Targeted disruption of the aromatase P450 gene (Cyp19) in mice and their ovarian and uterine responses to 17beta-oestradiol

Aromatase P450 (CYP19) is an enzyme catalysing the conversion of androgens into oestrogens. We generated mice lacking aromatase activity (ArKO) by targeted disruption of Cyp19 and report the characteristic features of the ArKO ovaries and uteri as revealed by histological and biochemical analyses. ArKO females were totally infertile but there were as many developing follicles in their ovaries at 8 weeks of age as in wild-type ovaries. Nevertheless, no typical corpus luteum was observed in the ArKO ovaries. Electron microscopy revealed the presence of well-developed smooth endoplasmic reticulum, few lipid droplets and mitochondria with less organized tubular structures in the ArKO luteinized interstitial cells. These ultrastructural features were different from those of the wild-type interstitial cells, where there are many lipid droplets and mitochondria with well-developed tubular structures, characteristic of steroid-producing cells. When ArKO mice were supplemented with 17beta-oestradiol (E(2); 15 microg/mouse) every fourth day from 4 weeks of age for 1 month, increased numbers of follicles were observed in the ovaries as compared with those of untreated ArKO mice, although no typical corpus luteum was detectable. Ultrastructural analysis revealed the disappearance of the accumulated smooth endoplasmic reticulum in the luteinized interstitial cells after E(2 )supplementation. Transcripts of pro-apoptotic genes such as p53 and Bax genes were markedly elevated in the ArKO ovaries as compared with those of wild-type mice. Although E(2) supplementation did not cause suppression of the elevated expression of p53 and Bax mRNAs, it caused marked enhancement of expression levels of lactoferrin and progesterone receptor mRNAs in the uteri as well as increases in uterine wet weight. At 8 months of age, ArKO mice developed haemorrhages in the ovaries, in which follicles were nearly depleted, while age-matched wild-type females still had many ovarian follicles. Furthermore, macrophage-like cells were occasionally observed in the ArKO ovarian follicles. These results suggested that targeted disruption of Cyp19 caused anovulation and precocious depletion of ovarian follicles. Additionally, analysis of mice supplemented with E(2) demonstrated that E(2) apparently supports development of ovarian follicles, although it did not restore the defect in ovulation.

Relationships between serum (ZZ)-bilirubin, its subfractions and biliverdin concentrations in infants at 1-month check-ups

In 150 infants, including those with breast milk jaundice, who were brought to our hospital for their 1-month check-ups, the serum concentrations of (ZZ)-bilirubin, its subfractions and biliverdin were measured by high-performance liquid chromatography and the relationships among them investigated. (ZZ)-Bilirubin was found to have the highest serum concentration, followed by (ZE)-bilirubin, accounting for 14.0 (geometric mean) % of (ZZ)-bilirubin. Biliverdin had a serum concentration of 0.95% of (ZZ)-bilirubin. There was only a small amount of total (di- and mono-) glucuronosyl bilirubin, 0.42% of (ZZ)-bilirubin. (ZE)-Bilirubin, (EZ)-bilirubin, (EZ)-cyclobilirubin. biliverdin, diglucuronosyl bilirubin and monoglucuronosyl bilirubin (C-8 and C-12) showed positive logarithmic correlations with (ZZ)-bilirubin (R2=0.16 or above, P<0.05). (ZE)-Bilirubin showed a significant positive logarithmic correlation with (ZZ)-bilirubin (R2=0.863, P<0.0001). Furthermore, (EZ)-cyclobilirubin, the most important photoisomer in phototherapy for neonatal hyperbilirubinaemia, was detected in very small amounts in approximately half of the neonates (84 of 150) when they were in conditions of only weak ambient light. The relationship between total glucuronosyl bilirubin and (ZZ)-bilirubin concentrations fitted a model of saturation kinetics of bilirubin UDP-glucuronosyltransferase.

