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Biomedical subjects

R Freeman

Publications and source records attributed to R Freeman.

At least 19 recordsLinked to original sources
PubMed1992

The high-risk liver allograft recipient. Should allocation policy consider outcome?

The Boston Center for Liver Transplantation has accumulated one of the larger series of liver allograft recipients. This review has provided an opportunity to examine recent pronouncements by Medicare regarding patient selection and survival and to question whether the current allocation scheme best utilizes a scarce supply of donor liver allografts. Patients with primary biliary cirrhosis, sclerosing cholangitis, and metabolic derangements have enjoyed excellent survival: in aggregate, 78.9% at 1 year. In contrast, patients suffering from acute hepatic failure, patients requiring life support, or patients with primary graft failure who need a second liver transplant did poorly compared with other recipient groups: 45% 1-year survival. This center's experience reflects a more realistic expectation of patient survival because it considers the high-risk recipient by diagnosis and urgency status. This study also suggests that assessment of outcome should be a component of allocation planning in the future.

Adult↗
PubMed1992

Peripheral 5-carboxamidotryptamine induces hindlimb scratching by stimulating 5-HT1A receptors in rats.

Treatment of rats with 5-carboxamidotryptamine (5-CT) or 5-methoxy-tryptamine (5-MeOT) induces a hindlimb scratch response. These compounds have high affinity for 5-HT1A and 5-HT1D receptors. The selective 5-HT1A receptor agonist N,N-dipropyl-5-CT (DP-5-CT) also induced hindlimb scratching while the selective 5-HT1D receptor agonist, sumatriptan, did not. 5-CT-induced hindlimb scratching was inhibited dose-dependently by several 5-HT1A antagonists (BMY 7378, NAN-190, MDL 73005EF and pindobind-5-HT1A) as well as the non-selective 5-HT antagonist, methiothepin. Pretreatment of rats with the serotonin (5-HT) synthesis inhibitor, p-chlorophenylalanine (PCPA) or the 5-HT depleting agent, reserpine, markedly attenuated 5-CT-induced hindlimb scratching. These data suggest that hindlimb scratching induced by 5-HT agonists may not be centrally mediated but rather may be mediated by a neuronal 5-HT1A receptor localized outside the blood-brain barrier.

5-Methoxytryptamine↗
PubMed1992

Pyrolysis mass spectrometry of Listeria monocytogenes isolates from sheep.

Forty-eight isolates of Listeria monocytogenes from sheep and silage, involved in five small outbreaks of listeriosis, were compared by pyrolysis mass spectrometry (PyMS). The method clustered isolates from single animals, and showed that epidemiologically associated isolates were closely related to each other. PyMS is a simple technique capable of analysing large numbers of samples daily, and its application in veterinary studies should help to elucidate the epidemiology of listeriosis.

Animals↗
PubMed1992

Application of pyrolysis mass spectrometry to the investigation of outbreaks of food poisoning and non-gastrointestinal infection associated with Bacillus species and Clostridium perfringens.

Eighteen isolates of Bacillus species and 15 of Clostridium perfringens, all of which had been associated with outbreaks of either food poisoning or non-gastrointestinal infection (NGI), were examined for relatedness by pyrolysis mass spectrometry (PyMS). The PyMS-analysis correctly clustered all the groups of epidemiologically related isolates of both genera, and distinguished all the single, epidemiologically unrelated isolates of the same species. PyMS is a simple, rapid and inexpensive technique which can provide useful and accurate inter-strain comparisons within both the Bacillus and Clostridium genera in complete accord with conventional serological typing results.

Bacillaceae Infections↗
PubMed1992

Pregnancy-associated subacute hemorrhage into a prolactinoma resulting in diabetes insipidus.

A young woman with a small pituitary tumor associated with hyperprolactinemia developed subacute intrapituitary hemorrhage during the third trimester of pregnancy and presented with central diabetes insipidus. Magnetic resonance imaging established the diagnosis. After transsphenoidal surgery, her visual findings resolved, and the patient had an uneventful spontaneous delivery.

Adult↗
PubMed1992

The pharmacotherapy of depressive illness in adolescence: II. Effects of lithium augmentation in nonresponders to imipramine.

The antidepressant value of lithium augmentation was assessed in a 3-week open trial involving 24 adolescents who remained highly depressed after 6 weeks of treatment with imipramine hydrochloride. Two patients responded dramatically during the first week, with an additional eight patients showing partial improvement during the 3-week trial. The overall magnitude of improvement in depression ratings was significantly greater than in an historical control group of nonresponders who continued to receive imipramine monotherapy during their hospital treatment. Results suggest the potential use of this adjunctive strategy in some tricyclic resistant adolescent depressives, although it appears less efficacious overall in this age group than in adults.

Adolescent↗
PubMed1992

The iron uptake mechanisms of enteropathogenic Escherichia coli: the use of haem and haemoglobin during growth in an iron-limited environment.

The iron uptake mechanisms of enteropathogenic Escherichia coli (EPEC) were examined and compared with those of control E. coli strains. The incidence of aerobactin production was similar (39% and 37% respectively) in the two groups. The quantities of enterochelin produced by aerobactin-negative EPEC and control strains were similar, as were the quantities of enterochelin produced by aerobactin-positive EPEC and control strains. The ability to use haem or haemoglobin as an iron source in an iron-restricted environment was found in 80.4% and 60.8% of EPEC strains respectively, and in 76.6% and 56.6% of control E. coli strains. The ability of E. coli strains to use these compounds was not related to the production of enterochelin or aerobactin or to the production of haemolysins, and may be an important characteristic of bowel organisms. When growing in an iron-limited environment, the iron contained in haemoglobin was used in preference to ovotransferrin-bound iron. During periods of haemoglobin-stimulated growth, the enterochelin uptake system was shown to be fully expressed and may be involved in transport of haemoglobin-derived iron into the cell. Uptake of ovotransferrin-bound iron took place immediately upon exhaustion of haemoglobin-derived iron. The ability to use iron derived from haem compounds represents an alternative iron uptake mechanism for organisms growing in an iron-limited environment and allows greater flexibility during growth in vivo.

