Biomedical subjects

R Lee

Publications and source records attributed to R Lee.

At least 19 recordsLinked to original sources

PubMed1992

Cloning of cDNAs encoding human caldesmons.

Caldesmon (CDM) is a potential actomyosin regulatory protein found in smooth muscle and nonmuscle cells. Domain mapping and physical studies suggest that CDM is an elongated molecule with an N-terminal myosin/calmodulin-binding domain and a C-terminal tropomyosin/actin/calmodulin-binding domain separated by a 40-nm-long central helix. An 1100-nucleotide (nt) cDNA probe encoding the C terminus of avian caldesmon (aCDM) was used to screen a human aorta library and clone smooth-muscle and non-muscle CDM-encoding cDNAs (CDM). The human (h) smooth-muscle hCDM is 3050-3630 nt long, having variation in length in the 3'-untranslated region. The predicted hCDM protein has a high degree of identity, greater than 90%, to aCDM in the N- and C-terminal-binding domains. The central helical domain is more variable, but retains characteristic repeated peptides and an 'i, i + 4' acidic/basic amino acid (aa) motif found in aCDM which can form intra-helical salt bridges to stabilize the central helix. The predicted smooth-muscle protein is 793 aa long (93,262 Da) with a calculated pI of 5.75. As is the case for the chicken, nonmuscle hCDM is missing the central helical domain, 256 aa overall. Our nonmuscle clone is not full length, but the C-terminal end is identical to the smooth-muscle form. If the N-terminal domain is identical, as it is in the chicken, the predicted protein is 537 aa (62,558 Da). Examination of the 'junctions' at either end of the deleted central domain gives a clear indication of the splice sites and suggests that the nonmuscle form is generated by exon skipping.(ABSTRACT TRUNCATED AT 250 WORDS)

Amino Acid Sequence↗

PubMed1992

Relationship of cross-brain oxygen content difference, cerebral blood flow, and metabolic rate to neurologic outcome after near-drowning.

We evaluated the relationship of global cerebral blood flow, cross-brain oxygen content difference, cerebral metabolic rate for oxygen, intracranial pressure, and cerebral perfusion pressure to functional neurologic outcome in 12 comatose children on 2 consecutive days after near-drowning. Five children survived with functional neurologic outcome; five died and two survived with severe neurologic damage. Children who survived with functional neurologic outcome had a significantly higher cross-brain oxygen content difference (7.89 +/- 2.62 vs 3.91 +/- 1.59 ml/dl; p = 0.028) at 24 hours and a higher cerebral metabolic rate for oxygen 48 hours after admission (3.19 +/- 2.86 vs 0.96 +/- 0.45 ml/100 gm per minute; p = 0.030) compared with those who died or survived in a damaged state. There were no significant differences in global cerebral blood flow, intracranial pressure, and cerebral perfusion pressure between groups at either 24 or 48 hours. Our preliminary data suggest that a higher cross-brain content difference value is an important early variable associated with functional neurologic recovery after near-drowning. However, a single cross-brain oxygen content difference value must be interpreted with caution because considerable variability may occur among patient groups.

Adolescent↗

PubMed1992

Phase II trial of chlorozotocin and fluorouracil in islet cell carcinoma: a Southwest Oncology Group study.

PURPOSE: A phase II trial that used fluorouracil (5-FU) and chlorozotocin (CTZ) was performed in patients with metastatic islet cell carcinoma to determine the response rate and toxicity. PATIENTS AND METHODS: Patients received four cycles of induction chemotherapy. Good-risk patients received 5-FU 800 mg/m2/d days 1 to 4 as a continuous intravenous (IV) infusion (CIV) and CTZ 175 mg/m2 IV on day 1. Poor-risk patients (previous radiation to > or = 25% bone marrow-bearing areas; serum bilirubin > or = 5 mg/dL; creatinine > 1.0 mg/dL) received 5-FU 600 mg/m2/d and CTZ 75 mg/m2 in a similar manner. In responding or stable patients, reduced doses of 5-FU and CTZ were continued as maintenance therapy (maximum, 18 months). RESULTS: Forty-seven of 51 patients were eligible, and 44 received chemotherapy. Fourteen of 44 patients had partial responses, with 13 of 36 (36%; 95% confidence interval [CI], 21.0% to 54.0%) good-risk patients and one of eight (12%; 95% CI, 0.3 to 52.6%) poor-risk patients responding. Median survival of all patients was 25 months, and the median response duration was 11 months. Side effects were moderate to severe and included myelosuppression and gastrointestinal toxicity. Thirteen patients developed renal toxicity, which was severe or life-threatening in five. This seemed to be related to the administration of cumulative doses of CTZ > or = 1,500 mg. CONCLUSION: These results demonstrate that the combination of 5-FU and CTZ has activity in islet cell carcinoma, but the occurrence of renal toxicity secondary to CTZ may limit the use of this agent.

