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Biomedical subjects

M McNamara

Publications and source records attributed to M McNamara.

At least 55 records · Page 3Linked to original sources
PubMed1995

Swim stress increases the potency of glycine at the N-methyl-D-aspartate receptor complex.

We have previously demonstrated that chronic administration of antidepressants results in a reduction in the potency of glycine to displace 5,7-[3H]dichlorokynurenic acid (5,7-[3H]-DCKA) from the strychnine-insensitive glycine recognition site of the NMDA receptor complex. We now report that exposure of rats to the forced swim test results in a 56% increase in the potency of glycine to displace 5,7-[3H]DCKA from frontal cortical homogenates. These data are consistent with the hypothesis that the forced swim test, a preclinical screen sensitive to acute administration of antidepressant drugs and NMDA receptor antagonists, also results in adaptation of the NMDA receptor complex. Moreover, these data lend further support to the hypothesis that glutamatergic pathways are involved in the neurobiological response to stress and, potentially, in the pathophysiology of depression.

Animals↗
PubMed1995

Expression and functionality of luteinizing hormone/chorionic gonadotropin receptor in the rat prostate.

In addition to androgens that are essential for maintenance of prostate growth and function, nonandrogenic hormones must also be considered to explain some regulatory events occurring in the prostate. The detection of LH/CG receptor (LH/CG-R) gene expression in some nongonadal tissues, has led us to consider LH as a potential regulatory factor of prostatic development and function. In this study, we have demonstrated by RT-nested polymerase chain reaction and Northern blotting that the rat prostate contains the same LH/CG-R transcript as the gonads. Western immunoblotting, ligand blotting, and binding analysis have shown that rat prostate also contains a 93-kDa receptor protein that is able to bind [125I]hCG specifically and with a high affinity (6.0 x 10(9) M-1). Our results also indicated that the concentration of binding sites was lower in the prostate than in the gonads. LH/CG-R sites of expression have been localized in the prostate by immunohistochemistry: specific staining was observed in all the epithelial cells of the gland, but the ventral lobes are much more immunoreactive than the lateral and dorsal lobes. Finally, the ability of this prostatic LH/CG-R to induce a physiological response was evaluated in an explant culture system. A time course experiment was carried out, and we observed a significant dose-dependent stimulation of cAMP production after 3 h of treatment: 3.0 +/- 0.4, 4.2 +/- 0.4, and 5.0 +/- 0.5 pmol/ml of cAMP for 0, 100, and 500 ng/ml of LH, respectively. In conclusion, LH is able to act directly on the prostatic gland through specific receptors that are structurally and functionally very similar to those expressed in the gonads and are mainly localized in the ventral lobe of the organ. These data suggest that LH plays a significant physiological role in the prostate.

Animals↗
PubMed1994

[Neoplastic thrombosis of the inferior vena cava involving the right atrium caused by adrenal cortical carcinoma. A new indication for vascular exclusion of the liver].

A large malignant adrenocortical carcinoma extending to the inferior vena cava and right atrium presented in the form of hemoptysis. Magnetic resonance imaging allowed precise evaluation without any other invasive procedure. Cardiopulmonary bypass is usually employed in these circumstances to remove the cavo-atrial thrombus. This approach may be advantageously replaced by the use of total vascular exclusion of the liver. The only unusual feature of the procedure is that the upper caval clamp is applied across the right atrium. Major collateral circulation due to caval thrombosis allows complete resection of the inferior vena cava up to the hepatico-caval confluence without the need for prosthetic replacement. After an uneventful postoperative course, malignant spread despite chemotherapy with op'-DDD led to death 4 months after surgery.

Adrenal Cortex Neoplasms↗
PubMed1992

The acute contrast enema in suspected large bowel obstruction: value and technique.

