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Biomedical subjects

M McCracken

Publications and source records attributed to M McCracken.

18 recordsLinked to original sources
PubMed2001

Breakthrough cancer pain: a randomized trial comparing oral transmucosal fentanyl citrate (OTFC) and morphine sulfate immediate release (MSIR).

Oral transmucosal fentanyl citrate (OTFC); Actiq) is a drug delivery formulation used for management of breakthrough cancer pain. Previous studies with open-label comparisons indicated OTFC was more effective than patients' usual opioid for breakthrough pain. The objective of this study was to compare OTFC and morphine sulfate immediate release (MSIR) for management of breakthrough pain in patients receiving a fixed scheduled opioid regimen. This double-blind, double-dummy, randomized, multiple crossover study was conducted at 19 US university- and community-based hospitals and clinics and comprised 134 adult ambulatory cancer patients. Patients were receiving a fixed scheduled opioid regimen equivalent to 60-1000 mg/day oral morphine or 50-300 microg/h transdermal fentanyl, were using a 'successful' MSIR dose (15-60 mg) as defined by entry criteria, and were experiencing 1-4 episodes of breakthrough pain per day. In open-label fashion, OTFC was titrated such that a single unit (200-1600 microg) provided adequate pain relief with acceptable side effects. Successfully titrated patients entered the double-blind phase of the study and received ten prenumbered sets of randomized capsules and oral transmucosal units. Five sets were the successful OTFC dose paired with placebo capsules, and five sets were placebo OTFC paired with capsules containing the successful MSIR dose. Patients took one set of study medication for each episode of target breakthrough pain. Pain intensity (PI), pain relief (PR) and global performance of medication (GP) scores were recorded. Pain intensity differences (PID) were calculated and 15-min PID was the primary efficacy variable. Adverse events were recorded. Sixty-nine percent of patients (93/134) found a successful dose of OTFC. OTFC yielded outcomes (PI, PID, and PR) at all time points that were significantly better than MSIR. GP also favored OTFC and more patients opted to continue with OTFC than MSIR following the study. Somnolence, nausea, constipation, and dizziness were the most common drug-associated side effects. In conclusion, OTFC was more effective than MSIR in treating breakthrough cancer pain.

Administration, Oral↗
PubMed2001

Radioimaging of implants in rats using Tc-99m-MDP.

Radiopharmaceutical isotopes are widely used clinically to detect tumors of osteogenic origin. One example is Technetium-99m methylene diphosphonate (Tc-99m-MDP). When viewed with a gamma camera, the concentration of the isotope (increased gamma activity) indicates an area of increased bone activity. This technology provides an opportunity to measure bone growth around implants in vivo. The purpose of this study was to measure Tc-99m-MDP activity around titanium alloy implants placed in the tibiae of rats. Some implant sites were treated with a growth factor; other sites served as controls. The hypothesis tested was that implants placed with a growth factor would have greater associated Tc-99m-MDP activity. Twelve adult male Sprague-Dawley rats were anesthetized and surgical access to the medial proximal tibiae was obtained. Titanium alloy screw implants were placed in six animals along with 65 microgram of acidic fibroblast growth factor (FGF-1); the other six animals received implants only and served as controls. After five days, rats were injected with 1500 microCi of Tc-99m-MDP. After 3 hours, rats were imaged with a gamma camera. The Tc-99m-MDP intensity associated with each implant was quantified and the means for each group were compared using ANOVA. Implants treated with FGF-1 demonstrated significantly more Tc-99m-MDP activity than implants alone. This suggests that Tc-99m-MDP analysis may be a useful tool for determining bone growth around implants in laboratory animals in vivo.

Analysis of Variance↗
PubMed2000

Dental erosion and aspirin headache powders: a clinical report.

The causes of tooth erosion are varied, but all are associated with a chemical attack on the teeth and resulting loss of tooth structure. Etiologic factors related to erosion cited in the literature include bulimia, eating acidic foods, soft drink consumption, acid reflux, and swimming, among others. This clinical report suggests that chronic use of headache powders can also be a factor leading to tooth erosion.

Administration, Sublingual↗
PubMed1999

Dental implant materials: commercially pure titanium and titanium alloys.

