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Biomedical subjects

R M Smith

Publications and source records attributed to R M Smith.

At least 73 records · Page 4Linked to original sources
PubMed2000

Usefulness of the modified 0-10 Borg scale in assessing the degree of dyspnea in patients with COPD and asthma.

INTRODUCTION: Rapid assessment and monitoring is essential for patients with acute bronchospasm. However, tools for measuring dyspnea or the state of being short of breath are often limited to peak flow, blood gas analysis, and asking patients multiple questions about their breathing at a time when they find speaking difficult. We thus decided to examine a tool called the modified Borg scale (MBS) that had the potential to provide quick, easy, and rapid information about a patient's subjective state of dyspnea. This 0 to 10 rated scale gave our ED patients a device they could use to measure and evaluate their dyspnea. For this reason, we added it to the triage assessment practice and included it in all posttreatment assessment notes on patients with exacerbations of asthma or chronic obstructive pulmonary disease (COPD) who were seen in the emergency department and urgent care clinic. STUDY QUESTIONS: (1) Can patients with acute bronchospastic asthma or COPD adequately communicate their level of dyspnea using the MBS? (2) Does subjective improvement in the patient's dyspnea using the MBS correlate with improvements in pulmonary functions as measured by the peak flow meter and cutaneous oxygen saturation (Sao(2))? METHODS: Routine and triage assessment of subjective dyspnea using the MBS was instituted at a hospital emergency department serving adult veterans. Concurrently, the MBS was added to our standardized treatment protocol for management of patients with bronchospasm. ED and urgent care records were reviewed to collect baseline and postrespiratory treatment data on peak expiratory flow rates (PEFR), MBS scores, and Sao(2) percentages. RESULTS: Four hundred male veterans aged 24 to 87 years presented with a chief complaint of dyspnea. The assessing physician identified 102 of these patients as having acute bronchospasm; 42 were diagnosed with asthma, and 60 were diagnosed with COPD. All study patients with acute bronchospasm were able to use the MBS to rate their perception of severity of dyspnea. As the peak flow measurements increased, the MBS scores of difficulty breathing decreased. For the asthma groups, the mean MBS score decreased from 5.1 at triage baseline to 2.4 after treatment. This finding indicated that a significant correlation existed between the change in MBS scores and the change in PEFR from pretreatment to posttreatment scores (r = -.31, P <.05). As the peak flow increased, the MBS scores decreased. Sao(2) only slightly improved in the asthma group compared with the COPD group. For patients with COPD, the mean MBS score decreased from 6.0 at triage baseline to 3.0 after treatment. This finding indicated that a significant correlation also existed between the change in MBS scores and the change in PEFR from pretreatment to posttreatment scores (r = -.42, P <.001). Cutaneous oxygen saturation also improved in the COPD group after treatment. The modality of treatment ordered by the physician was metered dose inhaler or nebulizer. These treatment modalities had no effect on the aforementioned results in the asthma or COPD group. CONCLUSIONS: The MBS is a valid and reliable assessment tool for dyspnea. This study demonstrated that it correlated well with other clinical parameters and could be useful when assessing and monitoring outcomes in patients with acute bronchospasm. Patients who used the MBS rated it with a high degree of satisfaction on ease of use and found that the language in this scale adequately expressed their dyspnea. The ED triage and primary care nursing staff rated the MBS as highly satisfactory, stating that it was quick and easy to use. Respiratory assessment in the triage notes and nursing notes were streamlined to consistently include 3 respiratory measures: PEFR, MBS, and Sao(2). Long respiratory narratives were found to be unnecessary in many cases. In addition, the MBS helped to include an important element of subjective assessment when evaluating the severity of dyspnea.

Adult↗
PubMed2000

Compressive and shear force generated in the lumbar spine of female rowers.

