Urban air: real samples for undergraduate analytical chemistry.
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Air Pollutants↗
Biomedical subjects
L P Johnson
Publications and source records attributed to L P Johnson.
Effects of massage on pain intensity, analgesics and quality of life in patients with cancer pain: a pilot study of a randomized clinical trial conducted within hospice care delivery.
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Adult↗
Cortisol metabolism and its inhibition by glycyrrhetinic acid in the isolated perfused human placental lobule.
We have previously reported the placental metabolism of prednisolone to prednisone, 20alpha- and beta-dihydroprednisone and 20beta-dihydroprednisolone. In this study, the disposition of cortisol was investigated in vitro in the dual perfused, isolated human placental lobule after the addition of cortisol (1.2 micromol, n = 3 and 12 micromol, n = 4) to the maternal compartment. Analysis of 5 h maternal and fetal perfusate samples by high performance liquid chromatography-electrospray-tandem mass spectrometry (HPLC-ESI-MS/MS) revealed that cortisol was mainly metabolized to cortisone, but a significant production of 20alpha-dihydrocortisone, 20beta-dihydrocortisone, 20alpha-dihydrocortisol and 20beta-dihydrocortisol was also detected. Saturability of metabolism but not transfer was demonstrated. Metabolism was eliminated by co-perfusion with the potent 11beta-hydroxysteroid dehydrogenase (11beta-HSD) enzyme inhibitor 18beta-glycyrrhetinic acid (GA). The disposition of GA was analysed using HPLC-atmospheric pressure chemical ionisation-MS/MS (HPLC-APCI-MS/MS). GA was found to transfer from the maternal to the fetal circulations without detectable metabolism during 6 h of perfusion.
11-beta-Hydroxysteroid Dehydrogenases↗
Methimazole and propylthiouracil equally cross the perfused human term placental lobule.
Propylthiouracil (PTU) is widely believed to cross the placenta less freely than methimazole (MMI) and is therefore regarded as the preferred drug for treatment of hyperthyroidism in pregnancy. Clinical studies comparing the two drugs show, however, no differences in maternal or fetal thyroid function. We investigated transfer from the maternal to the fetal circuit in the isolated perfused term human placental lobule of low and high doses of PTU (4 micrograms/mL and 40 micrograms/mL) and MMI (1.5 micrograms/mL and 15 micrograms/mL) in protein-free perfusate and low doses of both drugs with addition of 40 g/L of bovine albumin. Both drugs readily crossed the placenta, reaching equilibrium in all experiments in about 2 h. Drug concentrations in the two circuits fitted a two compartmental model. Transfer kinetics for the two drugs were similar, nonsaturable, and unaffected by addition of albumin. Clearances (mL.min-1.g-1, means +/- SD) of PTU from maternal to fetal circuits were: 0.229 +/- 0.110, 0.216 +/- 0.065, and 0.170 +/- 0.032; and for transfer of MMI: 0.165 +/- 0.025, 0.232 +/- 0.153, and 0.174 +/- 0.009 (for low doses without, low doses with, and high doses without albumin, respectively). Clearances of PTU from fetal to maternal circuits were: 0.147 +/- 0.072, 0.109 +/- 0.014, and 0.116 +/- 0.028; and for transfer of MMI: 0.095 +/- 0.029, 0.122 +/- 0.088, and 0.12 +/- 0.005 (in the same experiments). There was no significant difference between drugs or drug doses and no effect of addition of albumin. We conclude that PTU and MMI have similar placental transfer kinetics.
Animals↗
A comparison of Warner-Bratzler shear force assessment within and among institutions.
