Connectivity perception of partly occluded gratings in 4-month-old infants

Four groups of eight 4-month-old infants were each habituated to one of four displays consisting of a grating of either low (0.4 cycle deg(-1) or high (1.2 cycles deg(-1) spatial frequency, whose central portion was covered up with a horizontal occluder which was either narrow (1.33 deg) or broad (4.17 deg). Posthabituation displays consisted of a complete grating of the same frequency as the habituated grating, along with a separate grating whose central portion was replaced with a black gap of the same height as the occluder in the habituation displays. All the infants, except those who were habituated to the high frequency with the broad occluder, looked longer at the separate grating than the complete grating display during posthabituation trials. Previously, we found that infants under 1 month of age perceive the grating continuation only when the occluder height is less than about 0.5 cycle of the grating; our present results show that this figure increases to about 1.6 cycles of the grating frequency in the case of 4-month-old infants. These findings indicate that those developmental changes depend on both the sufficiency of visual information available and the efficiency of the perceptual ability of infants for grasping spatial relationships.

Two competing mechanisms underlying neon color spreading, visual phantoms and grating induction

Neon color spreading is closely related to the photopic visual phantom illusion, since these two completion phenomena are characterized by in-phase lightness induction, and the only difference in the stimulus configuration is the difference in the inducer height. This idea was supported by the present study. Neon color spreading showed almost the same function of critical spatial frequency as photopic visual phantoms (Experiment 1), and the critical spatial frequency was constant as the inducer height was changed (Experiment 2). We also examined the relationship between neon color spreading and grating induction (characterized by counterphase lightness induction) in critical spatial frequency (Experiment 3) and in magnitudes of lightness induction (Experiment 4) as a function of the inducer height. The inducer height at which in-phase (neon color spreading) appearance gave way to counterphase (grating) induction was approximately 0.1 deg. These results suggest that neon color spreading shares a common neural mechanism with the photopic visual phantom illusion and that this mechanism is different from, and competes with, the mechanism of grating induction.

Skeletal development of achondroplasia: analysis of genotyped patients

BACKGROUND

Achondroplasia is a skeletal dysplasia caused by substitution of arginine for glycine at codon 380 (G380R) mutation of the fibroblast growth factor receptor 3. To date, the developmental course of the phenotype (short stature and skeletal characteristics) has not been clarified in the genotyped population.

METHODS

The relationship between age and clinical data (height, arm span and measurements of skeletal radiographs) were statistically analyzed from 27 achondroplasia patients with the G380R genotype.

RESULTS

The height standard deviation score had positive correlation and decreased with age, while span-to-height ratio did not. Among measurements of skeletal radiographs, the pelvic index, which represents the squared pelvis deformity, were correlated and increased with age. However, interpedicular distance of the first and fourth lumbar vertebrae (L1:L4) ratio as an index for the caudally narrowed pattern of the lumbar spinal canal and fibula-to-tibia ratio for the disproportionally long fibulae were not correlated and did not increase with age.

CONCLUSION

In making a clinical diagnosis of achondroplasia in early infancy, it should be noted that short stature and squared pelvis deformity are not prominent.

Reaction of D-glycals with azidotrimethylsilane

The treatment of 2,3,4,6-tetra-O-acetyl-1,5-anhydro-D-arabino-hex-1-enitol with azidotrimethylsilane by the aid of a catalytic amount of Yb(OTf)(3) afforded 2,4,6-tri-O-acetyl-2,3-dideoxy-alpha-D-erythro-hex-2-enopyranosyl azide in high yield.

