Erythropoietin receptors that signal through Stat5 or Stat3 support fetal liver and adult erythropoiesis: lack of specificity of stat signals during red blood cell development

Erythropoietin (Epo) is essential for formation of mature red blood cells (RBC). However, the function of Epo receptor (EpoR)-dependent signaling pathways in the regulation of erythropoiesis remains unclear. To determine whether specific Stat signals are required for RBC development, we changed the Stat signaling specificity of the EpoR. The wild-type EpoR activates only Stat5. Thus, we substituted the major Stat5 binding sites (residues 343 and 401) in the EpoR cytoplasmic region with the Stat3 binding/activation motif from gp130. We demonstrated that activated EpoRs containing a single substitution stimulate Stat5 and Stat3, whereas an EpoR with both substitutions stimulates Stat3 but not Stat5. We then determined the ability of these receptors to support fetal liver and adult erythropoiesis. Our results show that erythropoiesis is stimulated by EpoRs that activate Stat5, both Stat5 and Stat3, or Stat3 in place of Stat5. These findings demonstrate that the specificity of EpoR Stat signaling is not essential for RBC development.

Search target selection in monkey prefrontal cortex

To explore a visual scene, the brain must detect an object of interest and direct the eyes to it. To investigate the brain's mechanism of saccade target selection, we trained monkeys to perform a visual search task with a response delay and recorded neuronal activity in the prefrontal (PF) cortex. Even though the monkey was not allowed to express its choice until after a delay, the response field of a class of PF neurons was able to differentiate between target and distractors from the very beginning of their response (135 ms). Strong responses were obtained only when the target was presented at the field. Neurons responded much less during a nonsearch task in which saccade target was presented alone in this response field. These results suggest that the PF cortex may be involved in the decision-making process and the focal attention for saccade target selection.

Treatment for pyothorax-associated lymphoma

In eight patients with pyothorax-associated lymphoma (PAL), which resulted from artificial pneumothorax for the treatment of pulmonary tuberculosis, seven patients received radiotherapy and five showed no local recurrence. All four patients treated by primary chemotherapy had disease progression. Radiotherapy of 50 Gy with wide margins is recommended to treat PAL.

Esophageal pressure and apnea hypopnea index in sleep-disordered breathing

Severity of negative esophageal pressure (Pes) and apnea hypopnea index (AHI) were investigated in six cases of upper airway resistance syndrome (UARS) and 11 cases of obstructive sleep apnea syndrome (OSAS). The severity of negative Pes was represented by the highest peak (Pes Max) and the number of increased episodes (more than 13.5 cmH2O) per h (NPesI13.5). There was no significant correlation between Pes indices and AHI. Pes Max and NPesI13.5 were not different among severe OSAS (AHI > 30), mild OSAS (AHI < 30) and UARS. Apnea hypopnea index failed to represent the severity of negative Pes, which is an important aspect of the pathophysiology of sleep-disordered breathing.

During pain-avoidance neurons activated in the macaque anterior cingulate and caudate

Lesions in either the anterior cingulate cortex (ACC) or the caudate nucleus (CN) impair avoidance behavior from noxious somatic stimuli, so these two areas may play a similar role in pain-avoidance behavior. To test this hypothesis, we recorded single neuronal activities in the ACC and in the CN of a monkey while it was performing a pain-avoidance task. Ten of 136 ACC and eleven of 160 CN neurons responded selectively during pain-avoidance behavior. We found little difference in the population distribution or in the response latency and duration. Our present findings are in accordance with previous lesion and anatomical studies which suggest that these two regions could function as one module in pain-avoidance behavior.

Developmental changes in enzyme activities and in morphology of rat cortex mitochondria

Development of mitochondria in rat brain cortex was investigated in terms of mitochondrial respiratory enzyme activities, and structural and numerical developments of mitochondria. Measurements of succinate-O2 and NADH-O2 oxidoreductase activities of mitochondria resulted in simultaneous changes of activities in postnatal rat. Both oxidoreductase activities were still low at 0-5 days old, increased until 15 days, decreased slightly at 21 days and drastically in adult mitochondria. In morphological study, the cross-sectional area of mitochondrion per cell increased gradually until 21 days old, but decreased drastically in adult. The area of a mitochondrion at 5 days increased about 1.5-fold in comparison with that at 0 days, and maintained at 15 and 21 days. However, the values of area of one mitochondrion from 10 days and adult are about half of a maximum value (21 days). Numbers of mitochondrion per cell were still low at 0-5 days, and high constantly (about twice) at 10-21 days. These findings suggest that the organelle division of mitochondria may be carried out at 5-10 days postnatal. The number of adult rat mitochondria decreased slightly. The small and undeveloped mitochondria were observed at 0 day postnatal by use of transmission electron microscopy (TEM). However, during development from 5 days postnatal, larger and elongated mitochondria were observed, and the maximal complexity of structure of cristae is observed at 15 days and 21 days by TEM. In adult cortex, the small mitochondria were also observed with compact and dense cristae. Our results indicate that the changes of activities of mitochondrial respiratory enzymes in rat cortex is good correlated with the structural maturation of mitochondria.