Our objective was to compare measurement of Warner-Bratzler shear force of beef longissimus within and among institutions when each institution used its own protocol and when all institutions used a standardized protocol. In Exp. 1, each of five institutions (A, B, C, D, and E) received two adjacent steaks from each of 27 beef strip loins (longissimus lumborum). Warner-Bratzler shear force was measured for both steaks using the procedures normally used at each institution. In Exp. 2, each institution received two adjacent steaks from each of 45 strip loins. Shear force was measured for both steaks using a standardized protocol. In Exp. 1, Warner-Bratzler shear force was highest (P < .05) for A (4.7 kg) and lowest (P < .05) for B (2.9 kg). Repeatability of shear force was highest for A and C (.73 and .72), intermediate for D (.63), and lowest for B and E (.39 and .44). In Exp. 2, Warner-Bratzler shear force was highest (P < .05) for A (5.1 kg) and lowest (P < .05) for E (3.7 kg). Repeatability of shear force was highest for A (.87), intermediate for B, D, and E (.81, .75, and .80), and lowest for C (.67). Shear force values differed within and among institutions due to protocol, execution of the protocol, and instrument variation. Thus, comparisons of Warner-Bratzler shear force data among institutions are currently not valid. However, it is possible for institutions to obtain the same mean shear force value and have high repeatability if a standard protocol is properly executed with calibrated equipment.
Analysis of Variance↗
Intractable epistaxis: transantral ligation vs. embolization: efficacy review and cost analysis.
After posterior nasal packing, the two most common therapies for intractable epistaxis are transantral ligation of the internal maxillary artery and percutaneous embolization of the distal internal maxillary artery. However, optimal management of intractable posterior epistaxis remains controversial. We retrospectively reviewed the charts of 21 patients treated for intractable epistaxis and obtained data on presentation, risk factors, treatment, success rates, complications, and cost. Twelve patients received percutaneous embolization, five underwent transantral ligation, and four required both. The success rates for transantral ligation and percutaneous embolization were 89% and 94%, respectively. No mortality or serious morbidity occurred with either technique. A cost comparison revealed that transantral ligation was moderately less expensive than percutaneous embolization ($5941 vs. $6783). Although some authors advocate transantral ligation or percutaneous embolization as the procedure of choice for intractable epistaxis, a direct comparison of efficacy and cost reveals that they are comparable procedures with specific strengths and weaknesses. We present our experience and a review of the literature, highlighting the indications and advantages of each technique. We conclude that the choice of treatment modality should be based on the benefits of each procedure as it pertains to the specific needs of the individual patient.
Adult↗
A report of accidental ethylene glycol ingestion in 2 siblings.
We describe a case of 2 siblings aged 2 1/2 and 3 1/2 yrs accidentally poisoned by ethylene glycol ingestion. We found estimating the level of ethylene glycol in plasma by calculation of osmolar gap too insensitive to be of value and advocate the availability of a specific method. In our study only one of the 2 children had a toxic level of ethylene glycol but assay by conventional assay and by proton magnetic resonance spectroscopy (1HMRS) of toxic metabolites viz glycolate, glyoxylate and oxalate showed both to be excreting grossly elevated levels. This indicates the desirability of assaying the toxic metabolites of the glycol as well as the parent compound in assessing ingestions.
Accidents, Home↗
Intraoral ultrasound evaluation of peritonsillar abscess.
Peritonsillar cellulitis and peritonsillar abscess are similar clinical entities with markedly different methods of treatment. Therefore, accurate diagnosis is paramount to appropriate treatment. This pilot study was designed to evaluate the sensitivity and specificity of intraoral ultrasound as a noninvasive method of differentiating abscess from cellulitis. Sixteen consecutive patients suspected of having peritonsillar abscess were prospectively evaluated with intraoral ultrasound. The results were confirmed with imaging or surgical drainage. Correct diagnoses were made in 9 (90%) of 10 abscesses and in 5 (83%) of 6 cases of cellulitis. Our results suggest that, while there is a learning curve for intraoral ultrasound, it is an accurate, noninvasive, and inexpensive tool to differentiate abscess from cellulitis. We believe that this will be a clinically useful technique in the future.