Cardioprotection with angiotensin converting enzyme inhibitor and angiotensin II type 1 receptor antagonist is not abolished by nitric oxide synthase inhibitor in ischemia-reperfused rabbit hearts

Although angiotensin converting enzyme (ACE) inhibitor and/or angiotensin II type 1 (AT1) receptor antagonist can protect the myocardium against ischemia-reperfusion injury, the mechanisms of the effect have not yet been characterized at the cellular level. We here examined the effect of the combination of an ACE inhibitor, temocaprilat, an AT1 receptor antagonist, CV-11974 and/or a nitric oxide synthase inhibitor, L-NAME, on the myocardial metabolism and contraction during ischemia and reperfusion by using phosphorus 31-nuclear magnetic resonance (31P-NMR) in Langendorff rabbit hearts. After normothermic 20 min global ischemia, postischemic reperfusion of 30 min was carried out. Twenty-one hearts were divided into three experimental groups consisting of 7 hearts each: a Tem+CV group perfused with a combination of temocaprilat and CV-11974; a Tem+CV+L-NAME group perfused with a combination of temocaprilat and CV-11974 plus L-NAME, and a control group. During ischemia, both the Tem+CV group and Tem+CV+L-NAME group showed a significant inhibition of the decrease in adenosine triphosphate (ATP) compared with the control group (p<0.01); the increase in ATP was 50+/-3%, 42+/-4%, and 19+/-4% in the Tem+CV group, Tem+CV+L-NAME group, and control group, respectively. Both experimental groups also showed a significant inhibition of the increase in left ventricular end-diastolic pressure (LVEDP) compared with the control group (p<0.01). After postischemic reperfusion, the Tem+CV group and Tem+CV+L-NAME group again showed a significant improvement of ATP as compared with the control group (p<0.01); the increase in ATP was 73+/-3%, 64+/-3%, and 47+/-4% in the Tem+CV group, Tem+CV+L-NAME group, and control group, respectively, and a significant decrease of LVEDP as compared with the control group (p<0.01). There were no differences in ATP, or LVEDP during ischemia and reperfusion between the Tem+CV group and Tem+CV+ L-NAME group. In conclusion, the combination of temocaprilat and CV-11974 showed significant potential for improving myocardial energy metabolism and relaxation during both myocardial ischemia and reperfusion. This beneficial effect was not dependent on NO synthase.

Similarity between Petter's effect and visual phantoms

Here we draw attention to similarity between Petter's effect and the visual phantom illusion. Phantoms are visible when the spatial frequency of the inducing grating is low or the occluder is thin, whereas phantoms are invisible when the spatial frequency of the inducing grating is high or the occluder is thick. Moreover, phantoms are perceived in front of the occluder when they are visible, whereas the occluder is seen in front of the inducing gratings when phantoms are invisible. These characteristics correspond to Petter's effect, in which the thicker region tends to be perceived in front of the thinner region when two regions of the same lightness and of different sizes overlap, since 'thick' corresponds to low spatial frequency of the inducing grating or a thick occluder while 'thin' corresponds to high spatial frequency of the inducing grating or a thin occluder.

Western blot analysis for diagnosis of Lyme disease in acute facial palsy

BACKGROUND

Lyme borreliosis has been implicated in the pathogenesis of acute peripheral facial palsy (APFP). Few studies, however, have used Western blot analyses to confirm the serological diagnosis.

PURPOSE

To analyze the prevalence of anti-Borrelia antibodies in patients with APFP compared with healthy control subjects living in Hokkaido Island, Japan.

PATIENTS AND METHODS

In total, 113 patients with APFP were analyzed. They included 32 patients with varicella zoster virus (VZV) reactivation (Ramsay Hunt syndrome and zoster sine herpete) and 81 patients with Bell's palsy. Fifty-eight healthy control subjects were also included. IgM and IgG antibodies to Borrelia garinii and afzelii were tested by Western blot, and diagnoses were made according to the Centers for Disease Control and Prevention criteria.

RESULTS

Five of 81 (6.2%) patients with Bell's palsy, 1 of 32 (3.1%) patients with VZV reactivation, and 1 of 58 control subjects (1.7%) were judged to have both IgM and IgG antibodies to Borrelia. This difference was not significant (P >.05, chi2 test). Patients with Bell's palsy who had herpes simplex virus type 1 (HSV-1) reactivation at the onset of palsy had a higher IgM-immunoreactivity to Borrelia afzelii.