In order to determine the value of the acute contrast enema (ACE) as compared to the plain abdominal film for the diagnosis of colonic obstruction and to determine the optimal technique for performing this examination, we reviewed 140 cases performed over a 4 year period. The study shows that when provided with the case history and the plain abdominal films of patients referred for an ACE the diagnosis of colonic obstruction can be made with a sensitivity of 84% and a specificity of 72%, whereas the ACE has a sensitivity of 96% and a specificity of 98%. The ACE resulted in two false negatives, one false positive and one technical failure, analysis of which has enabled an optimal technique for the performance of this examination to be recommended.

Colon↗
PubMed1991

Phase II study of 4'-deoxydoxorubicin (esorubicin) in advanced or metastatic adenocarcinoma of the stomach.

4'-deoxydoxorubicin (DxDx) was administered to 17 patients with locally advanced or metastatic gastric adenocarcinoma. Treatment cycles were repeated every 21 days. 15 eligible patients with a Karnofsky performance status of 50% or better (median: 70%) received at least one course of treatment; a median of 2 courses of DxDx was delivered (range 1 to 13). The median dose per treatment course was 26 mg/m2 (range 8.5 mg/m2 to 53 mg/m2). 69% of patients required dose reduction following the first course of therapy due to grade 3 or 4 myelosuppression, primarily neutropenia. The principal side effects included anemia, mild gastrointestinal toxicities, and alopecia; one patient experienced a 10% decrease in cardiac ejection fraction without clinical cardiac toxicity. Of the 15 patients assessable for response and toxicities, 1 patient had a partial response lasting 2.5 months. The median survival from the time of the first treatment was 3.3 months. We conclude that DxDx has only limited activity in the treatment of advanced gastric adenocarcinoma.

Adenocarcinoma↗
PubMed1989

Characterization of the hydroxyproline-rich protein core of an arabinogalactan-protein secreted from suspension-cultured Lolium multiflorum (Italian ryegrass) endosperm cells.

An arabinogalactan-protein (AGP) purified from the filtrate of liquid-suspension-cultured Italian-ryegrass (Lolium multiflorum) endosperm cells by affinity chromatography on myeloma protein J539-Sepharose was deglycosylated with trifluoromethanesulphonic acid to remove polysaccharide chains that are covalently associated with hydroxyproline residues in the peptide component of the proteoglycan. The protein core, which accounts for less than 10% (w/w) of the intact proteoglycan, was purified by h.p.l.c. It has an apparent Mr of 35,000, but reacts very poorly with both Coomassie Brilliant Blue R and silver stains. Amino-acid-sequence analysis of the N-terminus of the h.p.l.c.-purified protein core and of tryptic peptides generated from the unpurified protein reveals a high content of hydroxyproline and alanine. These are sometimes arranged in short (Ala-Hyp) repeat sequences of up to six residues. Polyclonal antibodies raised against the protein core do not cross-react with native AGP, the synthetic peptide (Ala-Hyp)4, poly-L-hydroxyproline or poly-L-proline. The results suggest that the polysaccharide chains in the native AGP render the protein core of the proteoglycan inaccessible to the antibodies and that the immunodominant epitopes include domains of the protein other than those rich in Ala-Hyp repeating units.

Amino Acid Sequence↗
PubMed1989

Inflammatory aneurysms of the abdominal aorta: incidence, pathologic, and etiologic considerations.

Among 486 patients undergoing repair for abdominal aortic aneurysm (AAA) during a 12-year period, 30 (6.2%) had evidence of "inflammatory" AAA. One patient (3%) had acute rupture, and six patients (20%) had chronic contained rupture. Ureteral obstruction was evident in 20% of the patients. In the early period of the study there were two postoperative deaths and operative time and blood loss were significantly increased. In the last period of the study, no attempt was made to separate the duodenum and the ureters from the aneurysm; there was no operative mortality, and operative time and blood loss were similar to that of patients with atherosclerotic aneurysms. In 23 of 100 specimens of atherosclerotic AAA, microscopic findings resembling inflammatory AAA were found. On the basis of our study we conclude the following: (1) Inflammatory AAAs are simply atherosclerotic aneurysms that show an unusual accentuation of the chronic inflammation observed in relation to atherosclerotic aneurysms. (2) Operative technique should be modified to avoid excessive dissection and lysis of ureters and duodenum. (3) Excellent early and late results can be expected with proper surgical technique. (4) The causes of AAA are multiple, and chronic contained rupture of the aneurysm and reactive lymphatic hyperplasia might play a role of greater significance than previously thought.