Adenoma, Islet Cell↗

PubMed1992

Implant economics.

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Costs and Cost Analysis↗

PubMed1992

Evaluation of ground ambulance, rotor-wing, and fixed-wing aircraft services.

It is hoped that this article has offered insightful suggestions and criteria in choosing the most appropriate method to transport patients. Ground ambulances, rotor-wing, and fixed-wing aircraft each have advantages and disadvantages in particular circumstances. The advantages and disadvantages of any mode of transport must be considered to best meet the needs of the patient. In the twentieth century alone, great strides have been made in the field of emergency stabilization and transport. An efficient, well-trained ground ambulance program remains the backbone of prehospital and interhospital transport systems. Helicopters and fixed-wing transports must be integrated into the EMS system. One advantage of the helicopter and fixed-wing aircraft is rapid travel times when time is critical. As Hicks et al said, "early resuscitation and timely transfer of selected patients are critical factors in reducing morbidity and mortality." The future holds many possibilities for enhanced patient transport. Hospitals may be able to use tilt-rotor, vertical landing, fixed-wing aircraft to combine the advantages of helicopter and fixed-wing aircraft. After all, our primary goal is to get the right patient, with the right personnel, to the right place in the right amount of time.

Aircraft↗

PubMed1991

Student selection.

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Schools, Veterinary↗

PubMed1991

Serologic evidence of Campylobacter jejuni/coli enteritis in patients with Guillain-Barré syndrome.

We performed serologic testing for Campylobacter jejuni in 17 consecutive patients with acute Guillain-Barré syndrome from the Boston, Mass area to compare the frequency of this preceding infection with the high rates reported from other areas of the world. The rate of seropositivity, 18%, was considerable, but it was lower than that reported in Australia. Moreover, all of our patients with definite serologic evidence of infection had severe enteritis before Guillain-Barré syndrome, usually with the organism cultured from stool samples. Campylobacter enteritis is an important antecedent illness for Guillain-Barré syndrome but did not precipitate the disease without enteritis.

Antibodies, Bacterial↗

PubMed1991

Circulating phospholipase A2 activity associated with sepsis and septic shock is indistinguishable from that associated with rheumatoid arthritis.

Elevation of circulating phospholipase A2 (PLA2) activity is associated with sepsis and septic shock. Elevated levels of PLA2 activity also are seen in association with chronic inflammatory disorders such as rheumatoid arthritis. The relationship between these phospholipases is unclear. We have developed a highly specific enzyme-linked immunosorbent assay (ELISA) capable of measuring human synovial PLA2 in plasma, using monoclonal antibodies raised to recombinant synovial PLA2. This ELISA has been used to quantitate circulating PLA2 levels in patients clinically diagnosed with sepsis. These elevated levels positively correlated with the elevation seen in plasma PLA2 enzyme activity. The antibodies also have been used to purify immunoreactive PLA2 from plasma of patients with sepsis, thus enabling characterization of the purified protein by amino-terminal sequence analysis. We conclude from this study that the increase in PLA2 activity seen in association with sepsis and septic shock results from a dramatic elevation in levels of a circulating PLA2 enzyme. This inflammatory PLA2 is indistinguishable, both immunologically and chemically, from that associated with rheumatoid arthritis. Therapeutic agents directed towards inhibition of this inflammatory PLA2 enzyme may have utility in the treatment of both chronic and acute inflammatory disease.

Adolescent↗

PubMed1991

Sequence of an avian non-muscle caldesmon.

We have sequenced a cloned cDNA from a chicken gizzard library which encodes a short version of caldesmon with the properties expected for the non-muscle protein. The predicted protein is 524 amino acids long with a molecular mass of 60,174 daltons. Expression in bacteria produces a protein with an apparent molecular weight on SDS gels of 75-77,000, that comigrates with human platelet caldesmon. The expressed protein binds to F-actin and is retained on calmodulin-Sepharose in the presence, but not absence of Ca2+. This non-muscle caldesmon isoform is identical to the smooth muscle protein at the N- and C-terminal ends, but is missing 232 amino acids from the centre. This central segment is thought to be helical, suggesting that non-muscle caldesmon is approximately 35 nm shorter, about 40 nm overall length, than smooth muscle caldesmon.