Manufacturers use six different titanium-based biomaterials to fabricate dental implants. Each of these materials, including four grades of commercially pure titanium and two titanium alloys, has distinct mechanical and physical properties. Clinicians should recognize these differences for optimal treatment planning and patient care.

Chromium Alloys↗
PubMed1997

Results of a combined dexamethasone suppression/thyrotropin-releasing hormone stimulation test in healthy horses and horses suspected to have a pars intermedia pituitary adenoma.

OBJECTIVE: To evaluate results of a combined dexamethasone suppression/thyrotropin-releasing hormone (TRH) stimulation test in horses suspected clinically to have a pars intermedia pituitary adenoma (PIPA). DESIGN: Case-control study. ANIMALS: 7 healthy adult horses and 5 horses suspected to have a PIPA. PROCEDURE: A baseline blood sample was collected, and dexamethasone (40 micrograms/kg [18 micrograms/lb] of body weight, IV) was administered; a second blood sample was collected 3 hours later, and TRH (1.1 mg, IV) was administered; serial blood samples were collected 15, 30, 45, 60, and 90 minutes and 21 hours after TRH administration (24 hours after dexamethasone injection). Cortisol concentration was determined for all blood samples. RESULTS: Baseline cortisol concentration was significantly lower in horses suspected to have a PIPA than in healthy horses. Cortisol concentration was suppressed by dexamethasone in both groups; however, after TRH administration, cortisol concentration returned to baseline values in horses suspected to have a PIPA, but not in healthy horses. Concentration was still less than the baseline value 24 hours after dexamethasone administration in healthy horses. CLINICAL IMPLICATIONS: The combined dexamethasone suppression/TRH stimulation test may be a useful diagnostic test in horses suspected to have a PIPA. For clinical application, collection of a blood sample 30 minutes after TRH administration is recommended.

Adenoma↗
PubMed1995

Liquid ventilation improves pulmonary function, gas exchange, and lung injury in a model of respiratory failure.

OBJECTIVE: The authors evaluated gas exchange, pulmonary function, and lung histology during perfluorocarbon liquid ventilation (LV) when compared with gas ventilation (GV) in the setting of severe respiratory failure. BACKGROUND: The efficacy of LV in the setting of respiratory failure has been evaluated in premature animals with surfactant deficiency. However, very little work has been performed in evaluating the efficacy of LV in older animal models of the adult respiratory distress syndrome (ARDS). METHODS: A stable model of lung injury was induced in 12 young sheep weighing 16.4 +/- 3.0 kg using right atrial injection of 0.07 mL/kg of oleic acid followed by saline pulmonary lavage and bijugular venovenous extracorporeal life support (ECLS). For the first 30 minutes on ECLS, all animals were ventilated with gas. Animals were then ventilated with either 15 mL/kg gas (GV, n = 6) or perflubron ([PFC], LV, n = 6) over the ensuing 2.5 hours. Subsequently, ECLS was discontinued in five of the GV animals and five of the LV animals, and GV or LV continued for 1 hour or until death. MAIN FINDINGS: Physiologic shunt (Qps/Qt) was significantly reduced in the LV animals when compared with the GV animals (LV = 31 +/- 10%; GV = 93 +/- 4%; p < 0.001) after 3 hours of ECLS. At the same time point, pulmonary compliance (CT) was significantly increased in the LV group when compared with the GV group (LV = 1.04 +/- 0.19 mL/cm H2O/kg; GV = 0.41 +/- 0.02 mL/cm H2O/kg; p < 0.001). In addition, the ECLS flow rate required to maintain the PaO2 in the 50- to 80-mm Hg range was substantially and significantly lower in the LV group when compared with that of the GV group (LV = 14 +/- 5 mL/kg/min; GV = 87 +/- 15 mL/kg/min; p < 0.001). All of the GV animals died after discontinuation of ECLS, whereas all the LV animals demonstrated effective gas exchange without extracorporeal support for 1 hour (p < 0.01). Lung biopsy light microscopy demonstrated a marked reduction in alveolar hemorrhage, lung fluid accumulation, and inflammatory infiltration in the LV group when compared with the GV animals. CONCLUSION: In a model of severe respiratory failure, LV improves pulmonary gas exchange and compliance with an associated reduction in alveolar hemorrhage, edema, and inflammatory infiltrate.

