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Biomedical subjects

J Freeman

Publications and source records attributed to J Freeman.

At least 199 records · Page 11Linked to original sources
PubMed1989

Accuracy of pulse oximetry to estimate HbO2 fraction of total Hb during exercise.

The accuracy of two pulse oximeters (Ohmeda 3700 and Biox IIa) was evaluated during cycle ergometer incremental exercise in 10 healthy subjects. The exercise protocol began at 30 W with the power output being increased 15 W.min-1 until volitional fatigue. Ear and finger probe pulse oximetry measurements of available hemoglobin (%Spo2) were compared with arterial oxyhemoglobin fraction of total hemoglobin (%HbO2) measured directly from arterial blood samples using a CO-oximeter. To provide a wide range of %HbO2 values, four subjects exercised under hypoxic conditions [inspired partial pressure of O2 (PIo2) = 107 Torr], while the remaining six subjects exercised under normoxic conditions (PIo2 = 150 Torr). Because carboxyhemoglobin (HbCO) or methemoglobin (MetHb) is not measured by pulse oximeters, %HbO2 was corrected for HbCO and MetHb and expressed as percent arterial O2 saturation of available Hb (%Sao2). Small and insignificant differences (P greater than 0.05) existed between SpO2 (all 3 instruments) and %SaO2 at the lowest work rate and the highest power output achieved. Regression analyses of %SpO2 vs. %SaO2 produced correlation coefficients of r = 0.82 [standard error of the estimate [(SEE) = 1.79], r = 0.89 (SEE = 1.48), and r = 0.93 (SEE = 1.14) for the Biox IIa, Ohmeda 3700 (ear), and the Ohmeda 3700 (finger) pulse oximeters, respectively. We conclude that pulse oximetry, within the above limits of accuracy, is useful in estimating %SaO2 during exercise in healthy subjects.

Adult↗
PubMed1989

The effects of ipratropium bromide and fenoterol nebulizer solutions in children with asthma.

The effects of nebulized solutions of ipratropium bromide and fenoterol combined were compared with the response to either preparation alone in single dose and longer-term administration in children who had asthma. The combination produced a slightly greater response than either alone, especially in peak expiratory flow. Over a 1-month period, there were no significant differences in symptom scores or lung function parameters between the combination of ipratropium bromide and fenoterol and fenoterol alone in a group of children who had asthma. It is possible that the addition of ipratropium bromide to a sympathomimetic drug may be useful in a subgroup of asthmatics, particularly if there is a considerable large airway contribution to bronchial narrowing.

Adolescent↗
PubMed1989

The Georgia diabetic retinopathy screening study.

The diabetic retinopathy screening study represents a major collaborative effort of many volunteer groups interested in decreasing the risk of severe visual loss to Georgia citizens. Results of the present study have stimulated intense interest in screening more high risk persons, such as minorities, without the exclusion of whites. While age-related macular degeneration is the predominant cause of blindness in the U.S., diabetic retinopathy is a major new cause of blindness. With the continuation and completion of this study, we believe that many more of Georgia's citizens will seek ophthalmologic examinations and benefit from previous research regarding the use of laser photocoagulation and vitreoretinal surgery in preventing or reducing the risk of blindness. Since diabetic retinopathy requiring treatment can be present in patients with normal vision, such patients should obtain an annual dilated eye examination by an ophthalmologist. The value of statewide screening for undetected diabetic retinopathy, the determination of how and where to screen in order to give the most benefit to the potentially affected individuals and citizens of Georgia are only a few of the questions that may be answered when this study is completed. Moreover, to our knowledge this study is the first statewide screening for diabetic retinopathy in the United States.

Adult↗
PubMed1989

Transhiatal esophagectomy with gastric transposition for pharyngolaryngeal malignant disease.

Between 1981 and 1988, 41 patients underwent pharyngolaryngoesophagectomy with transhiatal gastric transposition and primary pharyngogastrostomy for hypopharyngeal, laryngeal, and cervical esophageal carcinoma. All patients had squamous cell carcinoma. Twenty-one patients had been treated initially by high-dose radiotherapy, but the tumor had either persisted or recurred. Four patients had previously received high-dose local radiotherapy to the neck for unrelated diseases, and in 16 patients no preoperative radiotherapy was given. There was one operative death. Anastomotic leaks developed in nine previously irradiated patients and three required flap reconstructions. Thirty patients had satisfactory swallowing postoperatively and three swallowed poorly. Delayed gastric emptying was a serious problem in two patients, necessitating pyloric bag dilatation in one and pyloroplasty in another. The average postoperative stay was 31 days. Thirty-seven percent survived longer than 12 months and 15% longer than 24 months. The probability of survival after 2 years is 35%. All deaths from recurrent disease occurred within 412 days postoperatively. At present, pharyngolaryngoesophagectomy with gastric transposition and primary pharyngogastric anastomosis offers the best chance for cure or palliation with acceptable morbidity and function for selected patients with advanced hypopharyngeal and laryngeal tumors.

