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Biomedical subjects

J D Green

Publications and source records attributed to J D Green.

At least 37 records · Page 2Linked to original sources
PubMed1996

Design of biological equivalence programs for therapeutic biotechnology products in clinical development: a perspective.

The determination of biological equivalence requires that studies are conducted to establish that two molecules, two formulations, of two dosing regimens, for example, are indistinguishable with respect to safety and efficacy profiles that have been previously established. The criteria that are used to establish biological equivalence will depend on the nature of the change (e.g., molecular, process, formulation), the stage of the development program, the duration of treatment, and the intended clinical indications. Key components of an equivalence program include chemical characterization, in vitro and in vivo bioactivity against reference material, pharmacokinetics, and safety. Special considerations for patient populations, endogenous concentrations, environmental factors, immunogenicity, assay methodology, biochemical identity, pharmacodynamic equivalence, and statistical methodology are discussed. In addition, the role of preclinical in vivo assessments is addressed. Specific case studies provide insight into the varied nature of approaches that are currently employed.

Biotechnology↗
PubMed1996

A modification of sub-mental intubation.

In patients who have sustained base of skull fractures, the mode of intubation is controversial, with many anaesthetists arguing against nasal intubation. In several maxillofacial procedures temporary intermaxillary fixation (IMF) in the intraoperative period may be essential to achieve optimal results in fixation. For patients with combined facial and base of skull injury, tracheotomy may have to be performed. The submental approach to intubation allows IMF to be used without resort to nasal intubation or tracheotomy. We describe a modification of the original technique which is applicable to any reinforced tracheal tube and which does not compromise the airway.

Adult↗
PubMed1996

Conservative management of acoustic neuroma: an outcome study.

OBJECTIVE: This study analyzed selection criteria, clinical outcome, and tumor growth rates in patients with acoustic neuromas in whom the initial management strategy was observation. METHODS: A retrospective review of patients with conservatively managed unilateral acoustic neuromas was conducted. Minimum follow-up was 6 months. Patients with neurofibromatosis Type II were excluded. Differences in tumor growth rates were analyzed by use of the Wilcoxon rank sum test. RESULTS: Sixty-eight patients (31 men and 37 women) with a mean age of 67.1 years were followed for an average of 3.4 years after diagnosis. The reasons for a trial of observation included advanced age (55%), patient preference (21%), minimal symptoms (9%), poor general medical condition (7%), asymptomatic tumor (4%), and tumor in the only hearing ear (4%). Fifty-eight patients (85%) were successfully managed with observation alone. Ten patients (15%) ultimately required treatment (nine received microsurgical treatment and one patient underwent radiosurgical intervention) at a mean time interval of 4.0 years after diagnosis. Forty-eight tumors (71%) showed no growth and 20 (29%) enlarged during the study period. The mean tumor growth rate at the 1-year follow-up was significantly higher in the group requiring treatment (3.0 mm) than in the group not requiring treatment (0.36 mm) (P < 0.0001). Thus, the tumor growth rate at the 1-year follow-up was a strong predictor of the eventual need for treatment. CONCLUSION: Observation is a reasonable management strategy in carefully selected patients with acoustic neuromas. Diligent follow-up with serial magnetic resonance imaging is recommended, because some tumors will enlarge to the point at which active treatment is required.

Aged↗
PubMed1996

Efficacy of an intraperitoneal antibiotic to reduce the incidence of infection in the trauma patient: a prospective, randomized study.