Rowers have and accrue greater lumbar spine bone mineral density (BMD) associated with mechanical loading produced during rowing. The aim of this study was to estimate the mechanical loading generated at the lumbar spine (LS) that is apparently providing an osteogenic benefit. The cohort comprised 14 female rowers (average age: 19.7yrs; height: 170.9 cm, weight: 59.5 kg) and 14 female matched controls (average age: 20.9 m yrs; height: 167.5 cm; weight: 58.1 kg). BMD was assessed using the Hologic QDR 2000+ bone densitometer, indicating higher lumbar spine BMD in the rowers compared to the control subjects (1,069 +/- 0.1 vs. 1,027 +/- 0.1 g/cm2). No significant difference existed for BMD at any other site. All rowers performed a six-minute simulated race on a Concept II rowing ergometer. Mechanical loading generated at the lumbar spine during this task was assessed using a two-dimensional model of the spine, enabling the calculation of the compressive and shear forces at L4/L5. The shear force was the joint reaction force perpendicular to the spine at the L4/L5 joint. Peak compressive and shear force at the lumbar spine of the rowers were 2,694 +/- 609 (N) and 660 +/- 117 (N), respectively. Peak compressive force at the LS relative to body weight was 4.6 times body weight. The literature would suggest that forces of this magnitude, generated at the LS during maximal rowing, may be contributing to the site specific higher LS BMD found in the rowers.

Adolescent↗
PubMed2000

Factors related to outcome of salvage therapy for isolated cervical recurrence of squamous cell carcinoma in the previously treated neck: a multi-institutional study.

OBJECTIVE: The goal was to identify factors associated with the outcome of salvage therapy for patients with isolated cervical recurrences of squamous cell carcinoma in the previously treated neck (ICR-PTN). STUDY DESIGN AND SETTINGS: A tumor registry search for ICR-PTN patients was performed at 7 participating institutions, and the charts were reviewed. Kaplan-Meier plots for survival and time until re-recurrence were used to evaluate the significance of associated variables. RESULTS: Median survival and time until re-recurrence were both 11 months. Survival was better in patients with the following characteristics: nonsurgical initial neck treatment, negative initial disease resection margins, no history of prior recurrence, ipsilateral location of the ICR-PTN relative to the primary, and use of surgical salvage. CONCLUSIONS: By pooling the experience of 7 US tertiary care medical centers, we have identified 5 factors that are associated with outcome of salvage therapy for ICR-PTN. SIGNIFICANCE: Consideration of these factors, as well as the reviewed literature, should facilitate patient selection for salvage protocols.

Adult↗
PubMed2000

Custom retainer for the Blom-Singer adjustable tracheostoma valve.

This article presents a procedure that allows the laryngectomy patient to be fitted with a well-sealed custom device. The custom device provides near-normal speech during a variety of activities. The custom retainer for the Blom-Singer adjustable tracheostoma valve can be fabricated with medical grade silicone using routine prosthodontic techniques.

Biocompatible Materials↗
PubMed2000

Adaptation of a relocatable head frame for stereotactic radiotherapy.

An important role of the maxillofacial prosthodontist is to support the radiotherapist in the administration of therapy. For example, a device can be made that properly and repeatedly positions the patient for each radiation treatment. This article describes a procedure for adapting a relocatable head frame to be used during stereotactic radiotherapy, a treatment modality for malignant intracranial tumors.

Dose Fractionation, Radiation↗
PubMed2000

Interleukin-10 release and monocyte human leukocyte antigen-DR expression during femoral nailing.

This study determined the effect of femoral nailing on the expression of monocyte Class II antigens and interleukin-10 release and sought to differentiate any differences in the release of these elements of immune reactivity in patients undergoing reamed and unreamed nailing. Thirty-two patients presenting with an acute femoral fracture were studied. In 15 patients, the femoral fracture was stabilized with a reamed technique and in 17 patients with an unreamed technique. Venous blood samples were taken at presentation, at anesthetic induction, immediately after nail insertion, and subsequently at 1, 4, and 24 hours and at 3, 5, and 7 days after surgery. Serum interleukin-10 was measured by an enzyme-linked immunosorbent assay, and monocyte human leukocyte antigen-DR expression was quantified by flow cytometry. Serum interleukin-10 release and human leukocyte antigen-DR expression on monocytes showed a clear response to the nailing procedure. The group of patients undergoing a reamed femoral nailing procedure showed significantly higher interleukin-10 release and a significant depression in the expression of human leukocyte antigen-DR on monocytes compared with those whose nail had been inserted unreamed. One patient in the reamed femoral nailing group died of adult respiratory distress syndrome 3 days after injury. Reamed intramedullary nailing appears to be associated with greater impairment of immune reactivity than is the unreamed nailing technique.

