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Biomedical subjects

C E Smith

Publications and source records attributed to C E Smith.

At least 55 records · Page 3Linked to original sources
PubMed1999

Rocuronium versus vecuronium during fentanyl induction in patients undergoing coronary artery surgery.

OBJECTIVE: To evaluate the neuromuscular, ventilatory, and cardiovascular effects of rocuronium and vecuronium. DESIGN: Randomized, prospective, blinded study. SETTING: Tertiary care teaching center, single institution. PARTICIPANTS: Patients undergoing elective coronary artery bypass graft procedure. INTERVENTIONS: Patients received rocuronium, 1.0 mg/kg (n = 17), or vecuronium, 0.15 mg/kg (n = 15), during fentanyl induction of anesthesia. MEASUREMENTS AND MAIN RESULTS: Measures consisted of time to visual loss of orbicularis oculi twitches in response to facial nerve stimulation, ease of mask ventilation, hemodynamics, need for vasoactive drugs, and tracheal intubating conditions. Median time to twitch loss was faster (p < 0.05) after rocuronium (60 s) than after vecuronium (>84 s). Within 45 seconds, only 3 of 17 patients in the rocuronium group had moderate-to-severe difficulty with mask ventilation versus 12 of 15 patients in the vecuronium group (p < 0.05). Tracheal intubating conditions were excellent in all patients after rocuronium. In the vecuronium group, intubating conditions were excellent in 46%, good in 27%, and poor in 27% (p < 0.05 vrocuronium). Patients receiving vecuronium were more likely to require ephedrine and phenylephrine for hypotension (10/15 patients v 5/17 patients for rocuronium, p < 0.05). There were no clinically important differences in hemodynamic variables, oxygen metabolism, or myocardial ischemia between groups. CONCLUSION: During narcotic induction of anesthesia, rocuronium was associated with lower requirement for vasopressors, faster onset of neuromuscular blockade, and better conditions for mask ventilation and tracheal intubation compared with vecuronium.

Androstanols↗
PubMed1999

Ovarian prostatic tissue originating from hilar mesonephric rests.

Nonteratoid prostatic differentiation in the ovary of a parous, phenotypically normal, postmenopausal woman is reported for the first time, to the authors' best knowledge. The patient was a 70-year-old woman who underwent bilateral oophorectomy following pelvic ultrasound examination that showed enlargement of the left ovary and an equivocally abnormal Doppler signal. Histologic examination showed a normal right ovary and a left ovary enlarged by hilar cystic dilatation related to a proliferation of mesonephric remnants exhibiting various types of epithelial metaplasia, including hyperplastic rete and epididymal-like and clear cell epithelia resembling the lining of the seminal excretory system. These were closely associated, occasionally even merging, with a discrete area of prostatic acinar and smooth muscle differentiation in the cyst wall. The identity of the prostatic tissue was confirmed immunohistochemically by positive staining with prostate specific antigen and prostatic acid phosphatase. The lesion was associated with an incidental, microscopic hemangioma. A developmental malformative origin of this abnormality cannot satisfactorily be explained by current embryologic concepts. A hypothesis of a metaplastic induction of prostatic tissue by mesonephric remnants is proposed, since complex metaplastic changes coexisted within the cysts and even showed epithelial transitions with the prostatic acini.

Acid Phosphatase↗
PubMed1999

The failure of negative pressure rewarming (Thermostat) to accelerate recovery from mild hypothermia in postoperative surgical patients.

