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Biomedical subjects

R Jones

Publications and source records attributed to R Jones.

At least 721 records · Page 40Linked to original sources
PubMed1989

Free radical scavenging by myocardial fatty acid binding protein.

Recent investigations have indicated the presence of a fatty acid binding protein (FABP) in mammalian heart. This protein binds free fatty acids and their esters with high affinity, however, its physiological role remains unknown. Since FABP constitutes a significant amount of cystolic protein, it is likely that it would be a target for free radical attack. To test this hypothesis, FABP was examined for scavenging against free radicals such as the superoxide anion (O2-), hydroxyl radical (OH.) and hypochlorite radical (OCl.) which may be present in an ischemic reperfused heart. Our results suggest that FABP scavenges O2-, OH. and OCl. as indicated by the FABP inhibition of O2- -dependent reduction of cytochrome c, OH.-dependent hydroxybenzoic acid formation and OCl.-mediated chemiluminescence response. FABP was found to be a more potent scavenger of these free radicals compared to bovine serum albumin. Furthermore, FABP was more effective in scavenging OH. than O2-, and inhibited OH. mediated lipid peroxidation process. These results indicate that FABP can scavenge free radicals which may be present in an ischemic/reperfused heart and, thus, may play a significant physiological role in the heart during ischemia and reperfusion.

Albumins↗
PubMed1989

The chef's secret. "We aim to please".

Retail-quality foodservice is a top priority for Cary Soltz, executive chef at Cottage Hospital, whose menu savvy has pleased both patients & hospital staff.

California↗
PubMed1989

Injury and remodeling of pulmonary veins by high oxygen. A morphometric study.

Breathing 87% oxygen at normobaric pressure for 28 days injuries and remodels the wall of distal pulmonary veins (less than or equal to 150 mu). Occluded vessels are evident, as are vessel remnants in which wall integrity is lost (obliterated vessels). Significantly more veins have a muscular or partially muscular wall than normal (P less than or equal to 0.001 for veins in each size category less than or equal to 150 mu, chi-square test). In some veins new muscle develops between an external and internal lamina but in many it develops within the intima, beneath the endothelium and adluminal to a single lamina. Small veins (20-25 mu in ED) with a muscular or partially muscular wall are present only in the hyperoxic lung. Increase in the percent medial thickness (%MT) of veins indicates lumen narrowing: this is relatively greater in the smallest veins. Reduction in the cross-sectional area of venous segments that are immediately postcapillary, by lumen narrowing or occlusion, contributes to the restriction of the pulmonary vascular bed by hyperoxia.

Animals↗
PubMed1989

Crohn's disease.

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Crohn Disease↗
PubMed1989

Factors affecting the decision to consult with dyspepsia: comparison of consulters and non-consulters.

To identify factors associated with the decision to consult with dyspepsia, patients with dyspepsia were identified from a postal survey in the community. A random sample of 69 patients who had consulted their general practitioner and 66 patients with dyspepsia who had not consulted were interviewed in their homes. Differences in consultation behaviour were not explained by differences in self-reported severity or frequency of symptoms or by the presence of associated symptoms. The most striking difference between the two groups was concern among the consulters about the possible seriousness of symptoms. Consulters were also more likely to be worried about cancer and heart disease and to have experienced more disruptive or threatening life events than the non-consulters. These results emphasize the importance of looking beyond the presentation of common symptoms in general practice to patients' fears about the significance of the symptoms and to non-physical determinants of consultation behaviour.

Anxiety↗
PubMed1989

Community hospitals.

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Hospitals, Community↗
PubMed1989

Membrane remodelling during sperm maturation in the epididymis.

