Semisolid Enteral Nutrients Alter the Pharmacokinetics of Orally Administered Levetiracetam in Rats

Enteral nutrients (ENs) affect the plasma drug concentration of orally co-administered drugs, particularly those of antiepileptic drugs, such as phenytoin and carbamazepine. However, few studies have reported the interactions of levetiracetam (LEV), an upcoming antiepileptic drug, with ENs. In this study we aimed to investigate the pharmacokinetics of LEV in 55 rats after oral co-administration of LEV with liquid or semisolid ENs. Compared with the control group, co-administration with Terumeal ® Soft significantly decreased the plasma LEV concentration at 0.5, 1, and 2 h and area under the plasma concentration-time curve from 0 to 3 h (AUC0→3h) (P < 0.01). However, the AUC0→3h of LEV remained unchanged following the administration of Terumeal ® Soft 2 h after the initial LEV administration. Moreover, co-administration with semisolid Racol® NF delayed the absorption of LEV without decreasing the AUC0→3h, whereas liquid Racol ® NF did not alter LEV pharmacokinetics. Thus, co-administration of LEV with Terumeal® Soft reduced the absorption of LEV from the gastrointestinal tract, which was prevented by administering Terumeal ® Soft 2 h after LEV administration. Semisolid Racol ® NF altered LEV pharmacokinetics without decreasing its gastrointestinal absorption. Our findings suggested that careful monitoring of the plasma LEV levels is necessary when co-administering LEV with Terumeal ® Soft, semisolid Racol ® NF, or any other semisolid ENs, to prevent the inadvertent effects of the interaction between LEV and ENs.

Rapid screening using pathomorphological interpretation to detect BRAFV600E mutation and microsatellite instability in colorectal cancer

PURPOSE

Rapid decision-making is essential in precision medicine for initiating molecular targeted therapy for cancer patients. This study aimed to extract pathomorphological features that enable the accurate prediction of genetic abnormalities in cancer from hematoxylin and eosin (H&E) images using deep learning (DL).

EXPERIMENTAL DESIGN

A total of 1,657 images (one representative image per patient) of thin formalin-fixed, paraffin-embedded (FFPE) tissue sections from either primary or metastatic tumors with next-generation sequencing (NGS)-confirmed genetic abnormalities-including BRAFV600E and KRAS mutations, and microsatellite instability high (MSI-H)-that are directly relevant to therapeutic strategies for advanced colorectal cancer (CRC) were obtained from the nationwide SCRUM-Japan GI-SCREEN project. The images were divided into three groups of 986, 248, and 423 images to create one training and two validation cohorts, respectively. Pathomorphological feature-prediction DL models were first developed based on pathomorphological features. Subsequently, gene-prediction DL models were constructed for all possible combinations of pathomorphological features that enabled the predicting of gene abnormalities based on images filtered by the combination of pathomorphological feature-prediction models.

RESULTS

High accuracies were achieved, with areas under the curve (AUCs) &gt; 0.90 and 0.80 for 12 and 27, respectively, of 33 analyzed pathomorphological features, with high AUCs being yielded for both BRAFV600E (0.851 and 0.859) and MSI-H (0.923 and 0.862).

CONCLUSIONS

These findings show that novel next-generation pathology methods can predict genetic abnormalities without the need for standard-of-care gene tests and this novel next-generation pathology method can be applied for CRC treatment planning in the near future.

The role of B cells and IgG in aortic dissection

Background

Aortic dissection (AD) is one of the destructive and fatal aortic diseases, for which molecular pathogenesis is largely unknown. Recent studies have highlighted the importance of inflammatory response in AD. We and others reported that B cells and immunoglobulins participate in pathogenesis of abdominal aortic aneurysm, another form of aortic destructive disease, by promoting inflammatory response. It is not known whether and how B cells participate in AD pathogenesis.