Animals↗
PubMed1994

Effects of the menstrual cycle phase on the blood lactate responses to exercise.

The effects of menstrual cycle phase on the blood lactate response to exercise were examined in eumenorrheic women (n = 9). Exercise tests were performed at the mid-follicular and mid-luteal points in the menstrual cycle (confirmed by basal body temperature records and hormone levels). Blood lactates were measured at rest and during the recovery from exercise. Resting lactates were not different between the exercise tests; however, recovery lactates were significantly (p < 0.05) lower in the luteal compared to the follicular phase. The mechanism for these differences is unclear, but may be related to an estrogen mediated increased lipid metabolism inducing a concurrent reduction in carbohydrate metabolism. The present findings question the use of blood lactate monitoring as a suitable technique to measure exercise intensity in eumenorrheic women.

Adolescent↗
PubMed1993

Oxygen consumption and carbon dioxide production during liquid ventilation.

Liquid ventilation with perfluorocarbon (PFCV) has advantages over conventional gas ventilation (GV) in premature and lung-injured newborn animals. Indirect calorimetric measurement of both oxygen consumption (VO2) and carbon dioxide production (VCO2) during PFCV has not been previously performed. In addition, comparison to indirect calorimetric measurement of VO2 and VCO2 during GV has not been evaluated. Ten fasted normal cats weighing 2.6 to 3.9 kg were anesthetized with pentobarbital and pancuronium. Tracheostomy was performed. Gas exchange was measured across the native lung during GV and across the membrane lung of the liquid ventilator during PFCV. VO2 was measured using a modification of a previously described, indirect, closed-circuit, volumetric technique. VCO2 was analyzed by capnographic assay of the mixed-expired closed-circuit air. The VCO2/VO2 ratio (RQ) was calculated. There was no change in VO2, VCO2, or RQ during PFCV when compared with GV (VO2: GV = 5.7 +/- 0.3 mL/kg/min, PFCV = 5.6 +/- 0.5 mL/kg/min [P = NS]; VCO2: GV = 4.9 +/- 1.1 mL/kg/min, PFCV = 4.8 +/- 0.9 mL/kg/min [P = NS]; RQ: GV = 0.85 +/- 0.21, PFCV = 0.86 +/- 0.21 [P = NS]). During GV the PaO2 was higher than during PFCV (PaO2: GV = 335 +/- 70 mm Hg, PFCV = 267 +/- 83 mm Hg [P = .04]), as is expected because of the relative reduction in the inspiratory PiO2 of the perfluorocarbon during liquid ventilation.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1989

Sperm granuloma in a stallion.

A 7-year-old stallion with a history of abdominal pain after it fell was examined and found to have a swelling of the right testis and epididymis. Semen evaluation revealed an increase in secondary sperm abnormalities. The stallion was unilaterally castrated. The histologic diagnosis was sperm granuloma, with no evidence of infection. Periductal fibrosis was observed and appeared to have developed before the trauma occurred. The changes seen could be compatible with chronic blockade of efferent ductules, resulting in extravasation of spermatozoa.

Animals↗
PubMed1984

An information system for head and neck tumors: optimal use of abstracting and retrieval resources.

This report describes a symbiotic interaction between a hospital tumor registry and the physicians in a medical school department of otolaryngology. The tumor registry is responsible for collecting central registry data, entering both central registry and department-specific data, performing routine data maintenance functions, and tracking the patients over time. The departmental physicians collect site-specific data and, after entry into a computer-based data base management system, can access the information without intermediaries and at their convenience. The result is a comprehensive information resource for head and neck cancer. The development of a medical subspecialty information system, as a satellite to the central registry mechanism, is noteworthy in its low cost, frequent physician use, better patient tracking, improved patient care, and increased clinical relevance of registry activities. A subtle but pervasive benefit is the increased sense of mission experienced by all concerned.

Abstracting and Indexing↗
PubMed1979

Granular cell myoblastoma of the breast: a report of 2 cases.

Two cases of granular cell myoblastoma of the breast are presented occurring in women aged 20 and 22 years. The clinical findings, mammographic and naked eye appearances suggested carcinoma. The difficulties of diagnosis and the pathogenesis of this rare tumour are discussed. A definitive histological diagnosis of an apparently malignant breast lump, particularly in a young woman, is mandatory before proceeding to major surgery.

