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Biomedical subjects

D J Smith

Publications and source records attributed to D J Smith.

At least 343 records · Page 19Linked to original sources
PubMed1989

Determining undergraduate curriculum content in plastic surgery.

The purpose of this study was to determine the cognitive knowledge and clinical skills related to plastic surgery that are essential for inclusion in an undergraduate curriculum. A questionnaire was distributed to surgical clerkship directors, plastic surgeons, and 1980 graduates of four medical schools. Respondents were asked to rate (0-3) the importance of 74 knowledge items and 28 clinical skills in relation to the knowledge/proficiency necessary for students to achieve prior to graduating from medical school (0 = unnecessary, 3 = indepth knowledge/proficiency important). Results of the questionnaire enabled the determination of mean response scores and the hierarchical ranking of questionnaire items. There was a high degree of correlation between the rankings of the three groups of respondents indicating agreement on knowledge and clinical skills in plastic surgery that are essential, as well as those nonessential, for the competent practice of medicine.

Curriculum↗
PubMed1989

Prolonged whole-body cold water immersion: fluid and ion shifts.

To characterize fluid and ion shifts during prolonged whole-body immersion, 16 divers wearing dry suits completed four whole-body immersions in 5 degrees C water during each of two 5-day air saturation dives at 6.1 msw. One immersion was conducted at 1000 (AM) and one at 2200 (PM) so that diurnal variations could be evaluated. Fifty-four hours separated the immersions, which lasted up to 6 h; 9 days separated each air saturation dive. Blood was collected before and after immersion; urine was collected for 12 h before, during, and after immersion for a total of 24 h. Plasma volume decreased significantly and to the same extent (approximately 17%) during both AM and PM immersions. Urine flow increased by 236.1 +/- 38.7 and 296.3 +/- 52.0%, urinary excretion of Na increased by 290.4 +/- 89.0 and 329.5 +/- 77.0%, K by 245.0 +/- 73.4 and 215.5 +/- 44.6%, Ca by 211.0 +/- 31.4 and 241.1 +/- 50.4%, Mg by 201.4 +/- 45.9 and 165.3 +/- 287%, and Zn by 427.8 +/- 93.7 and 301.9 +/- 75.4% during AM and PM immersions, respectively, compared with preimmersion. Urine flow and K excretion were significantly higher during the AM than PM. In summary, when subjects are immersed in cold water for prolonged periods, combined with a slow rate of body cooling afforded by thermal protection and enforced intermittent exercise, there is diuresis, decreased plasma volume, and increased excretions of Na, K, Ca, Mg, and Zn.

Adult↗
PubMed1989

Biochemical aspects of peripheral muscle fatigue. A review.

Muscular fatigue is of critical importance to performance and as such has been the subject of numerous investigations. However, a clear cause remains elusive. Although many factors have been identified, this review deals only with those which occur distal to the neuromuscular junction. Factors discussed include: energy supply (ATP/creatine phosphate, glycogen, oxygen, and free fatty acids); the accumulation of metabolites (lactate/hydrogen ions, calcium, ammonium, electrolyte and water shifts); and, the special case of eccentric work. The results of many studies using various methodologies are examined. Peripheral fatigue appears to be a complex series of interactions with variable influence on the development of fatigue depending upon the nature of the work performed.

Energy Metabolism↗
PubMed1989

Isotype, subclass and molecular size of immunoglobulins in salivas from young infants.

