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M J O'Brien

Publications and source records attributed to M J O'Brien.

At least 73 records · Page 4Linked to original sources
PubMed1988

EEG coherence functions for normal newborns in relation to their sleep state.

While power spectra provide little information about the properties of the newborn EEG, the coherence functions (especially interhemispheric) have a characteristic shape for each of the 2 sleep states. Coherence functions may therefore be clinically more important than spectra. For this reason, baseline data for normal newborns have been produced as a reference against which coherences from patients can be compared. It is stressed that for a sleeping newborn the behavioural state must be known for the coherence function to be interpretable. Furthermore, since intraindividual variability is large, data from long recordings are required. The results are discussed in the light of the existing literature.

Brain↗
PubMed1987

Coherence patterns of the infant sleep EEG in absence of the corpus callosum.

The role of the corpus callosum in the relationship between the EEGs of the two cerebral hemispheres was studied by comparing 3 infants with congenital agenesis of the corpus callosum with a group of neurologically normal infants. Coherence functions were computed for symmetrical pairs of EEG derivations; in the frequency bands below 4 Hz they were in general much lower in the acallosal infants than in the normals.

Agenesis of Corpus Callosum↗
PubMed1987

Transient flattenings in the EEG of newborns--a benign variation.

A report on 43 instances of transient flattening of the EEG in sleeping newborns occurring near the onset of state 1 is presented. The depression of EEG activity is variable and lasts about 1 min. It is followed usually by highly discontinuous activity (tracé discontinu) which fades after a variable time (less than 1.5 min in 75% of cases), into a normal state 1 pattern. The incidence was 24% in a mixed group of infants of 43 weeks CA and under. Bilateral events were twice as common as unilateral ones. Flattenings were only seen at or close to the onset of the first state 1 in a sleep episode. We suspect that the phenomenon reflects the unusual functioning of mechanisms underlying the normal process of change from the low voltage continuous EEG in behavioural state 2 (active or REM sleep) to the higher voltage so-called synchronized discontinuous pattern of state 1 (non-REM or quiet sleep). Flattenings have no clinical significance beyond their importance as a normal variation in the neonatal EEG, about whose existence electroencephalographers should be aware. Post-flattening bursting should not be misinterpreted as epileptic activity.

Child Behavior↗
PubMed1987

Differential effects of Clostridium difficile toxins A and B on rabbit ileum.

The pathogenesis of Clostridium difficile enterocolitis appears to involve colonization of the bowel followed by release of toxin A, an enterotoxin, and toxin B, a cytotoxin. The purpose of this study was to determine the effect of purified toxins A and B on intestinal secretion, epithelial permeability, and morphology in perfused rabbit ileal loops. Intestinal permeability after toxin exposure was assessed by blood-to-lumen clearance of [3H]mannitol. Toxin A at doses of 5-100 micrograms/10 cm ileal loop caused a threefold to fivefold increase in [3H]mannitol permeability (p less than 0.001) vs. equal concentrations of toxin B or buffer control. In addition, perfusate from toxin A-exposed loops contained significantly more neutrophils (p less than 0.001) than toxin B or control loops. Toxin A caused severe epithelial cell necrosis with destruction of villi and polymorphonuclear infiltration. Electron microscopy of mucosa subjected to a low dose of toxin revealed widespread nonspecific dilatation of endoplasmic reticulum and mitochondrial swelling. In contrast to these effects of toxin A in ileal loops, in vitro experiments with ileal explants in short-term organ culture revealed that toxin A had no effect on epithelial cell permeability, protein synthesis, release of alkaline phosphatase, or morphology. Our results show that purified toxin A but not toxin B causes severe inflammatory enteritis in rabbit ileal loops, but has no discernable effect on rabbit ileum in vitro. We speculate that toxin A may contribute significantly to intestinal damage in C. difficile-associated colitis and diarrhea.

Animals↗
PubMed1987

Transcutaneous respiratory electromyographic monitoring.

The integrated diaphragm electromyogram (EMG) signal reflects function from the inspiratory centers to the neuromuscular junction. The feasibility and potential value of transcutaneous diaphragm electromyography (tcEMG) was confirmed in a group of infants using two prototype respiratory EMG monitors. Infants were monitored continuously for periods ranging from hours to days. One hundred were monitored for clinical reasons, looking for disordered respiratory behavior, while 47 were studied for technical/experimental reasons. Reliable measurements of diaphragm EMG activity were obtained, provided fully shielded electrode cables were used. Measurements in 28 ventilated infants and one adult confirmed that, unlike impedance and other non-electrophysiologic measures, tcEMG monitoring is not contaminated by ventilator-induced respiratory movements. The potential value of tcEMG monitoring in ventilated subjects is exemplified by illustrations of: diaphragmatic inactivity from phrenic nerve injury, inadequate central drive, and neuromuscular block; augmented expiratory muscle activity; and progressive increase in inspiratory diaphragmatic activity in the presence of a tension pneumothorax. TcEMG monitoring should prove a worthwhile addition to the available noninvasive respiratory monitoring techniques.