A 10-year-old boy with Marfan syndrome exhibiting cerebrovascular abnormalities

A young male with Marfan syndrome, diagnosed at the age of 10 years, presented with conspicuous elongation and tortuosity of the internal carotid, middle cerebral, vertebral and basilar arteries on cranial magnetic resonance and computed tomography angiography. There is a little mention of cerebral blood vessel examinations in the guidelines of the American Academy of Pediatrics for Marfan syndrome. Guidelines may be provided for the evaluation of cerebrovascular system for the patients with Marfan syndrome who have family history of Marfan syndrome as well as a family history of death from subarachnoid hemorrhage.

Cyclobilirubin formation by in vitro photoirradiation with neonatal phototherapy light

BACKGROUND

The main mechanism of phototherapy for neonatal hyperbilirubinemia is the production and excretion of (EZ)- and (EE)-cyclobilirubin (4E,15Z- and 4E,15E-cyclobilirubin). Thus, the clinical efficacy of the light source for phototherapy must be evaluated by cyclobilirubin formation from (ZZ)-bilirubin in in vitro photoirradiation.

METHODS

In the present study, we investigated the in vitro production pattern of bilirubin photoisomers by phototherapy light from the bilirubin-human serum albumin complex.

RESULTS

No clear difference was found in the curves relative to (ZZ)-bilirubin and its photoisomers under aerobic and anaerobic conditions. The ratio of (EZ)-cyclobilirubin to (ZZ)-bilirubin increased proportionately to the dose of irradiating light and no photoequilibrium state was observed analogous to that found in configurational photoisomerization. The concentration of (EZ)- and (EE)-cyclobilirubin increased proportionately with the grade of the percentage decrease in A(460 nm) from 0 to 23%. With a percentage decrease in A(460 nm) of 23% or more, the cyclobilirubin concentrations reached a steady state. The reason for this appears to be that the concentration of (ZZ)-bilirubin, a substrate for photoisomers, dropped below 1 mg/100 mL. Biliverdin was produced only in trace amounts. However, the absorption at 520--700 nm increased after a percentage decrease in A(460 nm) of more than 23%.

CONCLUSIONS

The results of the present study show that little bilirubin photooxidation occurred with in vitro aerobic photoirradiation. Before the concentration of cyclobilirubin reaches a steady state, it is theoretically valid to use the percentage decrease in A(460 nm) for the evaluation of the clinical efficacy of the light source.

Fortuitously discovered persistent left superior vena cava in young competitive athletes. Clinical implications of sports physicians

This report describes two athletes with persistent left superior vena cava (PLSVC) accidentally identified during preparticipation medical evaluation. The clinical implications of PLSVC for sports physicians are also discussed. A 16-year-old male ice hockey player and an 18-year-old male high-level field hockey player visited our institute for medical evaluation prior to participating in competition. Neither complained of palpitation, faintness or syncope, which would have suggested a possible cardiac rhythm disturbance, or had been informed of any abnormalities in previous physical examinations. Nonetheless, echocardiography revealed dilated coronary sinuses, and venography confirmed PLSVC and, in one case, showed the absence of the right superior vena cava. Electrocardiograms showed the field hockey player to have an ectopic atrial rhythm with left axis deviation of the frontal plane P-wave and the ice hockey player to have normal sinus rhythm. Symptom-limited treadmill testing revealed nothing abnormal, and after explaining the possible rhythm instability and the potential risk associated with cardiac surgery, the subjects were permitted full participation in competitive sports. Although information is scarce, available data on PLSVC suggest it is benign for competitive athletes. Nevertheless, complications arising from other cardiovascular anomalies, from potential cardiac rhythm disturbances, and from cardiac surgery necessitated by major injuries should be considered prior to participation in competitive sports.

Effects of ethanol on L-arginine transport in rat Ito cells in relation to nitric oxide production

BACKGROUND

Nitric oxide (NO) is a potent mediator of hepatic sinusoidal hemodynamics that is synthesized in the hepatic stellate cells (Ito cells, fat-storing cells) and affects these cells. NO production may depend on the induction of inducible nitric oxide synthase and on transport of extracellular L-arginine. The precise mechanism that controls NO production in stellate cells was characterized recently.

