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Biomedical subjects

R Lentz

Publications and source records attributed to R Lentz.

12 recordsLinked to original sources
PubMed2001

A multicenter, prospective, randomized trial evaluating a new hemostatic agent for spinal surgery.

STUDY DESIGN: A prospective, randomized trial comparing Proceed, a gelatin-based hemostatic sealant (treatment), with Gelfoam-thrombin (control) in stopping intraoperative bleeding during spinal surgery. OBJECTIVES: To determine the effectiveness and safety of Proceed. SUMMARY OF BACKGROUND DATA: Proceed has been tested in animal models to determine its safety and effectiveness as a hemostatic agent. The current study was conducted under a Food and Drug Administration-approved Investigational Device Exemption to evaluate the effectiveness and safety of Proceed in humans. METHODS: For this study, 127 patients undergoing spinal surgery were randomized into either the treatment or control group after standard surgical means to control bleeding had failed. The bleeding site was evaluated at 1, 2, 3, 6, and 10 minutes after the hemostatic agent was applied. The application was considered successful if the bleeding stopped within 10 minutes. Follow-up evaluation was performed at 12 to 36 hours, then at 6 to 8 weeks after surgery. RESULTS: Proceed stopped bleeding in 98% of the patients (first bleeding site only) within 10 minutes, as compared with 90% of the control patients (P = 0.001). At 3 minutes, successful hemostasis had been achieved in 97% of the Proceed group, as compared with 71% of the control group (P = 0.0001). There was no difference in the adverse event profile between the two groups. CONCLUSIONS: A significantly larger number of bleeding sites had achieved hemostasis with Proceed than with Gelfoam-thrombin at 1, 2, and 3 minutes after application. Proceed was as safe as Gelfoam-thrombin when used for hemostasis during spinal surgery procedures.

Administration, Topical↗
PubMed1999

Long distance telementoring. A novel tool for laparoscopy aboard the USS Abraham Lincoln.

BACKGROUND: As general surgeons perform a growing number of laparoscopic operations in increasingly specialized environments, the ability to obtain expert advice during procedures becomes more important. Technological advances in video and computer communications are enabling surgeons to procure expertise quickly and efficiently. In this article, we present laparoscopic procedures completed through an intercontinental telementoring system and the first telementored laparoscopic procedures performed aboard a naval vessel. METHODS: Video, voice, and data streams were linked between the USS Abraham Lincoln Aircraft Carrier Battlegroup cruising the Pacific Ocean and locations in Maryland and California, creating the Battlegroup Telemedicine (BGTM) system. Three modes of BGTM communication were used: intraship, ship to ship, and ship to shore. RESULTS: Five laparoscopic inguinal hernia repairs were completed aboard the Lincoln under telementoring guidance from land-based surgeons thousands of miles away. In addition, the BGTM system proved invaluable in obtaining timely expertise on a wide variety of surgical and medical problems that would otherwise have required a shore visit. CONCLUSIONS: Successful intercontinental laparoscopic telementoring aboard a naval vessel was accomplished using "off-the-shelf" components. In many instances, the high risk and cost of transporting patients to land-based facilities was averted because of the BGTM system. Also, the relationship between the on-site and telementoring surgeon was critical to the success of this experiment. Long-distance telementoring is an invaluable tool in providing instantly available expertise during laparoscopic procedures.

Adult↗
PubMed1995

Comparison ketoprofen, ibuprofen and naproxen sodium in the treatment of tension-type headache.

The safety and efficacy of treatment of tension-type headache with either ketoprofen or ibuprofen and naproxen sodium were evaluated in a prospective, randomized, double-blind parallel-group-study in 345 subjects. All patients were valid for evaluation of efficacy and safety. Headache pain intensity and pain relief were measured on categorical verbal scales 30, 45, 60, 120, 180 and 240 min after ingestion of a single dose of 12.5 mg or 25 mg ketoprofen, 200 mg ibuprofen and 275 mg naproxen sodium. At no time in four hours observation the efficacy of the four treatments differed, neither in pain intensity difference nor in the pain relief scale. A statistical comparison test was performed only once analysing the primary efficacy variable, the sum of pain intensity differences. There was no statistically significant difference among all treatments in this respect. The results of this clearly indicate that ketoprofen in a dosage of 12.5 or 25 mg, compared to 200 mg ibuprofen and 275 mg naproxen sodium, is an effective and safe treatment in tension-type headache.

Adolescent↗
PubMed1990

Molecular cloning and expression of a receptor for human tumor necrosis factor.