CONCLUSIONS

Although it is one of the endemic areas of Lyme disease in Japan, the prevalence of APFP caused by Lyme borreliosis is low in Hokkaido Island. In addition, cross-reactivity to B. afzelii in IgM blots is often observed in patients with HSV-1 reactivation, suggesting that careful interpretation of Borrelia IgM immunoblot data are needed for accurate serological diagnosis.

Clinical comparisons between two subsets of gastric antral vascular ectasia

BACKGROUND

The lesions of gastric antral vascular ectasia take two endoscopic forms, diffuse red spots and red stripes. In addition, they are often associated with cirrhosis. The main aim of the present retrospective study was to determine whether differences in endoscopic appearance and presence or absence of cirrhosis have relationships to clinical features and course.

METHODS

Gastric antral vascular ectasia in 30 patients was classified into 2 endoscopic subtypes, punctate type (21 patients) and striped type (8 patients); only 1 patient could not be categorized to either type. The 30 patients were divided into groups based on the presence (25) or absence (5) of cirrhosis.

RESULTS

All patients with punctate-type vascular ectasias had cirrhosis, whereas only 38% of patients with the striped type had cirrhosis. All patients without cirrhosis had the striped pattern. For patients with the 2 endoscopic types as well as those with and without cirrhosis, the outcomes of endoscopic treatment were similar.

CONCLUSIONS

The findings of the present study suggest that cirrhosis is strongly associated with the development of punctate-type vascular ectasias. The endoscopic appearance of vascular ectasias and the presence or absence of cirrhosis did not determine outcome of patients.

Mutations in the mitotic check point gene, MAD1L1, in human cancers

Aneuploidy is a characteristic of the majority of human cancers, and recent studies suggest that defects of mitotic checkpoints play a role in carcinogenesis. MAD1L1 is a checkpoint gene, and its dysfunction is associated with chromosomal instability. Rare mutations of this gene have been reported in colon and lung cancers. We examined a total of 44 cell lines (hematopoietic, prostate, osteosarcoma, breast, glioblastoma and lung) and 133 fresh cancer cells (hematopoietic, prostate, breast and glioblastoma) for alterations of MAD1L1 by RT-PCR-SSCP and nucleotide sequencing. Eight mutations consisting of missense, nonsense and frameshift mutations were found, together with a number of nucleotide polymorphisms. All the alterations in cell lines were heterozygous. Frequency of mutations was relatively high in prostate cancer (2/7 cell lines and 2/33 tumor specimens). We placed a mutant truncated MAD1L1, found in a lymphoma sample, into HOS, Ht161 and SJSA cell lines and found that it was less inhibitory than wild type MAD1L1 at decreasing cell proliferation. Co-expression experiments showed that the mutant form had a dominant-negative effect. Furthermore, this mutant impaired the mitotic checkpoint as shown by decreased mitotic indices in HOS cells expressing mutant MAD1L1 after culture with the microtubule-disrupting agent, nocodazole. Our results suggest a pathogenic role of MAD1L1 mutations in various types of human cancer.

Loss of the SEDL gene product (Sedlin) causes X-linked spondyloepiphyseal dysplasia tarda: Identification of a molecular defect in a Japanese family

A 23-year-old man was diagnosed as having X-linked spondyloepiphyseal dysplasia tarda (SEDT; MIM 313400) based on his disproportionately short trunk, short stature, characteristic radiological features of the spine (posterior hump, end plate sclerosis, and disc space narrowing) and the hips (short and thick femoral necks), and positive family history. This Japanese family was found to have an intragenic deletion flanking intron 2 and exon 3 of the SEDL gene that not only included the 5' untranslated region but also the coding sequence for the first methionine through the 25th alanine. This mutation was present in the proband and his unaffected mother (a heterozygote), but not in an unaffected sister and an unaffected uncle. The nature of the mutation predicted that the SEDL protein (Sedlin) was not produced in the proband, indicating that loss of Sedlin caused SEDT.

Effect of myopia on frequency-doubling perimetry

PURPOSE

To examine the effect of myopia, occasionally associated with glaucomatous eyes, on the results obtained by frequency-doubling perimetry (FDP).

