Growth of phage BF23 was restricted in Escherichia coli K-12 strains carrying a colicin I factor (ColIb); most infected cells lysed early without producing progeny phages. Either addition of chloramphenicol before phage infection or ultraviolet irradiation of phage prevented early abortive lysis, an indication that certain phage functions are required for this phenomenon. Very little or no phage-induced lysozyme was synthesized in the infected ColI(+) cells. This result suggests that early abortive lysis was not due to the lysozyme action. A small fraction (0.05) of BF23-infected ColI(+) cells showed normal phage growth. This "escaped growth" may reflect the physiological state of the host bacteria rather than the heterogeneity of the infecting phage. Host-controlled modification was not observed. A phage mutant, BF23hI, able to grow on ColI(+) cells, was isolated and was characterized to be recessive to the wild-type BF23 in its ability to undergo early abortive lysis. Among the T series phages, T5 induced early abortive lysis, and growth of T5 was restricted upon infection to ColI(+) cells. These results and the other observations, including the occurrence of phenotypic mixing between BF23 and T5, suggest that these two phages are related to each other even though the receptor sites for BF23 and T5 are apparently different.

Bacteriolysis↗

PubMed1966

Degradation of ribosomal RNA from Escherichia coli induced by colicine E2.

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Chromatography↗

PubMed1965

Cohesion occurring between DNA molecules of temperate phages phi 80 and lambda or phi 81.

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Chemical Phenomena↗

PubMed1962

A THEOREM ON CURVATURE TENSOR FIELDS.

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Journal Article↗

PubMedDate not supplied

Clinical evaluation of posterior embryotoxon in one institution.

To elucidate the pathogenesis of posterior embryotoxon, we estimated its incidence in our clinic and evaluated its associated ocular and systemic anomalies. Slit-lamp and gonioscopic examinations were performed on 440 randomly selected patients at Nagoya City University Hospital over a 10-month period. Posterior embryotoxon was detected in 107, 50 bilateral and 57 unilateral, cases (24.3%). Twelve (11.2%) of the 107 cases had open-angle glaucoma. Accompanying ocular anomalies included six cases of sclerocornea, two each of persistent pupillary membrane and familial exudative vitreoretinopathy, and 1 each of melanocytoma of the optic nervehead, choroidal nevus and subconjunctival dermoid cyst. Associated systemic anomalies included three cases of Alagille syndrome, two of congenital biliary atresia, and one each of congenital facial palsy with microtia, congenital adrenal hyperplasia, empty sella syndrome, Hirschsprung disease and Wilson disease. Many of these ocular and systemic anomalies were caused by the maldevelopment of neural crest cells. Patients with posterior embryotoxon should be examined for the possible presence of open-angle glucoma and for ocular and systemic anomalies related to maldevelopment of neural crest cells.

Adolescent↗

PubMedDate not supplied

Developmental eye abnormalities in mouse fetuses induced by retinoic acid.

To clarify the relationship between neural crest cells and various developmental eye abnormalities, pregnant mice were administered an intraperitoneal injection of 12.5 mg/kg retinoic acid (RA) suspended in corn oil on day 7 of pregnancy (RA group). Control mice received an equal volume of corn oil only (control group). The fetuses were removed by laparotomy on day 18 of gestation. The fetal mortality was 46.3% in the RA group and 2.2% in the control group. The live fetuses in both groups were observed grossly, and the eyes were examined histologically in serial sections. In the RA group, gross malformations were observed, including microphthalmos (95.5%), cleft lip and palate (36.4%), and central nervous system anomalies (31.8%). In the control group, these malformations were seen in only 6.7%, 0%, and 2.2%, respectively. Histologic examinations in the RA group revealed microphthalmos (47.7%), anophthalmos (38.6%), faulty closure of the embryonic fissure (36.4%), developmental abnormalities of the vitreous (34.1%), aphakia (22.7%), goniodysgenesis (18.2%), and faulty separation of the lens vesicle (15.9%). They were detected in only 3.3%, 1.1%, 3.3%, 8.9%, 1.l%, 2.2%, and 2.2%, respectively, of the control group. These developmental eye abnormalities arose from abnormal migration of neural crest cells.

Abnormalities, Drug-Induced↗

PubMedDate not supplied

Vestibular evoked myogenic potentials in patients with bilateral profound hearing loss.

We report vestibular evoked myogenic potentials (VEMPs) in 3 patients with bilateral profound hearing loss in order to confirm that they are not of cochlear origin. All of the 3 patients (31-year-old man, 67-year-old man and 47-year-old woman) had bilateral profound hearing loss. They were diagnosed as having congenital hearing loss, bilateral Ménière's disease and inner ear syphilis. Their pure-tone hearing ranged from 81 dB HL to nearly total hearing loss. Stimulation by click (95 dB nHL) evoked biphasic myogenic responses (p13-n23) on the sternocleidomastoid muscle ipsilateral to the stimulated ear. The ear in which the stimulation did not evoke biphasic myogenic responses did not have a caloric response either. These results suggested that VEMPs are not likely of cochlear origin but of vestibular origin.

