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Biomedical subjects

F Hayashi

Publications and source records attributed to F Hayashi.

At least 217 records · Page 12Linked to original sources
PubMed1966

Isolation, Crystallization, and Partial Identification of Potato Factor II from Potato Tubers.

The isolation, crystallization, and partial identification of potato factor II, a stimulator from the chemically neutral fraction of potato extract, is described. The compound was originally found to stimulate elongation of dwarf peas grown under red light, a gibberellin bioassay. It melts between 137 degrees and 139 degrees . In paper chromatography it migrates to R(F) 0.62 in isopropyl alcohol: ammonium hydroxide: H(2)O (10:1:1, v/v). Based on infrared and NMR data, it does not contain a lactone ring and possibly possesses an amide radical and an OH(-) group, as well as many methylene radicals. Potato factor II may be similar to certain of the fatty acid derivatives previously reported to stimulate growth of excised sections, but it is unique in that it stimulates growth of intact plants. This effect points to the need for completely separating neutral from acid gibberellin-like substances when the latter are assayed on dwarf peas.

Journal Article↗
PubMedDate not supplied

Comparison of diclofenac and fluorometholone in preventing cystoid macular edema after small incision cataract surgery: a multicentered prospective trial.

PURPOSE: To compare a nonsteroidal topical solution (0.1% diclofenac) to a steroidal topical solution (0.1% fluorometholone) in preventing cystoid macular edema (CME) and disruption of the blood-aqueous barrier. METHODS: A multicentered, prospective clinical trial was performed on eyes undergoing phacoemulsification followed by implantation of a foldable acrylic intraocular lens by the envelope technique. The presence and degree of cystoid macula edema (CME) was determined by fluorescein angiography. A breakdown of the blood-aqueous barrier was determined by laser flare-cell photometry. RESULTS: Five weeks after surgery, CME was present in 3 of 53 eyes (5.7%) receiving diclofenac and in 29 of 53 eyes (54.7%) receiving fluorometholone. This difference was statistically significant (P < .001). The amount of flare in the anterior chamber at 3 days, 1, 2, 5, and 8 weeks after surgery was also significantly lower (P < .01-P < .001) in the diclofenac group. The degree of flare at 3 days, 1, 2, 5, and 8 weeks after surgery was significantly higher in eyes with CME (P < .001). CONCLUSIONS: These findings suggest that diclofenac effectively prevents CME following cataract surgery and that CME is closely related to the breakdown of the blood-aqueous barrier.

Aged↗
PubMedDate not supplied

Corneal endothelial cell loss in phacoemulsification surgery with silicone intraocular lens implantation.

PURPOSE: To clarify the extent of corneal endothelial injury from silicone intraocular lens (IOL) implantation in small incision cataract surgery. METHODS: Two hundred forty eyes that had phacoemulsification surgery were divided into four groups: Group A comprised 70 eyes that received a conventional silicone IOL; Group B, 63 eyes that received a higher refractive index silicone IOL; Group C, 71 eyes that received a poly(methyl methacrylate) (PMMA) IOL; Group D, 36 eyes that had phacoemulsification without an IOL. Cell density of the corneal endothelium in all eyes was examined by specular microscopy preoperatively and 3 months postoperatively, and the percentage of endothelial cell loss was determined. The differences in endothelial cell loss between the four groups were statistically compared using the Kruskal-Wallis test. RESULTS: Percentages of endothelial cell loss were 4.5 +/- 5.1% in Group A, 4.3 +/- 5.3% in Group B, 6.3 +/- 5.4% in Group C, and 4.3 +/- 4.9% in Group D. No statistically significant difference was observed among these four groups, although the percentage of cell loss in Group C was slightly larger than that in the other groups. CONCLUSION: The implantation of silicone IOLs and PMMA IOLs causes minimal corneal endothelial cell loss in contemporary small incision surgery.

Aged↗
PubMedDate not supplied

Pattern formation and rhythm generation in the ventral respiratory group.

1. There is increasing evidence that the kernel of the rhythm-generating circuitry for breathing is located within a discrete subregion of a column of respiratory neurons within the ventrolateral medulla referred to as the ventral respiratory group (VRG). It is less clear how this rhythm is transformed into the precise patterns appearing on the varied motor outflows. 2. Two different approaches were used to test whether subregions of the VRG have distinct roles in rhythm or pattern generation. In one, clusters of VRG neurons were activated or inactivated by pressure injection of small volumes of neuroactive agents to activate or inactivate groups of respiratory neurons and the resulting effects on respiratory rhythm and pattern were determined. The underlying assumption was that if rhythm and pattern are generated by neurons in different VRG subregions, then we should be able to identify regions where activation of neurons predominantly alters rhythm with little effect on pattern and other regions where pattern is altered with little effect on rhythm. 3. Based on the pattern of phrenic nerve responses to injection of an excitatory amino acid (DL-homocysteate), the VRG was divided into four subdivisions arranged along the rostrocaudal axis. Injections into the three rostral regions elicited changes in both respiratory rhythm and pattern. From rostral to caudal the regions included: (i) a rostral bradypnoea region, roughly associated with the Bötzinger complex; (ii) a dysrhythmia/tachypnoea area, roughly associated with the pre-Bötzinger complex (PBC); (iii) a second caudal bradypnoea area; and, most caudally, (iv) a region from which no detectable change in respiratory motor output was elicited. 4. In a second approach, the effect of unilateral lesions of one subregion, the PBC, on the Breuer-Hering reflex changes in rhythm were determined. Activation of this reflex by lung inflation shortens inspiration and lengthens expiration (TE). 5. Unilateral lesions in the PBC attenuated the reflex lengthening of TE, but did not change baseline respiratory rhythm. 6. These findings are consistent with the concept that the VRG is not functionally homogenous, but consists of rostrocaudally arranged subregions. Neurons within the so-called PBC appear to have a dominant role in rhythm generation. Nevertheless, neurons within other subregions contribute to both rhythm and pattern generation. Thus, at least at an anatomical level resolvable by pressure injection, there appears to be a significant overlap in the circuitry generating respiratory rhythm and pattern.

Animals↗
PubMedDate not supplied

Fourier analysis of irregular astigmatism after trabeculectomy.

OBJECTIVE: To examine irregular astigmatism following trabeculectomy using Fourier analysis of videokeratography data. PATIENTS AND METHODS: Forty eyes of 40 glaucoma patients, undergoing primary trabeculectomy, underwent videokeratographic examinations preoperatively, and at 2 weeks and 1, 3, 6, and 12 months postoperatively. The dioptric data of the central cornea were decomposed into spherical, regular astigmatic, and irregular astigmatic (decentration and higher-order irregularity) components using Fourier analysis. RESULTS: The mean spherical equivalent did not change throughout the observation period. The regular astigmatic component from 2 weeks to 6 months post-operatively was greater than the preoperative diopter, but the increase was not significant. In contrast, the decentration component increased significantly after surgery, but returned to the preoperative level by 12 months. The higher-order irregularity component also presented a transient increase postoperatively. CONCLUSIONS: Irregular astigmatism, particularly decentration component, increases significantly after trabeculectomy, but returns to the preoperative level 12 months after surgery.

Adult↗