BACKGROUND: Antibiotic therapy in patients with blunt trauma remains an area of investigation. This study was undertaken in trauma patients evaluated with diagnostic peritoneal lavage to determine the effect of an intraperitoneal antibiotic on the following factors: infectious complications, length of hospital stay, and mortality. METHODS: A prospective, randomized double-blinded study compared using either 500 mg of intraperitoneal kanamycin or a saline control in 69 adult trauma patients requiring diagnostic peritoneal lavage was conducted over a 24-month period. Advanced trauma life support indications for performing diagnostic peritoneal lavage were used. Patients were randomized to receive 50 mL of solution intraperitoneally through a lavage catheter and were evaluated for all septic complications, length of hospital stay, and outcome. RESULTS: Over a 24-month period, 40 patients received kanamycin, and 29 patients received a placebo. Of patients receiving kanamycin, 27.5 percent experienced infectious complications compared to 65.5 percent of the control patients (p = 0.001, chi-square analysis). The average length of stay in the intensive care unit was 4.18 days in the kanamycin group and 6.96 days in the control group (p = 0.04, chi-square analysis). The average length of stay was 12.32 days for patients receiving kanamycin and 17.36 days for the control group (p = 0.03, chi-square analysis). The mortality rate for each group was 13 percent. CONCLUSIONS: Intraperitoneal kanamycin given to trauma patients requiring diagnostic peritoneal lavage within the first three hours following injury reduces the incidence of infectious complications and shortens intensive care unit and hospital stay.

Abdominal Injuries↗
PubMed1995

Three-dimensional structure of a lipoyl domain from the dihydrolipoyl acetyltransferase component of the pyruvate dehydrogenase multienzyme complex of Escherichia coli.

The structure of a lipoyl domain from the pyruvate dehydrogenase multienzyme complex of Escherichia coli has been determined by means of nuclear magnetic resonance spectroscopy. A total of 549 nuclear Overhauser effect distance restraints, 52 phi torsion angle restraints and 16 slowly exchanging amide protons were employed as input for the structure calculations. These were performed using a combined distance geometry-simulated annealing strategy. The domain is a hybrid between the N and C-terminal halves of the first and third lipoyl domains, respectively, of the dihydrolipoyl acetyltransferase component of the E. coli multienzyme complex, representing residues 1 to 33 and 238 to 289 (wild-type numbering). The lipoyl-lysine residue was also replaced by glutamine. Nonetheless, its structure, two four-stranded beta-sheets forming a flattened beta-barrel, closely resembles that of the lipoyl domain from the pyruvate dehydrogenase multienzyme complex from Bacillus stearothermophilus determined previously. As before, the lipoylation site is physically exposed in a tight turn in one of the beta-sheets, and the N and C-terminal residues are close together at the other end of the molecule in adjacent strands of the other beta-sheet. Another prominently conserved feature of the structure is the 2-fold axis of quasi-symmetry relating the N and C-terminal halves of the domain. Consistent with the high level of sequence similarity between lipoyl domains of 2-oxo acid dehydrogenase multienzyme complexes from many different sources, these results confirm that all lipoyl domains are likely to have closely related structures.

Acetyltransferases↗
PubMed1995

Ossiculoplasty with polymaleinate ionomeric prosthesis.

With the continued concern over the possible transmission of viral infections through homologous middle ear implants, there is increasing pressure to develop a truly biocompatible alloplastic middle ear prosthesis. The polymaleinate ionomer, which has been used in dentistry as a filling and luting material for more than 15 years, has recently been used to construct total and partial ossicular replacement prostheses. In an attempt to evaluate these new implants, a multicenter prospective clinical trial was initiated. To date, 92 patients have undergone implantation. The follow-up interval ranged from 3 months to 22 months. Although it is premature to discuss the long-term results, the preliminary surgical experience and audiometric data with these implants are reviewed. From a surgical perspective, the ionomeric prostheses were easily contoured with a diamond burr and were not prone to shattering. Preliminary follow-up audiometric data were available on 80 patients (59 partial ossicular replacement prostheses and 21 total ossicular replacement prostheses). Of the 59 partial ossicular replacement prostheses the air-bone gaps (average of 500 Hz, 1 kHz, 2 kHz and 3 kHz) were as follows: 0 dB to 10 dB, 15 (25%) of 59; 11 dB to 20 dB, 20 (34%) of 59; 21 dB to 30 dB, 11 (19%) of 59; and greater than 30 dB, 13 (22%) of 59. Of the 21 total ossicular replacement prostheses the air-bone gaps were as follows: 0 dB to 10 dB, 6 (29%) of 21; 11 dB to 20 dB, 6 (29%) of 21; 21 dB to 30 dB, 5 (24%) of 21; and greater than 30 dB, 4 (19%) of 21.