Methods and results

Immunohistochemical staining of human AD tissue revealed that B cells were clustered together with T cells, macrophages and neutrophils at the entry site of AD with medial disruption. B cell cluster was also observed at the site of medial disruption in mouse model of AD that was induced by continuous infusion of beta-aminopropionitrile and angiotensin II (BAPN+AngII). In muMT mouse, which is deficient for B cells and immunoglobulins due to genetic deletion of immunoglobulin heavy chain, BAPN+AngII induced significantly less severe AD compared to that in wild type. Depositions of IgG and fibrinogen, one of the endogenous antigen for natural IgG, were observed after BAPN+AngII infusion before and after AD development in wild type mice. Deposition of fibrinogen was also observed in mMT mice after BAPN+AngII infusion. The rate of aortic rupture and sudden death was approximately 42% in wild type mice, while that in muMT mouse was 12% (P&lt;0.05). Administration of mouse normal polyclonal IgG to muMT mice resulted in dramatic increase in aortic rupture and sudden death, starting at day 7 of BAPN+AngII infusion, and reaching 69% of rupture rate, indicating the critical role of IgG in AD.

Conclusion

These findings demonstrated B cells and IgG are critically involved in the destructive inflammation of AD pathogenesis. Further, the deposition of fibrinogen, one of the targets of natural IgG, precedes the development of AD. Our findings may provide the conceptual foundation of the diagnostic strategy for on-going tissue destruction and for the therapeutic opportunities to intervene the progressive tissue destruction in AD.

Funding Acknowledgement

Type of funding source: Public grant(s) – National budget only. Main funding source(s): The Japan Society for the Promotion of Science

Interaction between phenytoin and enteral nutrients and its influence on gastrointestinal absorption

The gastrointestinal absorption of phenytoin (PHT), an antiepileptic drug, is often affected by its interaction with co-administered enteral nutrients through a nasogastric (NG) tube, resulting in decreased plasma PHT concentration. In this study, we measured the recovery rate (%) of PHT (Aleviatin^® powder) passed through an NG tube when co-administered with distilled water or enteral nutrients (F2α^®, Racol^® NF, Ensure Liquid^® and Renalen^® LP). We also measured plasma PHT levels in rats, after oral co-administration of PHT with enteral nutrients. We demonstrate that PHT recovery rate was close to 100 % in all cases after passage through the NG tube. In the rat study, the AUC_0→∞ of PHT concentration after oral administration significantly decreased when it was co-administered with F2α^® and Racol^® NF compared to distilled water. However, the AUC_0→∞ of PHT was unchanged when co-administered with F2α^® 2 h after initial PHT administration. We therefore conclude that the co-administration of PHT with F2α^® and Racol^® NF caused a reduction in the absorption of PHT from the gastrointestinal tract to the blood, without adsorption to the NG tube. The administration of enteral nutrients 2 h after PHT is one clear way to prevent a decrease in plasma PHT concentration.

Risk factors increasing blood pressure in Japanese colorectal cancer patients treated with bevacizumab

Bevacizumab has been reported to increase blood pressure. However, the factors, including patient characteristics and laboratory data contributing to this side effect remain unclear. Therefore, we investigated the relationships between increased blood pressure and bevacizumab administration, patient characteristics, and laboratory data. Between April 2007 and January 2018, factor analysis was retrospectively conducted by monitoring increases in blood pressure, the status of bevacizumab administration, patient characteristics, and laboratory data before the first administration in Japanese patients with colorectal cancer who satisfied the criteria for this study. Sixty-seven patients were included, 34 of whom (50.7%) had an increase in blood pressure after bevacizumab administration. On univariate analysis, liver metastasis, antihypertensive drug use, systolic blood pressure at rest before the first bevacizumab administration, body mass index, creatinine, and blood platelet count were significantly different between the two groups. Multivariate analysis was conducted using increased blood pressure as an objective variable and the factors extracted by the univariate analysis as explanatory variables. The results suggested that liver metastasis, antihypertensive drugs, systolic blood pressure at rest before the first bevacizumab administration, and creatinine were associated with the increase in blood pressure. Furthermore, a log-rank test performed based on Kaplan-Meier curves demonstrated that liver metastasis in patients not taking antihypertensive drugs and antihypertensive drug use in patients without liver metastasis were significantly associated with increased blood pressure. Additionally, liver metastasis in patients with antihypertensive drug use was significantly associated with increased blood pressure. Our findings suggest that liver metastasis and antihypertensive drug use, which was previously reported, are risk factors for increased blood pressure.

