Self-organizing molecular networks.

Strong diffusional mixing and short delivery times typical for micrometer and sub-micrometer reaction volumes lead to a special situation where the turnover times of individual enzyme molecules become the largest characteristic time scale of the chemical kinetics. Under these conditions, populations of cross-regulating allosteric enzymes form molecular networks that exhibit various kinds of self-organized coherent collective dynamics.

[Severe chronic iron deficiency in a 17-year-old student].

A 17 year old male suffered from iron deficiency of undetermined cause for 2 years. Iron substitution was able to correct it for short periods. With the exception of fatigue and recurring abdominal pain attributed to oral iron therapy no further symptoms were present.

[Central lung embolism in chronic interstitial pneumopathy].

An 80 year old patient with known interstitial pneumopathy of unknown etiology was hospitalized because of acute onset and rapid deterioration of dyspnea at rest within days. A foregoing neurologic investigation including CT and EEG because of prior syncopes and cramp attacks had not revealed pathologic findings. Thorax X-ray at admission showed homogenous loss of transparency on the left side, calcified basal plaques on both sides and prominent central pulmonary vessels with jumping caliber.

Visually induced adaptation in three-dimensional organization of primate vestibuloocular reflex.

The adaptive plasticity of the spatial organization of the vestibuloocular reflex (VOR) has been investigated in intact and canal-plugged primates using 2-h exposure to conflicting visual (optokinetic, OKN) and vestibular rotational stimuli about mutually orthogonal axes (generating torsional VOR + vertical OKN, torsional VOR + horizontal OKN, vertical VOR + horizontal OKN, and horizontal VOR + vertical OKN). Adaptation protocols with 0.5-Hz (+/-18 degrees ) head movements about either an earth-vertical or an earth-horizontal axis induced orthogonal response components as high as 40-70% of those required for ideal adaptation.

Long-term deficits in otolith, canal and optokinetic ocular reflexes of pigmented rats after unilateral vestibular nerve section.

Static and dynamic otolith, horizontal vestibular and optokinetic ocular reflexes were investigated in pigmented rats 1-6 and more months after unilateral vestibular nerve (UVN) section. Evoked responses were compared with published data from control rats studied under identical conditions. Static lateral tilt of UVN rats in the light evoked a vertical deviation in static eye position that was as large as in controls.

Inertial vestibular coding of motion: concepts and evidence.

Central processing of inertial sensory information about head attitude and motion in space is crucial for motor control. Vestibular signals are coded relative to a non-inertial system, the head, that is virtually continuously in motion. Evidence for transformation of vestibular signals from head-fixed sensory coordinates to gravity-centered coordinates have been provided by studies of the vestibulo-ocular reflex.

Kinematic principles of primate rotational vestibulo-ocular reflex. II. Gravity-dependent modulation of primary eye position.

The kinematic constraints of three-dimensional eye positions were investigated in rhesus monkeys during passive head and body rotations relative to gravity. We studied fast and slow phase components of the vestibulo-ocular reflex (VOR) elicited by constant-velocity yaw rotations and sinusoidal oscillations about an earth-horizontal axis. We found that the spatial orientation of both fast and slow phase eye positions could be described locally by a planar surface with torsional variation of <2.

Kinematic principles of primate rotational vestibulo-ocular reflex. I. Spatial organization of fast phase velocity axes.

The spatial organization of fast phase velocity vectors of the vestibulo-ocular reflex (VOR) was studied in rhesus monkeys during yaw rotations about an earth-horizontal axis that changed continuously the orientation of the head relative to gravity ("barbecue spit" rotation). In addition to a velocity component parallel to the rotation axis, fast phases also exhibited a velocity component that invariably was oriented along the momentary direction of gravity. As the head rotated through supine and prone positions, torsional components of fast phase velocity axes became prominent.

Metabolic evaluation of patients with recurrent idiopathic calcium nephrolithiasis.

Background: Metabolic evaluation in recurrent idiopathic calcium renal stone-formers (RCSF) was analysed with respect to the following questions: (1) do three 24-h urines provide more diagnostic accuracy in the metabolic evaluation of RCSF than 1 or 2 urines?; (2) does time after stone event influence the diagnostic yield?; (3) is urine composition at weekends different from that at mid-week?; (4) what are the prevalences of the most important risk factors (RF) of idiopathic calcium nephrolithiasis, i.e. low volume (LV), hypercalciuria (HC), hyperoxaluria (HO), hyperuricosuria (HU), hypocitraturia (Hypo-Cit), and hypomagnesiuria (Hypo-Mg)?; and (5) do male RCSF differ from females with respect to urinary RFs?

Methods: Seventy-five RCSF (59 men, 16 women) collected three 24-h urines (U1-3) while on free-choice diet.

Ardacin for steers grazing endophyte-free fescue pasture: effects on live weight gain, forage intake, nitrogen and fiber digestion, ruminal fluid kinetics, ruminal fermentation, and serum hormones and metabolites.