An axonemal dynein at the Hybrid Sterility 6 locus: implications for t haplotype-specific male sterility and the evolution of species barriers

Poor sperm motility characterized by a distinct aberration in flagellar waveform known as "curlicue" is a hallmark of t haplotype (t) homozygous male sterility. Previous studies have localized "curlicue" and a flagellar developmental defect, "whipless", to the Hybrid Sterility 6 locus (Hst6), between the markers Pim1 and Crya1. More recent heterospecific breeding experiments between Mus spretus (Spretus) and Mus musculus domesticus (Domesticus) have mapped the primary source(s) of both "curlicue" and "whipless" to a small sub-locus of Hst6, Curlicue a (Ccua). Here we report the complete physical isolation of the Ccua locus and the identification of a candidate gene for expression of both "whipless" and "curlicue" at its proximal end, an axonemal dynein heavy chain gene, Dnahc8, formerly mapped by interspecific backcross analysis near Pim1. Dnahc8 mRNA expression commences in the Domesticus wild-type testis just prior to flagellar assembly and is testis-specific in the adult male. However, expression of Dnahc8 is not readily evident in the testis of either Spretus or "whipless" animals (Domesticus males homozygous for the Spretus allele of Dnahc8). Our results argue that Dnahc8 is fundamental to flagellar organization and function in Domesticus, but not Spretus, and suggest that Dnahc8 is integral to both Hst6- and t-specific male infertility.

Behavior of blood cells in contact with water-soluble phospholipid polymer

Omega-Methacryloyloxyalkyl phosphorylcholine (MAPC) polymer, which has various methylene chain lengths between the phosphorylcholine group and the backbone, was synthesized with attention to formation of the biomembrane. The effect of water-soluble poly(MAPC) on the function and activation of blood cells was evaluated to determine the interaction between blood cells and the MAPC polymer. The poly(MAPC) and the MAPC copolymer with a small amount of fluorescent units were synthesized by a conventional radical polymerization technique. Using a fluorescence spectrometer, it was determined that the MAPC polymer was adsorbed on the plasma membrane of platelets when the platelets were suspended in an aqueous solution of the MAPC copolymer. The hemolytic activity of poly(MAPC) was less than that of other water-soluble polymers, such as poly(ethylene glycol) and poly(1-vinyl-2-pyrrolidone) (PVPy). The change in the plasma membrane fluidity of platelets on contact with poly(MAPC) was determined with 1,6-diphenyl-1,3,5,-hexatriene. The plasma membrane fluidity of platelets decreased with an increase in the methylene chain length of the MAPC unit. The aggregation activity of platelets after contact with poly(MAPC) was also evaluated, but no significant difference between that of polymer-contacted platelets and native platelets was observed. Finally, the activity of platelets on contact with poly(MAPC) was determined by measuring the cytoplasmic calcium ion concentration ([Ca2+]i) in platelets. The increase in [Ca2+]i in the platelets after contact with poly(MAPC) was similar to that of native platelets. We conclude that the poly(MAPC) reduced platelet activation even though the poly(MAPC) adsorbed on the membrane surface of the platelets. In particular, poly(10-methacryloyloxydecyl phosphorylcholine) significantly reduced platelet activation compared with PVPy.

Comparison between deciduous and permanent incisor teeth in morphology of bovine enamel

Functional incisor teeth (deciduous and permanent teeth) from Bovidae (14 species) were prepared for scanning electron microscopic observation. Ultrastructural patterns of the enamel layer of deciduous and permanent incisor teeth varied (ex. prisms, arrangement pattern of matrices, and in thickness of enamel layer) in each species. The ultrastructures of prisms in longitudinal sections were classified into three types; A, radial, B, tangential, and C, mix of A and B arrangement enamel; modified Koenigswald's method (1982) in examined species. Type A was found in a large part of permanent and a small part of deciduous incisor teeth, while types B and C were mainly found in the deciduous teeth. These morphological features show the remarkable correlation between permanent and deciduous teeth.