Molecular species of prostaglandins involved in modulating luteinising hormone pulses of female rats under infectious stress conditions

Mammalian reproductive function is controlled by the hypothalamic-pituitary-gonadal (HPG) axis, which is suppressed under infectious stress conditions. By analysing the pulsatility of luteinising hormone (LH), we have previously demonstrated that prostaglandins (PGs) in the central nervous system mediate infectious stress to suppress the activity of the HPG axis. The present study aimed to characterise the types of PGs responsible for suppression of the HPG axis. We focused on three major types of PGs: PGE₂ , PGD₂ and PGF_2α . We used female rats overiectomised bilaterally 1 week before the experiments. Lipopolysaccharide (100 μg kg^-1 ) suppressed LH pulses at the same time as enhancing the concentration of all three PGs in the cerebrospinal fluid, which was restored by indomethacin (10 mg kg^-1 ). Subsequently, we observed LH pulsatility after a single injection of each PG and after co-injection of PGE₂ with PGF_2α into the third cerebral ventricle. A single injection of PGE₂ dose-dependently induced a transient increase in mean LH concentration and LH pulse amplitude, and PGD₂ significantly increased the amplitude of LH pulses, wereas PGF_2α did not affect LH pulsatility. On the other hand, co-injection of PGE₂ and PGF_2α induced a significant suppression of both the frequency and amplitude of LH pulses. These results suggest that PGE₂ and PGF_2α can represent two of the mediators that suppress the HPG axis in situations of infectious stress. Moreover, the results imply that there are two contradictory effects of PGE₂ on LH pulsatility: (i) enhancive when working alone and (ii) suppressive when working together with PGF_2α .

Pretreatment of Crude Pancreatic Islets with Mitomycin C (Mmc) Prolongs Islet Graft Survival in a Xenogeneic Rat-To-Mouse Model

In this study, we examined the effect of mitomycin C (MMC) treatment on graft survival and evaluated its efficacy in immunomodulation of islet graft for transplantation. Male WS rats were used as islet donors and streptozotocin-induced diabetic C57BL/6 mice as recipients. The isolated islets were treated with MMC at concentrations of 0, 0.1, 1, 3.2, 10, 32, 100, 320, and 1000 μg/mL for 30 min, and were cultured for 20 h. Then, 300–400 islets were transplanted into the renal subcapsular space of diabetic mice. Significant prolongation of graft survival was obtained when the islets were treated with MMC at a concentration of 10, 32, or 100 μg/mL (MST 23 ± 7.4, 17.5 ± 5.4, 29.6 ± 9.7 days: p < 0.003, p < 0.012, p < 0.001, respectively, vs. 12.3 ± 2.7 days for culturing alone). Islets treated with MMC at a concentration of 320 μg/mL or more failed to restore normoglycemia in the diabetic recipient mice after transplantation. Viability of islets incubated with doses up to 100 μg/mL, assessed under the confocal microscope after propidium iodide and Hoechst 33342 staining, was maintained well comparable to that of freshly isolated islets, while those treated at 320 μg/mL was significantly decreased. Thus, a therapeutic window for MMC efficacy was found at concentrations from 10 μg/mL to 100 μg/mL. This modality is simple and effective and underlying molecular mechanisms need to be determined in the future.

Impact of intra- and extrauterine growth on bone mineral density and content in the neonatal period of very-low-birth-weight infants

BACKGROUND

Very-low-birthweight infants (VLBWIs) are at high risk for suboptimal bone mineral density (BMD) and bone mineral content (BMC). Small-for-gestational-age (SGA) status also causes reduced bone mineralization in full-term infants. However, the impact of intrauterine and postnatal extrauterine growth on BMD and BMC in VLBWIs is inconclusive.

METHODS

We retrospectively investigated n=68 VLBWIs, comprising 45 appropriate-for-gestational-age (AGA) and 23 SGA infants who underwent lumbar spine dual-energy X-ray absorptiometry at term-equivalent age.

RESULTS

BMD and BMC did not differ between AGA and SGA VLBWIs. Subgroup analyses of infants with birthweight<1000 g vs 1000-1500 g, and GA<27 weeks vs ≥ 27 weeks also showed no differences in BMD and BMC between AGA and SGA infants. In contrast, infants with extrauterine growth restriction (EUGR) showed significantly lower values than those without (BMD: 0.124 ± 0.023 vs 0.141 ± 0.032 g/cm(2), P=0.02; BMC: 0.80 ± 0.26 vs 0.94 ± 0.23 g, P=0.04). There were no differences between AGA and SGA infants with EUGR. However, in the AGA cohort, infants with EUGR showed significantly lower values than those without (BMD: 0.121 ± 0.022; 0.141 ± 0.03 g/cm(2), P=0.02; BMC: 0.73 ± 0.23 vs 0.94 ± 0.23 g, P=0.005). Multiple regression analyses showed GA, weight and head circumference at birth, and weight percentile at term correlated with term BMD. Conversely, only weight percentile at term significantly correlated with term BMC.