Adolescent↗
Foodservice industry market profile study: nutritional and objective textural profile of foodservice ground beef.
Ground beef patties of three types (regular, lean, extra-lean) destined for the foodservice industry were collected from foodservice purveyors in 12 cities equally distributed across six geographical regions of the United States to assess nutritional and objective texture characteristics. Patties were cooked on a foodservice-style clamshell grill to a well (approximately 80 degrees C) degree of doneness (internal temperature) for nutritional analysis and objective texture measurements. Single 5.08-cm2 samples were removed from the center of each patty and sheared with a multiple-blade Allo-Kramer shearing device. Nutritional composition, including proximate analysis values and fatty acid profiles, was determined on both raw and cooked samples of the ground beef. Extra-lean ground beef contained the least (P < .05) fat (12.43%), lean had an intermediate level (17.45%), and regular ground beef contained the most fat (P < .05) (20.20%), on a raw basis. However, after cooking, fat content was similar (P > .05) for regular and lean ground beef. Fatty acid composition of lipid and cholesterol content of ground beef did not differ (P > .05) across types of ground beef or between raw and cooked samples and was similar to USDA Handbook 8-13 values. Cooking loss decreased (P < .05) as fat percentages decreased. Regular and lean ground beef was easier (P < .05) to shear (4.20 and 4.24 kg/g of sample, respectively) than extra-lean ground beef (5.08 kg/g of sample). On average, foodservice ground beef sampled in the present study is 15.5% leaner than retail ground beef as presented in the National Beef Market Basket Survey and 22.2% leaner than USDA Handbook 8-13 values.
Animals↗
Extending the limits of lung cancer resection.
Patients with locally advanced bronchogenic carcinoma are often considered to have unresectable disease because of invasion into vital structures, or they undergo resection with questionable or involved margins, which results in local recurrence later. Brachytherapy (direct application of radioactive sources to the tumor bed) offers the potential to provide tumoricidal doses of radiation to the target area with minimal toxicity to surrounding structures. In this study, one of two different techniques of brachytherapy was utilized to treat 15 highly selected patients with histologically positive (n = 8) or suspicious (n = 7) margins after resection. The techniques were easy to apply and were not associated with any complications directly related to their use. One postoperative death resulted from a perforated peptic ulcer. In the remaining 14 patients, at a mean follow-up of 38 months, local control was complete in 12 (86%) patients, and 8 patients are alive, with 7 free of disease. Thoracic brachytherapy may offer the potential for cure to patients whose disease would otherwise be considered inoperable.
Brachytherapy↗
Calibration of albumin-fatty acid binding constants measured by heptane-water partition.
Most measurements of binding affinity of albumin for long-chain fatty acids are based on heptane-water partition. In this method, equilibrium partition of fatty acid between heptane and an albumin-containing buffer is calibrated using the partition ratio between heptane and buffer in the absence of protein. In the current study, we used a variety of techniques to examine potential problems with this approach. Hydrophobic impurities in commercial [3H]palmitate preparations were incompletely removed by standard purification techniques. These impurities contributed from 5% of the total radioactivity in the heptane phase at low albumin concentrations (5 microM) to 62% at higher albumin concentrations (500 microM), thus confounding determination of binding affinity. These were identified by gas chromatography/mass spectroscopy as radio-labeled glycerol monopalmitate and monostearate. When albumin was not present, the partition ratio was similar to values reported by others. However, our results varied by a factor of four (265-1,119) depending on how the solutions were prepared. Although a true equilibrium partition must not depend on starting conditions, the partition ratio after 24-72 h was > 2x as large when tracer [3H]palmitate was added to the heptane phase than when it was added to the aqueous phase. Results also depended on the relative volumes of heptane and buffer used, approaching a maximum of 1,445 +/- 112 for very low heptane/buffer volume ratios. Much of this variability was due to hydrophilic impurities in [3H]palmitate, which ranged from 0.2 to 1.2% in commercial lots down to 0.1-0.5% after alkaline ethanol extraction and < 0.05% after thin-layer chromatography (TLC).(ABSTRACT TRUNCATED AT 250 WORDS)
Calibration↗
Foodservice industry market profile study: in-plant beef fat trim level survey and cutting yields.