Aged↗
PubMed1988

Psychological treatment of an asthmatic patient in crisis. Dreams, biofeedback, and pain behavior modification.

The purpose of this paper is to discuss a unique, integrated combination of various psychological methods that can be used in the treatment of asthma during an acute episode, as well as in long-term management. Illustrated by a case presentation, the therapeutic approach, totaling 14 treatment sessions for the patient and his wife, included: a psychological evaluation, the use of pain behavior-modification procedures usually performed conjointly with the patient's wife, the analytical use of dreams, the desensitization of anxiety present in dream material, and autogenic therapy combined with thermal biofeedback (i.e., using digital temperature to measure relaxation) both at the medical center and at home. Electromyography (EMG)--a measurement of tension--and electrodermal (EDR)--a measurement of galvanic skin response--biofeedback instruments were used nosologically and therapeutically to measure psychophysiological changes, as well as to reduce emotional stresses related to the patient's asthmatic condition.

Asthma↗
PubMed1987

Success of re-use of cardiac electrode catheters.

The feasibility of cardiac electrode catheter re-use was prospectively evaluated over a 5-year period (1981 to 1986), during which time 178 catheters were used 1,526 times for 847 electrophysiologic procedures. Detailed records of catheter testing and use were maintained. No complications were encountered during the study period. All re-used catheters functioned for cardiac pacing and electrographic recording. Surveillance cultures and biologic indicators revealed that adequate sterilization procedures were used. Thus, electrode catheters may be safely re-used provided a thorough cleaning, testing and record-keeping system is instituted. This may result in lower patient cost (approximately $30 per re-use vs [200 per single use) for electrophysiologic catheterization.

Cardiac Catheterization↗
PubMed1987

Tuberculosis affecting the oesophagus.

Three Asian patients presenting with dysphagia were shown to have oesophageal involvement secondary to adjacent tuberculous mediastinal lymph nodes. The findings included fistula between the oesophagus and the tracheobronchial tree and extrinsic compression of the oesophagus. These cases reflect the increasing incidence of mediastinal lymphadenopathy in adult tuberculosis, especially in our immigrant community.

Adult↗
PubMed1987

Clonazepam versus alprazolam in the treatment of panic disorder: interim analysis of data from a prospective, double-blind, placebo-controlled trial.

The authors present interim results of a prospective, random assignment, double-blind, placebo-controlled trial conducted to determine whether clonazepam is as effective as alprazolam in reducing the frequency of panic attacks and whether both agents are superior to placebo. Analysis on 44 of 60 randomized subjects showed no statistically significant differences between the clonazepam and alprazolam groups on the following clinically meaningful outcome measures: total number of panic attacks and percent of time subjects experienced anticipatory anxiety, extent of phobic avoidance, and fear. Statistically significant differences did exist among the drug and placebo groups on these measures. The authors conclude that this interim analysis of the data supports the inclusion of clonazepam in the treatment of panic disorder.

Adolescent↗
PubMed1986

Ontogeny of hypothalamic pituitary function in the pig: pituitary thyrotrophin in the fetus and neonate.

Thyrotrophin in individual pituitaries obtained from fetal and prepubertal pigs was quantified by homologous radioimmunoassay (RIA) and heterologous radioreceptor assay (RRA). Relative evolution of pituitary TSH contents and concentrations with age were in good agreement as measured by both assay systems although the quantity of TSH detected by RRA appeared consistently lower than that measured by RIA. Thyrotrophin was first detected in pituitaries of fetal pigs at day 75 of gestation. Thereafter the pituitary content of TSH increased to approximately 45 micrograms/pituitary in the oldest group tested (6 weeks of age). The pituitary TSH concentration rose sharply until birth (114 +/- 1 day post coitum) and thereafter remained increased at a concentration of approximately 400 ng/mg wet weight.