CONCLUSION

EUGR, rather than IUGR, is a risk factor for reduced BMD and BMC in the neonatal period in VLBWIs.

Nucleated red blood cell counts: an early predictor of brain injury and 2-year outcome in neonates with hypoxic-ischemic encephalopathy in the era of cooling-based treatment

BACKGROUND

Raised nucleated red blood cell (NRBC) counts in neonates may indicate in utero hypoxia and brain damage.

OBJECTIVE

The study aimed to examine the use of NRBC counts as a predictor of brain injury and neurodevelopmental outcomes in neonates with hypoxic-ischemic encephalopathy (HIE) treated under current cooling-based strategy.

METHODS

Forty-three neonates with asphyxia between 2004 and 2010 were retrospectively investigated. Twenty neonates with moderate/severe HIE underwent hypothermia (HT), and 23 with mild HIE were treated in normothermia (NT). Neonates were divided into groups according to the presence of cerebral parenchymal lesions on magnetic resonance imaging (MRI) at 2 weeks after birth. All patients were followed-up neurologically for ⩾ 24 months. NRBC counts during the first 3 days were compared between groups.

RESULTS

Eleven HT (HT-N) and 21 NT (NT-N) neonates had normal MRI, and 9 HT (HT-L) and 2 NT (NT-L) neonates had parenchymal lesions. NRBC counts, both absolute and /100 white blood cells (WBC) counts, during the first 3 days in HT-L and NT-L were significantly higher than those in HT-N and NT-N, particularly within 6 hours after birth (HT-N: 502 [0-3060]/mm(3) vs HT-L: 2765 [496-6192]; 0 [0-3417] vs NT-L: 4384 [3978-4789], median [range]). Neonates with /100 white blood cells ⩾ 6/mm(3) and absolute NRBC counts ⩾ 1324/mm(3) within 6 hours of birth had high risks of abnormal MRIs and 2-year outcomes.

CONCLUSIONS

NRBC counts can predict brain injury and neurological outcomes in cooled and non-cooled asphyxiated neonates.

Main metabolic pathways of TAK-802, a novel drug candidate for voiding dysfunction, in humans: the involvement of carbonyl reduction by 11β-hydroxysteroid dehydrogenase 1

To investigate species differences in the metabolism of TAK-802, in vitro and in vivo metabolic profiles were compared between humans and animals. TAK-802 was mainly metabolized to M-I, M-II, M-III and M-IV in human and animal liver microsomes. Especially the M-IV formation in humans was greater than that in animals. Likewise, M-IV was detected to a lower extent in the plasma and excreta of animals administered with TAK-802, whereas the AUC0-48 h of M-IV was approximately five-fold higher than that of TAK-802 in human plasma. These results indicate that the in vitro metabolic profile reflects the in vivo condition. Thus, to identify the metabolic pathway of TAK-802 in humans, the responsible enzyme to form M-IV was elucidated in vitro. Since M-IV is a reductive metabolite formed in microsomes, the possibility of involvement of 11β-hydroxysteroid dehydrogenase (11β-HSD), a carbonyl reductase located in microsomes, was first investigated. Consequently, M-IV formation was confirmed by incubation with human 11β-HSD1-expressing microsomes and was concentration-dependently inhibited by glycyrrhetinic acid, an inhibitor for 11β-HSD enzymes, indicating the involvement of 11β-HSD1 in the M-IV formation. In contrast, little M-IV formation was observed using rat 11β-HSD1, suggesting species differences between humans and rats. In addition, M-II was formed via M-IV, not via M-I and the CYP identification studies revealed that both M-I formation from TAK-802 and M-II formation from M-IV were mainly catalyzed by CYP3A4. In conclusion, 11β-HSD1 and CYP3A4 are principally responsible for the metabolism of TAK-802 in humans and 11β-HSD1 may be responsible for the observed species difference.