Adult↗
PubMed1988

Changes observed in the growth fraction, labeling index, duration of S phase, and total cell cycle times of HL-60 cells as they undergo differentiation in response to retinoic acid.

To assess the changes in the proliferation characteristics that occur during maturation, HL-60 cells were induced to differentiate along the granulocytic pathway by retinoic acid. Differentiation was documented by morphology, functional markers, and cytochemical staining. Durations of S phase, total cell cycle time, and the percentage of S-phase cells were determined simultaneously at each time point. In addition, the expression of two cell cycle related proteins with molecular weights of 110,000 (p110 measured by monoclonal antibody 5C2) and 145,000 (measured by monoclonal antibody p145) were measured to estimate the number of cycling cells or the "growth fraction." Our data demonstrate that as HL-60 cells undergo maturation in response to retinoic acid, a large proportion of cells exit from the cycle, the majority lose their proliferative potential, and the total cell cycle time becomes markedly longer. The slowing of the cell cycle seems to be the result of a prolongation in both S phase and the G1 phase of the cycle. We conclude that more mature myeloid cells cycle more slowly than immature cells. The clinical implications of these findings in myeloid leukemias are discussed.

Cell Cycle↗
PubMed1988

Effect of tetrahydrouridine on the clinical pharmacology of 1-beta-D-arabinofuranosylcytosine when both drugs are coinfused over three hours.

When 1-beta-D-arabinofuranosylcytosine (ara-C), 25 mg/m2, is infused over 3 h together with tetrahydrouridine (THU) at 10 to 350 mg/m2 to heavily pretreated patients with solid tumors, Michaelis-Menten type kinetic values are observed with leveling off of delta area under the curve, delta ara-C levels at 3 h, and delta total body clearance after 150 mg/m2 of THU. When the ara-C dose was increased to 50, 75, and 100 mg/m2 coinfusion of 250 or 350 mg/m2 of THU significantly increased plasma ara-C at peak and area under the curve. In contrast, total body clearance and volume of distribution decreased significantly. At 100 mg/m2 of ara-C coinfused with high doses of THU, i.e., at 350 mg/m2, the pharmacokinetics of plasma ara-C was changed from a biphasic decay of plasma ara-C at peaks (control) to a curve similar or identical to a monophasic curve, indicating that THU not only inhibits deamination but also changes the distribution of ara-C. This combination provides plasma ara-C levels (greater than or equal to 10 microM) comparable to high dose ara-C at 1 g/m2. Such plasma ara-C levels are considered to be sufficient for saturation of the kinases catalyzing the production of 1-beta-D-arabinofuranosylcytosine 5'-triphosphate. This reduced ara-C dose necessary to achieve saturation of kinases also reduces plasma 1-beta-D-arabinofuranosyluracil levels substantially. Toxicity of this combination was predominantly confined to bone marrow and gastrointestinal toxicity.

Adult↗
PubMed1988

Multiple intensive care unit outbreak of Acinetobacter calcoaceticus subspecies anitratus respiratory infection and colonization associated with contaminated, reusable ventilator circuits and resuscitation bags.

PURPOSE: Acinetobacter calcoaceticus subspecies anitratus (A. anitratus) can cause nosocomially and community acquired pneumonia. Source identification of the organism is often difficult. An outbreak of respiratory infection and colonization with A. anitratus affecting 93 ventilated patients in all six of a hospital's intensive care units (ICUs) over 10 months is described. PATIENTS AND METHODS: In April 1984, the infection control staff started to review positive culture results from all patients in all ICUs. At this point, information on significant isolates was recorded by patient, site, date, genus and species, and antimicrobial susceptibility. During the month of August 1984, an increased number of A. anitratus isolates from sputum began to be detected. Information was expanded to include the date of hospital admission, ICU admission, intubation, and extubation; the dates and types of all surgical procedures; the results and dates of all prior sputum cultures; and the use of nebulized bronchodilator medications. Monthly numbers of cases were compared for four months prior to the outbreak, during the outbreak, and for seven months after the outbreak. Plasmid DNA from isolates was prepared, electrophoresed, and visualized. Isolates were designated according to the molecular weights of visualized plasmids. RESULTS: Barrier precautions and improved staff handwashing did not diminish the frequency of new cases. When pasteurized, reusable ventilator circuits and resuscitation bags were cultured for the possibility of low-level contamination, 18 percent were positive for A. anitratus. Terminal ethylene oxide sterilization of these devices was associated with prompt control of the outbreak. Plasmid DNA analysis of isolates from patients involved in the outbreak, contaminated devices, and the hands of personnel responsible for device disinfection revealed two predominant plasmid profiles. After outbreak control, isolates with these profiles were found much less frequently in patient specimens. CONCLUSION: Contaminated, reusable ventilator support equipment may be a leading cause for the extent of A. anitratus in the sputum of intubated patients. This problem is potentially correctable by the use of terminal etyhlene oxide sterilization of reusable ventilator circuits and resuscitation bags.