Animals↗
PubMed1986

Developmental changes in gonadotrophins and testicular gonadotrophin receptors in the pig, from neonatal to adult life.

Changes in the concentrations of LH and FSH testicular receptors have been studied in the pig, from neonatal to adult life, and correlated with blood LH, FSH and testosterone concentrations. Quantification of gonadotrophin receptors was performed in equilibrium binding studies, using homologous systems. The presence of high-affinity binding sites for LH and FSH (association constant (Ka): LH approximately 20 litres/nmol; FSH approximately 10 litres/nmol) was demonstrated in the testes of all animals studied. The apparent affinity of LH and FSH receptors did not change significantly with age. During the first weeks of life, there was a transient rise in LH receptor content, reaching a maximum of 8.7 +/- 2.2 (mean +/- S.E.M.) pmol/g testis at 24 days of age. This was correlated with a peak in testosterone secretion and reflects the second wave of interstitial cell proliferation in the pig. A second increase in the number of LH receptors occurred after 12 weeks of age and corresponds to pubertal maturation and final differentiation of adult Leydig cells. During this period, circulating concentrations of testosterone markedly increased without any significant variation in LH blood levels, suggesting a change in testicular sensitivity to LH in the maturing pig. A continuous increase in FSH receptor content was observed from the neonatal to the adult pig. This increase occurred in two phases. During the first 2 months of life, the increase in the number of FSH receptors exceeded that of testis growth rate and resulted in an increase in FSH receptor concentrations which reached a peak at 12.1 +/- 1.8 pmol/g testis, at week 9.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1985

Magnetic resonance imaging in hypertrophic cardiomyopathy.

Gated magnetic resonance imaging (MRI) was performed using a 0.35-Tesla cryogenic system in 14 patients with hypertrophic cardiomyopathy (HC) in order to define the site and extent of abnormal wall thickness. These studies were compared with 2-dimensional (2-D) echocardiograms. Gated magnetic resonance imaging studies in 12 normal volunteers were used for comparison. In normal subjects and in patients with HC, the sharp demarcation of the myocardial wall permitted measurement of wall thickness. The thickness of the septal and posterolateral walls in normal subjects was 10.2 +/- 0.4 mm (+/- standard deviation) and 10.8 +/- 0.5 mm, respectively, whereas septal thickness in all but 1 patient with HC was 15.0 mm or greater. In patients with HC, septal and posterolateral wall thickness were 2.2 +/- 0.8 cm and 1.3 +/- 0.17 cm, respectively, by MRI. The 2-D echocardiographic measurements for septal and posterolateral walls were 2.4 +/- 0.6 cm and 1.4 +/- 0.7 cm, respectively. The severity and distribution of abnormal wall thickness were comparable on 2-D echo and MRI. Gated MRI is an effective and completely noninvasive technique for demonstrating the presence, site and extent of abnormal wall thickness in HC. The large field of view, ability to image directly in multiple planes, and discrete blood-endocardial interfaces are advantages for cardiovascular imaging.

Adult↗
PubMed1985

The ontogeny of hypothalamic pituitary function in the pig. I. Pituitary LH and FSH in the fetus and neonate.

Pituitaries were collected from fetal and postnatal pigs from day 55 p.c. until 6 weeks after birth at closely spaced intervals. LH and FSH in individual pituitaries were quantified by both homologous RIA and homologous RRA. No significant difference was found between results obtained by RIA and RRA. Both LH and FSH are first detected by RIA and RRA in the porcine fetal pituitary at 75 days p.c. Thereafter both LH and FSH pituitary content rises until term. LH pituitary concentration in both male and female fetuses and FSH pituitary concentration in males exhibit a peak just before birth. FSH pituitary concentration in females rises until birth and thereafter remains elevated. A statistically significant sex difference was found postnatally with regard to FSH content and concentration but not for LH.

Animals↗