Whole saliva samples from 17 infants who were between 3 and 20 weeks of age were analysed for isotype, subclass and molecular size of immunoglobulins. IgA concentrations ranged from 1.7 to over 60 micrograms/ml. IgM concentrations ranged from undetected to 59% of the IgA concentration in the respective saliva. Ratios of salivary IgM to salivary IgA were inversely correlated with the age of the infant. Gel filtration of 31 salivas on calibrated columns of Superose 6 revealed the IgA to elute in a position consistent with that of secretory IgA. IgM eluted in a position consistent with that of the pentameric molecule. IgA1 was the predominating subclass (IgA1/IgA1 + IgA2 = 0.64) in infant whole saliva. Both IgA subclass concentrations were significantly lower than concentrations measured in adult parotid salivas. Several infant salivas initially contained greater than 95% IgA1 but salivary IgA2 concentrations progressively increased as these infants grew older. These observations support the conclusions that essentially all IgA in whole saliva of predentate infants is of secretory origin, that adult salivary IgM/IgA proportions are achieved early in life, but that, at least in some infants, the salivary IgA subclass proportions are still changing during this time.

Female↗
PubMed1988

Resolution of diastereomers of N,N,N',N'-tetrakis(2-hydroxypropyl)ethylenediamine (quadrol) by reversed-phase high-performance liquid chromatography.

Quadrol, N,N,N',N'-tetrakis(2-hydroxypropyl)ethylenediamine, has been recently observed to display biological activity. It is an immunostimulant and has been implicated as a potentially useful agent in accelerated wound healing. Quadrol exists as a mixture of four unique diastereomers, each of which may, upon further investigation, display differences in biological activity. This paper describes an high-performance liquid chromatographic procedure (both analytical and prep) for the separation of the Quadrol diastereomers. Gas-liquid chromatography and NMR data are presented which corroborate the high-performance liquid chromatographic results. This procedure may be used to obtain pure Quadrol diastereomers, to monitor the progress of Quadrol synthesis from propylene oxide and ethylenediamine or to develop a quantitative assay for Quadrol diastereomers.

Adjuvants, Immunologic↗
PubMed1988

The mu opiate receptor is responsible for descending pain inhibition originating in the periaqueductal gray region of the rat brain.

Opiate agonists exhibiting selectivity for mu, kappa, sigma, and delta opiate receptors were microinjected into the periaqueductal gray region (PAG) of the brain of rats to determine the receptor subtype(s) associated with the initiation of descending pain inhibition. The spinally organized, heat nociceptive tail-flick reflex was used to detect analgesia. Only morphine (mu) and [D-Ala2,D-Leu5]enkephalin (DADLE) (delta greater than mu) produced analgesia. However, both drugs appeared to be acting through the mu (morphine) receptor, since: (1) the action of DADLE was not inhibited by delta receptor antagonists, (2) a more highly selective delta agonist [D-Pen2,D-Pen5]enkephalin was ineffective and (3) agonists selective at other non-mu receptor sites (ethylketocyclazocine and U50,488H for kappa; n-allylnormetazocine for sigma) were also ineffective. It appeared that DADLE might be acting as a partial agonist at the morphine receptor in the PAG. The peptide was an agonist with low efficacy, and when a maximally effective dose of the peptide was administered simultaneously with morphine antagonism was observed. Ethylketocyclazocine and n-allylnormetazocine were also found to antagonize morphine, an observation that is consistent with the suggestion that they may act as mu receptor antagonists in addition to their agonistic action at kappa and sigma receptors, respectively. Thus, mu receptors appear to be responsible for the spinopetal analgesia from the PAG of the rat.

Animals↗
PubMed1988

Origin of cerebellar projections to the region of the oculomotor complex, medial pontine reticular formation, and superior colliculus in New World monkeys: a retrograde horseradish peroxidase study.

