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Biomedical subjects

M Maeda

Publications and source records attributed to M Maeda.

At least 433 records · Page 24Linked to original sources
PubMed1997

Gastric GATA-6 DNA-binding protein: proteolysis induced by cAMP.

The rat gastric GATA DNA-binding protein, GATA-6 (GATA-GT1), was stably expressed in CHO-K1 cells. The GATA-6 protein was localized in the nucleus but not in the cytoplasm. Interestingly, when cells were treated with dibutyryl cAMP, the GATA-6 protein was specifically degraded. Such a phenomenon was not observed in the presence of 5'-AMP or dibutyryl cGMP. The cellular level of the GATA-6 protein was restored upon removal of dibutyryl cAMP. Degradation was also induced by cholera toxin, which increased the cellular cAMP concentration, and was inhibited by a protein kinase A inhibitor. However, activators of protein kinase C did not have any effect. The degradation was inhibited by proteasome inhibitors (PSI (benzyloxycarbonyl-Ile-Glu(O-t-Bu)-Ala-leucinal) and MG115 (benzyloxycarbonyl-Leu-Leu-norvalinal)) but not by those of lysosomes and serine proteases. These results suggest that a kinase-mediated protein phosphorylation is the cellular signal for degradation of the GATA-6 protein. This finding constitutes a novel aspect of regulation by GATA DNA-binding proteins, which are essential for developmental processes and tissue-specific transcription.

Amino Acid Sequence↗
PubMed1997

Regional differentiation of blood flow responses to microinjection of sodium nitroprusside into the nucleus tractus solitarius of anesthetized rats.

This study was undertaken to examine the effects of the activation of the neurons in the nucleus tractus solitarius (NTS) via microinjection of sodium nitroprusside (SNP), which spontaneously releases nitric oxide (NO), on the blood flows of the spleen, kidney, liver, brain and spinal cord and to investigate the regional differentiation of the blood flow changes between those organs. Employing urethane-anesthetized (1.5 g kg-1, i.p.), paralyzed and artificially ventilated rats, regional blood flows of those organs were determined simultaneously using radiolabeled microspheres (109Cd, 51Cr and 85Sr) Unilateral microinjection of SNP into the NTS (n = 9) decreased brain blood flow from 71 +/- 8 (mean +/- S.E.) to 54 +/- 6 (P < 0.01) and spinal cord blood flow from 58 +/- 8 to 43 +/- 5 ml min-1 (100 g)-1 (P < 0.05) and increased brain vascular resistance from 1.18 +/- 0.13 to 1.48 +/- 0.15 (P < 0.01) and spinal cord vascular resistance from 1.46 +/- 0.17 to 1.80 +/- 0.16 (P < 0.05) mmHg per [ml min-1 (100 g)-1]. Whereas the microinjection of SNP into the NTS increased splenic blood flow from 127 +/- 25 to 188 +/- 27 (P < 0.01) and renal blood flow from 346 +/- 28 to 371 +/- 26 ml min-1 (100 g) (P < 0.05) and decreased splenic vascular resistance from 0.77 +/- 0.13 to 0.44 +/- 0.06 (P < 0.01) and renal vascular resistance from 0.24 +/- 0.02 to 0.21 +/- 0.01 mmHg per [ml min-1 (100 g)-1] (P < 0.05). The blood flow of the liver was not significantly altered. Unilateral microinjection of NG-monomethyl-L-arginine, an inhibitor of the formation of NO from L-arginine, into the NTS (n = 10) did not significantly change the blood flows of all organs examined except for an increase in blood flow of the kidney. Unilateral microinjections of SNP into the area adjacent to the NTS (n = 9), of artificial cerebrospinal fluid into the NTS (n = 7) and of light-inactivated SNP into the NTS (n = 6) did not significantly alter the blood flows of all organs examined. These results suggest than the neurons in the NTS have a vasoconstrictor effect on the brain and spinal cord circulation and a vasodilator effect on the splenic and renal circulation. There is a regional qualitative differentiation of the blood flow responses between these organs during activation of the neurons in the NTS.