Acoustic Stimulation↗
PubMed1995

Spiral ganglion cell survival in labyrinthitis ossificans: computerized image analysis.

Obstruction of the cochlear scale by ossification and fibrosis, which can now be imaged by computed tomography, has been proposed as a predictor of ganglion cell survival. Subjects for this histopathologic temporal bone study were 12 profoundly deaf patients with labyrinthitis ossificans. Controls without ossification were 16 normal-hearing patients and 16 profoundly deaf patients. All temporal bones were graphically reconstructed. Computerized image analysis obtained the percentage of scalar obstruction in 12 temporal bones with labyrinthitis ossificans. Statistical analyses could demonstrate no relationship between spiral ganglion cell survival and obstruction. There was much interindividual variability in ganglion cell count among the 44 temporal bones. Ganglion cell survival was significantly less in the two deafness groups than in the normal group, but did not differ significantly between the two deafness groups. Therefore, cochlear labryinthitis ossificans is not a preditor of ganglion cell survival and should not be a contraindication to cochlear implantation.

Adolescent↗
PubMed1995

Meta-analysis of antibiotics in tube thoracostomy.

The use of antibiotics for patients undergoing tube thoracostomy was determined to be highly variable based on a study conducted at a national meeting of surgeons. A meta-analysis of six randomized studies previously reported was performed. The analysis was carried out using the Confidence Profile Method software FAST*PRO. The meta-analysis was structured using dichotomous outcomes of infectious chest processes (empyema, effusion, pneumonia, wound infection, tracheitis, etc.) versus no infectious chest process in patients with and without antibiotics. The effect measures calculated included actual difference in probabilities, relative risk, percent differences in probabilities, and odds ratio. The results of this meta-analysis suggest that antibiotics should be used in patients undergoing tube thoracostomy. Antibiotic selection should maximize therapy for Staph. aureus. The implementation of this practice guideline will require the co-operation of multiple specialty oriented physicians and surgeons.

Anti-Bacterial Agents↗
PubMed1994

Pharmacokinetics and tissue distribution of recombinant human transforming growth factor beta 1 after topical and intravenous administration in male rats.

Recombinant human transforming growth factor beta (rhTGF-beta 1) enhances the healing process after topical application to various animal wound models. A detailed pharmacokinetic and tissue distribution study was performed to support the clinical development of rhTGF-beta 1 for wound healing indications. Rats received radioiodinated or unlabeled rhTGF-beta 1 as an intravenous (iv) bolus or as a topical formulation applied to a full thickness wound. Plasma concentrations of TGF-beta 1 were estimated from TCA-precipitable radioactivity or were measured by ELISA. Following iv administration, the initial half-life was rapid (< 11 min), regardless of whether radiolabeled or unlabeled rhTGF-beta 1 was used. The terminal half-life was long (163 min) when the test material was radioiodinated and administered as a trace dose and relatively short (< or = 61 min) when given at high doses and assayed by ELISA. Analysis of plasma radioactivity by SDS-PAGE revealed a time-dependent clearance of the 25-kDa parent molecule without a significant appearance of lower molecular weight radiolabeled metabolites. The majority of the radioactivity was associated with highly perfused organs, known iodide elimination pathways, and the thyroid at 1 and 8 hr after iv injection. After topical administration of a high dose (0.8 mg/kg), no immunoreactive TGF-beta 1 was detectable in plasma samples taken over a 48-hr period. However, trace amounts (< or = 0.05 ng/mL) of acid-precipitable radioactivity were detected in plasma after topical application of [125I]rhTGF-beta 1 (1 microgram/kg, 126 microCi/kg).(ABSTRACT TRUNCATED AT 250 WORDS)

Administration, Topical↗
PubMed1994

Surgical management of iatrogenic facial nerve injuries.