METHODS

Kinetic analysis of L-arginine transport and reverse transcription-polymerase chain reaction for cationic amino acid transporter (CAT) were carried out by using stellate cells prepared from the male Wistar rat. The effect of ethanol on L-arginine transport and NO production of stellate cells was assessed in the presence of tumor necrosis factor (TNF)-alpha and interferon (IFN)-gamma.

RESULTS

The L-arginine transport system functioning in the hepatic stellate cells was system y+, possibly mediated by CAT-1 and CAT-2B (Km approximately 50 microM). IFN-gamma in combination with TNF-alpha induced NO production with an enhancement in CAT-2B mRNA expression and L-arginine transport, whereas L-arginine transport and NO production were suppressed by coincubated ethanol.

CONCLUSIONS

In hepatic stellate cells, ethanol has suppressive effects on NO production and extracellular L-arginine transport in the presence of TNF-alpha and IFN-gamma. The estimated Km of L-arginine transporter in hepatic stellate cells is very similar to the physiological L-arginine concentration in portal vein. Our findings may support the merit of further studies on the modulation of NO production via access to portal blood L-arginine concentration to control disturbed hepatic sinusoidal blood flow in patients with alcoholic liver disease.

Estimation of regional cerebral blood flow distribution in infants by near-infrared topography using indocyanine green

Near-infrared topography with indocyanine green was used to measure regional cerebral blood flow (rCBF) in the temporal lobes of infants. The mean rCBF in infants without neural abnormality was 14.5 +/- 3.1 ml/100 g/min, and the rCBFs in the fronto-temporal, temporal, and occipito-temporal regions were 15.1 +/- 3.9, 15.4 +/- 3.3, and 14.6 +/- 3.3 ml/100 g/min, respectively. Moreover, in one asphyxiated infant with infarction and one infant with subdural and intracerebellar hemorrhage, it was demonstrated that the area of defective blood flow could be detected as well as it can by SPECT. This technique makes it possible to estimate rCBF distribution in infants at the bedside. Thus, in the future, evaluation of various neonatal illnesses should be feasible.

cDNA sequence of human carbonic anhydrase-related protein, CA-RP X: mRNA expressions of CA-RP X and XI in human brain

A full-length cDNA clone of human carbonic anhydrase-related protein (CA-RP) X was obtained and sequenced. The 2720 bp long cDNA sequence was predicted to encode a 328 amino acid polypeptide. The deduced amino acid sequence showed an overall similarity of 25-57% to other CA isozymes and the highest % similarity to a CA-RP XI. Similar to CA-RP XI, CA-RP X lacked two out of three zinc-liganded histidine residues, suggesting no biological activity of CA. Northern blot analysis demonstrated an approx. 2.8 kb transcript in the human brain and kidney. RNA dot blotting showed significant signals for CA-RP X and XI mRNA expressions in the adult total brain and almost all parts of the central nervous system, but no expression in the fetal brain. These results suggest that CA-RP X and XI play some role in human brain, especially in brain development.

Expression of UDP-GalNAc: polypeptide N-acetylgalactosaminyltransferase isozymes T1 and T2 in human colorectal cancer

Uridine diphosphate (UDP)-GalNAc: polypeptide N-acetylgalactosaminyltransferase (GalNAc transferase) catalyzes the initial step in mucin type O-glycosylation, and its expression has been assumed to be altered between normal epithelial cells and cancer cells. We studied the alteration of GalNAc transferase expression during the carcinogenesis of human colorectal epithelial cells. We produced polyclonal antibodies against synthetic polypeptides with specific sequence to two GalNAc transferase isozymes, T1 and T2. Surgically resected specimens from 50 patients with colorectal cancer were immunohistochemically stained, and the staining grade (percentage of positively stained cells) was compared between cancer and its normal counterpart in the same specimen. Significant signals for both T1 and T2 expression were seen in the supranuclear region of normal and cancer cells, indicating the subcellular localization of the enzymes in the Golgi apparatus. The prevalence of positive staining for T1 and T2 expression in colorectal cancer was significantly higher than that in normal epithelium (P < 0.05). However, the difference in staining grades between cancer and normal tissues varied in each patient. These results indicate that there is variability in the expression patterns of GalNAc transferase isozymes in normal and cancerous cells colorectal among individuals.