Anesthesia↗
PubMed1997

A BALB/c 3T3-transformed cell line suitable for transfection assay of metastasis-inducing genes.

A clonal cell line, 1-1ras1000, transformed by the activated c-Ha-ras oncogene, does not form metastases after i.v. injection into mice (experimental metastasis assay). Here, we show that this cell line is useful as a recipient to detect metastasis-inducing genes, using a transfection assay. Cells (1-1ras1000) were susceptible to metastasis induction by transfection with either v-src or genomic DNA from a v-src-and v-fos-transferred highly metastatic rat cell line (SR202). The susceptibility of 1-1ras1000 cells for lung metastasis induction was suitable for a genomic transfection assay to detect a metastasis-inducing gene in the transfected cells which had incorporated genomic DNA from donor metastatic tumor cells. When DNAs extracted from 7 human tumors were tested for metastasis induction, 2 DNAs from nonmalignant tumors (non-tumorigenic tumors in athymic nude mice) (2/2) were negative and 4 DNAs from malignant tumors (4/5) were positive in 1-1ras1000 cells for primary transfection. in one of the resulting metastases, the ability to metastasize was also transferred in the second and third cycles of genomic DNA transfection at high frequencies. All of the resulting metastases carried the human repetitive Alu sequence. Neither re-arrangements of the endogenous c-Haras nor changes of protein amounts were detected. Recipient 1-1ras1000 cells had a negligible rate of spontaneously metastatic conversion during in vitro cultivation and transfection processes. The resulting metastasized cells were easily isolated from the lung after culturing in selection medium containing G418 (geneticin). Isolated cells stably retained the ability to form metastatic lung nodules when re-injected into mice. Thus, 1-1ras1000 cells appear to be a useful system for the isolation of metastasis-inducing genes from human metastatic tumors.

3T3 Cells↗
PubMed1997

The Dictyostelium mitogen-activated protein kinase ERK2 is regulated by Ras and cAMP-dependent protein kinase (PKA) and mediates PKA function.

The chemoattractant cAMP, acting through serpentine cAMP receptors, results in a rapid and transient stimulation of the Dictyostelium mitogen-activated protein kinase ERK2 activity (). In this study we show that other pathways required for aggregation, including Ras and cAMP-dependent protein kinase (PKA), are important regulators of ERK2 activation and adaptation. By examining both the level and kinetics of activation and adaptation of ERK2, we show that Ras is a negative regulator of ERK2. Activated Ras or disruption of a Ras GAP gene results in reduced ERK2 activation whereas disruption of putative Ras GEF or expression of dominant negative Ras proteins have a more rapid, higher, and extended activation. CRAC, a PH domain-containing protein required for adenylyl cyclase activation, is also required for proper ERK2 adaptation. PKA overexpression results in a more rapid, higher level of activation, whereas pka null cells show a lower level but more extended ERK2 activation. Furthermore, we show that constitutive expression of PKA catalytic subunit bypasses the requirement of ERK2 for aggregation and later development, indicating that PKA lies downstream from ERK2 and that ERK2 may regulate one or more components of the signaling pathway required for mediating PKA function, possibly by directly regulating PKA R or a protein controlling the intracellular level of cAMP.

Adenylyl Cyclases↗
PubMed1997

Effects of MCI-154, a calcium sensitizer, on left ventricular systolic and diastolic function in pacing-induced heart failure in the dog.