A human tumor necrosis factor (TNF) binding protein from serum of cancer patients was purified to homogeneity and partially sequenced. Synthetic DNA probes based on amino acid sequence information were used to isolate cDNA clones encoding a receptor for TNF. The TNF receptor (TNF-R) is a 415 amino acid polypeptide with a single membrane-spanning region. The extracellular cysteine-rich domain of the TNF-R is homologous to the nerve growth factor receptor and the B cell activation protein Bp50. Human embryonic kidney cells transfected with a TNF-R expression vector specifically bind both 125I-labeled and biotinylated TNF-alpha. Unlabeled TNF-alpha and TNF-beta were equally effective at displacing the binding of labeled TNF-alpha to TNF-R expressing cells. Northern analysis indicates a single species of mRNA for the TNF-R in a variety of cell types. Therefore, the soluble TNF binding protein found in human serum is probably proteolytically derived from the TNF-R.

Amino Acid Sequence↗
PubMed1990

Purification and characterization of an inhibitor (soluble tumor necrosis factor receptor) for tumor necrosis factor and lymphotoxin obtained from the serum ultrafiltrates of human cancer patients.

Serum ultrafiltrates (SUF) from human patients with different types of cancer contain a blocking factor (BF) that inhibits the cytolytic activity of human tumor necrosis factor alpha (TNF-alpha) in vitro. BF is a protein with a molecular mass of 28 kDa on reducing sodium dodecyl sulfate/polyacrylamide gel electrophoresis (SDS/PAGE). The active material was purified to homogeneity by a combination of affinity chromatography, PAGE, and high-pressure liquid chromatography. Amino acid sequence analysis revealed that BF is derived from the membrane TNF receptor. Purified BF blocks the lytic activity of recombinant human and mouse TNF-alpha and recombinant human lymphotoxin on murine L929 cells in vitro. However, BF inhibits the lytic activity of TNF-alpha more effectively than it does that of lymphotoxin. The BF also inhibits the necrotizing activity of recombinant human TNF-alpha when coinjected into established cutaneous Meth A tumors in BALB/c mice. The BF may have an important role in (i) the regulation and control of TNF-alpha and lymphotoxin activity in cancer patients, (ii) interaction between the tumor and the host antitumor mechanisms, and (iii) use of systemically administered TNF-alpha in clinical trials with human cancer patients.

Amino Acid Sequence↗
PubMed1990

Identification of TNF-LT blocking factor(s) in the serum and ultrafiltrates of human cancer patients.

Human serum ultrafiltrate (UFS) obtained from cancer patients contains material(s) which inhibit the cytolytic activity of tumor necrosis factor (TNF-alpha) and lymphotoxin (LT-TNF-beta) in vitro. These factors are found in UFS from patients with different types of cancers and are not detected in the sera of normal donors. Results from molecular sizing studies demonstrated that their molecular weights are over 30 kD. They appear to block by interfering with the early stages of cell lysis. It is not clear whether or not these TNF-LT blocking factor(s) are the same molecules. These factors may have adverse effects on the biological activities of TNF and LT in cancer patients.

Clinical Trials as Topic↗
PubMed1983

Electrolyte and other physiological abnormalities in patients with bulimia.

The frequencies of various forms of eating-related behaviour (such as vomiting and laxative abuse) are reported for a series of non-anorectic bulimia patients seen for evaluation in an eating disorders clinic. The results of serum electrolyte, glucose and other screening tests in these patients are presented. Electrolyte abnormalities were found in 82 of the 168 patients (48.8%) who were diagnosed as having either bulimia or atypical eating disorder. The most common abnormality was metabolic alkalosis (27.4%); hypochloremia (23.8%) and hypokalemia (13.7%) were also commonly seen. No significant blood sugar abnormalities were encountered. An elevated serum amylase level was found to be associated with frequent binge-eating and vomiting behaviour. The pathophysiology of electrolyte abnormalities in this patient group is briefly reviewed.

Adult↗
PubMed1976

Prostaglandins and aspirin therapy in Bartter's syndrome.

A young patient with Bartter's syndrome was treated for three months with 100 mg/kg/day of aspirin to inhibit prostaglandin synthesis. Clinical symptoms resolved and serum-potassium increased from 2-9 to 3-5 mmol/l. Urinary excretion and plasma concentration of prostaglandins E and F were significantly reduced during aspirin therapy. Plasma-renin activity declined from 85 to 20 ng/ml/h (normal 1-5-4 mg/ml/h) and hyperaldosteronism was corrected. These results suggest that overproduction of prostaglandins has a central role in the pathogenesis of Bartter's syndrome.

Aldosterone↗