Diaphragm↗
PubMed1987

Ultrastructural differentiation and CEA expression of butyrate-treated human pancreatic carcinoma cells.

The effects of butyrate (a biological response modifier) on cellular morphologic features and carcinoembryonic antigen (CEA) expression of human pancreatic carcinoma cells were studied and compared in a well-differentiated, CEA-producing cell line (CAPAN-1), and a poorly differentiated cell line (PANC-1). Butyrate treatment resulted in the acquisition of phenotypic traits commonly attributed to increased "differentiation," including a twofold increase in doubling time, decreased saturation densities, and approximately 50% reduction in colony forming efficiency in both cell lines. Elongation and flattening of cells with extending cellular processes were seen by light microscopy. Significant ultrastructural changes were seen only in the PANC-1 cells, including an increased number of intercellular desmosomes, tonofilaments, and lipid droplets. In contrast, to the coarsely clumped nuclear chromatin (heterochromatin) of untreated PANC-1 cells, the nuclei of the butyrate-treated cells consisted of finely dispersed chromatin (euchromatin). CAPAN-1 cells responded to butyrate with increased CEA synthesis and release. This effect was greatest in the stationary growth phase. Butyrate had no effect on the already low rate of CEA synthesis by PANC-1 cells. These studies suggest that CEA synthesis and state of differentiation are affected independently by butyrate treatment and that the original tumor phenotype plays an important role in response to such treatment.

Adenocarcinoma↗
PubMed1987

Isolation and characterization of an undifferentiated human colon carcinoma cell line (MIP-101).

An undifferentiated human colon carcinoma cell line was established from tumor tissue obtained from metastasis to the liver of colonic adenocarcinoma in a patient with fulminant Dukes D colorectal carcinoma. Histological analysis of the tumor biopsy from the liver confirmed the hospital pathology report of poorly differentiated colonic adenocarcinoma. Explants of this tumor tissue xenografted into a nude mouse were used to establish an epithelioid-like cell culture line, MIP-101. The cell line formed tumors in nude mice that histologically appeared undifferentiated and did not stain for carcinoembryonic antigen (CEA). No CEA was present either by radioimmunoassay (RIA) of the culture supernatant or by immunoperoxidase staining of the tumors or monolayers. MIP-101 appears to be one of the most undifferentiated human colon carcinoma cells lines available. It should prove useful in the search for markers of undifferentiated colonic cancer and in studies of colonic cancer differentiation.

Adenocarcinoma↗
PubMed1987

Diversion colitis. Pathologic findings in a resected sigmoid colon and rectum.

We present here the detailed pathologic findings in the resected colon and rectum from a paraplegic patient with severely symptomatic diversion colitis and lack of anorectal function. Previous reports of the pathology of this condition have been confined to biopsy findings. A diffuse nodularity caused by lymphoid hyperplasia and an inflammatory process confined to the colorectal mucosa with erosions, crypt abscesses, mucin granulomas, and aphthoid ulcers were the main features. There was minimal distortion of crypt architecture. The pathologic features of this entity are compared to those of other inflammatory disorders of the colon and rectum.

Adult↗
PubMed1986

Cholecystitis secondary to infusion chemotherapy.

This report centers on a patient with metastatic colorectal cancer who developed acute and chronic cholecystitis secondary to the infusion of FUDR (fluoro-deoxyuridine) into the hepatic artery. This was documented by sonography, cholescintigraphy, and, ultimately, pathologically on the surgically removed specimen. Undoubtedly, with increasing cumulative treatment days made possible through technological advances in delivery systems, this complication will be seen more frequently. Prophylactic removal of the gallbladder, at the time of pump placement, which does not significantly prolong the operative time nor increase the operative mortality, should be performed to prevent this complication from occurring.

Adult↗
PubMed1986

Abnormal fetal behavioural state regulation in a case of high maternal alcohol intake during pregnancy.

In the near term human fetus disturbed behavioural state organization has been found in cases of intra-uterine growth retardation or maternal type-1-diabetes. The present case report describes abnormal fetal behavioural state organization found in combination with maternal alcohol abuse during pregnancy. The abnormalities included frequent interruptions of the periods of concordant association of 2F-parameters, reflected by a high proportion of no-coincidence, and spontaneous awakenings (State 4F), always following stable periods of State 1F. The latter phenomenon was not found thus far by us or others, neither in normal nor in complicated pregnancies. After birth normal state organization was found. It is suggested that the abnormalities in fetal behaviour might have been due to maternal alcohol abuse, whereas a possible withdrawal effect might have occurred in utero.

Adult↗
PubMed1986

Budd-Chiari syndrome complicating hepatocellular carcinoma. Demonstration by multiple radiotracer scintigraphy.

