Proton beam therapy for malignancy in Bloom syndrome.

BACKGROUND AND PURPOSE: Bloom syndrome is a DNA repair disorder that is hypersensitive to radiotherapy. We describe the first case in which proton beam therapy (PBT) was used in a patient with Bloom syndrome to treat oropharyngeal cancer. PATIENTS AND METHODS: The patient was a 32-year-old woman with Bloom syndrome who was diagnosed with oropharyngeal cancer staged as T2N2bM0 poorly differentiated squamous cell carcinoma. The primary tumor was located on the right tongue base and extended to the right lateral pharyngeal wall. Several right upper region lymph nodes were positive for metastases. RESULTS: We selected PBT in anticipation of dose reduction to normal tissue. The clinical target volume was defined as the area of the primary tumor and lymph node metastases plus an 8-mm margin. After treatment with 36 GyE (Gray equivalent) in 20 fractions (4-5 fractions per week), dietary intake was decreased by mucositis and intravenous hyperalimentation was started. Termination of treatment for 2.5 weeks was required to relieve mucositis. Administration of 59.4 GyE in 33 fractions markedly reduced the size of the primary tumor, but also caused moderate mucositis that required termination of PBT. One month later, lung metastases and breast cancer developed and the patient died 9 months after PBT. At this time the reduction in size of the primary tumor was maintained without severe late toxicity. CONCLUSION: We obtained almost complete response for a radiosensitive patient with a deficiency of DNA repair, indicating the excellent dose concentration of proton beam therapy.

Effect of acoustic overstimulation on regulation of glucocorticoid receptor mRNA in the cochlea of the guinea pig.

Semi-quantitative reverse transcription polymerase chain reaction was performed to determine the distribution of mRNA levels of glucocorticoid receptor (GR) within the guinea pig cochlea and to examine the change in their expression after acoustic overstimulation. Using an original PCR primer for the guinea pig, the highest GR mRNA level was revealed in the modiolus and lowest in the medial portion including the organ of Corti. Total RNA was extracted from the whole cochlea of the guinea pig 0, 2, 6 and 24 h after exposure to a 2 kHz pure tone of 110, 120 or 130 dB SPL for 10 min. The level of GR mRNA significantly decreased immediately and 2 h after exposure to the sound of 120 dB SPL, and 2 and 6 h after exposure to that of 130 dB SPL. These results suggest the presence of a down-regulation of GR mRNA induced by acoustic overstimulation, although the exact mechanism of this phenomenon remains unsolved.

Hydroxyl radical formation in the perilymph of asphyxic guinea pig.

To elucidate the role of hydroxyl radical (.OH) species in the generation mechanism of the cochlear pathology induced by transient asphyxia and subsequent re-ventilation, the concentrations of 2,3-hydroxybenzoic acid (DHBA) and 2,5-DHBA, major products arising from the attack of .OH upon salicylate, were measured in the perilymph of the guinea pig by the high performance liquid chromatography-electrochemical/UV method. The mean value of 2, 3-DHBA concentration in the perilymph significantly increased from the pre-asphyxic level (6.4 microM) to 7.6 microM and 8.8 microM during asphyxia of 3 min duration and at 5 min after the onset of re-ventilation, respectively. The 2,5-DHBA concentration was 7.9 microM before asphyxia, and also significantly increased to 11.5 microM and 16.2 microM during and after asphyxia, respectively. These results strongly indicated that .OH was generated in the perilymph of the asphyxic and re-ventilated guinea pig cochlea, and the significance of this increased .OH in generating anoxia and re-perfusion injury is discussed with respect to iron and oxygen-derived free radicals.

Detection of a beta-parvalbumin isoform in the mammalian inner ear.