Cerebellar projections to oculomotor-related brainstem regions were studied in four groups of New World (capuchin, squirrel) monkeys by using the retrograde transport of horseradish peroxidase (HRP) to determine the origin of the principal cerebellar influence on eye movement. Group A monkeys had HRP injections or transcannular HRP gel implants into the oculomotor complex (OMC), the largest of which involved adjacent paraoculomotor nuclei (e.g., ventral periaqueductal gray, PAG; nucleus of Darkschewitsch, ND; medial accessory nucleus of Bechterew, MAB; dorsomedial parvicellular red nucleus, dmPRN). All of these cases contained large numbers of retrogradely labeled cells in cell group Y. Whereas the smallest OMC injection only labeled a few cells in the dentate nucleus (DN), injections involving paraoculomotor nuclei produced labeling in all of the cerebellar nuclei except the basal interstitial nucleus (BIN). Injections extending into the ND and MAB produced particularly heavy labeling within the interposed nuclei. Group B monkeys had injections/implants into the medial pontine tegmentum and dorsomedial basilar pons. The pontine tegmental cases contained labeled cells in all cerebellar nuclei, but the DN was the most heavily labeled when the implant involved the nucleus reticularis tegmenti pontis (NRTP). Cases with injections into the caudal medial pontine tegmentum (nucleus reticularis pontis caudalis, NRPC), including the physiological paramedian pontine reticular formation (PPRF), but not NRTP, contained the largest number of labeled cells in the fastigial nucleus (FN) and lacked retrograde labeling in the DN. Dorsomedial basilar pontine cases contained almost no labeled cells in the FN, anterior interpositus nucleus (AIN), and posterior interpositus nucleus (PIN) but did contain DN labeling when the injection involved the NRTP. Two dorsomedial pontine tegmental cases and one dorsomedial basilar pontine case had more labeled cells in the BIN than in other cases. Tegmental cases also contained a few labeled cells in cell group Y. Group C monkeys had injections into the parvicellular red nucleus (PRN) and had their heaviest labeling in the DN, although the AIN and PIN also contained labeled cells. The FN, BIN, and cell group Y, on the other hand, contained almost no labeling. Group D consisted of monkeys which had injections into the intermediate and deep superior colliculus (SC). These cases contained the largest numbers of labeled cells in the PIN and a lesser number in the ventrolateral FN. The DN, AIN, BIN, and cell group Y lacked labeled neurons in these cases.(ABSTRACT TRUNCATED AT 400 WORDS)

Animals↗
PubMed1988

The complete sequence of a frog alpha-tubulin gene and its regulated expression in mouse L-cells.

A frog alpha-tubulin cDNA and a frog alpha-tubulin gene, closely related to the cDNA, were cloned and sequenced and the structure of the gene deduced. The gene was introduced into mouse L-cells in order to investigate the transcription and regulation of the gene. The gene was transcribed and there was processing of the transcripts. Furthermore, the gene displayed the correct autoregulatory feedback control.

Amino Acid Sequence↗
PubMed1988

The effect of selective type A or type B monoamine oxidase inhibition on the intrasynaptosomal deamination of (3H)serotonin in rat spinal cord tissue.

The degree to which the type A and type B forms of monoamine oxidase participate in the intraneuronal deamination of (3H)serotonin (5-HT) was examined in synaptosomal-rich fractions of rat spinal cord tissue. Synaptosomes were labeled with (3H)5-HT and superfused with physiological buffers containing selective concentrations of a type A (clorgyline) or a type B (deprenyl) MAO inhibitor. The efflux of (3H)5-HT and newly-formed (3H)5-hydroxyindoleacetic acid (5-HIAA) was determined and compared to controls over time. In control samples, a slight decline in (3H)5-HT efflux occurred over the experimental superfusion period. However, a stable formation and efflux of (3H)5-HIAA was seen during this same period of time. When clorgyline was added to the superfusion buffer, a rapid decline in superfusate levels of (3H)5-HIAA was observed. Similar experiments in the presence of deprenyl were without effect. In order to elevate cytoplasmic concentrations of (3H)5-HT and therefore increase its chances for interaction with nerve terminal MAO, reserpine was added to the superfusion buffer. Reserpine caused a greater than 3-fold increase in (3H)5-HIAA formation with no change in (3H)5-HT efflux. Clorgyline inhibited this increase in (3H)5-HIAA formation but deprenyl was again without effect. In the presence of clorgyline, reserpine also caused an increase in (3H)5-HT efflux. These results strongly support the notion that 5-HT deamination within rat spinal cord nerve terminals occurs primarily, if not exclusively, through an interaction with type A MAO.