Adult↗
PubMedDate not supplied

Effects of the Y-U pyloroplasty on gastric emptying and duodenogastric reflux in the dog.

A Y-U pyloroplasty was performed on five healthy adult dogs. Gastric emptying half times (t1/2 GE) of a canned food meal were measured by scintigraphy three times before surgery and three times from 6 to 8 weeks after surgery. Fluoroscopic studies of gastric and duodenal motility were made before surgery and 3, 7, and 35 days after surgery. Clinical observations were made daily throughout the study. Gross and histologic evaluations of the gastroesophageal and pyloric regions were performed at the termination of the study. The t1/2 GE was significantly decreased after surgery. By positive contrast fluoroscopy, the vigor of antral contractions was seen to be decreased in three of the five dogs. On days 7 and 35, fluoroscopic findings were comparable to preoperative studies. Duodenogastric reflux was recognized fluoroscopically in three dogs on four different occasions. This may reflect normal reflux patterns in the dog. No gastrointestinal problems were evident after surgery in four dogs. Reflux esophagitis developed in one dog after surgery, which resolved with therapy. Studies of the Y-U pyloroplasty after 2 months indicated that it decreased gastric emptying time of solid food. Results of postmortem examination showed no abnormal gross or histopathologic changes of esophageal, gastric, or proximal duodenal tissues.

Analysis of Variance↗
PubMedDate not supplied

Bone response to titanium alloy implants placed in diabetic rats.

Although dental implants continue to provide consistent and predictable treatment options for most patients, some people with uncontrolled systemic disease may be denied implant treatment. Diabetes is one such disease. According to the U.S. Centers for Disease Control and Prevention, diabetes is a leading cause of blindness, kidney failure, and amputations of the lower extremities. These complications result from microvascular disturbances associated with diabetes. The effect of diabetes on the healing of titanium implants has not been well established. In this study of 32 rats, diabetes was induced in 16 animals by injection of streptozotocin (65 mg/kg); the remaining 16 animals served as controls. Titanium alloy implants were placed in the tibiae of all 32 rats using standard surgical techniques. Implants healed for 14 days. Blood samples were obtained for serum glucose, osteocalcin, and alkaline phosphatase analyses. Implants were retrieved and processed for histomorphometric analyses. Three quantities were measured using light microscopy, video capture, and computer analysis: percent osseointegration (i.e., linear bone interface), associated bone volume percent, and contact frequency. Diabetic animals demonstrated significantly less osseointegration than controls. However, bone volume percent in diabetic animals was about 4 times greater than controls. Biochemical analyses were mixed; diabetic animals demonstrated increased serum osteocalcin levels compared to controls but decreased alkaline phosphatase. Based on the results of this study, it was concluded that the bone response associated with titanium alloy implants in the tibiae of diabetic rats is uniquely different from controls.

Alkaline Phosphatase↗
PubMedDate not supplied

Analysis of Ti-6Al-4V implants placed with fibroblast growth factor 1 in rat tibiae.

Titanium-aluminum-vanadium (Ti-6Al-4V) implants were placed in the tibiae of 32 rats (male Sprague-Dawley, 350 g) to examine healing and bone response. Half of the implants were treated with fibroblast growth factor 1 (FGF-1) delivered in an activated fibrinogen matrix. Animals were injected with a radiopharmaceutical imaging agent, technetium-99m-methylene diphosphonate (Tc-99m-MDP), which concentrates in bone, especially in areas of higher osteoblastic activity. Binding of Tc-99m-MDP to the implant was detected in vivo by Anger gamma camera imaging. Fourteen days after implant surgery, specimens were recovered and prepared for histomorphometric analysis. Histologic examination revealed that samples treated with FGF-1 demonstrated significantly greater amounts of bone-to-implant contact (P < .05) compared to controls. Also, FGF-1-treated samples showed significantly greater amounts of bone (percent volume) adjacent to implants (P < .005). These findings were supported by analyses of the non-invasive Tc-99m-MDP images, which demonstrated significantly greater uptake of Tc-99m-MDP adjacent to FGF-1-treated implants (P < .05). Results of the experiments supported the hypothesis that FGF-1 could increase bone production around implants in a rat model.

Alloys↗