Identification of molecules or factors on spermatozoa that are involved in the recognition and binding to the zona pellucida of the egg is one of the central problems in current research on mammalian fertilization. This information is important, not just from the standpoint of scientific interest, but also for treatment of male infertility and design of future contraceptive technology. One of the most informative approaches to solving this puzzle has been to study the maturation of spermatozoa in the epididymis. The gradual development of motility and zona-binding capacity by spermatozoa after they leave the testis affords an opportunity to investigate what distinguishes a fertile from an infertile spermatozoon and what mechanisms are involved in the transformation from one state to the other. This chapter has reviewed some of the current information on sperm maturation in the epididymis and attempted to correlate it with concepts emerging from in vitro fertilization experiments. Emphasis has been placed on mechanistic aspects of maturation changes to the sperm plasma membrane, not only because in many species it is the surface membrane that encounters the zona and it is therefore likely to be the site of potential recognition molecules, but also because the plasma membrane influences many intracellular events and has a bearing on the maturation of the nucleus and axoneme as well. An example of the latter is shown by the induction of motility in demembranated testicular sperm by the addition of ATP and Mg2+ (Mohri and Yanagimachi 1980; White and Voglmayr 1986). This suggests that the motor apparatus for motility is essentially present in immature spermatozoa and that one of the requirements for it to become fully operative are subtle alterations to the permeability properties of the plasma membrane. A similar mechanism may also be true of the maturing sperm nucleus to which only passing reference has been made here. Very little is known about this aspect of sperm maturation beyond the increasing stabilization of the nucleoprotein by formation of disulphide bonds (Bedford 1975). The fact that isolated heads from immature spermatozoa fail to form pronuclei if injected directly into the egg (Uehara and Yanagimachi 1977) may explain, in part, the high embryonic mortality observed when not fully mature spermatozoa are induced to fertilize eggs (Orgebin-Crist et al. 1975). Thus maturation events within the nucleus are just as important as those on the surface membrane.(ABSTRACT TRUNCATED AT 400 WORDS)

Animals↗
PubMed1989

Horizontal fusional amplitudes. Evidence for disparity tuning.

The region of retinal disparity that is effective in maintaining binocular alignment of the eyes was investigated by measuring the horizontal fusional amplitudes for fixation targets consisting of a small central cross to which peripheral lines having various disparities were added. It was found that the addition of peripheral targets significantly facilitated binocular alignment, but only if the peripheral lines had less than about 0.5 degrees of disparity. This result indicates that the fusional mechanism responsible for binocular alignment is only narrowly tuned for retinal disparity. In light of current evidence that indicates that much larger disparities are capable of initiating vergence eye movements, the results support suggestions that fusional vergence consists of functionally dichotomous vergence initiating (coarse) and sustaining (fine) channels.

Computer Systems↗
PubMed1989

Combined retrolab-retrosigmoid vestibular neurectomy. An evolution in approach.

Since introducing the retrolabyrinthine vestibular neurectomy (RVN) in 1978, we have performed 78 procedures with good results. In 1985, we introduced the retrosigmoid-internal auditory canal vestibular neurectomy (RSG-IAC), which allowed a more complete transection of the vestibular nerves in the IAC. Vertigo control has been excellent. However, in 50% of cases postoperative headaches have been a significant problem. In 1987, we combined these two approaches into one procedure, the combined retrolab-retrosigmoid vestibular neurectomy (RSG-RVN). The procedure is similar to a RVN, in that all bone covering the lateral venous sinus (LVS) is removed. It differs from the RVN in that the dura is opened just behind the LVS. The LVS is retracted forward, thereby exposing the cerebellopontine (CP) angle. This allows the surgeon the option to sever the vestibular nerve either in the CP angle or in the IAC, depending on the presence or absence of a cochleovestibular (CV) cleavage plane in the CP angle. The technique, results, and complications will be reported in this article.

Cerebellopontine Angle↗
PubMed1988

Encephalitogenic T cell clones with variant receptor specificity.

We explored antigenic differences between guinea pig (GP)-basic protein (BP), rat (Rt)-BP, and respective peptides from the encephalitogenic region for Lewis rats by comparing the fine specificity of T lymphocyte lines and clones selected from animals primed with these Ag. Encephalitogenic T cell lines specific for GP-BP or Rt-BP predictably recognized the corresponding 72-89 and to a lesser degree the 72-84 (S55S) amino acid sequence. T cell lines selected from rats primed with GP-S55S responded preferentially to GP-S55S compared to other peptides. A T cell line raised to Rt-S55S, however, initially recognized the S55S and S72-89 peptides but were nearly unresponsive to the intact GP-BP or Rt-BP. T cell clones selected from the Rt-S55S line at that point had two distinct patterns of response: clones that recognized both of the BP and the S55S peptides adoptively transferred delayed-type hypersensitivity and experimental autoimmune encephalomyelitis. These clones also recognized residues 69-81 (S67) but not peptide S75-89. In contrast, T cell clones that responded only to synthetic peptides GP-S55S and Rt-S55S but not to the parent BP adoptively transferred delayed-type hypersensitivity but not disease in Lewis rats. The same clones failed to respond to either the S67 or the S75-89 sequences. These results demonstrate that the encephalitogenic Rt-S55S sequence houses a minimum of two T cell epitopes with differing specificities and functions. One epitope is immuno-dominant and resembles the encephalitogenic region of the intact BP molecule. The second non-encephalitogenic epitope is restricted to the S55S sequences and is not shared by the parent BP, the S67, or the S75-89 sequences. Both types of Rt-S55S-specific clones differ in fine specificity from encephalitogenic clones selected from GP-BP immunized rats, thus indicating that uniformity of T cell recognition of the encephalitogenic epitope is not an absolute condition for T cells to be encephalitogenic.