UNLABELLED: The Thermostat device (Aquarius Medical Corp., Phoenix, AZ) is used in a new technique to accelerate recovery from hypothermia by mechanically distending blood vessels in the hand, thereby increasing transfer of exogenous heat to the body core. We evaluated the use of the Thermostat device in patients with mild postoperative hypothermia (< 36 degrees C). We studied adult patients undergoing elective surgery, general anesthesia, and neuromuscular blockade. Patients with an initial postoperative tympanic membrane temperature < 36 degrees C were randomized into two groups: 1) Thermostat, which consisted of a hypothermia warming mitt/seal and thermal exchange chamber for 60 min, and 2) conventional treatment, which consisted of warm blankets and/or radiant heat. Of the 191 patients enrolled, 60 (31%) developed hypothermia and were randomized to receive the Thermostat (n = 30) or conventional methods (n = 30). Fourteen patients in the Thermostat group and 17 patients in the conventional group rewarmed to 36 degrees C before discharge from the recovery room (P is not significant). There were no differences in vital signs, rewarming time, time to discharge from the recovery room, or postoperative temperature between groups. We conclude that patients with mild postoperative hypothermia rewarmed in a similar fashion, regardless of whether the Thermostat or conventional methods were used. IMPLICATIONS: We found that a commercially available negative pressure rewarming device (Thermostat; Aquarius Medical Corp., Phoenix, AZ) was not effective in accelerating rewarming in postoperative hypothermic surgical patients after general anesthesia.

Adult↗
PubMed1999

Evaluation of tracheal intubation difficulty in patients with cervical spine immobilization: fiberoptic (WuScope) versus conventional laryngoscopy.

BACKGROUND: The WuScope is a rigid, fiberoptic laryngoscope designed to facilitate tracheal intubation without the need for head extension. The study evaluated the WuScope in anesthetized patients with neck immobilization. METHODS: Patients were randomized to one of two groups: those receiving fiberoptic laryngoscopy (WuScope, n = 43) and those receiving conventional laryngoscopy (Macintosh blade, n = 44). Manual in-line stablization of the cervical spine was done during intubation. Seven parameters of intubation difficulty were measured (providing an intubation difficulty scale score): number of operators, number of attempts, number of techniques, Cormack view, lifting force, laryngeal pressure, and vocal cord position. RESULTS: Successful intubation occurred in 95% of patients in the fiberoptic group and in 93% of patients in the conventional group. There were no differences in number of attempts. In the fiberoptic group, 79% of patients had an intubation difficulty scale score of 0, representing an ideal intubation: that is, one performed by the first operator on the first attempt using the first technique with full glottic visualization. Only 18% of patients in the conventional group had an intubation difficulty scale score of 0 (P < 0.001). More patients had Cormack grade 3 or 4 views with conventional than with fiberoptic laryngoscopy (39 vs. 2%, P < 0.001). Intubation times in patients with one attempt were slightly longer in the fiberoptic (median, 25th-75th percentiles: 30, 23-53 s) compared with the conventional group (24, 17-30 s, P < 0.05). Corresponding times in patients requiring > one attempt were 155 (range, 112-201) s and 141 (range, 95-186) s in the fiberoptic and conventional groups, respectively (P value not significant). CONCLUSIONS: Compared with conventional laryngoscopy, tracheal intubation using the fiberoptic laryngoscope was associated with lower intubation difficulty scale scores and better views of the laryngeal aperture in patients with cervical imnmobilization. However, there were no differences in success rates or number of intubation attempts.

Adult↗
PubMed1999

Pvlea-18, a member of a new late-embryogenesis-abundant protein family that accumulates during water stress and in the growing regions of well-irrigated bean seedlings.

Pvlea-18 is a novel stress gene whose transcript is present in the dry embryo and the endosperm from bean (Phaseolus vulgaris) seeds. It accumulates in vegetative tissues in response to water deficit and abscisic acid application (J.M. Colmenero-Flores, F. Campos, A. Garciarrubio, A.A. Covarrubias [1997] Plant Mol Biol 35: 393-405). We show that the Pvlea-18 gene encodes a 14-kD protein that accumulates during late embryogenesis. Related proteins have been detected in both monocots and dicots, indicating that PvLEA-18 is a member of a new family of LEA (Late Embryogenesis Abundant) proteins. We also show that the PvLEA-18 transcript and protein accumulate not only in different organs of the bean seedlings during water stress but also in well-irrigated seedlings. This accumulation occurs in seedling regions with more negative values of water and osmotic potentials, such as the growing region of the hypocotyl. This phenomenon has not previously been described for LEA proteins. Immunohistochemical localization showed that the PvLEA-18 protein is present in the nucleus and cytoplasm of all cell types, with a higher accumulation in the epidermis and vascular cylinder tissues, particularly in protoxylem cells and root meristematic tissues. We found a similar localization but a higher abundance in water-stressed seedlings.

