Production and synthesis of a novel 191Pt-labeled platinum complex and evaluation of its biodistribution in healthy mice

We previously reported that our sugar-conjugated platinum complex (cis-dichloro [(2-fluoro-α-d-glucopylanosidyl) propane-1,3-diamine] platinum: FGC-Pt) has low toxicity and tumor growth inhibitory effect comparable to that of cisplatin. We focused on radioactive Pt isotopes in order to analyze the kinetics of FGC-Pt using gamma-ray imaging techniques, assuming that FGC-Pt could be used for chemotherapy in the future. Therefore, in this study, we aimed to develop a non-invasive method to analyze the biodistribution of FGC-Pt using 191Pt-labeled FGC-Pt ([191Pt]FGC-Pt). 191Pt was produced via the (n,2n) reaction induced by accelerator neutrons. [191Pt]FGC-Pt was prepared using two different methods. In the first method, [191Pt]FGC-Pt (method A) was obtained through the accelerator neutron irradiation of FGC-Pt. In the second method, [191Pt]FGC-Pt (method B) was synthesized using [191Pt]K2PtCl4, which was obtained by the accelerator neutron irradiation of K2PtCl4. Highly purified [191Pt]FGC-Pt was obtained using the latter method, which suggests that the synthetic method using a 191Pt-labeled platinum reagent is suitable for the radioactivation of platinum complexes. We also aimed to investigate whether a significant correlation existed between the biodistribution of FGC-Pt and [191Pt]FGC-Pt in healthy mice 24 h after tail vein administration. FGC-Pt and [191Pt]FGC-Pt were similarly distributed in healthy mice, with a higher accumulation in the liver and kidney 24 h post injection. In addition, a significant correlation (p < 0.05, r = 0.92) between the 191Pt radioactivity concentration (%ID/g (gamma counter)) and platinum concentration (%ID/g (ICP-MS)) was observed in 13 organs. These results suggest that 191Pt-labeled compounds, synthesized using radioactive platinum reagents, can be used to confirm the biodistribution of platinum compounds. Our study on the biodistribution of [191Pt]FGC-Pt is expected to contribute to the development of novel platinum-based drugs in the future.

95gTc and 96gTc as alternatives to medical radioisotope 99mTc

We studied 95gTc and 96gTc as alternatives to the medical radioisotope 99mTc. 96gTc (95gTc) can be produced by (p, n) reactions on an enriched 96Mo (95Mo) target with a proton beam provided by a compact accelerator such as a medical cyclotron that generate radioisotopes for positron emission tomography (PET). The γ-rays are measured with an electron-tracking Compton camera (ETCC). We calculated the relative intensities of the γ-rays from 95gTc and 96gTc. The calculated γ-ray intensity of a 96gTc (95gTc) nucleus is as high as 63% (70%) of that of a 99mTc nucleus. We also calculated the patient radiation doses of 95gTc and 96gTc, which were larger than that of 99mTc by a factor of 2-3 based on the applied assumptions. A medical PET cyclotron which can provide proton beams with energies of 11-12 MeV and a current of 100 μA can produce 12 GBq (39 GBq) of 96gTc (95gTc) for operation time of 8 h, which can be used for 240 (200) diagnostic scans.

Analysis of cadmium in food by multiple prompt gamma-ray spectroscopy

The Cd concentration in food is a public concern related to the human health. In order to remove Cd-polluted food, the development and validation of a rapid and sensitive method of Cd analysis is required. By applying the multiple gamma-ray detection method to prompt gamma-ray analysis (PGA), the influence from nuclei which emit only one prompt gamma-ray at a time at every neutron capture reaction can be reduced, therefore the quantification limit of Cd is improved significantly. The limit of Cd contained in rice in the case of MPGA was evaluated, and under our proposed experimental conditions, it may be possible to quantify Cd content in rice to within 0.2 ppm in 10 min.

Isotopic ratio of 129I/127I in seaweed measured by neutron activation analysis with gamma-gamma coincidence

129I is a long-lived (1.6 x 10(7) y) radionuclide that is produced in nature as the result of spontaneous fission of heavy elements and reaction of xenon with cosmic rays. Recently, however, artificial sources from nuclear power plants and nuclear test explosions have become a significant component of environmental radioactive iodine. Coincidence gamma-ray detection using Ge detectors makes it possible to simultaneously resolve the numerous gamma-rays produced by neutron activation. In this study, the coincidence gamma-ray detection technique was combined with neutron activation analysis to determine the radioactive iodine composition of seaweed. The ratio of 129I/127I in this common Japanese food item collected from the Ibaraki prefecture has been derived without the need for radiochemical purification. The isotopic ratio of 129I/127I in Kajime algae is 3.5(5) x 10(-10).