METHODS

Sixty emmetropic or myopic normal volunteers (mean age, 26.2 +/- 0.35 years, mean +/- SEM; range, 19-34) with good visual acuity and without glaucoma were divided into three groups. The groups were emmetropia to low-myopia (mean refractive error, -1.16 +/- 0.23 D), intermediate-myopia (-4.95 +/- 0.17 D), and high-myopia (-8.12 +/- 0.36 D; n = 20 each). All subjects were tested on the FDP full-threshold C-20 program and the Humphrey Field Analyzer (HFA; Humphrey, Dublin, CA) full-threshold program on one randomly selected eye. FDP and the HFA test were conducted with the subjects wearing their full distance correction and with their distance correction with appropriate additional correction for near, respectively. The calculated mean sensitivity (MS), mean deviation (MD), pattern standard deviation (PSD), and test durations for FDP and the HFA test for the three groups were compared using one-way analysis of variance. The relationship between the refractive error and MS, MD, or PSD was also analyzed by simple regression analysis.

RESULTS

The MS and MD for the fields determined by the HFA decreased significantly as the refractive errors increased, but there were no significant differences in the MS, MD, and PSD for FDP between the three groups. There were no significant differences in the test durations between the three groups for both FDP and HFA testing. The refractive error was correlated with both MS and MD only for the fields determined by the HFA.

CONCLUSIONS

The results showed that lens-corrected myopia does not alter the visual fields obtained by FDP, and FDP can therefore be used regardless of the presence of myopia.

Alternative splicing of fibronectin transcripts in osteochondrogenic tumors

BACKGROUND

Fibronectin (FN) acts in many fundamental biological processes including cell adhesion, migration, proliferation and apoptosis. Although FN shows an ubiquitous expression pattern, alternative mRNA splicing modulates tissue-specific molecular heterogeneity at three regions: extra domain-B, extra domain-A and variable region.

MATERIALS AND METHODS

In the present study, we analyzed the FN mRNA splicing in osteochondrogenic tumors as well as in various normal tissues using the RT-PCR method.

RESULTS

Normal cartilage almost exclusively contained short mRNA lacking alternative exons in all regions. However, 14 osteochondrogenic tumors including osteochondroma, enchondroma, chondroblastoma, chondrosarcoma and osteosarcoma uniformly contained long mRNA with various patterns of alternative exons in the three regions.

CONCLUSION

These results indicated that the lack of regulation excluding the alternative exons may be associated with tumorigenesis in chondrocytes.

Use of intercostal nerves for neurotization of the musculocutaneous nerve in infants with birth-related brachial plexus palsy

OBJECT

The use of intercostal nerves (ICNs) for the neurotization of the musculocutaneous nerve (MCN) in adult patients with traumatic brachial plexus palsy has been well described. However, its use for brachial plexus palsy in infants has rarely been reported. The authors surgically created 31 ICN-MCN communications for birth-related brachial plexus palsy and present the surgical results.

METHODS

Thirty-one neurotizations of the MCN, performed using ICNs, were conducted in 30 patients with birth-related brachial plexus palsy. In most cases other procedures were combined to reconstruct all upper-extremity function. The mean patient age at surgery was 5.8 months and the mean follow-up period was 5.2 years. Intercostal nerves were transected 1 cm distal to the mammary line and their stumps were transferred to the axilla, where they were coapted directly to the MCN. Two ICNs were used in 26 cases and three ICNs in five cases. The power of the biceps muscle of the arm was rated Grade M4 in 26 (84%) of 31 patients. In the 12 patients who underwent surgery when they were younger than 5 months of age, all exhibited a grade of M4 (100%) in their biceps muscle power. These results are better than those previously reported in adults.

CONCLUSIONS

Neurotization of the MCN by surgically connecting ICNs is a safe, reliable, and effective procedure for reconstruction of the brachial plexus in patients suffering from birth-related palsy.