Amino Acid Sequence↗
PubMed1999

Selective but nonspecific immunolabeling of enamel protein-associated compartments by a monoclonal antibody against vimentin.

Vimentin, an intermediate filament component, has been identified in many mesenchymal cells by a variety of LM and EM immunolabeling techniques. In our study, several tissue-processing conditions and monoclonal and polyclonal antibodies against vimentin were screened for immunostaining of rat incisor odontoblasts. Using postembedding colloidal gold immunocytochemistry, we were unable to detect any convincing vimentin antigenicity in these cells, but one of the monoclonal antibodies (V9-S) unexpectedly resulted in intense labeling over intra- and extracellular compartments that normally are strongly immunoreactive with anti-amelogenin antibodies. Blocking experiments showed that V9-S binding was competed by anti-amelogenin antibody. Immunoblots indicated that enamel proteins reacted with this anti-vimentin antibody after fixation with glutaraldehyde. These data suggest that the observed immunoreaction is directed against an epitope apparently created by crosslinking of enamel proteins during fixation. Although the labeling cannot be considered specific, it is nevertheless selective because it is very precisely localized over compartments containing enamel proteins and shows no binding to other calcified dental tissues, including dentin and bone. The V9-S antibody can therefore be used as a reliable probe to identify the presence and distribution of amelogenins in fixed tissues. (J Histochem Cytochem 47:1237-1245, 1999)

Ameloblasts↗
PubMed1998

Preventing hypothermia: convective and intravenous fluid warming versus convective warming alone.

STUDY OBJECTIVE: To test the hypothesis that warming intravenous (i.v.) fluids in conjunction with convective warming results in less intraoperative hypothermia (core temperature < 36.0 degrees C) than that seen with convective warming alone. DESIGN: Prospective, randomized study. SETTING: University affiliated tertiary care teaching hospital. PATIENTS: 61 ASA physical status, I, II, and III adults undergoing major surgery and general anesthesia with isoflurane. INTERVENTIONS: All patients received convective warming. Group 1 patients received warmed fluids (setpoint 42 degrees C). Group 2 patients received room temperature fluids (approximately 21 degrees C). MEASUREMENTS AND MAIN RESULTS: Lowest and final intraoperative distal esophageal temperatures were higher (p < 0.05) in Group 1 (mean +/- SEM: 35.8 +/- 0.1 degrees C and 36.6 +/- 0.1 degrees C) versus Group 2 (35.4 +/- 0.1 degrees C and 36.1 +/- 0.1 degrees C, respectively). Compared with Group 1, more Group 2 patients were hypothermic at the end of anesthesia (10 of 26 patients, or 38.5% vs. 4 of 30 patients, or 13%; p < 0.05). After 30 minutes in the recovery room, there were no differences in temperature between groups (36.7 +/- 0.1 degrees C and 36.5 +/- 0.1 degrees C in Groups 1 and 2, respectively). Intraoperative cessation of convective warming because of core temperature greater than 37 degrees C was required in 33% of Group 1 patients (vs. 11.5% in Group 2; p = 0.052). CONCLUSIONS: The combination of convective and fluid warming was associated with a decreased likelihood of patients leaving the operating room hypothermic. However, average final temperatures were greater than 36 degrees C in both groups, and intergroup differences were small. Care must be taken to avoid overheating the patient when both warming modalities are employed together.

Adult↗
PubMed1998

The Brock procedure (closed infundibular resection) for Fallot's tetralogy: 43 years later.

