Age-related changes in cortical porosity of the midshaft of the human femur

Complete cross-sections from the femoral midshaft of 180 individuals of known height and weight, aged 21–97 y, from a modern Australian population were examined using automatic video image analysis to quantify total subperiosteal porosity (TSPP). More specifically, the aim was to investigate whether age changes were similar in both sexes in (1) total subperiosteal area (TSPA), cortical area (CA) and medullary area (MA), (2) intracortical porosity (ICP), and (3) the respective contributions to TSPP made by MA and intracortical void area (ICVA). Our findings indicated that both sexes showed a significantly greater height normalised TSPA in the 70s as compared with the 20s. Males had consistently larger bones with a greater height normalised CA. In both sexes CA showed a tendency to increase till the 7th decade and then to decline, more so in females. MA approximately trebled in females and doubled in males over the age range studied. Although ICP also increased, from 4–6% in young adults to over 9% in the elderly, it showed a significant difference between the sexes only in the 3rd decade, being greater in males at this stage. By contrast, TSPP became significantly greater in females (from that recorded in the 3rd decade) by the time they reached the 50s, while in males this did not occur till the 80s. It increased from ∼25% in young adults of both sexes to ∼50% in females and ∼37% in males in their 80s. However, in the elderly there was great variability in both sexes in the appearance of bones from individuals of similar chronological age. Some bones differed little from those in younger subjects, others showed greatly increased ICP, still others displayed reduced cortical widths with low ICP. The femoral midshaft resembles other skeletal sites in that age changes in TSPP are more marked in females than males.     

Should Radiofrequency Therapy Be Performed in Every Symptomatic Patient with Supraventricular Tachycardia? (Pro Drug Position)

The indication for treatment of paroxysmal supraventricular tachycardia depends on the frequency and severity of the tachycardia attacks. If the tachycardia attacks are mildly symptomatic and occur only once or twice a year, there is no indication for either continuous drug therapy or radiofrequency oblation. The only therapeutic measure required is termination of each acute event. If symptoms occur frequently, long-term antiarrhythmic drug therapy is then indicated and will be effective for chronic prophylaxis in most individuals with a low risk of proarrhythmic events. Only in patients with severe or life-threatening symptoms or cases refractory to drug therapy would radiofrequency ablation possibly be justified.     

THE [LACTATE]/[PYRUVATE] RATIO AND ALCOHOL METABOLISM: EXPERIMENTS WITH NALOXONE IN FASTING NORMAL MALE VOLUNTEERS

Naloxone administration to fasting normal male volunteers reversesthe acute ethanol-induced increase in the blood [lactate]/[pyruvate]ratio, but fails to lower blood-ethanol concentration. The resultsare discussed in relation to factors affecting ethanol eliminationand the mechanism of antagonism of acute alcohol intoxicationby naloxone.     

Bropirimine-Induced Embryolethality after Oral Administration to the Pregnant Rat

Oral bropirimine (an immunomodulator shown to induce interferon)was administered to timed-pregnant Sprague-Dawley rats in fiveexperiments utilizing several different dosing schedules. Concentrationsof 100, 200, and 400 mg/kg of bropirimine were used. Interferonlevels were determined in maternal serum, spleen, and wholeembryo extracts and uterine contents were evaluated for survivalof the embryos. Maternal toxicity occurred in all experimentsas evidenced by dose-related decreases in body weight duringthe first 24 hr postdosing. Hematoxicology analyses of maternalserum revealed significant decreases in urea nitrogen, potassium,and albumin, along with increases in aspartate transaminase,alanine transaminase, and total bilirubin, in bropirimine-treateddams as compared to the vehicle controls. In addition, the meansfor maternal thymus weight decreased while the means for spleenweight increased with increasing concentration of bropirimine.As compared to the vehicle controls, interferon titers werehigh in maternal serum, maternal spleen, and, to a lesser extent,whole embryos, 2 hr postdosing, but had decreased or were belowdetectable levels 24 hr postdosing. Embryolethality was pronounced(increases in pre- and postimplantational loss) after a singledose (Gestation Day 3, 4, 5, 8, 9, or 10) of bropirimine, aswell as after 7 or 8 consecutive days (Gestation Days 6–12or 6–13) of treatment. Although embryotoxicity never occurredin these experiments in the absence of pronounced maternal toxicity,the pregnant dams never died as the result of bropirimine treatment,whereas the embryos frequently failed to survive.     

Visual spatial attention to stimuli presented on the vertical and horizontal meridian: An ERP study

In the first experiment, 48 subjects carried out a visual spatial attention task. Stimuli were presented at the vertical meridian, either above or below a fixation dot, and the subjects were instructed to attend to one of these stimulus positions and ignore the other position. In three different conditions, the distances between stimulus positions and fixation were 0.5°, 0.9°, and 1.3°. Subjects searched for the presence of prememorized target letters at the attended location: memory load was one or four items in different conditions. The P1/N1 enhancement typically found on the horizontal dimension was not observed on the vertical dimension. Instead, a positive shift of the attended compared with the unattended stimuli was found, which was most prominent at anterior electrodes. This positivity showed effects of the distance manipulation. The N2b-P3a effect of attention and the effect of memory load (search negativity) normally present in this kind of selective search task were also found. Reaction times were faster when attention was directed above fixation than when it was directed below fixation. The event-related potential data suggested that this difference could be attributed to a more efficient neglecting of irrelevant stimuli presented below fixation. In Experiment 2, we examined whether the absence of the P1/N1 enhancement as the result of spatial attention in Experiment 1 could be attributed to (a) the presentation of stimuli along the vertical meridian instead of along the horizontal meridian, (b) the use of midline electrodes instead of lateralized electrodes, and (c) the relatively small spatial separation between the relevant and irrelevant stimuli. Twelve subjects searched for the presence of a single target letter at an attended position in three different conditions. In two of the conditions the letters were presented to the left or right of fixation. The distance between fixation and the stimulus positions was 1.3° in one of these conditions and 3° in the other condition. In the third condition, the stimuli were presented at 3° above or below fixation. In all three conditions effects similar to those in Experiment 1 were observed. In addition, in all three conditions an enhancement of the P1 and N1 components was found at two lateral occipitotemporal electrodes.     