Treatment of A-pattern esotropia with marked mongoloid slanting palpebral fissures

BACKGROUND

The association of oblique palpebral fissures and A- or V-pattern has not been clarified. We report two cases of A-pattern esotropia with marked mongoloid slanting palpebral fissures associated with vertical displacement of the horizontal rectus muscle.

CASES

Case 1 was a boy with Prader-Willi syndrome. He showed A-pattern esotropia with upward slanting palpebral fissures. Severe superior oblique muscle overaction was observed. Case 2 was a girl with meningocele. She also showed A-pattern esotropia with upward slanting palpebral fissures.

OBSERVATIONS

In case 1, weakening surgery of the superior oblique muscles did not improve the A-pattern. Coronal images of computed tomography showed one-half-muscle-width upward displacement of both lateral rectus muscles. After downward transposition surgery of the lateral rectus muscles, the preoperative A-pattern of 25 prism diopters (PD) was successfully corrected to 10 PD. In case 2 also, upward displacement of both lateral rectus muscles was shown by computed tomography. The preoperative A-pattern of 26 PD was corrected to 4 PD postoperatively after upward transposition surgery of the medial rectus muscles.

CONCLUSIONS

The vertical displacement of horizontal rectus muscles was considered the principal cause of A-pattern in these cases associated with marked mongoloid slanting palpebral fissures.

Blood stem-cell transplantation for chronic active Epstein-Barr virus with lymphoproliferation

A boy with chronic active Epstein-Barr virus infection (EBV) developed bilateral exophthalmos by infiltrating EBV-infected natural-killer cells during combined chemotherapy. This unusual presentation resolved completely after allogeneic bone-marrow transplantation, and EBV-infected peripheral T and natural-killer cells were also eradicated.

Cohen syndrome with high urinary excretion of hyaluronic acid

Cohen syndrome (MIM 216550) is an autosomal recessive disorder of unknown pathogenesis. The clinical manifestations of Cohen syndrome can be explained as a connective tissue disorder. We found a remarkably high level of urinary hyaluronic acid in 3 patients with Cohen syndrome. Hyperhyaluronic aciduria is a characteristic finding in Werner syndrome and some other conditions. We suggest that the basic defect of Cohen syndrome is associated with a metabolic abnormality in the extracellular matrix.

Weak association between retinopathy of prematurity and neurological disorders in childhood

An attempt was made to elucidate the association between retinopathy of prematurity (ROP) and neurological disorders in infants of very low birth weight. In this retrospective study, 1081 Japanese children weighing less than 1500 g at birth were classified into four subgroups according to birth weight. In each subgroup, the association among cerebral palsy (CP) or mental retardation (MR) and ROP, treated ROP, and cicatricial ROP was analyzed statistically. In the population as a whole, CP and MR were positively associated with ROP. However, in the birth weight subgroup analysis, no significant association was found. We can conclude that there is a weak association between ROP and CP or MR.

Ophthalmic findings in a case of hemophagocytic syndrome

PURPOSE

To report a case of hemophagocytic syndrome, which is characterized by hemophagocytosis of histiocytes; optic nerve involvement, and unusual retinal white patches.

METHOD

Case report. A 10-year-old boy had repeated relapses of hemophagocytic syndrome. He complained of swelling of the right upper eyelid and bilateral visual disturbance.

RESULTS

Ophthalmoscopic examination disclosed bilateral optic disk edema, retinal hemorrhages, and multiple perivenous white patches in the retina. Magnetic resonance imaging demonstrated enlargement of both optic nerves. After chemotherapy and bone marrow transplantation, his visual acuity improved in both eyes, and retinal patches changed to inactive-appearing scars.

CONCLUSION

Hemophagocytic syndrome may manifest with ophthalmic findings such as optic nerve involvement, retinal hemorrhages, and multiple white perivenous retinal patches.

Premature aging syndrome with osteosarcoma, cataracts, diabetes mellitus, osteoporosis, erythroid macrocytosis, severe growth and developmental deficiency

We describe a premature aging disorder in a 15-year-old girl with severe growth and developmental deficiency. Her clinical findings included osteosarcoma, nuclear and subcapsular cataracts, insulin-resistant diabetes mellitus, osteoporosis, epilepsy, foot ulcers, erythroid macrocytosis, and unusual facial appearance. Hyaluronic acid levels in serum and urine were normal. Cultured skin fibroblasts had a normal potential for in vitro growth. This finding represents a new and unique premature aging syndrome.

Rhabdomyoma of the orbit in a child

PURPOSE

To study a case of rhabdomyoma of the orbit in a 16-month-old boy.

METHOD

The child had progressive right proptosis for 1 month. He underwent a computed tomographic scan, which showed an irregular right retrobulbar mass and partial resection.

RESULTS

Histologic examination disclosed well-differentiated striated muscle cells with a mixture of collagen fibers and immature striated muscle cells with centrally placed nuclei. The specimen lacked nuclear atypia, indicating benign rhabdomyoma of the orbit. During the 1 1/2-year follow-up, the patient did not receive additional treatment, and no regrowth occurred.