Innovative cardiac surgery ('blind' or indirect infundibular resection) for tetralogy of Fallot on a child of 4 years was followed by survival for 43 years without further surgery. The patient remained well until about one year before death, when he developed clinical features of progressive biventricular failure associated with pulmonary hypertension and incompetence of the pulmonary and tricuspid valves. Postmortem examination showed severe damage to one of the leaflets of the pulmonary valve, interpreted as due to inadvertent avulsion during the original surgical procedure. A large ventricular septal defect was present, but there was no residual subpulmonary infundibular obstruction.

Autopsy↗
PubMed1998

Biological monitoring standards for industrial toluene exposure recommended for South Africa.

Coal combustion is used in many industrial processes in South Africa. The exposure of workers and the absence of international biological monitoring standards for toluene created a problem. A cross-sectional study on 100 workers indicated that the biological threshold for ortho-cresol:creatinine ratio reference value of < 1 mg/g could presently be used as a reference for non-industrial human exposure while the < 2 mg/g rate is for worker exposure in an industrial environment at a coal combustion plant.

Air Pollutants, Occupational↗
PubMed1998

Warming intravenous fluids reduces perioperative hypothermia in women undergoing ambulatory gynecological surgery.

UNLABELLED: We evaluated whether warming i.v. fluids resulted in less hypothermia (core temperature < 35.5 degrees C) compared with room-temperature fluids. Thirty-eight adult outpatients undergoing elective gynecological surgery of > 30 min were randomized to two groups: fluid warming at 42 degrees C or control (room temperature fluids at approximately 21 degrees C). All patients received general anesthesia with isoflurane, tracheal intubation, standard operating room blankets and surgical drapes, and passive humidification of inspired gases. Tympanic membrane (core) temperatures were measured at baseline and at 15-min intervals after induction. The incidence of shivering and postoperative requirement for meperidine and/or radiant heat were evaluated. Core temperatures were lower in the control compared with the warm fluid group at the end of surgery (35.6 +/- 0.1 degrees C vs 36.2 +/- 0.1 degrees C; P < 0.05). More patients had final core temperature < 35.5 degrees C in the control compared with the warm fluid group (35% vs 0%; P < 0.05). There were no differences in time to discharge from the postanesthesia care unit or the incidence of shivering between the groups. We conclude that fluid warming, in conjunction with standard heat conservation measures, was effective in maintaining normothermia during outpatient gynecological surgery; however, there was no improvement in patient outcome. IMPLICATIONS: Women who received i.v. fluid at body temperature had significantly higher core temperatures during and after outpatient gynecological surgery compared with women who received i.v. fluids at the temperature of the operating room.

Adult↗
PubMed1998

Comparative immunochemical analyses of the developmental expression and distribution of ameloblastin and amelogenin in rat incisors.

Mineralized tissues are unique in using proteins to attract and organize calcium and phosphate ions into a structured mineral phase. A precise knowledge of the expression and extracellular distribution of matrix proteins is therefore very important in understanding their function. The purpose of this investigation was to obtain comparative information on the expression, intracellular and extracellular distribution, and dynamics of proteins representative of the two main classes of enamel matrix proteins. Amelogenins were visualized using an antibody and an mRNA probe prepared against the major alternatively spliced isoform in rodents, and nonamelogenins by antibodies and mRNA probes specific to one enamel protein referred to by three names: ameloblastin, amelin, and sheathlin. Qualitative and quantitative immunocytochemistry, in combination with immunoblotting and in situ hybridization, indicated a correlation between mRNA signal and sites of protein secretion for amelogenin, but not for ameloblastin, during the early presecretory and mid- to late maturation stages, during which mRNA signals were detected but no proteins appeared to be secreted. Extracellular amelogenin immunoreactivity was generally weak near secretory surfaces, increasing over a distance of about 1.25 microm to reach a level slightly above an amount expected if the protein were being deposited evenly across the enamel layer. Immunolabeling for ameloblastin showed an inverse pattern, with relatively more gold particles near secretory surfaces and much fewer deeper into the enamel layer. Administration of brefeldin A and cycloheximide to stop protein secretion revealed that the immunoblotting pattern of amelogenin was relatively stable, whereas ameloblastin broke down rapidly into lower molecular weight fragments. The distance from the cell surface at which immunolabeling for amelogenin stabilized generally corresponded to the point at which that for ameloblastin started to show a net reduction. These data suggest a correlation between the distribution of amelogenin and ameloblastin and that intact ameloblastin has a transient role in promoting/stabilizing crystal elongation. (J Histochem Cytochem 46:911-934, 1998)

Amelogenin↗
PubMed1998

Cellular and chemical events during enamel maturation.