BACKGROUND: MCI-154 is a positive inotropic agent that increases the myofilament response to Ca2+. Whether MCI-154 has beneficial effects on left ventricular dysfunction in chronic heart failure is not known. We examined the effects of MCI-154 on left ventricular systolic and diastolic function in pacing-induced heart failure in dogs. METHODS AND RESULTS: We studied eight anesthetized dogs before and 2 to 4 weeks after rapid right ventricular pacing. Left cineventriculograms with simultaneous left ventricular pressures (tip manometer) were obtained before and during intravenous administration of MCI-154 (I.O. microgram.kg-1.min-1 for 15 minutes) in the control and heart-failure states. Left ventricular volume dynamics was derived from frame-by-frame (20-ms) analyses of left ventricular angiograms. In heart failure, left ventricular contractility as assessed by shifts of the end-systolic pressure-volume ratio, evaluated by inferior vena cava occlusion, was improved by MCI-154 (+ 1.94 mm Hg/mL, P < .05) to an extent similar to that in the control state (+2.47 mm Hg/mL, P < .05). MCI-154 also accelerated left ventricular relaxation, assessed by the time constant of isovolumic pressure decay (T1/2), in both states. The absolute decrease in T1/2 with MCI-154 in heart failure was significantly greater than in the control state (-8.2 versus -3.1 ms, P < .05). In heart failure, MCI-154 shifted the left ventricular diastolic pressure-volume relation clearly downward, suggesting increased diastolic distensibility. CONCLUSIONS: MCI-154 improved not only left ventricular systolic function but also diastolic relaxation and distensibility in a chronic heart failure model.

Animals↗
PubMed1997

Lipopolysaccharide-induced biphasic inositol 1,4,5-trisphosphate response and tyrosine phosphorylation of 140-kilodalton protein in mouse peritoneal macrophages.

We previously showed that a relatively high dose of LPS induced the selective translocation of protein kinase C-beta (PKC-beta) in LPS-responsive mouse macrophages. This result suggested that phosphatidylinositol-specific phospholipase C (PLC) might be activated in the upstream of PKC-beta. Stimulation of C3H/HeN mouse macrophages by LPS induced the characteristic phosphatidylinositol-1,4,5-trisphosphate (IP3) response, that is, a biphasic response consisting of a rapid increase occurring within the first 1 min, and another increase beginning at around 1 min after stimulation. Only the first response was disappeared when cells were treated with a platelet-activating factor receptor antagonist. LPS-inducible TNF-alpha gene activation, however, was not suppressed by the same antagonist, but suppressed by PKC inhibitors. LPS-stimulated macrophage lysates showed tyrosine phosphorylation of some proteins, and the strongest phosphorylation was observed at molecular mass of 140 kDa. The phosphorylation of this protein started at 40 s after LPS stimulation and continued to increase. Anti-PLC-gamma2 Ab seemed to recognize the same protein as the tyrosine-phosphorylated 140-kDa protein. A low dose of LPS (1 ng/ml) could not induce the tyrosine phosphorylation of this protein. Furthermore, LPS induced only the first phase change, but not the second phase increase in LPS-hyporesponsive C3H/HeJ mouse macrophages. These results indicate that the first phase rapid IP3 change, which is also seen in HeJ macrophages, is mediated via a platelet-activating factor receptor, and is not responsible for TNF-alpha production, while the second phase change mediated by a molecule other than CD14 is responsible for PKC-beta translocation and TNF-alpha production. The results also suggest that the later IP3 change is considered to be mediated through a gamma2 type of phosphatidylinositol-specific PLC.

Animals↗
PubMed1997

Dilated cardiomyopathy associated with deficiency of the cytoskeletal protein metavinculin.

BACKGROUND: The cytoskeleton plays an important role in maintaining cell structure and integrity. Defects in cytoskeletal proteins can cripple cell strength and may cause cardiomyopathy. We analyzed heart tissues from subjects with dilated cardiomyopathy for abnormalities in the cardiac cytoskeleton. Metavinculin, a cardiac isoform of the cytoskeletal protein vinculin, connects actin microfilaments to the intercalated disk and membrane costameres of the heart. METHODS AND RESULTS: Metavinculin and vinculin transcripts and protein were analyzed by polymerase chain reaction (PCR) and Western blotting. Thirty-three human heart specimens were studied, including 5 normal controls, 4 subjects with ischemic cardiomyopathy, 1 with X-linked cardiomyopathy, and 23 with idiopathic dilated cardiomyopathy (IDC). PCR of cardiac cDNA detected absence of the metavinculin transcript in cardiac tissue from a subject with IDC. PCR of genomic DNA showed that the metavinculin exon was present but not utilized in the cardiac transcript. Western blot analysis demonstrated absence of metavinculin protein in the heart from this subject. Immunostaining of cardiac vinculin in this heart showed disorganized intercalated disk structures. Metavinculin deficiency was associated with normal cardiac expression of the cytoskeletal proteins vinculin, alpha-actinin, and dystrophin. Normal metavinculin expression in the other heart specimens suggests that the defect is specific in the IDC subject identified. CONCLUSIONS: These results demonstrate an association between metavinculin deficiency and dilated cardiomyopathy due to a defect in alternative mRNA splicing.