A technique of percutaneous multidrilling osteotomy for limb lengthening and deformity correction

We have recently developed a technique of per-cutaneous multidrilling osteotomy for limb lengthening and deformity correction. The bone is drilled percutaneously, using a special drill guide, and osteotomy is accomplished by connecting the multiple drill holes with a small chisel. The bone segments are subjected to slow progressive distraction with an external fixation device. We have lengthened 33 limbs in 22 patients with congenital or post-traumatic limb shortening and/or bone deformities. All the patients underwent the proposed lengthening and/or correction of the bone deformities through a single-treatment procedure. None of the lengthened segments resulted in nonunion. This technique can prevent undesirable bone cracks and preserve soft tissue around the osteotomy site, and is also applicable to other fields of orthopedic surgery.

[A case of Sjögren's syndrome with dermatomyositis who died of rapidly progressive interstitial pneumonia]

We report a case of 55 year-old woman with six year history of Sjögren's syndrome developed fatal rapidly progressive interstitial pneumonia. She had been well until February 1999. She developed swelling and erythematous lesions in the cheek and hands in spring 1999. She was admitted to our hospital for investigations of skin lesions in May 1999. Physical examination on admission revealed small hemorrhagic lesions in the nailfold. Serum CK level was slightly elevated. Electromyogram and MRI suggested mild myositis in the proximal upper extremities. She was suspected to have dermatomyositis along with Sjögren's syndrome. Prednisolone 10 mg/day had been given for her skin problems since March 1999. Suddenly, dyspnea on exertion was appeared on 34th day of admission. Chest X-ray film showed an acute worsening of interstitial pneumonia. Methylprednisolone pulse therapy (1000 mg for 3 days) and cyclophosphamide pulse therapy (500 mg for a day) were started, and she was subsequently treated with 60 mg/day of prednisolone and 250 mg/day of Cyclosporin A. However, interstitial pneumonia did not respond to the treatment, and pneumomediastinum and pneumothorax have developed. She died of respiratory failure on 55th day. We consider that most likely explanation for fatal interstitial pneumonia is concomitantly occurred dermatomyositis.

Role of Cardiac ATP-Sensitive K+ Channels Induced by Angiotensin II Type 1 Receptor Antagonist on Metabolism, Contraction and Relaxation in Ischemia-Reperfused Rabbit Heart

The role of cardiac adenosine triphosphate-sensitive K+ (K(ATP)) channels induced by angiotensin II type 1 (AT1) receptor antagonist, CV-11974, on myocardial metabolism and contraction during ischemia, and reperfusion by the phosphorus 31-nuclear magnetic resonance in Langendorff-perfused rabbit hearts was investigated. After 20 min of continuous normothermic global ischemia, 30 min of postischemic reperfusion was carried out. CV-11974 with or without the K(ATP) channel blocker, glibenclamide, or the bradykinin B2 receptor antagonist, D-Arg-[Hyp3,D-Phe7]bradykinin, was administered 40 min prior to the global ischemia. Adenosine triphosphate (ATP), creatine phosphate (PCr), inorganic phosphate (Pi), intracellular pH (pHi), left ventricular systolic developed pressure, left ventricular end-diastolic pressure (LVEDP), and coronary flow were measured. Twenty-eight hearts were divided into 4 experimental groups consisting of 7 hearts each. Group I consisted of controls, Group II perfused with CV-11974 (10(-6) mol/L), Group III perfused with CV-11974 (10(-6) mol/L) in combination with glibenclamide (10(-6) mol/L), and Group IV perfused with CV-11974 (10(-6) mol/L) in combination with D-Arg-[Hyp3,D-Phe7]bradykinin (10(-6) mol/L). Group II showed a significant inhibition of the decrease in ATP during ischemia and reperfusion compared with Group I (p<0.01), being 42+/-3% and 19+/-4% at ischemia, 69+/-3% and 47+/-4% at reperfusion in Group II and Group I, respectively. Group II also showed a significant inhibition of the increase in LVEDP during ischemia and reperfusion compared with Group I (p<0.01), being 13+/-4 mmHg and 52+/-8 mmHg at ischemia, 8+/-2 mmHg and 26+/-5 mmHg at reperfusion in Group II and Group I, respectively. However, Group II did not inhibit the decrease in ATP and the increase in LVEDP during ischemia and reperfusion. Group IV also showed no inhibition of the aforementioned parameters during the same period. These results suggest that CV-11974 has a significant beneficial effect for improving myocardial energy metabolism and relaxation during both myocardial ischemia and reperfusion, which is provided by K(ATP) channels and bradykinin B2 receptor. The cardioprotective quality of the AT1 receptor antagonist is caused by the K(ATP) channels that are mediated by the bradykinin B2 receptor.