Fifty foodservice purveying companies were sampled in 12 U.S. cities evenly distributed across six geographical regions. Beef whole muscle cuts (WMC) and portion control items (PCI) from the primal rib and loin were evaluated for surface fat levels. Fat thicknesses were measured on WMC before and after fabrication, whereas additional PCI were measured for fat trim levels before distribution. The average initial fat thickness was 11.9 mm (174 Short Loin and 180A Strip Loin) and 15.6 mm (184 Top Sirloin Butt); maximum fat thicknesses ranged from 16.2 mm (strip loin) to 22.2 mm (top sirloin butt). After fabrication, average fat thicknesses were 6.2, 5.1, and 4.0 mm for resulting products from the short loin, strip loin, and top sirloin butt, respectively. The average initial fat thickness for the strip loin was greater (P < .05) in Southeast and Northeast regions than in Mountain/Desert, Midwest, and Southwest regions. In contrast, average trimmed fat thicknesses for products from the strip loin and top sirloin butt were lower (P < .05) in the Southeast and Northeast than in all other regions. Average fat trim levels for PCI were 3.0 (1112A Ribeye Roll steak, Lip-On), 5.3 (1173B/1174B T-Bone/Porterhouse steak), 5.0 (1180A Strip Loin steak), and 4.0 mm (1184B Top Sirloin steak). Maximum fat trim levels were 4.4 (IMPS 1112A), 7.4 (IMPS 1173B/1174B), 6.9 (IMPS 1180A), and 5.5 mm (IMPS 1184B). The PCI had average and maximum fat trim levels in compliance with USDA (1988) recommendations for fat trim specifications.(ABSTRACT TRUNCATED AT 250 WORDS)
Adipose Tissue↗
Shielding at the egress of a 23 mV linear accelerator.
Radiation shielding is required in radiotherapy accelerators to limit the dose equivalent rate from x-rays produced at the target in all directions except that of the useful forward directed beam. Calculations were made in terms of weekly workload of 50,000 cGy delivered to the isocenter per 5-day week, treating 25 patients per day at 400 cGy per patient. It is desirable to reduce the total exposure at the maze door below 30 Rem (0.30 Sv)/wk assuming full-time occupancy. The maze was designed to reduce the neutron dose to an acceptable level by slowing the neutrons to thermal velocities and then absorbing them in a low Z material in the egress.
Biophysical Phenomena↗
Effect of hot-fat trimming on factors associated with the subprimal yield of beef carcasses.
Thirty-two crossbred cattle (steers = 17; heifers = 15) exhibiting an ultrasound fat thickness at the 12 to 13th rib region of at least 10 mm were selected from a slaughter shift at a commercial packing plant. After splitting, alternating sides of each carcass were trimmed of 1) subcutaneous fat in excess of 6.4 mm; 2) all kidney, pelvic, and heart fat; and 3) all cod or udder fat and fat in the flank region. Both sides of each carcass were fabricated into subprimals (final trim level of 6.4 mm) according to normal industry procedures. Effect of hot-fat trimming, yield grade (3, 4, and 5), and gender on hot-fat trim, fabrication fat trim, major subprimal, and total subprimal yield of untrimmed and trimmed carcasses were determined. Higher numerical yield grade (YG) corresponded with higher (P less than .05) percentages of hot-fat trim. Hot-fat trimming increased (P less than .05) the difference in fabrication fat trim between steers and heifers and between YG 3 and YG 5. Steers and heifers differed (P less than .05) in percentage of major subprimals and total subprimals when processed conventionally, whereas hot-fat trimming eliminated this difference (P less than .05). Untrimmed YG 3 carcasses had 3.1 and 5.0% higher major subprimal yield (P less than .05) than untrimmed YG 4 and YG 5 carcasses, respectively, whereas hot-fat trimming reduced this difference to 2.5% for YG 4 and to 3.7% for YG 5.(ABSTRACT TRUNCATED AT 250 WORDS)
Adipose Tissue↗
Selective management of early glottic cancer.
