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Biomedical subjects

M C Smith

Publications and source records attributed to M C Smith.

At least 37 records · Page 2Linked to original sources
PubMed2000

On the interaction between linguistic and pictorial systems in the absence of semantic mediation: evidence from a priming paradigm.

Use of the letter search task in the context of the priming paradigm has proved to be an invaluable tool for the investigation of the strategic control of processes involved in word recognition. In particular, previous findings that letter search on a prime word interferes with the priming of semantically/associatively related targets, but not with the priming of either identical or morphologically related targets, suggests that letter search may selectively interfere with semantic processing, leaving other levels of processing intact. In the present experiments, this investigation was extended by exploring the priming of pictures following letter search of either a same-concept word (repetition priming) or a semantically/associatively related word (semantic priming). There was significant repetition priming of picture categorization following both silent reading and letter search of the prime word (Experiments 1 and 2). In contrast, semantic priming of pictures was found only following silent reading of the prime; there was no semantic priming following letter search of the prime (Experiment 2). This pattern of results suggests that focusing attention at the letter level during prime processing selectively attenuates activation of the semantic system by the prime. It does not prevent the spread of activation between the lexical and pictogen levels of representation of a given concept.

Humans↗
PubMed2000

Magnetoencephalography in children with Landau-Kleffner syndrome and acquired epileptic aphasia.

BACKGROUND AND PURPOSE: Landau-Kleffner syndrome (LKS) is epileptiform aphasia acquired during childhood and occurring in children with previously normal language development. The epileptiform activity in these children is thought to result in a functional ablation of eloquent speech areas. The purpose of this study was to investigate the usefulness of magnetoencephalography (MEG) for localizing the source of epileptiform activity in these patients. METHODS: Nineteen patients with acquired aphasia and a suspected diagnosis of LKS were referred for MEG evaluation. Patients ranged in age from 4 to 14 years. Fourteen MEG studies were performed on a 74-channel system, four on a 148-channel whole-head system, and one on a 37-channel system. RESULTS: Thirteen of the 19 patients had perisylvian MEG spikes. In 10 of the patients, the spikes were bilateral, and in three they were unilateral. Four other patients had non-sylvian spikes, and two patients had no spikes recorded. The results of MR imaging were normal or noncontributory for all 19 patients. CONCLUSIONS: MEG can play a useful role in evaluating children with LKS and acquired epileptiform aphasia, both in diagnosis and in aiding presurgical localization of epileptiform activity when surgery is being considered.

Adolescent↗
PubMed2000

Cross-sectional study of the association of abomasal displacement or volvulus with serum electrolyte and mineral concentrations in dairy cows.

The objective of this study was to evaluate serum mineral and electrolyte concentrations at the time of on-farm diagnosis of left displaced abomasum, right displaced abomasum, or abomasal volvulus in dairy cows. Data were collected from 104 affected cows and 96 control cows matched with cases, based on herd, parity, and stage of lactation. Cows with abomasal displacement or volvulus had significantly lower calcium, phosphorous, magnesium, potassium, and chloride concentrations and increased anion gap at the time of diagnosis compared with control cows from the same herds. The percentages of cases and controls with total serum calcium concentrations below the lower limit of the laboratory reference range (2.08 mmol/L [8.3 mg/dL]) were 70% and 23%, respectively. Based on the large percentage of cases with hypocalcemia, administering calcium salts at the time of treatment of field cases of abomasal displacement or volvulus may be beneficial.

Abomasum↗
PubMed1999

The complete genome sequence of the Streptomyces temperate phage straight phiC31: evolutionary relationships to other viruses.