Blotting, Western↗
PubMed1997

Mitogen-inducible SIPA1 is mapped to the conserved syntenic groups of chromosome 19 in mouse and chromosome 11q13.3 centromeric to BCL1 in human.

Sipa1, previously called Spa1, is transcriptionally induced in the murine lymphoid cells following mitogenic stimulation and encodes a protein with a domain related to Rap1 GTPase activating protein (Rap1GAP) at the N-terminus and to PEST sequences followed by a leucine zipper motif at the C-terminus. Herein mouse genomic Sipa1, which consisted of 16 exons, was cloned. Gene linkage analysis using (BXD) recombinant inbred strains indicated that Sipa1 was mapped to the most centromeric region of chromosome 19 syntenic with the long arm of human chromosome 11. Human SIPA1 cDNA exhibited a striking homology to that of mouse throughout the entire region, with the overall identity being 90% at the amino acid level. Human genomic clones, which hybridized with both mouse and human SIPA1 cDNA but not with RAP1GAP cDNA, were then isolated. Fluorescence in situ hybridization (FISH) analysis using the human genomic clones indicated that SIPA1 was indeed mapped to chromosome 11q13, most likely to the 11q13.3 subregion. It was further indicated by double-color FISH that SIPA1 was located in the centromeric neighborhood of CCND1/ PRAD1, a presumed BCL1 oncogene.

Animals↗
PubMed1997

Abnormal immunostaining for dystrophin in isoproterenol-induced acute myocardial injury in rats: evidence for change in dystrophin in the absence of genetic defect.

Abnormalities in the gene for Duchenne muscular dystrophy produce skeletal and myocardial changes, by impairing dystrophin production in patients with Duchenne and Becker muscular dystrophy. However, it is not known whether myocardial dystrophin may be altered in patients with other heart diseases. To investigate whether changes in myocardial dystrophin may be induced by acute myocardial injury, the immunostaining patterns of myocardial dystrophin were examined, together with those of myocardial actin, in rats with isoproterenol-induced myocardial damage. Hearts were excised at 6, 12, 24 and 48 h, and 1 and 4 weeks after the subcutaneous administration of 100 mg/kg of isoproterenol. Frozen serial sections were prepared for haematoxylin and eosin staining, and for immunostaining for dystrophin and actin. The immunostaining patterns of actin were used as an indicator of cell injury. The myocardial cells observed were classified into four types, according to staining pattern: normal for both actin and dystrophin (Type 1): normal for actin, but abnormal for dystrophin (Type 2); abnormal for actin, but normal for dystrophin (Type 3); and abnormal for both actin and dsytrophin (Type 4). The percentage of myocardial cells with abnormal staining (Types 2, 3 and 4) at 6, 12, 24 and 48 h after isoproterenol injection was 22.4, 12.6, 16.0 and 2.4%, respectively; most cells were Types 3 and 4. One week after injection or later, no Type 3 or 4 cells were detected, while the percentages of Type 2 cells were 2.7% for 1 week and 2.2% for 4 weeks, significantly higher than the corresponding value in the control group. In conclusion, changes in myocardial dystrophin may occur in isoproterenol-induced myocardial injury in rats.

Actins↗
PubMed1997

A 5' dystrophin duplication mutation causes membrane deficiency of alpha-dystroglycan in a family with X-linked cardiomyopathy.