Acinetobacter↗
PubMed1988

[Use of flumazenil (RO 15-1788) after prolonged infusion of midazolam in anesthesia for intracranial surgery].

Midazolam, with a half-life of about 1.5-3.5 h, is inappropriate for the maintenance of anaesthesia during long procedures, especially when rapid recovery is necessary. The efficacy of flumazenil, a specific benzodiazepine antagonist, in the treatment of patients with benzodiazepine overdose suggests that rapid recovery from anaesthesia induced and maintained with midazolam might be obtained in patients needing immediate assessment. The rate of recovery, the side-effects and the feasibility of an early and accurate neurological assessment were studied in 18 ASA III patients after craniotomy in whom the prolonged effects of midazolam had been antagonized by flumazenil. Surgery lasted 5.5 +/- 1.3 h (means +/- SD). The induction dose of midazolam was 0.32 +/- 0.08 mg.kg-1 and the infusion rate was 0.2 +/- 0.08 mg.kg-1.h-1. Fentanyl was added at a dose and rate of 5.0 +/- 3.6 micrograms.kg-1 and 2.0 +/- 0.9 micrograms.kg-1.h-1 respectively. At the end of the dressing, 0.5 mg of flumazenil (t0) was injected, followed by 0.1 mg every minute up to a total of 1 mg. After 2 min, 14 patients (78%) opened their eyes (p less than 0.05) and 13 (72%) obeyed orders (p less than 0.05). After 10 min, 16 patients (89%) were extubated and speaking. During the first 10 min, the Glasgow score and the sedation score used for this study showed the same progression, with 13 patients (72%) having a Glasgow score of 14-15 (p less than 0.05). Thereafter, both scores decreased progressively till t60, then increased again, reaching their t10 level at t120. Three patients required another dose of antagonist.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1988

Plasma pituitary hormone levels in severe trauma with or without head injury.

In order to evaluate the effect of head injury in severely traumatized patients on the response of ACTH, GH, PRL, and TSH plasma levels, 36 patients were prospectively studied over 5 consecutive days following injury. They were divided into three groups: Group I, severe isolated head injury (n = 14); Group II, multiple injury combined with severe head injury (n = 12); Group III, multiple injury without head injury (n = 10). No significant trend was observed during the 5 consecutive days. The following changes in plasma levels were observed, compared to normal reference value (median values): ACTH was normal in the three groups; PRL was elevated in Group II and normal in the other groups; GH was elevated in all groups; TSH was elevated in Group III and reduced in Groups I and II. Intergroup comparisons showed significantly lower plasma levels for PRL (p less than 0.05) and TSH (p less than 0.01) in Groups I and II, i.e., head-injured patients, compared to Group III, i.e., traumatized patients without head injury. A relationship was observed between the severity of head injury, as expressed by Glasgow Coma Score, intracranial pressure levels, outcome, and TSH and PRL levels.

Adolescent↗
PubMed1988

Percutaneous transtracheal ventilation for laser endoscopic treatment of laryngeal and subglottic lesions.

Obstructive lesions of the larynx and subglottic space are always a challenging problem for the endoscopist and anaesthetist. At this level, the efficacy and innocuity of a carbon dioxide laser treatment are related to the degree of endoscopic exposure. Thanks to the transtracheal high frequency jet ventilator, it is now possible to assure a free laryngeal endoscopic operative field. The transtracheal catheter is introduced percutaneously through the cricothyroid membrane into the trachea under endoscopic control and connected to a high frequency jet ventilator. From November 1983 to April 1985, this technique has been used in 65 cases. In 12 cases, it was the only alternative to avoid a tracheostomy. The other indications were: laryngeal papillomatosis, resection of T1a cancers of the vocal cords, fibrous strictures secondary to long term intubation, laser arytenoidectomies and benign lesions of the vocal cords. Among many advantages, the following are the most convincing: clear vision of the operative field for the surgeon, complete relaxation of the patient, good respiratory gas exchange, elimination of the risk of ignition of an endotracheal tube by laser, decreased risks of broncho-aspiration of blood and debris, and the facility to provide oxygen and/or mechanical ventilation in the postoperative period. The only complication encountered was a case of cervico-mediastinal emphysema caused by displacement of the tracheal catheter.

Adult↗