The completed genome sequence of the temperate Streptomyces phage straight phiC31 is reported. straight phiC31 contains genes that are related by sequence similarities to several other dsDNA phages infecting many diverse bacterial hosts, including Escherichia, Arthrobacter, Mycobacterium, Rhodobacter, Staphylococcus, Bacillus, Streptococcus, Lactobacillus and Lactococcus. These observations provide further evidence that dsDNA phages from diverse bacterial hosts are related and have had access to a common genetic pool. Analysis of the late genes was particularly informative. The sequences of the head assembly proteins (portal, head protease and major capsid) were conserved between straight phiC31, coliphage HK97, staphylococcal phage straight phiPVL, two Rhodobacter capsulatus prophages and two Mycobacterium tuberculosis prophages. These phages and prophages (where non-defective) from evolutionarily diverse hosts are, therefore, likely to share a common head assembly mechanism i.e. that of HK97. The organisation of the tail genes in straight phiC31 is highly reminiscent of tail regions from other phage genomes. The unusual organisation of the putative lysis genes in straight phiC31 is discussed, and speculations are made as to the roles of some inessential early gene products. Similarities between certain phage gene products and eukaryotic dsDNA virus proteins were noted, in particular, the primase/helicases and the terminases (large subunits). Furthermore, the complete sequence clarifies the overall transcription map of the phage during lytic growth and the positions of elements involved in the maintenance of lysogeny.

Amino Acid Sequence↗
PubMed1999

Wada difference a day makes: interpretive cautions regarding same-day injections.

OBJECTIVE: To determine whether memory scores after second intracarotid amobarbital procedure (IAP) injections are affected by the time between the first and second injections. METHODS: Sixty-two patients received their second IAP injection on the day after the first injection. Forty-three other patients received the second injection on the same day as the first injection. Both groups underwent similar IAP protocols and memory assessments, except for the timing of the second injection. RESULTS: The second IAP memory scores in the two-day group were significantly higher (p < 0.05) than those in the one-day group. Timing of second injection was a significant correlate of second memory scores, but amobarbital dosage, first IAP memory score, and pre-IAP measures of memory and intelligence were not significant correlates. CONCLUSION: One-day and two-day IAP protocols do not result in similar memory scores after the second injection. Nineteen percent of a subset of patients in the one-day protocol were misclassified, in terms of IAP memory ratings, because of the deleterious effect of having both injections on the same day. It is recommended that correction scores be considered, for some patients who receive two IAP injections on one day, to approximate what the second IAP memory score would have been had the second injection occurred on a second day.

Adolescent↗
PubMed1999

Evolutionary relationships among diverse bacteriophages and prophages: all the world's a phage.

We report DNA and predicted protein sequence similarities, implying homology, among genes of double-stranded DNA (dsDNA) bacteriophages and prophages spanning a broad phylogenetic range of host bacteria. The sequence matches reported here establish genetic connections, not always direct, among the lambdoid phages of Escherichia coli, phage phiC31 of Streptomyces, phages of Mycobacterium, a previously unrecognized cryptic prophage, phiflu, in the Haemophilus influenzae genome, and two small prophage-like elements, phiRv1 and phiRv2, in the genome of Mycobacterium tuberculosis. The results imply that these phage genes, and very possibly all of the dsDNA tailed phages, share common ancestry. We propose a model for the genetic structure and dynamics of the global phage population in which all dsDNA phage genomes are mosaics with access, by horizontal exchange, to a large common genetic pool but in which access to the gene pool is not uniform for all phage.

Bacteriophages↗
PubMed1999

Factors associated with inadequate blood pressure control in hypertensive hemodialysis patients.

