Physiological dissection revealed that both uptake and assimilation are the major components regulating different growth responses of two tobacco cultivars to nitrogen nutrition.

K326 and HD represent major tobacco cultivars in China, which required large N fertiliser input but at different application rates. To understand primary components affecting tobacco N use physiology, we adopted these two varieties as valuable genetic material to assess their growth response to N nutrition. We established a hydroponic culture system to grow plants supplied with different N regimes. Plant biomass, N, ammonium, nitrate, arginine, GS and NR activity, N transfer and use efficiency as well as root uptake were examined. Our data revealed the preference of K326 and HD to utilise nitrate or ammonium nitrate but not ammonium alone, with 2 mm N supply probably sufficient and economical to achieve good biomass production at the vegetative stage. Moreover, both varieties were very sensitive to ammonium, perhaps due to lack of or abnormal signalling related to nitrate and/or arginine rather than impairment of N acquisition and initial assimilation; this was supported by measurements of the plant content of N, ammonium and activities of GS and NR. Notably, short-term 15 N root influx studies identified differential uptake kinetics of K326 and HD, with distinct affinities and transport rates for ammonium and nitrate. The data suggest that the growth adaptation of K326 or HD to higher or lower N may be ascribed to different competences for effective N uptake/translocation and assimilation. Thus, our work provides valuable information to prompt deeper investigation of the molecular basis controlling plant N use efficiency.

A 90-day subchronic toxicity study of neem oil, a Azadirachta indica oil, in mice.

To determine the no-observed-adverse-effect level (NOAEL) of exposure and target organs of neem oil for establishing safety criteria for human exposure, the subchronic toxicity study with neem oil in mice was evaluated. The mice (10 per sex for each dose) was orally administered with neem oil with the doses of 0 (to serve as a control), 177, 533 and 1600 mg/kg/day for 90 days. After the treatment period, observation of reversibility or persistence of any toxic effects, mice were continuously fed without treatment for the following 30 days. During the two test periods, the serum biochemistry, organ weight and histopathology were examined. The results showed that the serum biochemistry and organ coefficient in experimental groups had no statistical difference compared with those of the control group. At the 90th day, the histopathological examinations showed that the 1600 mg/kg/day dose of neem oil had varying degrees of damage on each organ except heart, uterus and ovarian. After 30-day recovery, the degree of lesions to the tissues was lessened or even restored. The NOAEL of neem oil was 177 mg/kg/day for mice and the target organs of neem oil were determined to be testicle, liver and kidneys.

Role of lateral alkyl chains in modulation of molecular structures on metal surfaces.

We use low energy electron diffraction, scanning tunneling microscopy, first-principles density-functional theory, and molecular mechanics calculations to analyze the adsorption and growth of quinacridone derivatives (QA) with alkyl chains of 4 and 16 carbon atoms on a Ag(110) substrate. Surprisingly, we find that the alkyl chains determine the orientation of the molecular overlayers. While the interaction of QA and the Ag substrate is primarily due to chemical bonding of oxygen to the silver substrate, determining the molecular orientation and preferred adsorption site, the intermolecular arrangement can be adjusted via the length of alkyl chains. We are thus able to fabricate uniform QA films with very well controlled physical properties.

Selective analysis of molecular states by functionalized scanning tunneling microscopy tips.

Selective analysis of molecular states in scanning tunneling microscopy (STM) has so far been achieved in a few cases by tuning the bias range of the STM in high-resolution measurements. Correspondingly, perylene adsorbed in a close-packed monolayer on Ag(110) is imaged mainly through the pi states of the molecule. By contrast, functionalizing the STM tip with a perylene molecule leads to a mismatch between the energy levels of the STM tip and the molecule adsorbates and, instead, images only the metal states of the underlying silver surface. The observation opens a route for better energy selectivity in electron transport measurements through organic interfaces.

Retinal micromovements, the visual line, and Donders' law.