CONCLUSION

Rhabdomyoma can occur in the orbit of a child. Because of differences in treatment, rhabdomyoma must be distinguished from rhabdomyosarcoma.

Macular coloboma-like lesions and pigment abnormalities as complications of cryotherapy for retinopathy of prematurity in very low birth-weight infants

PURPOSE

Cryotherapy for retinopathy of prematurity (ROP) is effective in reducing the incidence of blindness in premature infants. However, macular complications associated with successful treatment have not yet been well studied.

METHODS

Eighteen very low birth-weight (< 1,251 g) infants (32 eyes) who received cryotherapy for ROP were examined serially for regression of disease and for development of macular abnormalities. Patient characteristics and treatment factors were evaluated to identify risk factors associated with the development of macular abnormalities after successful cryotherapy.

RESULTS

Eleven of 32 eyes (34.4%) that had undergone cryotherapy developed significant macular abnormalities, including macular coloboma-like change (six eyes), macular hyperpigmentation (two eyes), irregularly mottled macular hyperpigmentation and hypopigmentation (two eyes), and macular hyperpigmentation and hypopigmentation with subretinal proliferation (one eye). Corrected visual acuity in affected eyes ranged from 0.15 to 0.03 (20/133 to 20/666) compared with 1.0 to 0.2 (20/20 to 20/100) in treated eyes without macular abnormality (P = .0002). No difference in gestational age was noted between infants who did or did not develop macular coloboma-like lesions or pigment abnormalities. Eyes with macular abnormality had more posterior disease (P = .037) and received significantly more cryotherapy than did eyes without macular abnormality (P = .0005).

CONCLUSIONS

In very low birth-weight infants receiving cryotherapy for ROP, development of macular coloboma-like lesions and macular pigment abnormalities were related to greater severity of ROP and a greater amount of cryotherapy. Macular abnormalities were associated with markedly worse visual outcomes than were treated eyes without macular abnormality.

Mathematical analysis and experiment on the corneal reflex test in spectacle wearers

An experimental study and mathematical analysis of the corneal reflex test was undertaken in spectacle wearers. In the experimental study, photographs were taken of the corneal reflex through spectacles and the conversion ratios determined as measured in degrees/mm. In the mathematical analysis, the magnification effect of the lens was elucidated by three methods: geometrical analysis; real measurement of magnification factor; and ray tracing analysis. The real measurement of the conversion ratios was in good agreement with the conversion ratios determined by the three mathematical analyses. These results clearly showed that the corneal reflex test can be clinically useful even in wearers of spectacles.

The progression of retinopathy of prematurity and fluctuation in blood gas tension

In this study, the relationship between the fluctuation in blood oxygen and carbon dioxide tension and the progression of acute retinopathy of prematurity (ROP) was evaluated. Eighteen extremely premature infants were selected on the basis of the following criteria: gestational age less than 26 weeks, oxygen supply or mechanical ventilation for more than 50 days, transcutaneous oxygen pressure (TcPO2) recorded almost once per hour, and arterial oxygen pressure (PaO2) and arterial carbon dioxide pressure (PaCO2) measured intermittently, for over 8 weeks after birth. All of these infants developed ROP, which ceased progressing in 7 infants (group I, stage 1 or 2 ROP, international classification), but advanced in 11 (group II, stage 3 or 3+). The fluctuations in TcPO2, PaO2, and PaCO2 are represented as coefficients of both variation (CV) and mean difference (D) in these two groups. The results demonstrate that both the CV and D values of TcPO2 are significantly elevated in group II infants compared with group I infants, in the first and second 3-weeks periods, and over the entire 9-week period after birth. The incidences of extreme hyperoxemia (TcPO2 > or = 100 mm Hg) and hypoxemia (TcPO2 < 30 mm Hg) in recorded TcPO2 time series show no significant differences between these two groups. We conclude that extremely premature infants with widely fluctuating arterial oxygen tension may have a greater chance of developing progressive ROP.

[Short-term and long-term prognosis of recession-resection surgery for exotropia]

The short- and long-term results of recession-resection surgery on 141 exotropic patients were analyzed. The corrected angle of exodeviation one week after surgery was not affected by age at surgery, state of binocular vision or the type of intermittent exotropia. The corrected exodeviation was larger when the pre-operative exodeviation exceeded 30 prism diopters or when previous surgery had been performed. Since there was no difference between the angle of deviation at 4 and 8 years postoperatively, the period of four years was considered to be appropriate for long-term assessment. Post-operative exophoria of less than 15 prism diopters were obtained in patients whose short-term results were overcorrected or were under 5 prism diopters of exodeviation. The surgical guideline for exotropia should be determined considering the short-term and the long-term prognosis. It was concluded that the optimal time for surgery was between 5 and 10 years of age.