Hypertension is common in hemodialysis patients and increases cardiovascular morbidity and mortality. We determined the prevalence of inadequate control of hypertension in 489 patients receiving hemodialysis and identified factors associated with uncontrolled hypertension. We interviewed the patients and abstracted demographic and clinical information from a computerized database. The prevalence of uncontrolled hypertension (average predialysis blood pressure, > or =160/90 mm Hg) was 62%. Ninety-one percent of patients with uncontrolled hypertension were receiving submaximal antihypertensive drug therapy, and 59% withheld their medications before dialysis. Uncontrolled hypertensives had a greater interdialytic weight gain (3.8% v 3.5%, P = 0.07) and a greater excess weight gain (3.1 +/- 1.6 kg v 2.5 +/- 1.4 kg; P < 0.05) compared with controlled hypertensives. Patients with uncontrolled hypertension showed higher interdialytic weight gain (2.7 +/- 0.06 kg v 2.2 +/- 0.13 kg; P < 0.05), were more likely to be black (94% v 81%; P < 0.05), were more likely to have hypertension as the cause of their end-stage renal disease (ESRD) (42% v 24%; P < 0.05), and had been receiving hemodialysis for a shorter time (4.3 +/- 2 yr v 6.1 +/- 0.9 yr; P < 0.05) compared with normotensive patients. There was significant correlation between diastolic blood pressure and both interdialytic weight gain (r = 0.31, P < 0.05) and percent weight gain (r = 0.34, P < 0.05) in the hypertensive but not in the normotensive patients (r = -0.21). Interdialytic weight gain and hypertension as a cause of ESRD were independent predictors of predialysis systolic blood pressure. We conclude that hypertension is uncontrolled in most patients undergoing hemodialysis. Submaximal antihypertensive therapy, excessive interdialytic weight gain, and withholding antihypertensive medication before dialysis are correctable factors potentially contributing to uncontrolled hypertension.

Algorithms↗
PubMed1999

Pharmacy and herbal medicine in the US.

Herbal medicine is increasing in popularity in the United States. The market continues to grow, with a presence being established for commercially-prepared herbal products in community pharmacies throughout the nation. This survey was conducted to describe that presence in pharmacies and to describe pharmacists' perceptions of this product class. A response rate of 26.3% (n = 512) was achieved for a five-page mail survey sent to a geographically stratified random sample of community pharmacies in the United States. Approximately 73% of pharmacists responding indicated that their pharmacy carried commercially-prepared herbal products. Attitudinal items were included to measure pharmacists' perceptions toward these products, as those perceptions have the potential to influence attitudes and subsequently behavior (such as clinical involvement with patients wishing to integrate herbal products into an existing regimen). Pharmacists, on average, did not believe that herbal products are well standardized, or that the products are well accepted by the Food and Drug Administration or the National Association of Boards of Pharmacy. Much potential exists for pharmacists to fill a role as information provider to patients who self-medicate with herbal medicines; must their perceptions of the product class be changed first?

Adult↗
PubMed1999

Caring and the science of unitary human beings.

The purpose of this article is to clarify the ambiguity surrounding the concept of caring through situating it within one conceptual system, the Science of Unitary Human Beings. An analysis of the dialogue on caring in nursing is presented. A process of concept clarification was developed to examine points of congruence between existing literature on caring and theoretical niches expressing similar meanings in the Science of Unitary Human Beings. The process resulted in the synthesis of five constitutive meanings of caring in the Science of Unitary Human Beings: manifesting intentions, appreciating pattern, attuning to dynamic flow, experiencing the infinite, and inviting creative emergence. Narratives were developed to ground the abstract meanings in concrete human experience.

Communication↗
PubMed1999

Effects of the nonpeptide V(1) vasopressin receptor antagonist SR49059 in hypertensive patients.