Increased lysosomal biogenesis in activated microglia and exacerbated neuronal damage after traumatic brain injury in progranulin-deficient mice

Progranulin (PGRN) is known to play a role in the pathogenesis of neurodegenerative diseases. Recently, it has been demonstrated that patients with the homozygous mutation in the GRN gene present with neuronal ceroid lipofuscinosis, and there is growing evidence that PGRN is related to lysosomal function. In the present study, we investigated the possible role of PGRN in the lysosomes of activated microglia in the cerebral cortex after traumatic brain injury (TBI). We showed that the mouse GRN gene has two possible coordinated lysosomal expression and regulation (CLEAR) sequences that bind to transcription factor EB (TFEB), a master regulator of lysosomal genes. PGRN was colocalized with Lamp1, a lysosomal marker, and Lamp1-positive areas in GRN-deficient (KO) mice were significantly expanded compared with wild-type (WT) mice after TBI. Expression of all the lysosome-related genes examined in KO mice was significantly higher than that in WT mice. The number of activated microglia with TFEB localized to the nucleus was also significantly increased in KO as compared with WT mice. Since the TFEB translocation is regulated by the mammalian target of rapamycin complex 1 (mTORC1) activity in the lysosome, we compared ribosomal S6 kinase 1 (S6K1) phosphorylation that reflects mTORC1 activity. S6K1 phosphorylation in KO mice was significantly lower than that in WT mice. In addition, the number of nissl-positive and fluoro-jade B-positive cells around the injury was significantly decreased and increased, respectively, in KO as compared with WT mice. These results suggest that PGRN localized in the lysosome is involved in the activation of mTORC1, and its deficiency leads to increased TFEB nuclear translocation with a resultant increase in lysosomal biogenesis in activated microglia and exacerbated neuronal damage in the cerebral cortex after TBI.

Predictors of neurological outcome in cooled neonates

BACKGROUND

We define clinical predictors of neurological outcome in neonates with hypoxic-ischemic encephalopathy undergoing hypothermia therapy.

METHODS

Twenty-one neonates who underwent selective head cooling between 2004 and 2010 and were followed neurologically for ≥ 24 months were investigated retrospectively. Patients were divided according to the neurological outcome at 2 years of age into group A (n = 11), patients with normal neurological function, and group B (n = 10), patients with neurological disabilities (n = 9) or those who died (n = 1). Predictors were determined by χ(2) and Mann-Whitney U-tests, anova, Spearman rank correlations and receiver-operator curves.

RESULTS

Group B showed higher average blood lactate levels during the first day, particularly at 24 h of life; lower day-3 cerebral blood flow resistance index; higher maximum dobutamine dose used; higher rate of thiamylal sodium used; more severe background electroencephalogram suppression during the first week (group A: 11/11 cases ≤ grade 3; group B: 7/9 cases at grade 4-5) and higher rate of cerebral lesions on magnetic resonance imaging in the second week (group A: 1/11 case; group B: 9/10 cases) than group A. The most useful predictor of poor prognosis was cerebral parenchymal lesions on magnetic resonance imaging with 90%, 90% and 90% of sensitivity, specificity and accuracy, followed by week-1 background electroencephalogram ≥ grade 4 with 70%, 100% and 85% and day-3 cerebral blood flow resistance index < 0.46 with 71%, 88% and 80%, respectively.

CONCLUSIONS

Prediction of post-cooling neurological outcome could be improved substantially by evaluating multiple factors.

Two-week cast immobilization induced chronic widespread hyperalgesia in rats

It has been postulated that physical immobilization is an essential factor in developing chronic pain after trauma or surgery in an extremity. However, the mechanisms of sustained immobilization-induced chronic pain remain poorly understood. The present study, therefore, aimed to develop a rat model for chronic post-cast pain (CPCP) and to clarify the mechanism(s) underlying CPCP. To investigate the effects of cast immobilization on pain behaviours in rats, one hindlimb was immobilized for 2 weeks with a cast and remobilization was conducted for 10 weeks. Cast immobilization induced muscle atrophy and inflammatory changes in the immobilized hindlimb that began 2 h after cast removal and continued for 1 week. Spontaneous pain-related behaviours (licking and reduction in weight bearing) in the immobilized hindlimb were observed for 2 weeks, and widespread mechanical hyperalgesia in bilateral calves, hindpaws and tail all continued for 5-10 weeks after cast removal. A sciatic nerve block with lidocaine 24 h after cast removal transitorily abolished bilateral mechanical hyperalgesia in CPCP rats, suggesting that sensory inputs originating in the immobilized hindlimb contribute to the mechanism of both ipsilateral and contralateral hyperalgesia. Intraperitoneal injection of the free radical scavengers 4-hydroxy-2,2,6,6-tetramethylpiperydine-1-oxy1 or N-acetylcysteine 24 h after cast removal clearly inhibited mechanical hyperalgesia in bilateral calves and hindpaws in CPCP rats. These results suggest that cast immobilization induces ischaemia/reperfusion injury in the hindlimb and consequent production of oxygen free radicals, which may be involved in the mechanism of widespread hyperalgesia in CPCP rats.