Actins↗

PubMed1991

Acute airway management in the critically ill child requiring transport.

Airway compromise was found to be a common problem in children requiring critical care transport to our hospital. This retrospective review of 39 infants and children was undertaken to assess the frequency and degree of airway compromise in these children, to document the management required and to determine who performed it. Ninety-seven per cent of children had airway difficulties associated with their disease, and one-third of these required further airway management on the arrival of the transport team. Airway specialists had not been involved in the care of these children before the arrival of the transport team. This indicates that greater attention should be paid to airway management as soon as children are identified as being sufficiently ill to require transport to a tertiary care facility.

Anesthesiology↗

PubMed1991

Mediastinal ependymoma.

A mediastinal ependymoma in a 35-year-old Caucasian woman is reported. The tumor was located in a paravertebral posterior mediastinal location. No continuity with the spinal canal or with the lung was identified. The diagnosis was confirmed by immunoperoxidase staining for glial fibrillary protein and by the presence of cilia within intracytoplasmic vacuoles. To the best of our knowledge, this is the second reported case of ependymoma in this location.

Adult↗

PubMed1991

Cerebral blood flow, cross-brain oxygen extraction, and fontanelle pressure after hypoxic-ischemic injury in newborn infants.

The relationship between mean arterial pressure, intracranial pressure, cerebral blood flow, cross-brain oxygen extraction, cerebral metabolic rate, and outcome was studied during therapy in nine neonates on 3 consecutive days after severe hypoxic-ischemic cerebral injury. Cross-brain oxygen extraction was significantly higher (5.06 +/- 0.5 vs 2.05 +/- 0.8 ml/dl; p = 0.012) in the five neonates who survived with normal neurologic outcome than in the four who died or sustained severe brain damage. In contrast, global cerebral blood flow in the five neonates with normal neurologic outcome was significantly lower (25.6 +/- 8.2 vs 83.2 +/- 44.9 ml/100 gm brain/min; p less than 0.05) during the study period. The differences in cross-brain oxygen extraction and global cerebral blood flow between infants who had neurologic recovery and those who died or sustained brain damage occurred in the presence of acceptable values for intracranial pressure, mean arterial pressure, and cerebral perfusion pressure. Our preliminary data suggest that cross-brain oxygen extraction and possibly global cerebral blood flow may be important variables associated with severe neuronal injury and death after hypoxic-ischemic cerebral injury.

Asphyxia Neonatorum↗

PubMed1991

The effects of acute moderate exercise on serum lipids and lipoproteins in mildly obese women.

The extent and duration of serum lipid and lipoprotein changes were examined in 12 mildly obese women who walked 45 minutes at 60% VO2max in a laboratory setting. A two-factor, 2 x 6 design with repeated measures on both factors was utilized. The first factor was condition (exercise and rest) and the second factor was time (six times of measurement over a 24-hour period) with treatment counterbalanced. The patterns of change in total high-density lipoprotein-cholesterol (HDL-C) [F(5,55) = 5.75, p less than 0.001] and HDL3-C [F(5,55) = 2.62, p = 0.034], but not HDL2-C [F(5,55) = 1.15, p = 0.346], were significantly different between conditions. Relative to baseline and the rest condition, total HDL-C tended to rise due to a significant 11.6% increase in HDL3-C immediately post-exercise, with values returning to baseline 1.5 hours post-exercise. The interaction statistic for triglycerides was significant with trends for a decrease in triglycerides at 1.5 and 23 hours post-exercise relative to baseline and the rest condition. No significant differences were seen between the exercise and rest conditions for total cholesterol, low-density lipoprotein cholesterol, glucose, or plasma volume. These data indicate that an exercise intensity achievable by brisk walking (7.4 kph) is sufficient to evoke significant but short-term changes in serum HDL3-C concentrations in women.

Adult↗

PubMed1991

Investigating whether education of residents in a group practice increases the length of the outpatient visit.