Seventy patients with stage I and II glottic cancer were treated at the University of Utah School of Medicine hospitals from 1980 through 1987. Forty-four patients had stage I cancer and 26 patients had stage II. The overall survival in the stage I group was 82%. Primary site control was 93% with only three deaths due to laryngeal cancer. Local control rates were 93% with CO2 laser excision, 80% with CO2 laser and irradiation, and 67% with radiation alone. Stage II glottic patients had an overall survival of 61.5% with a local control rate of 76%. Twenty-one of 24 patients were treated by full-course irradiation. Of the eight patients who recurred at the primary site, all were irradiation failures who had initial bulky disease and impaired vocal cord mobility. Selective CO2 laser excision was highly effective, whereas radiation therapy results were somewhat disappointing. Open partial laryngectomy should be considered in bulky stage II disease patients.
Adult↗
The prediction of percentage of protein in pork carcasses.
Determination of percentage of protein in a pork carcass is a very costly and lengthy process. Therefore, we attempted to identify an easy and economical means to predict protein content of pork carcasses. Forty-seven market-weight pigs were slaughtered. The right side of each carcass was skinned, deboned and ground for composition analysis. Carcass data were collected on the left side and specific gravity analysis was performed on the side, ham and 8-9-10 rib loin section of each carcass. The hams and loin sections were dissected into skin, bone, subcutaneous fat, seam fat and individual muscles. After these components were weighted, they were analyzed for chemical composition. Percentage of chemical protein of each animal was determined and correlated with each of the weights and measurements taken on the carcass, ham and loin sections. Stepwise regression was used to predict decimal fraction of protein using either the carcass data, specific gravity ham measurements, loin section measurements or various combinations of these. In prediction equation, specific gravity of the carcass accounted for 73.4% of the variation found in percentage of protein. Prediction equations using indicators from the ham and loin section resulted in equations with R-square values as high as .783. These results suggest that specific gravity or indicators from the carcass, ham or loin section can be employed to predict percentage of protein in pork carcasses.
Adipose Tissue↗
The prediction of percentage of fat in pork carcasses.
Forty-seven market-weight pigs were slaughtered in order to determine percentage of chemical fat and in an attempt to determine an easily obtainable and inexpensive method to predict this value. The hams and 8-9-10 rib loin sections were removed from the left side of each carcass and dissected into subcutaneous and seam fat, individual muscles, skin and bone. Weights and chemical analysis were determined for each component. Numerous weights, measurements and specific gravity were determined on the carcass, ham and loin section of each pig. Percentage of chemical fat of each ham, loin section and carcasses was determined and correlated with the various weights and measurements taken. Stepwise regression was used to develop prediction equations using carcass data, specific gravity, ham or loin measurements or various combinations of these as dependent variables. The single best indicator of the decimal fraction of chemical fat in the pork carcass was determined to be specific gravity of the carcass half, the prediction equation using this variable had an R-square of .64. By adding 10th rib fat thickness to this equation, the R-square increased to .72. The best equation using carcass variables included 10th rib fat and marbling (R-square = .67). The loin section proved to be an accurate indicator of composition; ham measures were not as accurate as specific gravity and carcass measurements for predicting percentage of carcass fat. This research suggests that the percentage of chemical fat in the pork carcass can be predicted by an easy and inexpensive means.
Adipose Tissue↗
Paranasal sinus applications of surgical lasers.
This review presents uses of surgical lasers in the treatment of paranasal sinus disease. The author also discusses briefly the applications of lasers that require further investigation.
Humans↗