon underwent a stretch-shortening cycle, thus having potential for elastic energy storage and utilisation. In general, the interaction between muscle and tendon components may be organised in a manner that takes advantage of the basic properties of muscle at given submaximal and variable activity levels of normal human locomotion. Accepted: 28 June 2000     

S-Ketamine Anesthesia Increases Cerebral Blood Flow in Excess of the Metabolic Needs in Humans

Background: Animal studies have demonstrated neuroprotective properties of S-ketamine, but its effects on cerebral blood flow (CBF), metabolic rate of oxygen (CMRO2), and glucose metabolic rate (GMR) have not been comprehensively studied in humans.

Methods: Positron emission tomography was used to quantify CBF and CMRO2 in eight healthy male volunteers awake and during S-ketamine infusion targeted to subanesthetic (150 ng/ml) and anesthetic (1,500-2,000 ng/ml) concentrations. In addition, subjects' GMRs were assessed awake and during anesthesia. Whole brain estimates for cerebral blood volume were obtained using kinetic modeling.

Results: The mean +/- SD serum S-ketamine concentration was 159 +/- 21 ng/ml at the subanesthetic and 1,959 +/- 442 ng/ml at the anesthetic levels. The total S-ketamine dose was 10.4 mg/kg. S-ketamine increased heart rate (maximally by 43.5%) and mean blood pressure (maximally by 27.0%) in a concentration-dependent manner (P = 0.001 for both). Subanesthetic S-ketamine increased whole brain CBF by 13.7% (P = 0.035). The greatest regional CBF increase was detected in the anterior cingulate (31.6%; P = 0.010). No changes were detected in CMRO2. Anesthetic S-ketamine increased whole brain CBF by 36.4% (P = 0.006) but had no effect on whole brain CMRO2 or GMR. Regionally, CBF was increased in nearly all brain structures studied (greatest increase in the insula 86.5%; P < 0.001), whereas CMRO2 increased only in the frontal cortex (by 15.7%; P = 0.007) and GMR increased only in the thalamus (by 11.7%; P = 0.010). Cerebral blood volume was increased by 51.9% (P = 0.011) during anesthesia.     

Long-term Results of Vein Sparing Varicose Vein Surgery

The aim of this study was to assess the long-term functional outcome of vein sparing varicose vein surgery using handheld Doppler ultrasound (HHD). The series consisted of 171 consecutive day-case surgery patients operated on for uncomplicated lower limb varicose veins. Venous segments considered competent were spared based on clinical examination and HHD, which was performed preoperatively only when deemed necessary by the surgeon. After a mean follow-up of 8 years all patients were examined, a systematic HHD evaluation was performed, and the findings were classified according to the CEAP (Clinical, Etiological, Anatomical, Pathophysiological) classification, and disability scoring was performed. During the follow-up period 17% of the legs were reoperated or scheduled for reoperation. At follow-up 79% of all patients were asymptomatic without reoperation. In 24%, recurrent varicosities were present and venous reflux was demonstrated by HHD. Recurrence was two times more common when the saphenofemoral junction had originally been left intact. Of all recurrent cases, reflux was demonstrated in the long saphenous vein (LSV) above the knee in 62%, in the LSV below the knee in 7%, in the short saphenous vein (SSV) in 16%, in the posterior arch vein in 38%, and in a thigh perforator in 8%. Of the legs reoperated during the follow-up period 41% presented with venous reflux at the follow-up visit. We conclude that HHD efficiently reveals sites of reflux that have been missed during previous surgery and that a thorough preoperative HHD examination and marking of reflux routes is required.     

Cynical hostility as a determinant of poor oral health status in an adult population

Our aim in this study was to determine whether there is an association between cynical hostility and clinically determined poor oral health, and whether this association is confounded by socioeconomic position and mediated by health behavior. The sample consisted of 4,207 dentate Finns, 30–64 yr of age. Oral health was measured in terms of numbers of missing teeth, of decayed teeth, and of teeth with periodontal pockets (≥ 4 mm). Cynical hostility was measured using the cynical distrust self-administered questionnaire. The subjects with the highest level of cynical hostility had fewer teeth, and a greater number of decayed teeth as well as teeth with deepened periodontal pockets compared to subjects with the lowest level of cynical hostility. The associations between cynical hostility and number of missing and decayed teeth were clearly confounded by level of education. Poor oral health behavior was shown to be a possible mediator between cynical hostility and number of decayed teeth, but not of missing teeth or teeth with deepened periodontal pockets. General health-related behavior did not serve as a possible mediator in any of the associations. In conclusion, cynical hostility can be considered as a risk marker for poor oral health. Interventions aimed to improve oral health should focus on psychosocial factors and on less-educated subjects.     

Hunger/craving responses and reactivity to food stimuli during fasting and dieting

One group of fasting obese patients and one group of dieting obese patients were instructed to report their feelings of hunger and craving on a continuous basis before and during a three-week treatment period. Once a week they were also exposed to food slides to measure their reactivity to food stimuli. The frequency of hunger/craving responses and reactivity to food stimuli showed radically different changes over time in the fasting and dieting groups. During the last week of fasting, reactivity to food slides was completely abolished, and the frequency of hunger/craving responses was close to zero. Only slight changes of frequency of hunger/craving responses and reactivity to food stimuli were observed in the dieting group. The results suggest that the frequency of hunger/craving responses and reactivity to food stimuli show parallel decreases during fasting, but no changes during dieting.     