Adult↗

PubMedDate not supplied

Effect of particle size of polymeric nanospheres on intravitreal kinetics.

In this study, we injected nanospheres containing a fluorescein derivative into the vitreous cavity of pigmented rabbit eyes and evaluated their intraocular kinetics as drug carriers in vivo. Polystyrene nanospheres (2 microm, 200 nm and 50 nm in diameter) containing a fluorescein derivative were used in this study. A suspension of each particle was prepared by diluting with distilled water at a concentration of 10 microg/ml equivalent to sodium fluorescein. The suspension of nanospheres was injected once into the vitreous cavity of unilateral eyes of pigmented rabbits. A sodium fluorescein solution of the same concentration was injected once into the vitreous cavity of the other eye as the control. The intraocular kinetics of nanospheres was evaluated by measuring vitreous fluorescence using a scanning fluorophotometer. To investigate elimination pathways of nanospheres in detail, serial cross-sections of the eyes were examined with a fluorescence microscope. The fluorescence derived from nanospheres was observed in the vitreous cavity for over 1 month (2 microm: t(1/2) = 5.4 +/- 0.8 days, 200 nm: t(1/2) = 8.6 +/- 0.7 days, 50 nm: t(1/2) = 10.1 +/- 1.8 days), whereas that in the control eyes completely disappeared within 3 days (t(1/2) = 7.8 +/- 0.7 h). The elimination half-life from the vitreous cavity correlated well with the particle diameter (r = -0.997, p = 0.007). Histological studies using a fluorescence microscope revealed that nanospheres with a diameter of 2 microm were seen in the vitreous cavity and trabecular meshwork, while nanospheres with a diameter of smaller than 200 nm were also observed in the retina as well as these tissues. Our findings indicated that nanospheres may be beneficial as a drug carrier to the retina, vitreous and trabecular meshwork.

Animals↗

PubMedDate not supplied

Maldevelopment of neural crest cells in patients with typical uveal coloboma.

PURPOSE: To clarify the pathogenesis of ocular and systemic anomalies associated with typical uveal coloboma. METHODS: The records of 72 patients with typical uveal coloboma (35 males and 37 females) treated at Nagoya City University Hospital during a 16-year period were reviewed. RESULTS: Typical uveal coloboma was bilateral in 33 patients and unilateral in 35 patients; 4 patients were unclassified because of severe contralateral microphthalmos. Uveal coloboma was an isolated defect in 23 (37%) patients. Other ocular anomalies were present in 19 (31%) patients, systemic anomalies were found in 7 (11%) patients, and both other ocular and systemic anomalies were noted in 13 patients (21%). The associated ocular anomalies included microphthalmos in 28 eyes of 23 patients, persistent pupillary membrane in 28 eyes of 18 patients, and posterior embryotoxon in 20 eyes of 15 patients. The accompanying systemic anomalies included ear anomalies, retarded growth, and retarded development in 18 patients; heart anomalies in 13 patients; genital hypoplasia in 12 patients; and congenital facial palsy in 10 patients. The collection of malformations known as the CHARGE association was diagnosed in 14 (19%) patients. CONCLUSION: Abnormal development of neural crest cells appeared to be responsible for the majority of associated ocular and systemic anomalies in patients in the present series, suggesting that typical uveal coloboma may be related to maldevelopment of the neural crest cells. The present findings indicated that ophthalmologists should be aware of the possible association of typical uveal coloboma with systemic anomalies.

Abnormalities, Multiple↗

PubMedDate not supplied

Replacement of myocardium with a Dacron prosthesis for complications of acute myocardial infarction.

From July 1983 to April 1986, four patients (three with ventricular septal perforations and one with left ventricular free-wall rupture) underwent replacement of the myocardium with a Dacron prosthesis for complications of acute myocardial infarction. There were three males and one female, ages ranging from 53 to 70 years (mean 63.3). Three of the four patients survived; the one with the ventricular septal perforation died of severe cardiac failure five days after operation. Replacement of the infarcted myocardium with a Dacron prosthesis seems to be an excellent operative technique for the treatment of complications of acute myocardial infarction when the left ventricular cavity is predicted to be small after resection of the myocardium.

Cardiac Surgical Procedures↗

PubMedDate not supplied

Electron microscopy of tRNA crystals. I. Thin crystals negatively stained with uranyl acetate.

The first attempt to study crystal structures of tRNA by electron microscopy is described. Sufficiently thin crystals were prepared from yeast tRNAphe. The thickness of the thinnest was estimated at 130 A corresponding to a bilayer of the molecules. The L-shaped structure seemed to be maintained even after the negative staining with uranyl acetate. Optically filtered images from electron micrographs were compared with those simulated from the drawing of the molecular model by optical transform. The results suggest that the observed images reflect the real molecular arrangements within the crystal lattice although the shape of tRNA molecules seems to be somewhat modified by the uneven staining.

Crystallography↗