PURPOSE: To report the relationship of the retinal micromovements to the visual line and to confirm the validity of Donders' Law. METHODS: Two video cameras suspended from a headband were used to record eye (video-oculography) and head movements. Eye positions in held gaze and following various trajectories to a target were recorded in five normal, young subjects. The videotapes were analyzed off-line using a computer algorithm. RESULTS: Retinal micromovements cause the visual line to trace a zigzag pathway across the foveola, which has an approximate diameter of 350 microm (about 2 degrees). The mean micromovement was about 10 microm in 33.3 msec. The cumulative effect of successive micromovements may move the visual line across the foveola from edge to edge depending on the elapsed time. When the visual line reaches the edge of the foveola it changes its direction. When the eye resets to the same target by different trajectories, the visual line may alight up to about 350 microm from its original location anywhere within the foveola. CONCLUSIONS: Donders' Law is upheld because for each direction of gaze, and regardless of the trajectory used to reach that direction of gaze, the retina has a constant orientation to an index head plane at any given moment in time. Failure to consider that the micromovements cause a shift in the position of the visual line within the foveola may account for the exceptions to Donders' Law found by contemporary researchers using invasive recording techniques.

A closed chamber technique for repair of iridodialysis.

We have developed a surgical technique for repair of traumatic iridodialysis, in which a 25-gauge hypodermic needle is used to place a 10-0 polypropylene suture in sewing-machine fashion through a closed anterior chamber. The technique also can be modified to secure a posterior capsule with a partial zonular dialysis, such as may occur during phacoemulsification or cortical clean-up.

The primary position of the eyes, the resetting saccade, and the transverse visual head plane. Head movements around the cervical joints.

Photographic and video analyses show that the primary position of the eyes is a natural constant position in alert normal humans, and the eyes are automatically saccadically reset to this position from any displacement of the visual line. The primary position is not dependent on fixation, the fusion reflex, gravity, or the head position. The primary position is defined anatomically by head and eye planes and lines that are localized by photography, magnetic resonance imaging, and x-rays of the head and neck. The eyes are in the primary position when the principal (horizontal) retinal plane is coplanar with the transverse visual head (brain) plane (TVHP), and the equatorial plane of the eye is coplanar with a fixed orbital plane (Listing's plane). Evidence is presented to indicate an active neurologic basis for the primary position instead of passive mechanical forces. A different understanding of the primary position and the conception of the TVHP may be valuable in analyzing oculomotor defects.

Intraocular pressure-dependent dynamic changes of optic disc cupping in adult glaucoma patients.

The authors performed a study of intraocular pressure-dependent changes in optic disc cupping in 17 adults with chronic open-angle glaucoma. Analyses with the Rodenstock Optic Nerve Head Analyzer were performed at baseline low intraocular pressure during therapy, after elevation of intraocular pressure (from therapeutic failure or noncompliance), and after reduction of intraocular pressure with successful therapy. Optic disc cupping increased significantly upon short-term increase of intraocular pressure from baseline of 20.4 +/- 2.5 mmHg to 31.1 +/- 5.9 mmHg. Optic disc cupping reverted to baseline after persistent intraocular pressure reduction to 19.3 +/- 4.8 mmHg. These data demonstrate intraocular pressure-dependent dynamic changes of optic disc cupping in patients with demonstrable glaucomatous optic nerve damage. They underscore the detrimental effect of elevated intraocular pressure and the beneficial effect of intraocular pressure reduction on optic disc cup changes.

Intraocular pressure-dependent retinal vascular change in adult chronic open-angle glaucoma patients.