This prospective study, carried out over an eight-week period in 1990, compared the amount of time required for 468 outpatients in an academic group practice (pediatric orthopedics) to be evaluated by an attending surgeon working with a resident with the time required for 216 patients in the same practice to be evaluated by the attending surgeon only. On the average, 24.2 minutes were added when a resident was involved: 12.6 of these for the resident's examination of the patient and the remaining 11.6 for the resident's discussion of the case with the attending surgeon. These findings suggest that the education process builds in a time cost not only for the patient but for the attending surgeon, who has less time to see additional outpatients than does a private practitioner or a physician in a health maintenance organization.

Academic Medical Centers↗

PubMed1991

Ankle mortise stability in Weber C fractures: indications for syndesmotic fixation.

A Weber type C ankle fracture was sequentially reproduced in 12 cadaver lower extremities and an external rotation torque was applied at each interval. The fractures were then repaired in staged fashion and the rotational stability of the mortise evaluated. Maximum external rotation of the talus within the mortise averaged 7.7 degrees in the intact ankle and increased by 311% to 31.8 degrees after creation of a Weber C injury. Rigid fixation of the fibular fracture restored 32% of the rotational stability, whereas isolated fixation of the medial malleolus reconstituted 57%. Fibular fixation combined with a syndesmotic screw restored 51% of original stability, and the addition of medial malleolar fixation improved stability to 101%. Bimalleolar fixation without a syndesmotic screw yielded 73% of the original rotational stability. The results of this study suggest that when rigid medial and lateral osteosynthesis can be achieved, syndesmotic fixation may not be necessary.

Ankle Injuries↗

PubMed1991

Brachial plexus birth injury.

Brachial plexus birth injuries occur at a frequency of 1-2 per 1000 births. Many of these injuries spontaneously resolve. Should spontaneous recovery not occur within the first 4-6 months of life, the prognosis for attaining movement and function of the affected appendage is significantly impaired. The child demonstrates a lifelong disfiguring and functional handicap. With advances in technology, diagnosis and microsurgical techniques, surgical exploration of the brachial plexus has been revived. A multidisciplinary approach has provided dynamic results. At present only one institution in the United States utilizes this innovative protocol. This article addresses the collaborative perioperative nursing implications for a child with brachial plexus birth injury.

Birth Injuries↗

PubMed1991

Plasma volume expansion in humans after a single intense exercise protocol.

We used intense intermittent exercise to produce a 10% expansion of plasma volume (PV) within 24 h and tested the hypothesis that PV expansion is associated with an increase in plasma albumin content. The protocol consisted of eight 4-min bouts of exercise at 85% maximal O2 uptake with 5-min recovery periods between bouts. PV, plasma concentrations of albumin and total protein (TP), and plasma osmolality were measured before and during exercise and at 1, 2, and 24 h of recovery from exercise. During exercise, PV decreased by 15%, while plasma TP and albumin content remained at control levels. At 1 h of recovery, plasma albumin content was elevated by 0.17 +/- 0.04 g/kg body wt, accounting for the entire increase in plasma TP content. PV returned to control level at 1 h of recovery without fluid intake by the subjects, despite a 820 +/- 120-g reduction in body weight. At 2 h of recovery, plasma TP content remained significantly elevated, and plasma TP and albumin concentration were significantly elevated. At 24 h of recovery, PV was expanded by 4.5 +/- 0.7 ml/kg body wt (10 +/- 1%), estimated from hematocrit and hemoglobin changes, and by 3.8 +/- 1.3 ml/kg body wt (8 +/- 3%), measured by Evans blue dye dilution. Plasma albumin content was increased by 0.19 +/- 0.05 g/kg body wt at 24 h of recovery. If 1 g of albumin holds 18 ml of water, this increase in plasma albumin content can account for a 3.4-ml/kg body wt expansion of the PV. No significant changes in plasma osmolality occurred during recovery, but total plasma osmotic content increased in proportion to PV.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗

PubMed1991

Effects of ginsenoside Rb1 on central cholinergic metabolism.

Ginsenosides, the saponins of ginseng, are bioactive ingredients which exert many beneficial effects. One ginsenoside, Rb1, extracted from North American ginseng (Panax quinquefolium L.), partially prevents the memory deficits induced by a cholinergic agent (scopolamine) in rats. In vitro studies show that Rb1 has no effect on quinuclidinyl benzylate binding or on acetylcholinesterase activity, but facilitates the release of acetylcholine (ACh) from hippocampal slices. The increase in ACh release is associated with an increased uptake of choline into nerve endings; however, calcium influx is unaltered. The ability of Rb1 to prevent memory deficits may be related to facilitation of ACh metabolism in the central nervous system.

Acetylcholine↗