Psychiatric disorders in the first-degree relatives of probands with bulimia nervosa

Data from a family study of psychiatric disorders showed higher rates of major affective disorders, eating disorders, and alcoholism in first-degree relatives of 40 bulimic probands than in first-degree relatives of 24 control subjects. More importantly, the data showed higher rates of major affective disorders in relatives of bulimic probands who themselves had no history of major affective disorders than in relatives of control subjects. This significant finding indicates a familial relationship between bulimia nervosa and major affective disorders, which suggests the possibility of a common diathesis.     

PaO2 increases with coughing in patients with chronic lung disease

We considered if the cyanosis frequently observed during a cough attack in patients with chronic lung disease was due to worsening hypoxemia. To investigate the effects of cough on PaO2, we measured arterial blood gases before and after a voluntary coughing period of 45 sec, in 11 patients with Interstitial Lung Disease (ILD) and 14 patients with Chronic Obstructive Lung Disease (COPD). All patients significantly increased (p less than 0.05) their PaO2 (COPD: from 49 +/- 2 to 60 +/- 2 mmHg; ILD from 44 +/- 2 to 51 +/- 3 mmHg, mean +/- SD) and decreased their PaCO2. We conclude that stable patients with COPD and ILD increase their PaO2 with coughing most likely due to hyperventilation. The cyanosis observed could be due to peripheral circulatory effects of coughing.     

Natural history of experimental pulmonary atelectasis in dogs with closed chest

In order to establish an animal model of pulmonary vasoconstriction we followed the time course of intrapulmonary shunt (Qs/Qt) in a canine model of lobar atelectasis with closed chest. Ten mongrel dogs were studied. Bronchial occlusion of the right lower lobe (RLL) was performed by inflating the balloon of a Foley catheter placed through a rigid bronchoscopy. Analysis of variance was used for statistical analysis. (15 minutes) After occlusion Qs/Qt reached its maximum increasing from 8.2 +/- 3.6 to 29.7 +/- 11.7% (p less than 0.05) and PaO2 decreased from 357 +/- 49 to 100 +/- 43 mm Hg (p less than 0.05). Afterwards, there was a progressive decline of Qs/QT accompanied by an also progressive increase in PaO2. At the end of the experiment (3 hrs post atelectasis) Qs/Qt was 11.2 +/- 4.9 and PaO2 251 +/- 124 mm Hg (p less than 0.05). Pulmonary vascular resistance increased post atelectasis from 439 +/- 168 to 598 +/- 256 d.s.cm-5 (p less than 0.05). Complete atelectasis of the RLL was confirmed postmortem. As the changes in Qs/Qt and PaO2 did not parallel the change in cardiac output we conclude that the mechanism of decrease in Qs/Qt was hypoxic vasoconstriction.     

Phenotypic properties of catecholamine-positive cells that differentiate in avian neural crest cultures

We have investigated several phenotypic features of the catecholamine-positive (CA+) cell population that develops in quail neural crest cultures. The number, spatial distribution, and morphology of CA+ and tyrosine hydroxylase-positive (TH+) cells are similar at all ages examined, suggesting that these 2 cell classes are identical. Neither CA+ nor TH+ cell bodies or processes were stained using antisera that recognize the 70 or 160 kDa subunits of chicken neurofilament protein. Other cell bodies and fibers in the cultures (which were CA- and TH-) were stained with these neurofilament antisera. The uptake and storage of 3H-norepinephrine by neural crest cultures containing CA+ cells were inhibited in the presence of desmethylimipramine and by incubation at 0 degrees C, but were unaffected by normetanephrine. Overnight treatment with reserpine eliminated histochemically detectable CA fluorescence from the cultures. Chronic reserpine treatment from day 2 to 7 in vitro prevented the appearance of CA+ cells, while normal numbers of TH+ and somatostatin-like immunoreactive (SLI) cells developed. The number and light-microscopic morphology of the CA+ cells that developed in these cultures were not dramatically altered by either exogenous NGF or 6-hydroxydopamine. Using the method of Grillo et al. (1974), we have demonstrated that the CA+ cells observed in the light microscope corresponded to cells containing abundant cytoplasmic granular vesicles (GV) characteristic of catecholamine storage granules observed in other systems. The GV diameters were quite similar in cells examined after 5, 7, 14, and 21 d in vitro. Most GV were 50-200 nm in diameter and were distributed in a unimodal manner, with the observed modal values in the range of 85-115 nm at the ages examined. The number of GV/micron2 of cytoplasmic area remained quite constant at all ages examined. These data, taken together with other available information, suggest that the CA+ cells that differentiate in our neural crest cultures resemble, in many respects, the small, intensely fluorescent cells found in autonomic ganglia and extra-adrenal chromaffin tissue of many species. At present, we do not know if the CA+ cells that differentiate in our neural crest cultures are a stable endpoint of development or whether they are a developmental intermediate in adrenergic differentiation that is normally observed only transiently during the development of avian sympathetic ganglia in vivo, but that can persist under our tissue culture conditions.     