Animals↗
PubMed1988

Transformation of Penicillium chrysogenum with a dominant selectable marker.

We have cloned a mutant oligomycin resistance allele of the mitochondrial ATP synthase subunit 9 gene from the filamentous fungus Penicillium chrysogenum. The gene was isolated using the equivalent gene from Aspergillus nidulans as a hybridisation probe. Using the cloned gene it is possible to select for oligomycin resistance in P. chrysogenum transformation experiments. This transformation system was used to introduce further copies of the P. chrysogenum isopenicillin N synthetase gene, which were stably maintained without selection. An assessment of the frequency with which homologous integration occurs was also made. With this system, it should prove possible to transform any strain of P. chrysogenum.

Chromosome Mapping↗
PubMed1988

Biosynthetic compound dressings--management of hand burns.

To achieve optimal hand function, wound closure becomes the most important ingredient in hand burns. This study documents the use of a biosynthetic compound dressing (Biobrane) which has been fabricated as a glove for management of hand burns. The glove allowed rapid active motion and minimized the pain of open wounds. Forty-two Biobrane glove applications were evaluated with 50 per cent applied over superficial hand burns and 50 per cent over deep partial thickness or full thickness injuries. In the superficial hand burns, the patients were discharged home after a mean time of 2.8 days. With the deep burns the dressing provided a closed wound after early excision of eschar without the use of an autograft or biological dressing. Based on these studies, we conclude that the biosynthetic compound dressing glove is a useful adjunct to be added to the armamentarium for treatment of the burned hand.

Biocompatible Materials↗
PubMed1988

Use of glutaraldehyde stabilized mammalian pericardium in hand surgery.

Initial feasibility studies of glutaraldehyde-stabilized bovine pericardium show promise for use in hand surgery. The pericardium exhibits excellent handling characteristics with no obvious biologically adverse reactions. Testing in the experimental models show a decrease in adhesion formation and an increase in tendon gliding. Clinical use of the bovine pericardium in selected cases appears to be confirm the experimental results.

Animals↗
PubMed1988

DRG-driven change in burn wound management: a success story.

We have devised an algorithm employing the exclusive use of biosynthetic dressing (Biobrane) to treat the less extensive burn wounds of patients under DRG 460. This protocol has allowed us to decrease the hospital stay of these patients by 46 percent and turn this patient group from a deficit for the hospital to a substantial profit.

Biocompatible Materials↗
PubMed1988

Clinical, microbiological and immunological features of subjects with destructive periodontal diseases.

76 subjects with prior evidence of destructive periodontal diseases were monitored clinically and immunologically every 2 months for up to 5 years. Clinical parameters measured included bleeding on probing, gingival redness, plaque accumulation, suppuration, pocket depth and attachment level. Blood samples were taken by venipuncture and serum antibody levels to a series of 18 subgingival species determined. 33 of these subjects showed evidence of active disease during the monitoring period, based on changes in attachment level measurements assessed using the tolerance method of analysis. Mean attachment loss in these 33 subjects varied from 1.4 mm to 9.0 (median value 3.4 mm) and subjects whose mean attachment level was above the median showed a higher % of pockets greater than 3 mm and more suppuration. Severity of gingival inflammation related poorly to mean attachment loss. Subgingival plaque samples were taken from the active site(s) and from control sites of equal pocket depth and attachment loss in the same active disease subjects, prior to therapy, for predominant cultivable microbiota studies. 50 randomly selected isolates were identified from each sample. Predominant cultivable species in 170 pretreatment active and inactive sites combined (8500 isolates) were enumerated. The most frequently detected species were F. nucleatum (112 sites) and S. intermedius (106 sites), although the predominant species in the samples from each subject differed. The distribution of putative pathogens differed among subjects. For example, A. actinomycetemcomitans was found in 21 samples in 11 subjects and B. forsythus was found in 18 samples from 10 individuals. Antibody response patterns to the 18 subgingival species also varied among subjects.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