Blood pressure analysis

SUMMARY  Arterial blood pressure is influenced by sleep-related breathing disorders. As cardiovascular consequences can be diagnosed by an accurate recording and analysis of blood pressure, new recording methodologies and an approach to analysis are presented here. Invasive continuous blood pressure recording is the common reference for all methodologies. As blood pressure varies rapidly in parallel with sleep-related breathing disorders it is indispensible to record blood pressure continuously. To introduce non-invasive methodology the Finapres system was used during sleep studies; a validation study showed severe limitations. This study was followed by the validation of an improved system called Portapres, which is portable, has two finger cuffs and a hydrostatic height compensation.
Analysis of continuous blood pressure in patients with sleep apnoea is carried out to detect mechanisms which influence the cardiovascular risk. Spectrum analysis of systolic blood pressure showed two different major oscillations present in patients with obstructive sleep apnoea. One oscillation (<0.06 Hz) occurs in parallel with each apnoeic episode and the other oscillation (0.2-0.4 Hz) occurs in parallel with the obstructive efforts during each apnoea and in parallel with respiration during periods of snoring. These two oscillations were so specific that the use of non-invasive continuous blood pressure recording allowed an estimation of the extent of underlying breathing disorders, and assessment of cardiovascular risk in a patient with obstructive apnoea in terms of hypertension and on the basis of ambulatory monitoring.     

Antihistamines Block Radiation-Induced Increased Intestinal Blood Flow in Canines

Antihistamines Block Radiation-Induced Increased IntestinalBlood Flow in Canines. COCK-ERHAM, L. G., DOYLE, T. F., DONLON,M. A., AND GOSSETT-HAGERMAN, C. J. (1985). Fundam. Appl. Toxicol.5, 597–604. Radiation-induced systemic hypotension isaccompanied by increased intestinal blood flow (IBF) and anincreased hematocrit (HCT) in dogs. Histamine infusion leadsto increased IBF and intestinal edema with consequent secretionof fluid into the intestinal lumen. This study was performedto determine whether these effects could be diminished by prioradministration of H₁ and H₂ histamine blockers. Dogs were givenan iv infusion of mepyramine (0.5 mg/min) and cimetidine (0.25mg/min) for 1 hr before and for 1 hr after radiation (H₁ andH₂ blockers, respectively). Mean systemic arterial blood pressure(MBP), IBF, and HCT were monitored for 2 hr. Systemic plasmahistamine levels were determined simultaneously. Data obtainedindicated that the H₁ and H₂ blockers, given simultaneously,were successful in blocking the increased IBF and the increasedHCT seen after 100 Gy, whole-body, radiation. However, thepostradiation hypotension was only somewhat affected, with theMBP falling to a level 28% below the preradiation level. Plasmahistamine levels reached a sharp peak, as much as 20% abovebaseline, at 4 min postradiation. These findings implicate histaminein the radiation-induced increase in IBF and HCT but not forthe gradual decrease in postradiation blood pressure     

Effect of Chronic Aromatase Inhibition by Δ1 -Testolactone on Pituitary-Gonadal Function in Oligozoospermic Men

Aromatase inhibition by delta 1-testolactone (Teslac, 500 mg twice daily) for 6 months in 9 patients with idiopathic oligozoospermia lowered the levels of serum estradiol (E2) and thereby sex hormone binding globulin (SHBG) (rS = +0.40, p less than 0.025) to values -35 and -25%, respectively, below the pretreatment values (P less than 0.001 and less than 0.005). The E2 decrease was accompanied by a temporary increase (+50%) in the levels of follicle stimulating hormone (FSH), not of luteinizing hormone (LH), and of 17 alpha-hydroxyprogesterone (17 alpha-OHP), but less of testosterone (T) (+30%), which led to a transient rise in the 17 alpha-OHP/T ratio. The T/E2 ratio and "free T" index (T/SHBG) almost doubled until the end of the treatment period. During delta 1-testolactone treatment the mean sperm density gradually rose from 8.1 +/- 1.3 (SEM) before to 21.3 +/- 6.7 X 10(6)/ml after 6 months (P less than 0.01), whereas the total sperm count almost threefold increased (P less than 0.05). Sperm concentrations exceeding 20 X 10(6)/ml were achieved in 4 of the 9 patients. Two of these patients' wives became pregnant. Although the data point to a pivotal role of estrogens in the pathogenesis of the spermatogenic lesion in some patients with idiopathic oligozoospermia, the lack of a beneficial effect of estrogen lowering in others points to a multicausal nature of the disease entity.