Comparative study of superoxide dismutase in normal and hereditary cataract (UPL) rats

In the present study, the levels of SOD activity and Cu, Zn-SOD mRNA in the brain, kidney, liver and eye of normal and Upjohn Pharmaceutics Limited (UPL) rats, a new hereditary cataract model derived from Sprague-Dawley rats, were measured. Although the levels of SOD activity in the eye and brain of UPL rats were significantly decreased compared with those of normal rats 3 and 5 weeks after birth, the levels of SOD activities in the kidney and liver were the same in both groups. The levels of Cu, Zn-SOD mRNA in kidney and liver of UPL rats were the same as those of normal controls. The level of Cu, Zn-SOD mRNA in the brain of normal rats 5 weeks after birth was about twofold greater than that of UPL, and that in the eye of UPL rats 3 weeks after birth was significantly decreased compared with that of normal controls. The sequences of cDNA encoding Cu, Zn-SOD and the sequences of the regulatory region of the Cu, Zn-SOD gene were confirmed to be the same in normal and UPL rats. These results indicated that the decreases in levels of SOD activity and Cu, Zn-SOD mRNA in the brain and eye of UPL rat were not due to mutation of the genomic Cu, Zn-SOD gene in UPL rats or differences in the sequence of the regulatory region of the Cu, Zn-SOD gene between normal and UPL rats.

Effect of a novel cardioprotective agent, JTV-519, on metabolism, contraction and relaxation in the ischemia-reperfused rabbit heart

The effect of a novel cardioprotective agent, JTV-519 on myocardial metabolism and contraction during ischemia and reperfusion was investigated by means of phosphorus 31-nuclear magnetic resonance (31P-NMR) in Langendorff rabbit hearts. Normothermic, 20-min, global ischemia was followed by 30-min of postischemic reperfusion and JTV-519 was administered from 40 min prior to the global ischemia. Adenosine triphosphate (ATP), creatine phosphate (PCr), inorganic phosphate (Pi), intracellular pH (pHi), left ventricular developed pressure (LVDP), left ventricular end-diastolic pressure (LVEDP) and coronary flow were measured. Fourteen hearts were divided into 2 experimental groups of 7: Group I were controls and Group II were perfused with JTV-519 (10(-6) mol/L). During ischemia, Group II showed a significant (p<0.01) inhibition of the increase in Pi and LVEDP and the decrease in ATP and pHi, compared with Group I. After postischemic reperfusion, Group II also showed a significant (p<0.01) improvement in ATP and pHi as compared with Group I. There were no differences in LVDP or coronary flow during ischemia and reperfusion between the 2 groups. In conclusion, JTV-519 had a significant beneficial effect on myocardial energy metabolism and relaxation during both myocardial ischemia and reperfusion.

Assessment of the presence and severity of esophagogastric varices by splenic index in patients with liver cirrhosis

PURPOSE

To determine whether spleen size is related to the severity of esophageal varices or associated gastric varices and liver functions in patients with cirrhosis.

METHOD

The authors retrospectively studied spleen size on CT (splenic index [SI] = length x width x height of the spleen), liver functions, and the results of esophagogastric endoscopy in 110 patients with cirrhosis. They also analyzed SI in 112 controls.