A small, acidic calcium-binding protein (CBP-15) has been detected in the guinea pig organ of Corti, the auditory receptor organ. The apparent molecular weight (15,000) and very low isoelectric point (pI approximately 3.1) suggest that CBP-15 is a beta-parvalbumin isoform. Consistent with this hypothesis, CBP-15 exhibits extreme homology to the mammalian oncofetal parvalbumin called oncomodulin. Sequence data have now been obtained for 30 residues in the N-terminal third of CBP-15. Identity with oncomodulin is observed at all 30 positions. This finding could necessitate revision of the assumption that postnatal mammals utilize a single alpha-parvalbumin isoform in muscle and nonmuscle settings alike.

Calcium-binding proteins in organ of Corti and basilar papilla: CBP-15, an unidentified calcium-binding protein of the inner ear.

In a previous paper (Thalmann et al., 1993) we reported that the amino acid sequence of OCP2, a low molecular weight acidic protein present in extremely high concentrations in the organ of Corti and absent in the basilar papilla, exhibits a rudimentary EF-hand--a potential calcium-binding domain. The present study was undertaken to determine whether OCP2 binds 45-calcium under non-denaturing conditions following separation by isoelectric focusing and transblotting. The same criterion was used to determine whether the EF-hands of several other calcium-binding proteins (CBP) are functional in organ of Corti and basilar papilla. OCP2 exhibited no 45-calcium binding. Calmodulin, present in the organ of Corti in extremely high concentrations and lower in basilar papilla, showed strong 45-calcium binding in both structures. While calbindin represents a major protein in basilar papilla and binds 45-calcium, this protein is a minor component in the organ of Corti; whether it binds 45-calcium remains to be decided. By extending the pI range in the acidic region of isoelectric focusing, a 15 kDa, highly acidic (pI approximately 3.1) protein was revealed that constitutes a major protein in the organ of Corti; the protein was not detectable in the basilar papilla, spiral ligament/stria vascularis complex and numerous other organs tested. It remains to be resolved whether this protein represents an isoform of parvalbumin or a novel CBP. The differential make-up of CBPs between the mammalian organ of Corti and the avian basilar papilla is discussed.

Effect of asphyxia on the composition of cationic elements in the perilymph.

To elucidate the role of free radicals in the cochlea, cationic elements in the perilymph of the scala tympani in normal and asphyxic guinea pigs were measured by an inductively coupled plasma atomic emission spectrometer. The concentrations of 7 cationic elements (i.e., calcium, copper, iron, magnesium, phosphorus, lead and zinc) were measured simultaneously in a sample of the perilymph taken before, during and after asphyxia. There was no significant change in these cationic elements during asphyxia for 3 min. In contrast to the stationary level during asphyxia, the iron concentration was significantly elevated at 5 min after re-ventilation following asphyxia and decreased rapidly toward the pre-asphyxic level thereafter, although no significant change was observed in other cationic elements. These results were comparable to the theory of non-protein-bound iron accumulation produced by an O2-dependent mechanism during re-perfusion.

Protein profile of human perilymph: in search of markers for the diagnosis of perilymph fistula and other inner ear disease.

Recent developments in high-resolution two-dimensional polyacrylamide gel electrophoresis, combined with amino acid sequencing and computer-assisted image analysis, have allowed separation of approximately 100 proteins and identification and quantitation of some 30 proteins in human perilymph. The majority of proteins were found to be present in perilymph at levels in basic agreement with the total protein gradient between perilymph and plasma (1:35). However, several striking differences were observed: (1) beta 2-transferrin, known to be absent from normal plasma but present in cerebrospinal fluid, was detected in perilymph at a concentration roughly equal to that in cerebrospinal fluid; and (2) two high-density lipoprotein-associated apolipoproteins--apo D (formerly PLS:33) and apo J or NA1 and NA2 (formerly PSL:29/30), the latter showing identity with SP40/40, or cytolysis inhibitor--were found to be present at concentrations 1 to 2 orders of magnitude higher when examined in terms of total protein and to be comparable with or higher than plasma levels when examined in terms of absolute concentrations. The functional significance of the extremely high levels of the two apolipoproteins is not known at this time. An attempt was made to use beta 2-transferrin, as well as apo D and apo J (NA1/NA2), as markers for the diagnosis of perilymph fistula, one of the most controversial and challenging problems for the otologist today. It was determined that the technique is indeed applicable when relatively pure fistula samples are analyzed. Limitations and potential improvements of the technique are discussed. In addition, the potential usefulness of two-dimensional polyacrylamide gel electrophoresis in other pathologic conditions of the inner ear is discussed briefly.