This review focuses on the process of enamel maturation, a series of events associated with slow, progressive growth in the width and thickness of apatitic crystals. This developmental step causes gradual physical hardening and transformation of soft, newly formed enamel into one of the most durable mineralized tissues produced biologically. Enamel is the secretory product of specialized epithelial cells, the ameloblasts, which make this covering on the crowns of teeth in two steps. First, they roughly "map out" the location and limits (overall thickness) of the entire extracellular layer as a protein-rich, acellular, and avascular matrix filled with thin, ribbon-like crystals of carbonated hydroxyapatite. These initial crystals are organized spatially into rod and interrod territories as they form, and rod crystals are lengthened by Tomes' processes in tandem with appositional movement of ameloblasts away from the dentin surface. Once the full thickness of enamel has been formed, ameloblasts initiate a series of repetitive morphological changes at the enamel surface in which tight junctions and deep membrane infoldings periodically appear (ruffle-ended), then disappear for short intervals (smooth-ended), from the apical ends of the cells. As this happens, the enamel covered by these cells changes rhythmically in net pH from mildly acidic (ruffle-ended) to near-physiologic (smooth-ended) as mineral crystals slowly expand into the "spaces" (volume) formerly occupied by matrix proteins and water. Matrix proteins are processed and degraded by proteinases throughout amelogenesis, but they undergo more rapid destruction once ameloblast modulation begins. Ruffle-ended ameloblasts appear to function primarily as a regulatory and transport epithelium for controlling the movement of calcium and other ions such as bicarbonate into enamel to maintain buffering capacity and driving forces optimized for surface crystal growth. The reason ruffle-ended ameloblasts become smooth-ended periodically is unknown, although this event seems to be crucial for sustaining long-term crystal growth.

Ameloblasts↗
PubMed1998

Isolation of amelogenin-positive ameloblasts from rat mandibular incisor enamel organs by flow cytometry and fluorescence activated cell sorting.

The purpose of this study was to use amelogenin as a marker to examine the feasibility of isolating ameloblasts from enamel organ cell populations by fluorescence activated cell sorting. After treating dissected rat enamel organs with proteolytic enzymes to loosen cell attachments and labial connective tissues, dissociated cell suspensions were fixed, then immunostained with rabbit anti-rM179 recombinant amelogenin antibody and FITC-conjugated goat anti-rabbit Ig G antibody. Flow cytometry indicated that about 70% of the total cell sample and virtually all the larger cells therein were amelogenin-positive. Fluorescence activated cell sorting yielded a sample of amelogenin-positive cells at 97% purity. Immunofluorescence microscopy indicated that these isolated amelogenin-positive cells varied widely in size and morphology. This was attributed to loss of intercellular support for ameloblasts once they were dissociated from each other, and to some fragmentation caused when the cells were initially physically removed from the teeth. The results demonstrate that viable ameloblast cell fractions, especially representing cells at the secretory stage, can be purified from enzymic digests of rat enamel organ by sorting on the basis of cell size alone. From these fractions, subpopulations of ameloblasts may be identified when differentiation specific cell surface markers become available.

Ameloblasts↗
PubMed1998

Degradative changes in whole enamel homogenates incubated in vitro in the presence of low calcium ion concentrations.