Clinical characteristics of upper airway resistance syndrome

Polysomnographic findings and clinical symptoms were investigated in 14 cases of upper airway resistance syndrome. The mean scores of the Epworth sleepiness scale and self-rating depression scale in eight cases were 13.5 and 38.6, respectively. The mean sleep latency of the multiple sleep latency test in four cases was 10.2 min. Seven cases were treated with continuous positive airway pressure (CPAP), and one with hormone replacement therapy. The most common symptom was daytime sleepiness. Five cases had hypertension. CPAP reduced increasing negative esophageal pressure (Pes) and frequency of EEG arousals, and improved hypertension in one case. Hormone replacement therapy ameliorated increasing negative Pes and clinical symptoms.

Frequent breathing-related electroencephalogram arousals in four patients with mild obstructive sleep apneas

We report cases of four patients with mild obstructive sleep apnea syndrome (OSAS) with frequent breathing-related electroencephalogram (EEG) arousals which led to excessive daytime sleepiness. In spite of a relatively low apnea hypopnea index (AHI), sleep was disrupted by frequent EEG arousals associated with respiratory effort as observed in upper airway resistance syndrome. The effects of sleep stage and sleep position on EEG arousals were also investigated. We consider that AHI alone is not a sufficient index to assess severity of OSAS, and it is very important to examine microarousals by the alteration of esophageal pressure in addition to the effect of sleep position.

Neurons in the temporal cortex changed their preferred direction of motion dependent on shape

To investigate neuronal mechanisms that integrate different visual modalities such as motion and shape, neuronal activities in the superior temporal polysensory area (STP) were recorded from monkeys that were watching rotating images. In total, 194 neurons were identified as visually responsive. Of these, 73 neurons (38%) showed differential response depending on both shape and direction of motion (MS neurons). Of these 73 neurons, 21 (29%) were identified as reversal type MS neurons (MSr neurons), that is, they responded to an opposite preferred direction when the shape was different. The results confirm that neurons in the STP can be simultaneously activated by different attributes of visual stimuli. The data also suggest that individual STP neurons can process more than one type of visual stimulus.

[A case of rheumatoid arthritis with bucillamine-induced myasthenia gravis treated by immunoadsorption therapy]

We report a case of 48-year old female with rheumatoid arthritis (RA) complicated with myasthenia gravis. In 1988, she was diagnosed of having RA, and several therapeutic drugs were administered, but her disease activity was in poor control. In July 1993, bucillamine (BU) was started at a dose of 100 mg/day, and her arthritis subsided. However, in October 1996, she was admitted with a rapidly progressive ptosis and double vision in the left eye, which became prominent in the evening. Because serum concentration of the antibody to acetylcholine receptors (AchR Ab) was elevated at 12.6 nmol/l, and the ptosis was reversed immediately after a tensilon test, ocular type myasthenia gravis (MG) was diagnosed and it was thought to have been induced by BU. Immunoadsorption therapy was started after discontinuation of this drug, and was continued for 6 months, resulting in improvement of neurological symptoms and decrease in AchR Ab level. MG has not recurred since. Although several cases of D-penicillamine (DP) induced MG are reported, only two cases are reported which were induced by BU, sulfhydryl compound which has a structure similar to DP. Since BU has been widely used as one of the disease modifying anti-rheumatic drugs in Japan, MG induced by this drug should be paid attention as one of the adverse effects.

Immunocytochemical study of the maxilla and maxillary sinus during human fetal development

We quantitatively examined the distribution of the proliferating cell nuclear antigen (PCNA), which is associated with cell division, and of components of the ECMs (collagen types I and III, tenascin and osteonectin) in the immature zones at three sites: palatine, inferior and vertical surface region of the fetal human maxilla as well as the maxillary sinus (MS) at 12, 16, 20, 24, and 28 weeks gestation. The percentage of PCNA-positive cells was the highest at 16 weeks in the immature zones of maxilla. Tenascin and fibrillar collagens (collagen types I and III) were especially present in the cellular zone linked to the bone and cartilage matrices of the immature zones of the maxillary bone at 20-24 weeks gestation. The osteonectin was detected on the maxillary bone from 24 weeks. These distributions of ECMs revealed the specific and contrasting profiles of development in the human maxillary bone and might reflect the formation of paranasal sinus as MS.

Nociceptive neurons in the macaque anterior cingulate activate during anticipation of pain

Since the anterior cingulate cortex (ACC) is known to be involved both in nociception and in anticipation that precedes the avoidance of aversive stimuli, the linking of these functions may be processed in the ACC. To test this hypothesis, we recorded single neuronal activities in the ACC of a macaque monkey while it was performing a pain-avoidance task and examined them with nociceptive cutaneous electric stimuli (ES). Thirty-six neurons responded in anticipation of the ES. Of these, 22 neurons were tested with the ES and 11 responded. These neurons could be those that are involved both in nociception and in pain anticipation that precedes the avoidance of noxious stimuli.

