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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

Mandibulotomy in the irradiated patient.

Though the "mandibular swing," as an approach to certain upper aerodigestive tract malignancies, has been gaining popularity in recent years, there has been little reported as to the feasibility of this procedure in subjects who have received radical preoperative radiotherapy. We have recently reported the results of 23 such patients, and we now present an update. The results presented are of a retrospective analysis of 44 patients, 50% of whom received radical preoperative radiotherapy to fields including the osteotomy site. As in the previous study, there were no statistically significant differences between the complication rates in the irradiated and nonirradiated patient populations. All the patients were orally rehabilitated.

Adult↗
PubMed1989

Incidence of phlebitis in peripheral parenteral nutrition: effect of the different nutrient solutions.

To determine the influence of peripheral parenteral nutrition (PPN) on the incidence of phlebitis and the effect of simultaneous infusion of lipid emulsion, 68 surgical patients were assigned randomly to 3 nutrition groups: (1) amino-acid 4% solution and dextrose 8% (AA + DX) + Intralipid (IL) 10% in the ratio 1.5:1 (2) AA + DX and IL 20% in the ratio 3:1 (3) AA + DX alone. Group 4 (control group) consisted of 25 patients receiving maintenance solutions and iso-osmotic drugs. No filters were used. The cannulae were studied for 72 hours and the cannula sites were evaluated daily for phlebitis. Mean age of patients was 52.3 +/- 17.7 years, with a similar sex ratio in the 4 groups. One hundred and twenty-five cannulae were studied. At 72 h, the following cumulated phlebitis rates were recorded: 22% in Group 1 (712 mOsm/L), 48% in Group 2 (802.5 mOsm/L), 44% in Group 3 (920 mOsm/L) and 26% in Group 4 (260-314 mOsm/L). The phlebitis incidence was similar in groups 1 and 4 (control) throughout the study. Both Groups 2 and 3 had higher phlebitis rates on days 2 and 3 (II: p < 0.05, III: p < 0.01). It is concluded that PPN with simultaneous IL 10% in the ratio 1.5:1 is no more phlebogenic than the usual maintenance solutions during the first 72 h. This is probably due to the lower osmolality and lower DX and K concentrations of the solution with IL 10%. Intralipid 20% does not have the same protective venous effect. The lower complication rate, the limited need for nursing, and lower costs compared to central parenteral nutrition, make PPN a safe nutrition technique for up to 10 days in patients needing no volume restriction.

Journal Article↗
PubMed1989

Enhanced immunogenicity of a T cell immunogenic peptide by modifications of its N and C termini.

The modification of the terminal ionizable charges of an immunogenic peptide, HEL (46-61), was found to greatly increase the immunogenicity of the peptide. The modified peptide had 100- to 1000-fold enhanced activity in both in vitro and in vivo T cell assays. The mechanism of the enhancement was investigated by determining the binding affinities to I-Ak as well as circular dichroism (CD) studies. The native and enhanced peptides had indistinguishable binding affinities, as well as similar kinetics. The CD studies revealed that in aqueous solution, neither peptide had any detectable helicity; however, the addition of trifluoroethanol did result in significant helicity; with the two peptides being indistinguishable. These same modifications were also shown to enhance other immunogenic peptides if they contained a basic carboxy-terminal amino acid residue. Thus, by modifying the termini of T cell epitopes, their immunogenicity can be dramatically increased, but the molecular basis for this enhancement is still unclear.

Amino Acid Sequence↗
PubMed1989

Effects of propranolol on resting metabolic rate after severe head injury.

Postabsorptive resting metabolic rate (RMR), measured by indirect calorimetry, and the effect of iv propranolol administration were studied in 12 nonseptic patients with severe head injury by means of indirect calorimetry. Before propranolol RMR was moderately increased (126 +/- 10.4% of predicted values) whereas urinary excretion of catecholamines was markedly elevated (p less than .01 vs. normal values). RMR was significantly correlated with both resting heart rate (HR) (r = .72, p less than .01) and 24-h urinary N excretion (r = .85, p less than .001). The administration of iv propranolol (0.1 mg/kg) produced a rapid decrease in HR (-10 +/- 4%, p less than .001) and in RMR (-6.1 +/- 2.3%, p less than .001). Further administration of propranolol produced no additional reduction in either HR or RMR. We conclude that severely head-injured patients are moderately hypermetabolic in resting and postabsorptive conditions, and that acute iv propranolol administration induces a reduction of about one quarter of the resting hypermetabolism.

Adolescent↗
PubMed1989

Effect of three pretreatment techniques on hemodynamic and CSFP responses to skull-pin head-holder application during thiopentone/isoflurane or propofol anesthesia.

The effects of three different pretreatment techniques on ICP and MAP responses to pin head-holder application (HH) were studied. Thirty-two patients for elective intracranial surgery were assigned randomly to three pre-treatment groups: group I-local scalp infiltration with lidocaine (6-8 ml of 2% solution); group II-deepening of general anesthesia with either thiopentone (2 mg/kg) or propofol (0.6 mg/kg); and group III-intravenous fentanyl (4 mug/kg). Two anesthetic techniques were used, subdividing the three groups into subgroup A (thiopentone-isoflurane) and subgroup B (propofol). Measurements of MAP, cerebrospinal fluid pressure (CSFP), cerebral perfusion pressure (CPP), and heart rate (HR) were made at pretreatment, just before HH (time T0: baseline), and 0.5, 1, 2, 3, 4, and 5 min after HH. Within each group, MAP, HR, CPP, and CSFP varied similarly in both subgroups, so the data from A and B were cumulated. After HH application, MAP, HR, CPP, and CSFP increased in all groups, but significantly less in group I. The maximal MAP increase occurred at T1 and was 6.7 +/- 2.2% in group I, 27.9 +/- 4.9% in group II, and 27.1 +/- 6.5% in group III (difference between I and II-III: p <0.005). HR increased similarly in the three groups, but less in group I. The maximal CSFP increase occurred at T0.5 and was 12.2 +/- 10.0% in group I, 31.9 +/- 10.8% in group II, and 24.5 +/- 5.6% in group III (difference between I and II-III: p < -0.05). The changes in CPP paralleled MAP changes. In conclusion, the thiopentone-isoflurane sequence and continuous propofol anesthesia provide similar hemodynamic conditions and responses to nociceptive stimuli; local lidocaine infiltration achieves better control of MAP, HR, CSFP, and CPP after HH application than the deepening of general anesthesia or intravenous fentanyl.

Journal Article↗
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↗