Oestrogen at the neonatal stage is critical for the reproductive ability of male mice as revealed by supplementation with 17beta-oestradiol to aromatase gene (Cyp19) knockout mice

Aromatase P450 (CYP19) is an enzyme responsible for the conversion of androgens to oestrogens. We generated CYP19 knockout (ArKO) mice by targeted disruption of Cyp19 and studied the role of oestrogens in male reproductive ability. Approximately 85% of ArKO males were unable to sire offspring. However, no obvious difference was found in testicular and epididymal weights, numbers of sperm in the epididymis or the ability of sperm to fertilize eggs in vitro between wild-type and ArKO males. An examination of mating behaviour demonstrated that ArKO males showed an impairment in mounting behaviour against sexually mature females. The inability of more than 90% of ArKO males to sire offspring was reversed by repeated subcutaneous injections of 17beta-oestradiol when initiated on the day of birth. The effects of 17beta-oestradiol on reproduction were concentration dependent and evident when supplementation was initiated on day 7, but not on day 15 after birth. These findings suggest that oestrogens acting during neonatal life are required for normal mating behaviour in adulthood.

Functional imaging of the brain in sedated newborn infants using near infrared topography during passive knee movement

Near infrared topography was used for functional imaging of the sensorimotor cortex of newborn infants during passive knee movement under sedated sleep. Contralateral knee movement caused a marked increase in oxyhemoglobin and total hemoglobin from the baseline values at almost all locations in the primary sensorimotor area of all neonates and a decrease in local deoxyhemoglobin in six of seven neonates. During ipsilateral knee movement, oxyhemoglobin and total hemoglobin showed slighter changes at a few locations, equal to 30% (mean) and 29% (mean) of the changes that occurred with contralateral stimulation, respectively. The mean times corresponding to maximal changes were 11.9 s for oxyhemoglobin and 19.1 s for deoxyhemoglobin, demonstrating that oxyhemoglobin has a much faster response than does deoxyhemoglobin.

Eosinophil-induced liver injury: an experimental model using IL-5 transgenic mice

BACKGROUND/AIMS

In certain liver diseases, activated eosinophils are considered to be important effector cells in addition to T-cell-mediated cytotoxicity. No experimental model, however, has been developed for in vivo analysis of the cytotoxic mechanisms.

METHODS

Interleukin-5 (IL-5) transgenic mice (C3H/HeN-TgN(IL-5)Imeg), which exhibit marked eosinophilia without liver injury, were injected once with 25 microg of lipopolysaccharide (LPS) intraperitoneally. The mice were sacrificed weekly and eosinophilic injuries were assessed microscopically. To clarify the role of Kupffer cells and tumor necrosis factor-alpha (TNF-alpha) in the liver injury, gadolinium chloride (GdCl3) and anti-TNF-alpha neutralizing antibody were administrated before the LPS injection.

RESULTS

Two weeks after injection, transgenic mice exhibited marked infiltration of eosinophils and extensive lobular necrosis. Transmigration of eosinophils through vascular endothelium and degranulation of eosinophil cytotoxic granules in inflamed areas were observed. These eosinophilic injuries were transient, but liver-specific. Pre-administration of GdCl3 and anti-TNF-alpha markedly reduced the hepatic inflammation, suggesting that LPS-activated Kupffer cells play a key role in producing the cytotoxicity of eosinophils by releasing TNF-alpha.

CONCLUSIONS

We have established an experimental model of eosinophil-induced liver injury using IL-5 transgenic mice. Since this model is simple and highly reproducible, it will be useful for analysis of in vivo cytotoxic mechanisms of eosinophils.

Differences in transcutaneous bilirubin readings in Japanese term infants according to feeding method

BACKGROUND

Controversy has existed for many years over whether infant feeding methods are related to serum bilirubin concentrations during the first few days of life. Differences in initial jaundice patterns according to the feeding method until 72 h after birth have not been elucidated hitherto. The difference may become clear in Japanese neonates because jaundice shows a much higher peak bilirubin concentration and a later peak in Japanese neonates than in Caucasian neonates.