Progranulin enhances neural progenitor cell proliferation through glycogen synthase kinase 3β phosphorylation

Progranulin (PGRN) is an estrogen-inducible growth factor thought to affect multiple processes in the CNS, including brain sexual differentiation, adult neurogenesis in the hippocampus, and development of neurodegenerative diseases. However, the precise physiological functions of PGRN in individual nerve cells are not fully understood. The aim of the present study was to enhance the understanding of PGRN function in the CNS by investigating the effects of PGRN on neural progenitor cells (NPCs). We found that significant amounts of endogenous PGRN were secreted from isolated NPCs in cultures. To assess the bioactivities of endogenous and exogenous PGRN, we studied NPCs derived from wild-type mice (WT-NPCs) and PGRN-deficient mice (KO-NPCs). We found that proliferation of KO-NPCs was significantly enhanced by PGRN treatment; however, PGRN treatment apparently did not affect proliferation of WT-NPCs perhaps because of the high levels of endogenous PGRN expression. NPC death and asymmetric cellular division of KO-NPCs and WT-NPCs, which results in production of neural stem cells, astrocytes, or oligodendrocytes, were not affected by PGRN treatment. We also investigated the signaling mechanism(s) that mediate PGRN-induced NPC proliferation and found that phosphorylation of serine 9 (S9) of glycogen synthase kinase 3-beta (GSK3β), which was dependent on phosphatidylinositol 3-kinase (PI3K) activity, was induced by PGRN treatment. In addition, a GSK3β-specific inhibitor enhanced NPC proliferation. Taken together, our observations indicate that PGRN enhanced NPC proliferation, at least in part, via inducing GSK3β phosphorylation.

Hemodynamic studies of intracranial dural arteriovenous fistulas using arterial spin-labeling MR imaging

Arterial spin-labeling (ASL) magnetic resonance imaging (MRI) enables non-invasive acquisition of the brain perfusion information in cerebrovascular disease. We investigated hemodynamic changes in intracranial dural arteriovenous fistulas (DAVFs) using ASL-MRI. ASL-MRI by a Q2TIPS sequence on a 3.0-Tesla MRI was performed for three patients with Cognard's IIa+b type of DAVFs before and after treatment. Perfusion images obtained by ASL-MRI (ASL images) before treatment were visually compared with those by single-photon emission computed tomography images (SPECT images). Increasing rates of temporal changes of regional perfusion values in ASL images (ASL values) before and after treatment were also calculated. In all three patients, ASL images before treatment demonstrated high perfusion in regions around the shunting areas, where normal or low perfusion were detected on SPECT images; thus, ASL images might have demonstrated the abundant arterial shunting flow via the fistulas. On days eight to 20 after treatment, ASL values around the shunt areas remained the same or decreased, and those in the regions other than the shunt areas increased in all three patients. This might have been due to a combination of the following: a decrease in shunt flow volume, an amelioration of venous congestion, and a sustained an upward shift in the autoregulation of the brain perfusion pressure. All regional ASL values decreased on days 112 and 120 after treatment in two patients, which possibly reflects a reduction in the upward shift in autoregulation. ASL-MRI might be useful for identifying the hemodynamic behavior of DAVFs before and after treatment.

Low-dose vasopressin infusion therapy for refractory hypotension in ELBW infants

BACKGROUND

Severe hypotension in infants, especially in preterm infants, is associated with poor neurological outcome and high mortality. In adults, low-dose vasopressin (arginine vasopressin: AVP) infusion therapy has been effective for treating hypotension that is refractory to vasopressors and inotropes.