Adolescent↗
PubMed2000

Birthweights and growth of infants in five Aboriginal communities.

OBJECTIVES: To improve, by culturally appropriate means, birthweights and growth of children up to three years of age over 14 months in five Aboriginal communities in north-western Australia. METHODS: Frequent individual nutritional assessment of infants and children with counselling of mothers and carers and of pregnant women and the introduction of the Aboriginal-controlled Strong Women, Strong Babies, Strong Culture maternal support program. Outcomes compared with those in the same communities for the five years preceding intervention. RESULTS: By international standards, pre-intervention birthweights of full-term infants (37-42 weeks) were only moderately depressed and recovered to exceed standard weight-for-age within two weeks of birth. Growth of full-term infants slowed abruptly after six months. Prevalence and duration of breastfeeding were very high. Prevailing low average birthweight was chiefly attributable to a prevalence of pre-term birth approaching 20%. Intervention was not accompanied by any change in full-term birth weight but was associated with increased weight gain after six months. From 12 to 36 months growth rose by 30 g per month (p = 0.001). Average birthweights of pre-term infants were < 2,500 g and average weight-for-age did not improve during intervention. CONCLUSIONS: Both low birthweight and a disproportionate part of intransigent failure to grow by Aboriginal infants were associated with pre-term birth. Depressed average growth of full-term infants appeared to respond to nutritional counselling accompanied by a community support program. IMPLICATIONS: Investigation of the causes of the exceptionally high rate of Aboriginal pre-term birth in the region is urgently required.

Birth Weight↗
PubMed2000

The auricular impression: an alternate technique.

Several conditions necessitate surgical or prosthetic ear reconstruction. If an auricular prosthesis is planned, accurate impressions of both the affected and unaffected ears are essential. This article describes a technique that uses a wax-customized, rigid impression tray and irreversible hydrocolloid to minimize distortion during the procedure.

Colloids↗
PubMed2000

Mapping and characterization of the N-terminal I domain of human immunodeficiency virus type 1 Pr55(Gag).

Human immunodeficiency virus (HIV) type 1 particles assemble at the plasma membrane of cells in a manner similar to that of the type C oncoretroviruses. The Pr55(Gag) molecule directs the assembly process and is sufficient for particle assembly in the absence of all other viral gene products. The I domain is an assembly domain that has been previously localized to the nucleocapsid (NC) region of Gag. In this study we utilized a series of Gag-green fluorescent protein (GFP) fusion proteins to precisely identify sequences that constitute the N-terminal I domain of Pr55(Gag). The minimal sequence required for the I domain was localized to the extreme N terminus of NC. Two basic residues (arginine 380 and arginine 384) within the initial seven residues of NC were found to be critical for the function of the N-terminal I domain. The presence of positive charge alone in these two positions, however, was not sufficient to mediate the formation of dense Gag particles. The I domain was required for the formation of detergent-resistant complexes of Gag protein, and confocal microscopy demonstrated that the I domain was also required for the formation of punctate foci of Gag proteins at the plasma membrane. Electron microscopic analysis of cells expressing Gag-GFP fusion constructs with an intact I domain revealed numerous retrovirus-like particles (RVLPs) budding from the plasma membrane, while I domain-deficient constructs failed to generate visible RVLPs. These results provide evidence that Gag-Gag interactions mediated by the I domain play a central role in the assembly of HIV particles.

Amino Acid Sequence↗
PubMed2000

Guanine nucleotide transport by atractyloside-sensitive and -insensitive carriers in isolated heart mitochondria.