Intraocular pressure (IOP)-dependent retinal vascular changes were investigated in 33 eyes of 33 adult chronic open-angle glaucoma (COAG) patients by measuring major retinal vascular calibers at the optic disc border before and after mean (+/- standard deviation) IOP reduction from 35.3 (+/- 7.2) to 16.5 (+/- 4.7) mmHg for 11.2 (+/- 13.5) weeks. Both mean arterial and venous calibers were significantly reduced (P less than 0.0001 for each), from 87.8 (+/- 14.2) and 128.3 (+/- 20.8) microns at high IOP to 82.0 (+/- 13.8) and 121.4 (+/- 18.5) microns at low IOP. Arterial and venous caliber decreases correlated positively with magnitude of IOP reduction (r = 0.503, P less than 0.01 and r = 0.555, P less than 0.001, respectively). While the IOP-dependent retinal arterial caliber change was highly significant in patients 55 years of age or younger (r = 0.636, P less than 0.01) and in the overall study group, it was not significant in patients older than 55 years (r = 0.205, P greater than 0.1). Age seems to be more influential than magnitude of IOP reduction in patients older than 55. Thus, diminished IOP-dependent retinal arterial caliber change in the elderly may be one factor contributing to the higher incidence and prevalence of glaucoma in this population.

Reversal of glaucomatous optic disc cupping in adult patients.

A prospective study of reversal of glaucomatous optic disc cupping was performed by topographic optic disc analysis using the optic nerve head analyzer (Rodenstock analyzer, G. Rodenstock Instrumente GMBH, Munich, West Germany) in 13 adults with chronic open angle glaucoma. Intraocular pressure decreased from the mean (+/- SD) initial intraocular pressure of 33.2 +/- 8.2 mm Hg to the final intraocular pressure of 16.9 +/- 6.1 mm Hg over 13.6 +/- 10.4 weeks. Mean (+/- SD) cup-disc ratio decreased significantly, from 0.573 +/- 0.207 to 0.499 +/- 0.198, and mean (+/- SD) neuroretinal rim area increased significantly, from 0.913 +/- 0.341 to 1.042 +/- 0.284 mm2. The decrease of mean (+/- SD) cup volume from 0.592 +/- 0.966 to 0.451 +/- 0.703 mm3 was only marginally significant. However, more meaningful was a finding that reversal of cup volume, like reversals of cup-disc ratio and rim area, was directly proportional to the percent IOP reduction (r = .669 for cup volume reversal; r = .626 for cup-disc ratio reversal; and r = .675 for rim area reversal).

Is it worthwhile to add dipivefrin HCl 0.1% to topical beta 1-, beta 2-blocker therapy?

In a prospective study, the addition of dipivefrin hydrochloride 0.1% twice daily to one eye of 32 patients with early primary open-angle glaucoma or ocular hypertension, maintained on a bilateral beta 1-, beta 2-blocker twice daily, resulted in a significant decrease of mean intraocular pressure (IOP) from 22.7 +/- 3.9 to 20.2 +/- 3.4 mmHg at 1 week (P = 0.0001) and to 21.0 +/- 3.8 mmHg at 12 weeks (P less than 0.02) in the dipivefrin-treated eyes. On the other hand, no significant change was noted in the fellow eyes (from 21.7 +/- 4.1 to 21.6 +/- 4.0 mmHg at 1 week and to 21.3 +/- 4.2 mmHg at 12 weeks). The addition of dipivefrin resulted in an IOP reduction of 2 mmHg or more in 50% and 3 mmHg or more in 19% of the eyes throughout the 12-week therapy. The result of the current study provides a realistic guideline as to what to expect from the common practice of adding dipivefrin hydrochloride to a beta 1-, beta 2-blocker regimen.

[Synthesis and antifertility actions of gossypol derivatives and phenol aldehydes].

A series of trihydroxynaphthaldehydes, polyhydroxybiphenol-asdehydes, polyhydroxybinaphthyl aldehydes and some gossypol derivatives were synthesized for antifertility experimental studies.

Glycosylation of lens proteins in senile cataract and diabetes mellitus.

We have investigated glycosylation of lens proteins in diabetic and non-diabetic senile cataract patients. Our study reveals that glycosylation of lens cortical proteins, but not of nuclear proteins, is significantly higher in diabetic patients with senile cataract. This finding serves to clarify the confusion over glycosylation of lens proteins as it relates to diabetes mellitus and further contributes to an understanding of glycosylation of lens tissues as a distinct posttranslational modification.