Bacterial Outer Membrane Proteins↗
PubMed1992

Nosocomial infection with Clostridium difficile investigated by pyrolysis mass spectrometry.

Fifty-eight isolates of Clostridium difficile from two distinct outbreaks were examined for inter-strain similarity by pyrolysis mass spectrometry (PMS). The first outbreak began on a geriatric acute unit and spread to a long stay geriatric facility. PMS analysis showed that most isolates from both sites were indistinguishable. Isolates obtained in the preceding year from the long stay facility were found to be closely similar to these outbreak isolates. In the second, smaller outbreak on a female medical ward in another general hospital, PMS again showed that a single strain was probably responsible. Representative isolates from these two different outbreaks were shown to be distinct. The ability to compare rapidly large numbers of isolates of C. difficile makes PMS attractive for initial screening in suspected outbreaks, providing important information for outbreak management and allowing conventional typing methods to be concentrated on relevant isolates.

Aged↗
PubMed1992

Rapid differentiation of Mycobacterium xenopi from mycobacteria of the Mycobacterium avium-intracellulare complex by pyrolysis mass spectrometry.

Thirty four cultures of slow growing, Tween-80 negative mycobacteria were analysed by pyrolysis mass spectrometry. The results showed that pyrolysis mass spectrometry could positively distinguish strains of Mycobacterium xenopi from those of the Mycobacterium avium-intracellulare (MAI) complex. Pyrolysis mass spectrometry may be a useful technique for the rapid characterisation of non-tuberculous mycobacteria in such clinical settings as their isolation from immunocompromised patients-for example, those with AIDS.

Hot Temperature↗
PubMed1992

Lovastatin/gemfibrozil myopathy: a clinical, histochemical, and ultrastructural study.

Lovastatin has been used with increasing frequency over the past few years to reduce serum cholesterol. The onset of muscle weakness, one of the most serious side effects of long-term treatment with the drug, constitutes a contraindication to the continuation of therapy and commonly occurs in patients who are also receiving gemfibrozil or cyclosporine. We report the clinical and pathologic findings in a patient treated for hypercholesterolemia with lovastatin and gemfibrozil who developed a rapidly progressive necrotizing myopathy. A 57-year-old woman with hyperlipidemia, treated with lovastatin and gemfibrozil, was admitted to the hospital for evaluation of muscular weakness in her legs and neck. Neurologic examination revealed severe proximal muscle weakness involving both upper and lower extremities as well as proximal muscle tenderness and areflexia in the lower limbs. A biopsy of the quadriceps muscle showed multiple foci of mononuclear cell infiltration with myophagocytosis and slight variation in the size and shape of muscle fibers. Electron microscopy of the affected fibers showed accumulations of subsarcolemmal autophagic lysosomes. The patient's condition dramatically improved after discontinuation of lovastatin-gemfibrozil therapy.

Drug Therapy, Combination↗
PubMed1992

Communication, body language and dental anxiety.

Fear of dental treatment is commonplace in dental surgeries, and with more demands being made upon the dental team's already limited time, occupational stress has become more prevalent. Dentists should examine the various aspects of communication which will forewarn them of potentially difficult clinical situations, so that they can minimize the patient's anxiety and their own stress.

Communication↗
PubMed1992

A study into the mechanism of the Crystal Violet reaction in Staphylococcus aureus.

The mechanism of the Crystal Violet (CV) reaction, a trait which has been related to biotype, source and pathogenicity in Staphylococcus aureus, was investigated in agar and broth studies. White reactions could be converted to purple and vice versa by altering the incubation conditions on agar. Broth reactions examined macroscopically and by spectrophotometry revealed that both white and purple human biotype strains take up CV but the former then progressively modify the dye more quickly than the latter. A cell-associated product of CV was detected in white and purple strains by reverse-phase thin-layer chromatography of methanol extracts. White strains appear to produce a second additional product from CV. The white reaction was not inhibited by chloramphenicol or azide but did depend on viable cells with a nutrient source. CV MICs and MBCs for 10 white and 10 purple reactors showed no gross differences in susceptibility, while a standardized assay for the rate of CV modifying activity (52 strains) demonstrated that the two categories comprise discrete populations which alter CV at different rates. Although most white strains belong to either or both of phage-typing groups V and II, purple strains with this pattern of susceptibility and white strains without it both occur. The capacity to modify CV slowly or rapidly appears to subdivide human biotype strains independently of their phage group and is associated in the former case with their capacity to produce hospital-acquired and invasive infections.

Animals↗
PubMed1992

An anatomical commentary on the concept of infantile oral sadism.

Although this paper is entitled 'An anatomical commentary on the concept of infantile oral sadism' it is also an attempt to examine hypotheses regarding the sources of oral sadism. Freud did not explicitly refer to an oral sadistic phase of development in early infancy, believing as he did that sadism was a component instinct. Abraham postulated that oral sadism arises when the teeth erupt and the jaw muscles function. Melanie Klein, however, came to claim that oral sadistic impulses operate from birth and arise from the infant's innate potential for fantasy. This hypothesis is akin to Freud's theory of primal fantasies. The anatomical record supports Abraham's theory of the source of oral sadism.

Female↗