METHODS

The effects of AVP infusion therapy for refractory hypotension were retrospectively evaluated in extremely low-birthweight infants. Between January 2002 and November 2005, 22 infants with refractory hypotension treated with low-dose AVP infusion were reviewed. The average birthweight was 658 g (+/-142 g), and the average gestational age was 24.9 weeks (+/-1.4). The changes in blood pressure, urinary output, and other parameters in response to AVP therapy were analyzed in all the infants.

RESULTS

After AVP infusion, systolic blood pressure increased from 30 mmHg to 43 mmHg (P < 0.0001), and the diastolic pressure increased from 15 mmHg to 24 mmHg (P < 0.0001). The urine output dramatically increased from 1.5 mL/kg per h to 4.0 mL/kg per h (P < 0.0001). AVP infusion, however, was not effective in four of the 22 patients (18%). The sodium concentration in the serum decreased mildly after administration. In six patients the serum sodium concentration decreased below 130 mEq/L. Severe mitral regurgitation was observed in two patients. Three infants showed a transient decrease in the platelet count during AVP infusion.

CONCLUSIONS

Low-dose AVP therapy should be considered as rescue therapy when high-dose catecholamine therapy and/or steroid administration do not produce sufficient increase in the blood pressure. Further investigations are required to prove the efficacy and safety of AVP infusion therapy in preterm infants.

Possible involvement of microglia containing cyclooxygenase-1 in the accumulation of gonadotrophin-releasing hormone in the preoptic area in female rats

Prostaglandins (PGs), especially PGE(2), are involved in the hypothalamic control of gonadotrophin-releasing hormone (GnRH) release, acting at least in part on the terminal of GnRH axons in the median eminence. The present study aimed: (i) to clarify the role of PG(s) in regulating GnRH cell function at the level of the perikarya in the preoptic area; (ii) to determine the cyclooxygenase (COX) isozyme responsible for producing PG(s) that regulates GnRH perikarya; and (iii) to identify cell types that contain the responsible COX isozyme in female rats. A surge of luteinising hormone (LH) secretion was induced by oestrogen and progesterone in ovariectomised rats. Treatment of the rat before the LH surge with indomethacin, a nonselective COX inhibitor, or NS-398, a selective COX-2 inhibitor, did not interfere with the surge. However, treatment with indomethacin or flurbiprofen, a selective COX-1 inhibitor, significantly reduced the number of GnRH-immunoreactive cells in the preoptic area at the time of peak LH secretion during the surge. NS-398 did not affect the GnRH immunoreactivity. Double-labelled immunofluorescent histochemistry revealed COX-1 immunoreactivity in the vicinity of, but not within, GnRH containing neurones in the preoptic area. COX-2 immunoreactivity was not found in the same area. The COX-1 immunoreactivity was almost entirely localised in microglia in the preoptic area, but not in neurones or astrocytes. These results suggest that microglia in the preoptic area containing COX-1 are responsible for producing PG(s), which, in turn, facilitates the accumulation of GnRH during the gonadotrophin surge in female rats.

High expression of interleukin-1beta in the corneal epithelium of MRL/lpr mice is under the control of their genetic background

MRL/Mp mice bearing the Fas deletion mutant gene, lpr (MRL/lpr), spontaneously develop polyarthritis, sialoadenitis and dacryoadenitis, resembling rheumatoid arthritis (RA), and also corneal involvement such as keratopathy and scleritis, which is a major complication in RA patients. In this study, we found that the expression levels of IL-1beta and MMP-1 mRNAs in cornea were high in both MRL/lpr and MRL/Mp-+/+ strains of mice at an age younger than when they develop any inflammatory lesions. This was not true of other inbred strains, even those bearing the lpr gene, and also not of (NZB x NZW) F1 lupus mice. There was no significant difference in the expression of IL-1alpha and TGFbeta in cornea in these strains. Using crosses between MRL/lpr and C3H/HeJ-lpr/lpr (C3H/lpr) mice, at least the expression of IL-1beta was found to be under the control of the MRL genetic background, likely with a recessive mode of inheritance. Considering that IL-1beta in cornea was detected particularly in the epithelial layer, the high expression of IL-1beta in cornea is most likely involved in the genetic predisposition for corneal involvement and possibly also for arthritis in an MRL strain of mice.