Growth differentiation factor-9 induces Smad2 activation and inhibin B production in cultured human granulosa-luteal cells

The TGF beta family member growth differentiation factor-9 (GDF-9) is an oocyte-derived factor that is essential for mammalian ovarian folliculogenesis. GDF-9 mRNAs have been shown to be expressed in the human ovarian follicle from the primary follicle stage onward, and recombinant GDF-9 has been shown to promote human ovarian follicle growth in vitro. In this study with primary cultures of human granulosa-luteal (hGL) cells, we investigated whether recombinant GDF-9 activates components of the Smad signaling pathways known to be differentially activated by TGF beta and the bone morphogenetic proteins (BMPs). As with TGF beta, GDF-9 treatment caused the phosphorylation of endogenous 53-kDa proteins detected in Western blots with antiphospho-Smad2 antibodies (alpha PS2). However, unlike BMP-2, GDF-9 did not activate the phosphorylation of antiphospho-Smad1 antibody (alphaPS1)-immunoreactive proteins in hGL cells. Infection of hGL cells with an adenovirus expressing Smad2 (Ad-Smad2) confirmed that GDF-9 activates specifically phosphorylation of the Smad2 protein. Infection of hGL cells with Ad-Smad7, which expresses the inhibitory Smad7 protein, suppressed the levels of both GDF-9-induced endogenous and adenoviral alpha PS2-reactive proteins. Furthermore, GDF-9 increased the steady state levels of inhibin beta(B)-subunit mRNAs in hGL cells and strongly stimulated the secretion of dimeric inhibin B. Again, Ad-Smad7 blocked GDF-9-stimulated inhibin B production in a concentration-dependent manner. We identify here for the first time distinct molecular components of the GDF-9 signaling pathway in the human ovary. Our data suggest that GDF-9 mediates its effect through the pathway commonly activated by TGF beta and activin, but not that activated by many BMPs. The results are also consistent with the suggestion that in addition to endocrine control of inhibin production by gonadotropins, a local paracrine control of inhibin production is likely to occur via oocyte-derived factors in the human ovary.     

Short-Term Bone Biochemical Response to a Single Bout of High-Impact Exercise

Bone response to a single bout of exercise can be observed with biochemical markers of bone formation and resorption. The purpose of this study was to examine the response of bone biochemical markers to a single bout of exhaustive high-impact exercise. 15 physically active young subjects volunteered to participate. The subjects performed continuous bilateral jumping with the ankle plantarflexors at 65 % of maximal ground reaction force (GRF) until exhaustion. Loading was characterized by analyzing the GRF recorded for the duration of the exercise. Venous blood samples were taken at baseline, immediately after, 2h and on day 1 and day 2 after the exercise. Procollagen type I amino terminal propeptide (P1NP, marker of bone formation) and carboxyterminal crosslinked telopeptide (CTx, marker of bone resorption) were analyzed from the blood samples. CTx increased significantly (32 %, p = 0.015) two days after the exercise and there was a tendensy towards increase seen in P1NP (p = 0.053) one day after the exercise. A significant positive correlation (r = 0.49 to 0.69, p ≤ 0.038) was observed between change in P1NP from baseline to day 1 and exercise variables (maximal slope of acceleration, body weight (BW) adjusted maximal GRF, BW adjusted GRF exercise intensity and osteogenic index). Based on the two biochemical bone turnover markers, it can be concluded that bone turnover is increased in response to a very strenuous single bout of exhaustive high-impact exercise.

Key points

• Studies on bone acute biochemical response to loading have yielded unequivocal results.
• There is a paucity of research on the biochemical bone response to high impact exercise.
• An increase in bone turnover was observed one to two days post exercise.

Key words: Bone biochemical marker, jumping, bone turnover, osteogenic index     

Psychotic boys performing well in school are at increased risk of suicidal ideation

Aim:  This study investigated how the level of school performance is associated with suicidal behavior and psychiatric disorders among adolescent psychiatric inpatients aged 12–17 years.
Methods:  Data were collected from 508 adolescents (300 girls, 208 boys; age 12–17 years) admitted to inpatient psychiatric hospitalization between April 2001 and March 2006. Information on the adolescents' school performance, suicidal ideation, suicide attempts and self-mutilation as well as psychiatric DSM-IV diagnoses was obtained using the Schedule for Affective Disorder and Schizophrenia for School-Age Children.
Results:  An elevated risk of suicidal ideation (OR = 3.6, 95% CI 1.3–10.2, P  = 0.017) and of psychotic disorders (OR = 3.2, 95% CI 1.0–10.0, P  = 0.048) was observed among male adolescents performing well in school. In addition, adolescents with poor school performance had an increased likelihood of substance-related disorder both in boys (OR = 2.6, 95% CI 1.1–6.1, P  = 0.027) and girls (OR = 2.5, 95% CI 1.2–5.1, P  = 0.011).
Conclusions:  Our findings indicate that psychotic inpatient male adolescents performing well in school are at an elevated risk of suicidal ideation. Although good school performance is often considered a marker of high intelligence and good general ability, symptoms of major psychiatric disorders and suicidality need to be taken very seriously among adolescents performing well in school.