5'-mutations in the dystrophin gene can result in cardiomyopathy without clinically-apparent skeletal myopathy. The effect of dystrophin mutations on the assembly and stability of the dystrophin associated protein (DAP) complex in human heart are not fully understood. The molecular defect in the dystrophin complex was explored in a family with an X-linked pedigree and severe dilated cardiomyopathy. Dystrophin gene analysis demonstrated a 5' duplication involving exons 2-7, which encodes the N-terminal actin binding domain of dystrophin. Ribonuclease protection and PCR assays demonstrated a reduction in muscle promoter transcribed dystrophin mRNA in the heart compared to skeletal muscle. A deficiency of cardiac dystrophin protein was observed by Western blot and lack of membrane localization by immunocytochemistry. The cardiac expression of the dystrophin related protein utrophin was increased, and the 43 kDa (beta-dystroglycan), 50 kDa (alpha-sarcoglycan) and 59 kDa (syntrophin) dystrophin associated proteins (DAPs) were co-isolated and present in nearly normal amounts in the membrane. However, cardiac dystrophin deficiency and increased utrophin expression were associated with loss of extracellular 156 kDa dystrophin associated glycoprotein (alpha-dystroglycan) binding to the cardiomyocyte membrane. alpha-Dystroglycan is responsible for linkage of the dystrophin complex to the extracellular matrix protein laminin. Therefore, 5' dystrophin mutations can reduce cardiac dystrophin mRNA, protein expression, and dystrophin function in X-linked cardiomyopathy (XLCM). The presence of membrane-associated beta-dystroglycan, alpha-sarcoglycan, syntrophin, and utrophin are insufficient to maintain cardiac function. This XLCM family has a 5' dystrophin gene mutation resulting in cardiac dystrophin deficiency and a loss of alpha-dystroglycan membrane binding.

Adolescent↗
PubMed1997

New endoscopic treatment for chronic pancreatitis, using contrast media containing ulinastatin and prednisolone.

The preventive effects of contrast media containing ulinastatin (UST) and/or prednisolone (PDN) on potential complications associated with endoscopic retrograde cholangiopancreatography (ERCP) were studied in 111 patients. The incidence of abdominal pain and the elevation in the serum amylase level after ERCP were lower in the UST group than in the control group and abdominal pain and the elevated serum amylase level were almost completely suppressed in the PDN and UST/PDN groups. Based on these findings, a comparative study was conducted to evaluate the effectiveness of a combination of UST and PDN, given via the pancreatic duct, in alleviating pain symptoms in 57 patients with chronic pancreatitis and abdominal pain. The post-ERCP serum amylase level in some patients in the PDN and UST/PDN groups was lower than the pretreatment value. After ERCP, the abdominal pain that had been experienced before ERCP was relieved, and the value of the bentiromide-paraaminobenzoic acid (BT-PABA) test had improved. These results suggest that the use of contrast media containing PDN or UST/PDN in patients with chronic pancreatitis is extremely effective not only for preventing potential complications related to ERCP but also as a new diagnostic treatment method.

Abdominal Pain↗
PubMed1997

Neuronal integrity and astrocytic reaction in cold injury: an immunohistochemical investigation.

The relationship between extravasation of serum albumin and damage to the neuronal elements as well as the astrocytic reaction was investigated following cold injury, using immunohistochemistry for albumin, microtubule-associated protein I and II (MAPs) and glial fibrillary acidic protein (GFAP). After 30 min, spreading of albumin to the neuropil and uptake into nerve cell bodies and dendrites were clearly observed in the area surrounding the cold lesion. Extravasation of albumin was maximal at 24 h and extended to the ipsilateral hippocampus and thalamus as well as to the paramedian part of the contralateral cerebral hemisphere. Uptake of albumin was seen in neurons with and without loss or reduction of the reaction for MAPs, but the former was confined to the area surrounding the cold lesion. When extravasated albumin receded from the neuropil, the positive reaction for albumin also disappeared from the neuronal elements and those neurons recovered immunoreactivity for MAPs. Astrocytes immunopositive for albumin were observed at 24 h in the white matter, and reactive astrocytes became notable even in the gray matter surrounding the cold lesion. Although reactive astrocytes persisted even after resolution of cerebral edema, immunopositivity for albumin disappeared from astrocytes soon after the disappearance of the reaction from the neuropil. As to the mechanism, rapid endo- and exocytosis may take place in response to the amount of edema fluid in the surrounding extracellular space, where albumin may be eliminated through the transvascular route and/or via the cerebrospinal fluid space.