Mutations of the CYP21 gene in nonclassical steroid 21-hydroxylase deficiency in Japan

To determine whether nonclassical steroid 21-hydroxylase deficiency in Japan has the same molecular basis as in western countries, we have characterized the mutations of the CYP21 gene in 7 Japanese patients with nonclassical (NC) steroid 21-hydroxylase deficiency. In the Japanese NC cases the P30L was present in one allele in 5 of the 7 patients and on both alleles in one patient. By contrast, the V281L mutation, which was present in about 60% of NC cases in western countries, was not identified in any patient. Among our 7 cases, 4 were detected through neonatal mass screening by a mild increase in serum 17-hydroxyprogesterone (without any symptoms of CAH) at birth, but the 2 cases who were diagnosed as adults were born before nationwide neonatal screening was instituted, so that the Japanese neonatal screening program does detect some cases of NC steroid 21-hydroxylase deficiency. We suggest that P30L mutation is more frequent in Japanese NC CAH than V281L and that the frequency of the mutations causing NC steroid 21-hydroxylase deficiency in Japan might be different from that in western countries.

Absence of cytokine receptor-dependent specificity in red blood cell differentiation in vivo

Erythropoietin (EPO) is required for red blood cell development, but whether EPO-specific signals directly instruct erythroid differentiation is unknown. We used a dominant system in which constitutively active variants of the EPO receptor were introduced into erythroid progenitors in mice. Chimeric receptors were constructed by replacing the cytoplasmic tail of constitutively active variants of the EPO receptor with tails of diverse cytokine receptors. Receptors linked to granulocyte or platelet production supported complete erythroid development in vitro and in vivo, as did the growth hormone receptor, a nonhematopoietic receptor. Therefore, EPOR-specific signals are not required for terminal differentiation of erythrocytes. Furthermore, we found that cellular context can influence cytokine receptor signaling.

Prenatal diagnosis of steroid 21-hydroxylase deficiency by the modified polymerase chain reaction to detect splice site mutation in the CYP21 gene

A splicing junction mutation at nucleotide 656 (A-> G substitution, I2G) in the steroid 21-hydroxylase gene (CYP21) is the most frequently detected mutation in patients with the salt-wasting and simple-virilizing forms of steroid 21-hydroxylase deficiency (approximately 60%). In this disease, prenatal diagnosis and treatment to minimize the effects of excess androgen in affected females has been advocated. Therefore, to detect the I2G mutation rapidly, accurately, and without the use of radioisotope, we developed a modified polymerase chain reaction (PCR) with a mismatched 3' nucleotide primer to introduce a new restriction site upon PCR amplification of the mutant allele. This allowed the mutant allele to be identified readily by restriction enzyme digestion of the PCR product, and subsequently this PCR product was subjected to restriction enzyme digestion for diagnosis. Chorionic villus biopsy samples (CVS) were obtained at 10 to 11 weeks gestation from two females carrying fetuses at risk for steroid 21-hydroxylase deficiency. Prenatal diagnosis was successful in both cases. One affected female was treated with dexamethasone to term. In the other case, treatment was withdrawn at an early stage when testing revealed a normal fetus. The results demonstrate the rapid and accurate detection of the I2G mutation by this method, thereby indicating the feasibility of for prenatal diagnosis of the I2G mutation.

Alteration of esophageal pressure in sleep-disordered breathing

We investigated the alteration of esophageal pressure (Pes) in 10 patients with upper-airway sleep-disordered breathing (UASDB) and the relationship among Pes, breathing patterns and EEG arousals. Increased negative Pes without apnea or hypopnea, appeared not only in upper airway resistance syndrome but also in obstructive sleep apnea syndrome. This phenomenon produced frequent EEG microarousals leading to sleep fragmentation and daytime sleepiness. Moreover, increased negative Pes occasionally continued for more than 20 min without an EEG arousal, which might be considered to be one of the factors to cause complications of UASDB.

Two cases of sleep-disordered breathing in climacteric

Two cases of sleep disordered-breathing in climacteric were reported. Polysomnography including esophageal pressure (Pes) measurement was performed. Case 1 was diagnosed as upper airway resistance syndrome. Case 2 was diagnosed as obstructive sleep apnea syndrome, while many episodes of upper airway resistance also existed. Hormone replacement therapy improved clinical symptoms, and in case 1, Pes nadir was improved but incidence of arousals which was induced by breathing disturbances was not significantly changed. Sleep disordered-breathing should be suspected as a cause of sleep disorder even in females, especially in climacteric age. Pes measurement and evaluation of arousals is required. Hormone replacement therapy may release the upper airway resistance.