We assessed the clinical and pharmacological profile of the orally active V(1) vascular vasopressin (AVP) receptor nonpeptide antagonist SR49059 (SR) during the osmotic stimulation of AVP release in hypertensive patients. In a double-blind crossover-versus-placebo study, 24 untreated stage I or II essential hypertensive patients (12 whites and 12 blacks) received a single 300 mg oral dose of SR 2 hours before the stimulation of AVP secretion with a 5% hypertonic saline infusion. Hemodynamic, humoral, and hormonal parameters were monitored for up to 28 hours after drug administration. SR did not alter blood pressure or heart rate before the saline infusion and did not reduce the blood pressure increment induced by the hypertonic saline infusion. However, the blood pressure peak at the end of the hypertonic saline infusion was slightly lower in the presence of SR (P=0.04). Heart rate was significantly faster between 4 and 6 hours after SR administration (P=0.02). The rise in plasma sodium and osmolality triggered by the saline infusion was not modified by SR, but AVP release was slightly greater in the presence of SR (P<0.0003). AVP-induced aggregation of blood platelets in vitro was significantly reduced by SR, with a peak effect 2 hours after drug administration that coincided with the SR peak plasma concentration. Plasma renin activity and aldosterone before and after the saline infusion were not modified by SR. Urine volume and osmolality were not altered by SR administration. SR effects were similar in the 2 ethnic groups as well as in salt-sensitive versus salt-resistant patients. In a situation of AVP osmotic release and volume expansion in hypertensive patients, a single oral dose of the V(1) vascular AVP receptor nonpeptide antagonist SR49059, which is able to block AVP-induced platelet aggregation, exerts a transient vasodilation effect that is not associated with a sustained blood pressure reduction. SR49059 is a pure V(1) vascular receptor antagonist that is devoid of V(2) renal receptor actions.

Administration, Oral↗
PubMed1999

Benefits of massage therapy for hospitalized patients: a descriptive and qualitative evaluation.

CONTEXT: Some acute and long-term care facilities are instituting massage therapy programs to support their patients' health, healing, and quality of life. Evaluation of the impact of these programs from the perspective of patients, providers, and therapists is important for administrative decision making and the design of future outcomes research. OBJECTIVE: To uncover and elucidate a range of patient outcomes of a therapeutic massage program within an acute care setting. DESIGN: Descriptive and qualitative evaluation. Surveys and narrative reports were completed by 70 patients, 14 healthcare providers, and 4 massage therapists. SETTING: A large university hospital. PATIENTS: 113 hospitalized patients received 1 to 4 massages during the course of their hospital stay. INTERVENTION: Massage therapy. MAIN OUTCOME MEASURES: Narrative data were coded into 8 categories (pain, sleep, tension/anxiety, body awareness, physical functioning, psychological support, enhancing healing, and value). Selected patient responses were included to elaborate the meanings of these categories. RESULTS: The most frequently identified outcomes were increased relaxation (98%), a sense of well-being (93%), and positive mood change (88%). More than two thirds of patients attributed enhanced mobility, greater energy, increased participation in treatment, and faster recovery to massage therapy. Thirty-five percent stated that benefits lasted more than 1 day. CONCLUSIONS: The study supported the value of this hospital-based massage therapy program and uncovered a range of benefits of massage therapy for hospitalized patients that should be studied further.

Colorado↗
PubMed1998

Subacute and non-acute casemix in Australia.

The costs of subacute care (palliative care, rehabilitation medicine, psychogeriatrics, and geriatric evaluation and management) and non-acute care (nursing home, convalescent and planned respite care) are not adequately described by existing casemix classifications. The predominant treatment goals in subacute care are enhancement of quality of life and/or improvement in functional status and, in non-acute care, maintenance of current health and functional status. A national classification system for this area has now been developed--the Australian National Sub-Acute and Non-Acute Patient Classification System (AN-SNAP). The AN-SNAP system, based on analysis of over 30,000 episodes of care, defines four case types of subacute care (palliative care, rehabilitation, psychogeriatric care, and geriatric evaluation and management and one case type of non-acute care (maintenance care), and classifies both overnight and ambulatory care. The AN-SNAP system reflects the goal of management--a change in functional status or improvement in quality of life--rather than the patient's diagnosis. It will complement the existing AN-DRG classification.

Aged↗
PubMed1998

Chronic renal insufficiency: a diagnostic and therapeutic approach.