RESULTS

In controls, body weight, height, and age affected the SI. The SI in patients with uncompensated cirrhosis was greater compared with the SI in those with well-compensated disease (p = 0.0363). The SI in patients with esophageal varices was greater than in patients without esophageal varices (p<0.0001), but patients with and without gastric varices had similar SI values. The SI in patients with the red color signs (red wale marking, cherry red spot, and hematocystic spot) on esophageal varices or with risky varices (enlarged tortuous varices with beady, nodular, or tumor shape associated with red color signs) was greater than in patients without these signs (p = 0.0029 and p = 0.0030, respectively).

CONCLUSION

The SI is a good indicator of the severity of esophageal varices and hepatic functional reserve in patients with cirrhosis.

Transferrin receptor 2-alpha supports cell growth both in iron-chelated cultured cells and in vivo

In most cells, transferrin receptor (TfR1)-mediated endocytosis is a major pathway for cellular iron uptake. We recently cloned the human transferrin receptor 2 (TfR2) gene, which encodes a second receptor for transferrin (Kawabata, H., Yang, R., Hirama, T., Vuong, P. T., Kawano, S., Gombart, A. F., and Koeffler, H. P. (1999) J. Biol. Chem. 274, 20826-20832). In the present study, the regulation of TfR2 expression and function was investigated. A select Chinese hamster ovary (CHO)-TRVb cell line that does not express either TfR1 or TfR2 was stably transfected with either TfR1 or TfR2-alpha cDNA. TfR2-alpha-expressing cells had considerably lower affinity for holotransferrin when compared with TfR1-expressing CHO cells. Interestingly, in contrast to TfR1, expression of TfR2 mRNA in K562 cells was not up-regulated by desferrioxamine (DFO), a cell membrane-permeable iron chelator. In MG63 cells, expression of TfR2 mRNA was regulated in the cell cycle with the highest expression in late G(1) phase and no expression in G(0)/G(1). DFO reduced cell proliferation and DNA synthesis of CHO-TRVb control cells, whereas it had little effect on TfR2-alpha-expressing CHO cells when measured by clonogenic and cell cycle analysis. In addition, CHO cells that express TfR2-alpha developed into tumors in nude mice whereas CHO control cells did not. In conclusion, TfR2 expression may be regulated by the cell cycle rather than cellular iron status and may support cell growth both in vitro and in vivo.

Effect of beta-blocker on metabolism and contraction of doxorubicin-induced cardiotoxicity in the isolated perfused rabbit heart

The effect of beta-blocker (propranolol) on the metabolism and contraction of doxorubicin-induced cardiomyopathy during pacing or ischemia was examined by the phosphorus 31-nuclear magnetic resonance (31 P-NMR) in Langendorff hearts of chronically treated rabbits after cumulative doses of 16 mg doxorubicin/kg. After 8 weeks of doxorubicin treatment, beta-blocker (propranolol) was given orally over a period of 2 weeks for a cumulative dose of 1.4 mg/kg. Isolated hearts were paced at higher heart rates, or hearts were perfused on low flow. Adenosine triphosphate (ATP), creatine phosphate (PCr), inorganic phosphate (Pi), pH, left ventricular systolic developed pressure (LVDev P), and coronary flow were measured. The hearts were divided into three experimental groups: Group I consisted of controls, Group II consisted of doxorubicin treatment, and Group III consisted of doxorubicin treatment with propranolol. Group II showed a significant decrease of ATP during pacing (48 +/- 2%) and during low flow (61 +/- 6%) compared with Group I (86 +/- 9% at pacing, 94 +/- 6% on low flow). But Group III showed a significantly marked improvement of ATP during pacing (95 +/- 10%) and during low flow (83 +/- 3%) compared with Group II. Furthermore, Group II showed a significant decrease of LVDev P during pacing (69 +/- 6 mm Hg) and during low flow (63 +/- 3 mm Hg) compared with Group I (101 +/- 5 mm Hg at pacing, 95 +/- 9 mm Hg on low flow). But Group III showed a significantly marked improvement of LVDev P during pacing (93 +/- 5 mm Hg) and during low flow (83 +/- 14 mm Hg) compared with Group II. In conclusion, propranolol had a significant beneficial effect on metabolism and contraction during high-energy demand and during low oxygen supply of doxorubicin cardiomyopathy.