Animals↗
PubMed1997

Relationship of nutritional status to length of stay, hospital costs, and discharge status of patients hospitalized in the medicine service.

OBJECTIVE: This study was conducted to determine the relationship, if any, between nutritional status, length of stay (LOS) in hospital, discharge placement, readmission rates, and hospital costs and charges in patients hospitalized in the medicine service. DESIGN: Data regarding medical diagnosis, LOS, hospital costs, charges, discharge destination, and readmission rates were collected prospectively from medical records and through patient interviews on patients admitted to the medical service who were classified to be at risk or not at risk for malnutrition on the basis of established criteria (weight for height < 75% ideal body weight, admission serum albumin level < 30 g/L, or > or = 10% unintentional weight loss within 1 month before admission). SUBJECTS: All patients admitted directly to any of three medicine units during December 1994 who met study criteria were included in the study. Off-service patients, transfer patients, and patients discharged before screening (usually admitted and discharged within 72 hours) were excluded. Data were collected on 173 patients. STATISTICAL ANALYSIS PERFORMED: At-risk and not at-risk patients were compared for LOS, costs and reimbursement, and discharge placement (to home, to home with home health care services, or to another facility for further care). Two sample t tests and alpha survival analysis technique were used to compare continuous variables between the two study cohorts. Nonparametric tests were used for LOS and readmission data. chi 2 Tests were used for categoric variables. An alpha level of .05 was used throughout to determine statistical significance. RESULTS: Median LOS in the not-at-risk population (n = 56) was significantly greater than in the not-at-risk population (n = 117): 6 days (25th percentile = 4 days, 75th percentile = 8 days) vs 4 days (25th percentile = 3 days, 75th percentile = 7 days) (P < .01). Mean hospitalization cost per patient was also higher in the at-risk group ($6,196 vs $4,563, P < .02). Readmission rate per month of follow-up was not significantly different. At-risk patients were significantly less likely to be discharged home with self-care (23[41%] vs 77 [66%], P < .05). At-risk patients were significantly more likely to use home health care service than not-at-risk patients (17[31%] vs 14 or [12%], P < .001). APPLICATIONS: Patients at risk for malnutrition had significantly higher LOS, costs, and home health care needs, despite the fact that 51, or 91%, received nutrition intervention while hospitalized. Further research should explore the use of nutrition screening and intervention before, during, and after hospitalization to ensure that appropriate nutrition intervention, as indicated by medical patients' clinical condition and nutritional risk status, is initiated and continued.

Cohort Studies↗
PubMed1997

G1 phase-specific suppression of the Cdk2 activity by ginsenoside Rh2 in cultured murine cells.

Ginsenoside Rh2, a plant glycoside with a dammarane skeleton resembling a steroid skeleton as an aglycone, has anticancer potentials in vitro or in vivo. To elucidate the molecular mechanisms of the effects of Rh2, we have examined the Cyclin-dependent kinase-2 (Cdk2) activity in G1 arrested B16 melanoma cells and in S phase-arrested Meth-A sarcoma cells, that have been treated with Rh2. The kinase activity was suppressed in B16 cells but not in Meth-A cells. In addition, Rh2 was found to induce G1 arrest and concomitantly suppress the Cdk2 activity in carcinogen-susceptible BALB/c 3T3 A31-1-1 and A31-1-13 cell lines. Thus, Rh2 has a G1 phase-specific suppressive effect on the Cdk2 activity, supporting further evaluation of Rh2 and its related compounds in cancer chemoprevention studies.