Chronic renal insufficiency ultimately culminating in end-stage renal disease requiring dialysis or transplantation is a major health problem in the United States. The first task confronting the physician caring for a patient with renal disease is to decide whether the renal insufficiency is acute or chronic. The initial differential diagnostic approach to chronic renal insufficiency consists of determining whether the patient has glomerular disease or interstitial or vascular disease on the basis of a careful history taking, urinalysis, and measurement of 24-hour protein excretion. Further refinement of diagnostic considerations often requires serologic studies, renal biopsy, or imaging the urinary tract with ultrasonography or computed tomography. Management considerations begin with the identification and correction of any acute reversible causes of renal insufficiency in patients with chronic renal disease. Recent studies have shown that effective antihypertensive therapy, especially with angiotensin-converting enzyme inhibitors, restriction of dietary protein, and excellent glycemic control in patients with diabetes, can retard the progression of chronic renal disease. Once these therapeutic strategies are in place, it is important to anticipate and treat the multiple manifestations of chronic progressive renal insufficiency: fluid overload, hyperkalemia, metabolic acidosis, abnormalities of calcium, phosphorus, and vitamin D metabolism, and anemia.

Humans↗
PubMed1998

Oligomeric properties and DNA binding specificities of repressor isoforms from the Streptomyces bacteriophage phiC31.

Three protein isoforms (74, 54 and 42 kDa) are expressed from repressor gene c in the Streptomyces temperate bacteriophage phiC31. Because expression of the two smaller isoforms, 54 and 42 kDa, is sufficient for superinfection immunity, the interaction between these isoforms was studied. The native 42 kDa repressor (Nat42) and an N-terminally 6x histidine-tagged 54 kDa isoform (His54) were shown by co-purification on a Ni-NTA column to interact in Streptomyces lividans . In vitro three repressor preparations, containing Nat42, His54 and the native 54 and 42 kDa isoforms expressed together (Nat54&42), were subjected to chemical crosslinking and gel filtration analysis. Homo- and hetero-tetramers were observed. Previous work showed that the smallest isoform bound to 17 bp operators containing aconservedinvertedrepeat (CIR) and that the CIRs were located at 16 loci throughout the phiC31 genome. One of the CIRs (CIR6) is believed to be critical for regulating the lytic pathway. The DNA binding activities of the three repressor preparations were studied using fragments containing CIRs (CIR3-CIR6) from the essential early region as templates for DNase I footprinting. Whereas Nat42 bound to CIR6, poorly to CIR5 but undetectably to CIR3 or CIR4, the Nat54&42 preparation could bind to all CIRs tested, albeit poorly to CIR3 and CIR4. The His54 isoform bound all CIRs tested. Isoforms expressed from the phiC31 repressor gene, like those which are expressed from many eukaryotic transcription factor genes, apparently have different binding specificities.

Bacteriophages↗
PubMed1998

In vitro site-specific integration of bacteriophage DNA catalyzed by a recombinase of the resolvase/invertase family.

The genome of the broad host range Streptomyces temperate phage, phiC31, is known to integrate into the host chromosome via an enzyme that is a member of the resolvase/invertase family of site-specific recombinases. The recombination properties of this novel integrase on the phage and Streptomyces ambofaciens attachment sites, attP and attB, respectively, were investigated in the heterologous host, Escherichia coli, and in an in vitro assay by using purified integrase. The products of attP/B recombination, i.e., attL and attR, were identical to those obtained after integration of the prophage in S. ambofaciens. In the in vitro assay only buffer, purified integrase, and DNAs encoding attP and attB were required. Recombination occurred irrespective of whether the substrates were supercoiled or linear. A mutant integrase containing an S12F mutation was completely defective in recombination both in E. coli and in vitro. No recombination was observed between attB/attB, attP/attP, attL/R, or any combination of attB or attP with attL or attR, suggesting that excision of the prophage (attL/R recombination) requires an additional phage- or Streptomyces-encoded factor. Recombination could occur intramolecularly to cause deletion between appropriately orientated attP and attB sites. The results show that directionality in phiC31 integrase is strictly controlled by nonidentical recombination sites with no requirement to form the topologically defined structures that are more typical of the resolvases/invertases.

Amino Acid Sequence↗