Amino Acid Sequence↗
PubMed1988

Validation of disease diagnoses reported to the National Animal Health Monitoring System from a large Colorado beef feedlot.

Clinical observation and collection of biological specimens from a large beef feedlot (approximately 30,0000 animals) were used to evaluate 6 approaches for validation of a disease reporting system. Data collected during a 12-month period were used to evaluate each approach. A subsample of disease cases reported to the National Animal Health Monitoring System (NAHMS) was compared with the clinical observations of the investigators. Although the agreement between clinical diagnosis by the NAHMS veterinarian and by feedlot health crews was high, the sensitivity and specificity of specific diagnoses varied from 100 to 18% and from 99 to 76%, respectively, which suggests that regular clinical observations by a veterinarian are needed to validate disease diagnoses reported to NAHMS by producers. Subsampling of a group of cattle by means of paired serologic determination of antibodies to infectious bovine rhinotracheitis virus, bovine viral diarrhea virus, bovine respiratory syncytial virus, and parainfluenza-3 virus revealed a high serologic conversion rate to infectious bovine rhinotracheitis, and high levels of preexisting antibody to bovine respiratory syncytial and parainfluenza-3 viruses. It was concluded that the current method of data collection for Colorado feedlots provides an acceptable level of sensitivity and specificity for the program. However, disease events that are not of economic importance to the feedlot operator will be underestimated. If an objective of NAHMS is to develop a base line of animal health conditions, diagnosis of diseases by current methods will be satisfactory. Occasional validation through clinical observations by a veterinarian will suffice to monitor quality of collected data.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1988

Pleistocene dates for the human occupation of New Ireland, northern Melanesia.

Pleistocene dates from three cave sites indicate the human capacity to colonise across two oceanic straits to the east of a former Tasmania-Australia-New Guinea continent by 33 kyr BP. The sites demonstrate exploitation of costal marine and lowland tropical forest resources. They extend Pleistocene occupation into island Melanesia and demonstrate that the large islands of northern Melanesia have an antiquity of human occupation of the same order as the adjacent Greater Australian continent.

Animals↗
PubMed1988

ARDS after accidental inhalation of zinc chloride smoke.

Five soldiers were injured by inhalation of hexite smoke (ZnCl2) during military training. Two soldiers, not wearing gas masks breathed hexite for 1 or 2 min, they slowly developed severe adult respiratory distress syndrome (ARDS) over the ensuing 2 weeks. This slow, progressive clinical course has not been previously described. In both patients, an increased plasma zinc concentration was measured 3 weeks after the incident. Intravenous and nebulized acetylcysteine increased the urinary excretion of zinc, and briefly decreased the plasma levels. In an attempt to arrest collagen deposition in the lungs, L-3,4 dehydroproline was administered. Both patients died of severe respiratory failure (25 and 32 days after inhalation). At autopsy diffuse microvascular obliteration, widespread occlusion of the pulmonary arteries and extensive interstitial and intra-alveolar fibrosis was observed. Three soldiers wearing ill fitting gas masks, immediately developed severe coughing and dyspnea. They improved, and 12 months after exposure their lung function tests were nearly normal, but they still had slight dyspnea on exercise.

Acetylcysteine↗
PubMed1988

Renal cell carcinoma in cadaver donor kidney.

A cadaver kidney, reported to contain a "simple cyst," was received from another institution. Frozen section biopsy prior to transplant showed renal cell carcinoma. The contralateral kidney already had been transplanted at the other medical facility.

Cadaver↗