Surgical management of an iatrogenic facial nerve injury represents a significant challenge for the otologic surgeon. The decision to perform facial nerve grafting is a difficult one and is based on the extent of injury to the nerve. We conducted a review of 22 patients who had sustained iatrogenic facial nerve injuries during otologic surgery that required surgical exploration. The facial nerve was transected more than half its diameter in 13 of the patients. All of these patients' nerves were repaired either with direct reanastomosis of the facial nerve or with a cable nerve graft. The transection was less than 50% in nine of the patients in the study group. Eight of these patients underwent only decompression of the facial nerve. No patient with a neural repair (direct anastomosis or cable graft) had better than a House grade III result. All of the patients undergoing direct anastomosis of the nerve obtained a House grade III result. The most common result in patients undergoing cable nerve grafting was a House grade IV. The only patients with normal or near-normal facial nerve function (House grade I or II) had only decompression of the facial nerve. Five of the eight patients undergoing decompression had results similar to those undergoing cable nerve grafts. We conclude that acceptable results can be obtained when the facial nerve is repaired by direct anastomosis or a cable nerve graft. These results are comparable with those of patients treated with decompression only. When in doubt as to the extent of injury, it is preferable to repair the facial nerve, because the extent of injury may be underestimated.

Adolescent↗
PubMed1994

Surgical management of previously untreated glomus jugulare tumors.

The treatment of glomus jugulare tumors is controversial. Changes in the surgical treatment of glomus jugulare tumors at The House Ear Clinic have allowed complete resection in 85% of patients with minimal morbidity and no surgical mortalities. Our experience with 52 previously untreated patients with glomus jugulare tumors is reviewed. Two primary surgical techniques were used. The mastoid/neck approach was used in 9 patients with small tumors limited to the jugular bulb. The infratemporal fossa approach was used in the remaining 43 tumors. Lower cranial nerve preservation was possible in the majority of patients with normal preoperative function. Modifications in the management of the facial nerve during the infratemporal fossa approach have resulted in good recovery of facial function (House grade I/VI or II/VI) in 95% of patients. Most patients (85%) were able to fully resume all preoperative activities. Our results suggest that surgical management is the treatment of choice in younger patients with glomus jugulare tumors.

Adult↗
PubMed1994

Iatrogenic facial nerve injury during otologic surgery.

Perhaps the most devastating complication in otologic surgery is that of inadvertent injury to the facial nerve. A review of 22 patients who had sustained an iatrogenic facial nerve injury was conducted. Although the most common procedure being performed during the injury was mastoidectomy (55%), a surprising number of patients had injury during tympanoplasty (14%) or during removal of exostoses (14%). The most common area of injury to the facial nerve in this series was in the tympanic segment. In 79% of the patients, the facial nerve injury was not detected at the time of surgery. All patients underwent surgical exploration of the facial nerve. Otologic surgeons are cautioned to be familiar with the normal course of the facial nerve and to be aware of the potential for facial nerve injury when performing transcanal surgery.

Adolescent↗
PubMed1994

The Mayo Clinic experience with the cochlear implant.

The implantation of a cochlear electronic prosthetic device is an acceptable means of improving the communication ability of pre- and postlingually deafened children and adults. A significant number of patients in this series are in the senior citizen age group. It has been beneficial in improving communication ability in selected profoundly deafened individuals. There has been a significant improvement in the cochlear electronic prosthetic device since the initial report of Djourno in 1957.

Adult↗
PubMed1994

Effect of short-term infusion of recombinant human relaxin on blood pressure in the late-pregnant rhesus macaque (Macaca mulatta).

OBJECTIVE: To test a recombinant human relaxin preparation, developed for potential therapeutic application, for possible hypotensive actions in near-term pregnant rhesus monkeys. METHODS: Groups of four females received 1-hour intravenous infusions of 0, 0.1, or 2.0 mg recombinant human relaxin/kg on gestation day 147 (term = 165 days). Maternal heart rate, electrocardiogram, and diastolic, systolic, and mean arterial pressure; and fetal heart rate were monitored before, during, and after the infusion. After spontaneous delivery, physical, neurobehavioral, and physiologic examinations were conducted on the newborn. RESULTS: No effects of recombinant human relaxin were detected by statistical analysis or examination of data records. CONCLUSION: Intravenous infusion of up to 2.0 mg recombinant human relaxin/kg in conscious pregnant rhesus monkeys had no effect on maternal cardiovascular indices or fetal heart rate.

Animals↗