METHODS

In the present study, we investigated variations in the transcutaneous bilirubin reading (TcB) obtained within 72 h after birth among 177 breast-fed and 494 formula-fed healthy Japanese term neonates.

RESULTS

There was no difference between TcB in formula-fed and breast-fed infants until the first 30 h, after which time the rate of increase in TcB was lower in formula-fed infants. Among breast-fed neonates, a good linear regression between time after birth and TcB was maintained. Similarly, weight losses in breast-fed infants at 24-48 h and 48-72 h after birth were greater than those in formula-fed infants.

CONCLUSIONS

The jaundice pattern in Japanese neonates from 30 to 72 h after birth according to the feeding method was different from that in Caucasian neonates.

A loss of aggressive behaviour and its reinstatement by oestrogen in mice lacking the aromatase gene (Cyp19)

Aromatase P450 (CYP19) is an enzyme responsible for conversion of androgens to oestrogens. We generated CYP19 knockout (ArKO) mice by targeting disruption of the CYP19 gene and observed that the ArKO males exhibited a complete loss of aggressive behaviour against intruder mice when examined using a resident-intruder paradigm. The defect in the behaviour of ArKO males was reinstated when the mice received supplements of 17beta-oestradiol soon after birth. Nevertheless, the cumulative duration of the behaviour displayed by the treated mice during the test period of 15 min was 19+/-10 s, which was much shorter than that displayed by wild-type males, 90+/-17 s. When the supplementation was started at 7 days after birth, the defect was not restored. These findings illustrate an absolute requirement for oestrogen during the neonatal stage of a male's life for the development of the potential for aggression observed in adulthood. Furthermore, the present study demonstrates that ArKO males are a useful model in which to investigate the neural mechanisms by which aggressive behaviour is controlled.

Prognostic impact of plasma brain natriuretic peptide for cardiac events in elderly patients with congestive heart failure

BACKGROUND

Plasma brain natriuretic peptide (BNP) has been reported to be useful in determining the prognosis of patients with ischemic heart disease and cardiomyopathy. However, aging increases the level of plasma BNP; therefore, the prognostic impact of plasma BNP in elderly patients with congestive heart failure has not been fully established.

OBJECTIVE

We sought to determine whether plasma BNP could predict recurrent cardiac events in elderly patients with congestive heart failure.

METHODS

Forty-eight consecutive elderly patients (>65 years old) were enrolled in the present study. All patients were admitted with their first episode of congestive heart failure. Clinical characteristics, plasma BNP, left ventricular ejection fraction, and left ventricular mass index were compared between patients with and those without recurrent cardiac events.

RESULTS

During the follow-up period, twelve cardiac events were observed. The New York Heart Association functional class was signi- ficantly higher in patients with cardiac events than in those without (p < 0.05). The plasma BNP level in pa- tients with cardiac events was significantly higher than in those without (521.0 +/- 156.0 vs. 126.8 +/- 20.1 pg/ml, p<0.001), despite more frequent treatment with angiotensin-converting enzyme inhibitors (75 vs. 28%, p<0.05). The left ventricular ejection fraction was significantly lower and the left ventricular mass index higher in patients with cardiac events as compared with those without (38.1 +/- 5.0 vs. 49.2 +/- 2.4%, p < 0.05; 193.8 +/- 14.3 vs. 132.6 +/- 7.8 g/m(2), p < 0.001, respectively). The plasma BNP was selected as an independent factor associated with cardiac events besides New York Heart Association functional class, left ventricular ejection fraction, and left ventricular mass index using multivariate Cox proportional-hazards regression analysis (hazard ratio = 2.656, p<0.05). The cardiac event rate was significantly higher in patients with a plasma BNP concentration >132 pg/ml using Kaplan-Meier analysis (p < 0.001). Moreover, the plasma BNP level correlated inversely with the length of time from hospital discharge to a cardiac event (r = -0.575, p<0.05).

CONCLUSION

Measuring the plasma BNP level before hospital discharge in elderly patients with congestive heart failure was more useful than other conventional examinations for predicting the recurrence of cardiac events.