The purpose of this study was to investigate overall degradative changes occurring to enamel matrix proteins in small, freeze-dried pieces of rat incisor enamel homogenized and incubated directly for 0-48 hours in a synthetic enamel fluid solution (165 mM total ionic strength with 0.153 mM calcium chloride) versus other samples homogenized and incubated for the same time intervals in distilled water. The results indicated that many alterations in the apparent molecular weights of enamel matrix proteins took place under both conditions although the rates for many degradative changes over a 48 hour period were often slower in distilled water than in synthetic enamel fluid. Freeze-dried enamel samples homogenized and incubated in 165 mM Tris-HCl buffer at pH 8.0 showed changes comparable to those seen with distilled water. This suggested that differences observed between samples incubated in enamel fluid versus distilled water were unrelated to pH or ionic strength of the solutions and may be the result of a requirement by some enamel proteinases for small amounts of free calcium ions in incubation media. Of interest were findings that some enamel matrix proteins, especially those in strips taken from the first half of the secretory stage of amelogenesis, were degraded much faster in distilled water than in synthetic enamel fluid. The reasons for this effect are unclear although, in this case, calcium ions could be inhibitory to hydrolysis of certain matrix proteins by the enamel proteinases.

Animals↗
PubMed1998

A survey of computer technology utilization in school nursing.

Computer technology offers a solution to problems associated with paper-based health records. The purposes of this descriptive study were to identify the utilization of and support for computer technology in managing student health data and documenting school nurse practice. Findings from a sample of school nurse respondents to the Computer Technology and School Nursing Survey (CTSNS) indicated that of the 65% that used computers, nearly two-third used computers for three years or less. Although there was an increase in computer use when compared with an earlier study, more training, financial support, and research are needed for optimal utilization of computer technology.

Attitude of Health Personnel↗
PubMed1997

Protease-resistant form of insulin-like growth factor-binding protein 5 is an inhibitor of insulin-like growth factor-I actions on porcine smooth muscle cells in culture.

IGFs are pleiotrophic mitogens for porcine smooth muscle cells (pSMC) in culture. The effects of IGFs on cells are modulated by various insulin-like growth factor-binding proteins (IGFBP). IGFBP-5 is synthesized by pSMC and binds to the extracellular matrix. However, IGFBP-5 is also secreted into conditioned medium of cultured cells and is cleaved into fragments by a concomitantly produced protease. These fragments have reduced affinity for the IGFs and cleavage makes it difficult to assess the role of intact IGFBP-5. To study the consequence of accumulation of intact IGFBP-5 in medium, we determined the cleavage site in IGFBP-5 and prepared a protease resistant mutant. Amino acid sequencing of purified IGFBP-5 fragments suggested Arg138-Arg139 as the primary cleavage site. Arg138-Arg139-->Asn138-Asn139 mutations were introduced to create protease-resistant IGFBP-5, which has the same affinity for IGF-I as the native protein. This mutant IGFBP-5 remained intact even after 24 h of incubation and it inhibited several IGF-I actions when added to pSMC culture medium. The mutant IGFBP-5 (500 ng/ml) decreased IGF-I stimulated cellular DNA synthesis by 84%, protein synthesis by 77%, and it inhibited IGF-I stimulated migration of pSMC by 77%. It also inhibited IGF-I stimulation of IRS-1 phosphorylation. In contrast, the same amount of native IGFBP-5 did not inhibit IGF-I actions. The significance of inhibitory effects of the protease resistant IGFBP-5 was further demonstrated in pSMC transfected with mutant or native IGFBP-5 cDNAs. The mutant IGFBP-5 accumulated in culture medium of transfected cells, while native IGFBP-5 was degraded into fragments, PSMC overexpressing the mutant IGFBP-5 also responded poorly to IGF-I compared with mock transfected cells. IGF-I (5 ng/ml) increased [35S]methionine incorporation into control cells by 36% above the basal level, but it did not significantly change (4%) in pSMC cultures that were producing the mutant IGFBP-5. In conclusion, the accumulation of protease-resistant IGFBP-5 in the medium was inhibitory to IGF-I actions on pSMC. This suggests that proteolysis can prevent IGFBP-5 from acting as an inhibitor of IGF-I-stimulated effects and that it serves as an important mechanism for regulating cellular responsiveness to IGF-I.

Amino Acid Sequence↗