A case of hepatocellular carcinoma (HCC) complicated by the Budd-Chiari syndrome is described. The antemortem diagnosis of both conditions was made with the unique findings of multitracer scintigraphy. The difficulty of diagnosing these two conditions by the conventional approach is reviewed. The advantages of using multitracer scintigraphy for evaluation of hepatic lesions are also discussed.

Budd-Chiari Syndrome↗
PubMed1985

The specific diagnosis of hepatocellular carcinoma by scintigraphy. Multiple radiotracer approach.

The accuracy of scintigraphy in diagnosing hepatocellular carcinoma (HCC) at Boston City Hospital between January 1, 1978 and September 30, 1983 is retrospectively reviewed. A combined protocol using technetium-99m sulfur colloid (TsSC), gallium (Ga), and scintiangiography (STA) was employed in order to enhance diagnostic specificity. There were 14 cases of HCC, of which 10 were proven histologically. The others were diagnosed clinically and angiographically. With one exception, all patients who had triple tracer scintigraphy showed a specific pattern of findings: (1) cold defects with TcSC; (2) Ga-avid foci, and (3) increased vascular supply from hepatic arteries. One false-positive study and one false-negative study were originally reported, although in both cases, strict adherence to the three criteria above would have avoided diagnostic error. These results indicate that triple tracer scintigraphy may be an effective diagnostic test for HCC. The relative efficacy of scintigraphy, ultrasonography, and computerized tomography in diagnosing HCC is also discussed.

Adult↗
PubMed1985

Early gastric cancer. Clinicopathologic study.

The incidence and clinicopathologic features of early gastric cancer encountered among surgical specimens from gastric resections for carcinoma in a recent three-year period, 1977 to 1979, at the Mallory Institute of Pathology were studied and compared with those of a pre-endoscopic period 10 years earlier, 1967 to 1969. It was found that early gastric cancer now comprises a greatly increased proportion of lesions leading to gastric resection, mainly as a result of endoscopy and biopsy of gastric ulcers of benign appearance. In the recent period, there were six early gastric cancers in a total of 22 gastric resection specimens compared with one in 27 gastric resections performed for carcinoma in the pre-endoscopy period. Five of the six patients in the recent period are alive without evidence of disease four to five years following surgical resection. The single patient in the earlier period died postoperatively. Applying the classification of the Japanese Endoscopic Society, there were three depressed or ulcerated lesions (type IIc or III), three elevated or polypoid lesions (type I or IIa), and a single flat lesion (type IIb). All three ulcerated lesions were interpreted as benign peptic ulcers on conventional upper gastrointestinal studies. Findings on endoscopic biopsy were positive in all cases (six of six). Although not encountered frequently in the United States, early gastric cancer, nonetheless, appears to be indistinguishable from the disease as it is described in Japan in terms of its pathologic morphology, growth patterns, coexistent or related lesions of the stomach, and curability by surgical resection. If early gastric cancer is to be recognized more frequently, knowledge of the disease and a high index of suspicion on the part of physicians are essential.

Adenocarcinoma↗
PubMed1985

Respiratory EMG findings in relation to periodic breathing in infants.

Intercostal and diaphragm EMG activity was analysed in periodically breathing infants. The aim was to investigate relationships between changes in tonic activity in the respiratory muscles and switches in spontaneous breathing pattern from periodic to continuous and vice versa. A heterogeneous group of 13 normal and neurologically suspect infants was studied. They had all previously undergone polygraphic investigation and were selected because their polygraphic records showed at least three minutes uninterrupted periodic breathing (PB). PB appeared to represent an oscillation with a length of about 16 seconds superimposed on the basic state related irregular and regular breathing patterns. The development of a normal level of tonic activity in the respiratory muscles at the transition from state 2 to state 1 coincided with the switching from periodic to continuous breathing. Continuation of PB throughout a state 1 epoch in the presence of tonic respiratory muscle activity was exceptional. Sighs alone or sighs together with brief movements during state 1 were followed on occasion by a drop in tonic activity and a switch from continuous to periodic breathing. If the tonic activity rose again, PB either stopped or became less pronounced. TcPO2 level measured in four infants rose when tonic activity rose and was lower during PB than during continuous breathing. The observations made in this study suggest that mechanical or chemical changes caused by changes in tonic activity level may affect the stability of respiratory control in infancy.

Diaphragm↗
PubMed1985

Fraud and abuse of government medical benefit programs by psychiatrists.

Government rosters of physicians suspended from the Medicare and Medicaid programs because of fraud and abuse indicate that psychiatrists form a disproportionately large segment of the total. Of the factors contributing to this situation, the most notable is that because psychiatrists charge for time rather than for services, they are more readily apprehended if they violate the rules. The authors speculate on whether in fact psychiatrists break the law more than physicians in other-specialties or whether the statistics are purely artifactual.

Crime↗