Immobilization-induced muscle atrophy is not reversed by lengthening the muscle

In clinical practice, repaired tendocalcaneus (Achilles tendon) ruptures are often protected in immobilization casts for 4 weeks in the fully plantar flexed position and for up to another 4 weeks after returining the ankle to joint neutral. Moderate to severe muscle atrophy occurs within 4 weeks of immobilization in plantar flexion, but it is not known if this atrophy is minimized or reversed following restoration of joint neutral position. We tested the hypothesis that the extent of atrophy could be reduced by returning the ankle to joint neutral after 4 weeks of immobilization. Eighteen rabbits were anesthetized, and their right hindlimbs were casted with the knee flexed 90° and the ankle fully planter flexed. Three animals each were studied after 3, 4, 6, or 8 weeks of immobilization. After 4 weeks of immobilization, the immobilization casts of the remaining six rabbits were modified to reture the ankle to joint neutral for another 2 or 4 weeks. For muscle studies, the animals were anesthetized, and the soleus (SOL), plantaris (PLN), and gastrocnemius (GST) muscles were removed and weighed; the SOL and PLN were quick frozen and processed for histochemical fiber typing and fiber cross-sectional area measurement. All three muscles showed significantly reduced muscle weight to body weight ratios after 3 weeks of immobilization. SOL was the most affected, and GST was least affected. There was no significant further atrophy through 8 weeks of immobilization. The atrophy corrolated with a significant reduction of mean fiber area (MFA) for Types I, IIo, and IIc fibers in SOL and PLN. In PLN, Type IIg fiber area was not significantly reduced. MFAs of fibers of SOL and PLN muscles that were lengthened by returning to ankle joint neutral for 2 or 4 weeks were not different from those from those of limbs kept at planter flexion for 6 or 8 weeks. These data indicate that atrophy had reached a near-maximal extent within 4 weeks and that subsequent lengthening of the muscles did not reverse the atrophy. © 1992 Wiley-Liss, Inc.     

Isovergence surfaces: the conjugacy of vertical eye movements in tertiary positions of gaze

Conjugate gaze is often defined as the equal angle rotation of the two eyes. For fixation at far distances, the optical axes are parallel and conjugacy is defined irrespective of the coordinate system. For nearby or finite fixation distances, the evaluation of conjugacy for many gaze postures depends on the coordinate system used to measure it. For example, if the eye is elevated or depressed and the eye is rotated about a vertical axis, the intersections of lines of sight with a tangent screen will describe either straight lines for arcs depending on whether the vertical axis is fixed with respect to the head or to the eye. Because of the horizontal separation of the two eyes, the binocular fixation of near targets at tertiary positions of gaze will require a vertical vergence component for head-referenced but not eye-referenced measurements. The vertical gaze alignment of three human subjects was measured as they viewed targets placed at secondary and tertiary eye positions at two different distances. Vertical vergence was either held open or closed-loop. The lines of sight were found lo intersect (i.e. vertical gaze was aligned) regardless of target position or viewing condition.