In previous work (McKee EE, Bentley AT, Smith RM Jr, and Ciaccio CE, Biochem Biophys Res Commun 257: 466-472, 1999), the transport of guanine nucleotides into the matrix of intact isolated heart mitochondria was demonstrated. In this study, the time course and mechanisms of guanine nucleotide transport are characterized. Two distinct mechanisms of transport were found to be capable of moving guanine nucleotides across the inner membrane. The first carrier was saturable, displayed temperature dependence, preferred GDP to GTP, and did not transport GMP or IMP. When incubated in the absence of exogenous ATP, this carrier had a V(max) of 946 +/- 53 pmol. mg(-1). min(-1) with a K(m) of 2.9 +/- 0.3 mM for GDP. However, transport of GTP and GDP on this carrier was completely inhibited by physiological concentrations of ATP, suggesting that this carrier was not involved with guanine nucleotide transport in vivo. Because transport on this carrier was also inhibited by atractyloside, this carrier was consistent with the well-characterized ATP/ADP translocase. The second mechanism of guanine nucleotide uptake was insensitive to atractyloside, displayed temperature dependence, and was capable of transporting GMP, GDP, and GTP at approximately equal rates but did not transport IMP, guanine, or guanosine. GTP transport via this mechanism was slow, with a V(max) of 48.7 +/- 1.4 pmol. mg(-1). min(-1) and a K(m) = 4.4 +/- 0.4 mM. However, because the requirement for guanine nucleotide transport is low in nondividing tissues such as the heart, this transport process is nevertheless sufficient to account for the matrix uptake of guanine nucleotides and may represent the physiological mechanism of transport.

Adenosine Triphosphate↗
PubMed2000

Effect of recombinant SP-C surfactant in a porcine lavage model of acute lung injury.

Synthetic surfactants allow examination of the effects of specific components of natural surfactant. To determine whether surfactant containing apoprotein C, dipalmitoyl-phosphatidylcholine, phosphatidylglycerol, and palmitic acid restores gas-exchanging function in acute lung injury (ALI), we administered such surfactant (in doses of 50 or 100 mg/kg and in volumes from 1 to 6 ml/kg) or phospholipid (PL) alone, by intratracheal instillation, to pigs with ALI induced by massive saline lavage. Animals ventilated with 100% O(2) and receiving 1, 2, 4, or 6 ml/kg of 50 mg/kg recombinant surfactant apoprotein C (rSP-C) surfactant or 2 ml/kg of 50 mg/kg PL (control) had mean arterial PO(2) values, 4 h after treatment, of 230, 332, 130, 142, or 86 Torr, respectively. Animals receiving 1, 2, or 4 ml/kg of 100 mg/kg rSP-C surfactant or 2 ml/kg of 100 mg/kg PL (control) had mean arterial PO(2) values of 197, 214, 148, or 88 Torr, respectively. Surfactant PL distribution was homogeneous. Hyaline membrane formation was reduced in treated animals. Thus, in this model of ALI, rSP-C with PL has the capacity to improve gas exchange and possibly modify lung injury.

Animals↗
PubMed2000

Is Echo a complex adaptive system?

We evaluate whether John Holland's Echo model exemplifies his theory of complex adaptive systems. After reviewing Holland's theory of complex adaptive systems and describing his Escho model, we describe and explain the characteristic evolutionary behavior observed in a series of Echo model runs. We conclude that Echo lacks the diversity of hierarchically organized aggregates that typify complex adaptive systems, and we explore possible explanations for this failure.

Algorithms↗
PubMed2000

Nonunion of the femoral diaphysis. The influence of reaming and non-steroidal anti-inflammatory drugs.

We assessed factors which may affect union in 32 patients with nonunion of a fracture of the diaphysis of the femur and 67 comparable patients whose fracture had united. These included gender, age, smoking habit, the use of non-steroidal anti-inflammatory drugs (NSAIDs) the type of fracture (AO classification), soft-tissue injury (open or closed), the type of nail, the mode of locking, reaming nu non-reaming, infection, failure of the implant, distraction at the fracture site, and the time to full weight-bearing. Patients with severe head injuries were excluded. Both groups were comparable with regard to gender, Injury Severity Score and soft-tissue injury. There was no relationship between the rate of union and the type of implant, mode of locking, reaming, distraction or smoking. There were fewer cases of nonunion in more comminuted fractures (type C) and in patients who were able to bear weight early. There was a marked association between nonunion and the use of NSAIDs after injury (p = 0.000001) and delayed healing was noted in patients who took NSAIDs and whose fractures had united.

Adolescent↗