3T3 Cells↗
PubMed1997

Molecular cloning of mouse Doc2alpha and distribution of its mRNA in adult mouse brain.

We have previously isolated from a human brain cDNA library, a new protein having two C2-like domains which interact with Ca2+ and phospholipid, and named Doc2alpha. Doc2alpha is abundantly expressed in brain, where it is highly concentrated on the synaptic vesicle fraction, and is implicated in Ca2(+)-dependent exocytosis. We have isolated here a mouse Doc2alpha cDNA and determined the localization of its mRNA in adult mouse brain. The amino acid sequence of the mouse Doc2alpha cDNA is 92% identical with that of the human counterpart. Northern blot analysis and in situ hybridization on adult mouse brain sections have revealed that Doc2alpha is predominantly expressed in mouse brain, where it is expressed in neuronal cells, but not in non-neuronal cells. Doc2alpha is highly expressed in the olfactory bulb, cerebral cortex, hippocampus, amygdaloid complex, and ventromedial hypothalamus nucleus, but not in the cerebellum, caudate-putamen, or ventral thalamus. These results indicate that Doc2alpha is expressed heterogeneously in mouse brain, where it is predominantly expressed in neuronal cells, and suggest that Doc2alpha plays a specific role in the area where it is expressed.

Amino Acid Sequence↗
PubMed1997

Should C-section be applied to fetal arrhythmia?

OBJECTIVE: To investigate the efficacy of fetal arterial oxygen saturation (SpO2) monitoring in cases of fetal arrhythmia. STUDY DESIGN: Continuous fetal SpO2 was obtained by infrared pulse oximetry (Nellcor Puritan Bennett Inc.). The relationship between SpO2 and FHR pattern was studied in 47 cases. Then three cases of congenital complete A-V block and two cases of supraventricular tachyarrhythmia were prospectively managed by SpO2 monitoring during labor. RESULTS: Whenever the FHR was reassuring, the range of SpO2 was stable between 40 and 80%. Although a variation in SpO2 values were noted during decelerative patterns, a more acidotic tendency was found in cases where SpO2 was below 40% prior to delivery. SpO2 values of all five cases of fetal arrhythmia were stable between 40 and 80% and safe vaginal delivery proved to be possible. CONCLUSIONS: Fetal SpO2 monitoring seemed to be a useful method to evaluate fetal oxygenation during labor in cases of fetal arrhythmia.

Adult↗
PubMed1997

Basal forebrain and cerebral cortical muscarinic receptors mediate increase in cortical blood flow provoked by periaqueductal gray matter.

The midbrain periaqueductal gray matter has been identified as a reflex centre located uppermost in the central organization of diverse defensive reactions. We recently found that when activated, the caudal third of the lateral periaqueductal gray was also capable of provoking a marked increase in cortical blood flow. The response may be the combined outcome of a flow increase of nitrergic origin and that coupled to a possible concomitant cortical activation. In the present study, we attempted to clarify the neural substrates for mediation of the increase in flow (observed by laser-Doppler flowmetry), in 49 anaesthetized, artificially ventilated, and cervically cordotomized rats. The flow increase provoked by stimulation of the particular subdivision of the periaqueductal gray with N-methyl-D-aspartate (1 mM, 100 nl) was unaffected by i.v. pentolinium tartrate (10 mg/kg), suggesting little contribution by the cerebrovasodilator parasympathetic nervous system to the response. The response was abolished by i.v. or topical cortical administration of scopolamine hydrobromide (3.16 mg/kg or 1.0 mM, respectively). Placement of bilateral lesions in the basal forebrain with alpha-amino-3-hydroxy-5-methyl-4-isoxazole propionic acid (15 mM) impaired the cortical choline acetyltransferase activity and attenuated the flow response. Overall, we suggest that the cholinergic corticopetal neurons of the nucleus basalis of Meynert and cortical muscarinic receptors may form a principal efferent arm of a central circuitry emanating from the subdivision of the periaqueductal gray, in the mediation of the increase in cortical blood flow and possible cortical activation.

Animals↗