Neuronal activities in the ventral premotor cortex during a visually guided jaw movement in monkeys

Neuronal activities in the ventral part of the premotor cortex (PMv) and the primary motor cortex (MI) were analyzed during a visually guided jaw movement task. Based on the type of neuronal activity observed, when monkeys closed or opened their mouths in response to a visual stimulus, PMv neurons could be classified into three categories: (1) signal-related neurons, which transiently responded to visual stimuli, (2) movement-related neurons which were time-locked to jaw opening and/or jaw closing movements, and (3) set related neurons which exhibited gradually increasing activities while jaw position was maintained. However, all MI neurons exhibited movement-related activities and responded differently between the closing and opening dynamic phases. These results suggest that PMv neurons may be involved in motor preparation, initiation and control of jaw movements and task behavior based on visual information, and that MI neurons may be involved in controlling jaw movements, especially contraction of the masticatory muscles.

Redundant and selective roles for erythropoietin receptor tyrosines in erythropoiesis in vivo

Cytokine receptors have been shown in cell culture systems to use phosphotyrosine residues as docking sites for certain signal transduction intermediates. Studies using various cellular backgrounds have yielded conflicting information about the importance of such residues. The present studies were undertaken to determine whether or not tyrosine residues within the erythropoietin receptor (EPOR) are essential for biologic activity during hematopoiesis in vivo. A variant of the EPOR was constructed that contains both a substitution (R129C) causing constitutive receptor activation as well as replacement of all eight cytoplasmic tyrosines by phenylalanines (cEPORYF). A comparison between animals exposed to recombinant retroviruses expressing cEPOR and cEPORYF showed that efficient red blood cell (RBC) development in vivo is dependent on the pressence of tyrosine residues in the cytoplasmic domain of the EPOR. In addition, an inefficient EPOR tyrosine independent pathway supporting RBC development was detected. Tyrosine add-back mutants showed that multiple individual tyrosines have the capacity to restore full erythropoietic potential to the EPOR as determined in whole animals. The analysis of primary erythroid progenitors transduced with the various cEPOR tyrosine mutants and tyrosine add-backs showed that only tyrosine 343 (Y1) and tyrosine 479 (Y8) were capable of supporting immature burst-forming unit-erythroid progenitor development. Thus, this receptor is characterized by striking functional redundancy of tyrosines in a biologically relevant context. However, selective tyrosine residues may be uniquely important for early signals supporting erythroid development.

Reduction of surface-induced platelet activation on phospholipid polymer

omega-Methacryloyloxyalkyl phosphorylcholine (MA-PC) polymers which have been synthesized with attention to the surface structure of a biomembrane show excellent blood compatibility, i.e., resistance to protein adsorption and blood cell adhesion. To clarify the stability of platelets in contact with the MAPC polymer surfaces, cytoplasmic free calcium concentration ([Ca2+],) in the platelets was measured. A platelet suspension was passed through a column packed with various polymer beads after treatment with plasma, and the [Ca2+]i in the platelets eluted from the column was measured. The [Ca2+]i in contact with the MAPC polymers, i.e., poly[2-methacryloyloxyethyl phosphorylcholine-co-nbutyl methacrylate (BMA)] (PMEB) and poly(6-methacryloyloxyhexyl phosphorylcholine-co-BMA) (PMHB), was less than that in contact with poly(BMA). However, poly(10-methacryloyloxydecyl phosphorylcholine-co-BMA) (PMDB) was not effective in suppressing the increase in [Ca2+]i, and thus was at the same level as in the poly(BMA). This result indicated that platelets in contact with PMEB or PMHB were less activated compared with those in contact with PMDB and poly(BMA). Moreover, the state of the platelets adhered to these polymer surfaces, both morphologically and immunologically, was examined. Scanning electron microscopic observation of the polymer surface after contact with a platelet suspension revealed that many platelets adhered and changed their shape on the poly(BMA). The numbers of adhetent platelets were reduced on all MAPC polymer surface. The relative amount of alpha-granule membrane glycoprotein (GMP-140) which appears on the cell membrane by activation of platelets on the PMEB surfaces was less than that on poly(BMA) and poly(2-hydroxyethyl methacrylate). These results suggest that PMEB and PMHB suppressed not only platelet adhesion but also activation of the platelets in contact with these surface.