[Effects of acoustic overstimulation and perilymph perfusion--with Joro spider toxin on the concentrations of amino acids in the perilymph].

Glutamate (Glu) is considered one of the most probable neurotransmitter candidates in primary afferent nerves of the cochlea. In the present study, the amino acid profile in the perilymph was determined in order to investigate the effects of acoustic overstimulation and perilymph perfusion with Joro Spider Toxin (JSTX), a specific antagonist of the quisqualate sensitive Glu receptor, on the stimulus-induced release of Glu. In the first series of experiments (control group; n = 10), samples of the scala tympani perilymph (PST) were collected from albino guinea pigs at 60 and 75 min after initiating cochlear perfusion with an artificial perilymph. In the second series of experiments (acoustic overstimulation group; n = 7), the PST samples were collected before (at 60 min after the initiation of perilymph perfusion) and after (at 75 min after the initiation of perilymph perfusion) exposure to a pure tone (2000 Hz, 110 dBSPL for 15 min). In the third series of experiments (JSTX group; n = 8), the PST samples were collected as described above under condition of cochlear perfusion with an artificial perilymph containing of 3.54 x 10(-8) M and 3.54 x 10(-6) M of JSTX. The concentrations of Glu, aspartate, glycine, alanine and leucine were measured by high-performance liquid chromatography (HPLC) using phenylisothiocyanate derivatization. There was no significant effect of acoustic overstimulation or perilymph perfusion with JSTX on the levels of amino acids.(ABSTRACT TRUNCATED AT 250 WORDS)

Pharmacokinetics of furosemide in endolymph.

To investigate the pharmacokinetics of organic anions in the endolymph of the guinea pig, 100 mg/kg furosemide, an organic anion, was intravenously given to measure the concentration in the cochlear endolymph by high-performance liquid chromatography with fluorescence detection. In the endolymph, the concentration of the furosemide increased slowly for 1 hr to 1.6 micrograms/ml and gradually declined thereafter. Pretreatment with 200 mg/kg probenecid, an anion transport inhibitor, had no effect on the furosemide elimination in the endolymph except on the concentration at 2 hr. This was contrary to the drastic change observed in the perilymph of the scala tympani by the same pretreatment. Analogous to the effect in the endolymph, probenecid showed no change in the concentration of the serum, while a pronounced gradient of furosemide concentration existed between them. The present results suggest that the furosemide passively transfers from blood to the endolymph at a relatively low penetrability.

Metallic elements in the perilymph measured with an inductively-coupled plasma atomic emission spectrometer.

Metallic elements in the perilymph of the scala tympani in normal and acoustically overstimulated guinea pigs were measured using a new method, an inductively-coupled plasma atomic emission spectrometry. The concentrations of phosphorus and eight metallic elements, i.e. calcium, copper, iron, potassium, magnesium, sodium, lead and zinc were measured simultaneously in a 2 microliters sample of perilymph. The mean concentration values of calcium, copper, iron, magnesium, phosphorus, lead and zinc were 2.03 mM, 38.5 microM, 69.3 microM, 0.822 mM, 0.851 mM, 43.5 microM and 25.0 microM, respectively. There was no significant effect of acoustic overstimulation on the concentrations of these elements except for magnesium, which decreased significantly after the exposure to a intense sound (2 kHz, 115 dB SPL) for 15 min. This is the first report describing the synchronous determination of metallic poly-elements, including copper, iron, lead and zinc, in the perilymph.