Growth and digestion studies were conducted to evaluate the use of ardacin as a feedgrade antibiotic for enhancing digestive function and growth in grazing steers. In Exp. 1, 90 yearling steers (average initial BW of 248 kg) used in a randomized complete block design (block = weight group) grazed fescue pasture without supplementation (CON) or with daily supplements (DM basis) of .

[Nephrolithiasis--rational etiological assessment].

Although underlying metabolic abnormalities do not differ fundamentally in patients with either first or recurrent nephrolithiasis and 35% of patients with a first event may have to face a recurrence 5 years later, extended metabolic investigations in patients with a first renal calculus should be restricted to particular, exceptional cases. However, in patients with a first calculus basic investigations with respect to specific causes for a concrement such as primary hyperparathyroidism, incomplete renal-tubular acidosis, recurrent urinary tract infection and cystinuria are mandatory. This includes, in addition to a laboratory investigation of blood and urine after a 2-hour-fasting period, analysis of the stone and a urography.

Phenotype of arylsulfatase A-deficient mice: relationship to human metachromatic leukodystrophy.

Metachromatic leukodystrophy is a lysosomal sphingolipid storage disorder caused by the deficiency of arylsulfatase A. The disease is characterized by progressive demyelination, causing various neurologic symptoms. Since no naturally occurring animal model of the disease is available, we have generated arylsulfatase A-deficient mice.

Adaptation of primate vestibuloocular reflex to altered peripheral vestibular inputs. II Spatiotemporal properties of the adapted slow-phase eye velocity.

1. The ability of the vestibuloocular reflex (VOR) to undergo adaptive modification after selective changes in the peripheral vestibular system was investigated in rhesus monkeys by recording three-dimensional eye movements before and after inactivation of selective semicircular canals. In the preceding paper we showed that the horizontal VOR gain evoked by passive yaw oscillations after lateral semicircular canal inactivation recovers gradually over time in a frequency-specific manner.

Adaptation of primate vestibuloocular reflex to altered peripheral vestibular inputs. I. Frequency-specific recovery of horizontal VOR after inactivation of the lateral semicircular canals.

1. The adaptive plasticity of the vestibuloocular reflex (VOR) following a selective lesion of the peripheral vestibular organs was investigated in rhesus monkeys whose lateral semicircular canals were inactivated by plugging of the canal lumen in both ears. Gain and phase of horizontal, vertical, and torsional slow-phase eye velocity were determined from three-dimensional eye movement recordings obtained acutely after the plugging operation, as well as in regular intervals up to 10 mo later.

Spectrally silent transitions in the bacteriorhodopsin photocycle.

The photocycle kinetics of bacteriorhodopsin were analyzed from 0 to 40 degrees C at 101 wavelengths (330-730 nm). The data can be satisfactorily approximated by eight exponents. The slowest component (half-time 20 ms at 20 degrees C) belongs to the 13-cis cycle.

Targeted disruption of the arylsulfatase B gene results in mice resembling the phenotype of mucopolysaccharidosis VI.

Mucopolysaccharidosis VI (MPS VI) is a lysosomal storage disease with autosomal recessive inheritance caused by a deficiency of the enzyme arylsulfatase B (ASB), which is involved in degradation of dermatan sulfate and chondroitin 4-sulfate. A MPS VI mouse model was generated by targeted disruption of the ASB gene. Homozygous mutant animals exhibit ASB enzyme deficiency and elevated urinary secretion of dermatan sulfate.

Contributions of single semicircular canals to caloric nystagmus as revealed by canal plugging in rhesus monkeys.

We demonstrated specific responses from the anterior and the posterior semicircular canal to irrigation of the outer ear canal with cold water in the Rhesus monkey. This required i) three-dimensional analysis of the evoked eye movements in the planes of the semicircular canals (canal plane vectors, CPV); ii) assessing these CPV responses in eight different head positions relative to gravity; iii) comparing the responses in 6 normal animals (12 ears) with responses after selective plugging of pairs of semicircular canals (all, both lateral, and right anterior + left posterior). The results showed: i) Irrigation of the outer ear canal with cold water induces thermoconvection also in the posterior and anterior semicircular canals.

Three-dimensional organization of otolith-ocular reflexes in rhesus monkeys. II. Inertial detection of angular velocity.

1. The dynamic contribution of otolith signals to three-dimensional angular vestibuloocular reflex (VOR) was studied during off-vertical axis rotations in rhesus monkeys. In an attempt to separate response components to head velocity from those to head position relative to gravity during low-frequency sinusoidal oscillations, large oscillation amplitudes were chosen such that peak-to-peak head displacements exceeded 360 degrees.

Three-dimensional organization of otolith-ocular reflexes in rhesus monkeys. I. Linear acceleration responses during off-vertical axis rotation.

1. The dynamic properties of otolith-ocular reflexes elicited by sinusoidal linear acceleration along the three cardinal head axes were studied during off-vertical axis rotations in rhesus monkeys. As the head rotates in space at constant velocity about an off-vertical axis, otolith-ocular reflexes are elicited in response to the sinusoidally varying linear acceleration (gravity) components along the interaural, nasooccipital, or vertical head axis.