Carbonic anhydrase isozymes in the human pancreas

Recently, an increasing number of carbonic anhydrase (CA) isozymes have been discovered in the human pancreas. These isozymes are classified as the CA family with various molecular structures and different subcellular localizations: cytoplasmic CA II, mitochondrial CA VB, secretory CA VI, membrane-bound CA IV, and transmembrane CA IX and XII. However, there is little evidence concerning their pathophysiological roles. Here, we reviewed the expression of CA isozymes in the human pancreas and proposed hypotheses related to their physiological and pathological roles.

[Systemic inflammatory response syndrome triggered by necrotizing cholecystitis after treatment of underlying low titer cold agglutinin disease]

In April 1996, a 77-year-old man initially presented with fever, rash and polyarthralgia, and was diagnosed as having low titer cold agglutinin disease with acute hemolytic anemia. The patient's condition and laboratory findings improved after administration of corticosteroid (prednisolone 60 mg). In June 1996, however, he developed acute cholecystitis and died due to sepsis, disseminated intravascular coagulation and multiple organ failure. During the course, the levels of inflammatory cytokines such as TNF-alpha and IL-6 were correlated with the pathology, and the disease was diagnosed as systemic inflammatory response syndrome (SIRS). Autopsy revealed necrotizing cholecystitis, erythrophagocytosis in the liver, and cytomegalovirus infection in the lung and gall bladder. This was considered to be a rare case of low titer cold agglutinin disease complicated by SIRS.

Successful treatment of disseminated Fusarium infection in an infant with leukemia

Disseminated Fusarium infection in an immunocompromised host is intractable and results in high mortality. We provide the first full case report on successful treatment of a disseminated Fusarium infection in an infant. The 6-month-old infant, whose family raised livestock, had infantile leukemia. During the neutropenic period after intensive chemotherapy, vomiting, diarrhea, fever, subcutaneous nodes, and coughing appeared. Pneumonia was diagnosed, and Fusarium moniliforme was isolated from blood culture. A central venous catheter was removed. Granulocyte colony-stimulating factor (G-CSF) and amphotericin B (AMPH-B) (total dose, 65 mg/kg) were administered continuously for 8 weeks. The infection was resolved according to improvement of clinical and laboratory findings, and intensive chemotherapy was restarted for the leukemia. Cord blood stem cell transplantation from an unrelated donor was performed. The Fusarium infection did not recur, but after transplantation, leukemia relapsed. Treatment of neutrophils using G-CSF, AMPH-B, and local treatment induced resolution of the disseminated Fusarium infection in this immunocompromised host with malignancy. We suggest caution for patients living in an environment conducive to the development of Fusarium infection because of the particular risk of infection.

Physiological profile of middle-aged and older climbers who ascended Gasherbrum II, an 8035-m Himalayan peak

BACKGROUND

The purpose of this study was to investigate the physiological characteristics of a group of middle-aged and older Japanese climbers who ascended Gasherbrum II, an 8035-m peak in the Karakoram Range of the Himalayas.

METHODS

Body composition, cardiac structure, and respiratory gas exchange during exercise were estimated in eight climbers with differing levels of experience (seven men and one woman, aged 54 to 63 years) 6 months before their expedition.

RESULTS

Using supplementary O2, the four experienced climbers ascended beyond Camp 4 (7400 m) without showing any health problems and were able to attempt the summit. In contrast, the others, who had minimal experience at extreme altitude, suffered from altitude sickness on the way to Camp 4. Body mass index values were relatively high, but their low percentage of body fat (14.9%-21.4%) was indicative of the climbers' substantial lean body weight. Cardiac structures were generally normal, although three experienced male climbers had borderline hypertension and eccentric hypertrophy of the left ventricle. Peak VO2 ranged from 30.9 to 45.6 ml/kg/min, and no significant relationship between fitness level and the success or failure of the ascent was evident.

CONCLUSIONS

Even sexagenarians are capable of safely climbing 8000-m peaks with supplementary O2. An exceptionally high fitness level, as is seen in elite older athletes, does not appear to be required. What is essential, however, is moderate fitness, good health, and extensive experience.