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Biomedical subjects

R B O'Gorman

Publications and source records attributed to R B O'Gorman.

11 recordsLinked to original sources
PubMed1988

Management of vascular injuries in the lower extremities.

From 1981 through 1985, 220 consecutive patients with presumed vascular injuries in the lower extremities underwent operation at the Ben Taub General Hospital. More than 81% of injuries were due to penetrating wounds, and blunt and iatrogenic injuries accounted for the remainder. A preoperative emergency center arteriogram was performed in 63.2% of patients, and physical examination alone prompted operation in 36.8%. Eight patients underwent immediate amputation; the remaining 212 patients were found to have 225 arterial (63.9%) and 127 venous (36.1%) injuries. More than 50% of patients were noted to have both arterial and venous injuries. Arterial repair was most commonly accomplished by segmental resection with an end-to-end anastomosis (28.4%) or insertion of a graft (38.8%). Venous repair was most commonly accomplished by lateral venorrhaphy (48.8%), ligation (19.7%), or insertion of a conduit (18.1%). Postoperative infection in closed wounds, in wounds left open because of the magnitude of injury, and in adjacent fractured bone occurred in 13% of patients. Late amputations were necessary in only four patients, three of whom had infection as the cause.

Adult↗
PubMed1987

Lymphocyte function and abdominal operations. Trauma vs elective surgery.

An alteration of in vitro phytochemagglutinin-induced lymphocyte transformation immediately following abdominal trauma has been demonstrated. In this study the results of lymphocyte transformation in 30 patients who had suffered abdominal trauma (27 laparotomies; three observed) were compared with those of 20 patients who had undergone laparotomy for elective surgical problems. Response to mitogen was measured by incorporation of tritiated thymidine as a function of lymphocyte concentration, with a constant amount of phytochemagglutinin and a standard incubation period. A saturation curve was obtained, and lymphocyte response was measured as the concentration necessary for half-maximal incorporation of the radioactive label. No alteration of in vitro lymphocyte response was present in patients after elective abdominal or abdominal wall operations. In contrast, lymphocyte transformation was markedly depressed in patients who underwent surgery following abdominal trauma.

Abdominal Injuries↗
PubMed1986

Arteriography performed in the emergency center.

Arteriography is a sensitive, accurate diagnostic tool for the evaluation of suspected peripheral arterial injuries. A single hand injection study in the emergency center offers a simple, cost-effective, and time-saving maneuver for accomplishing this goal. It is noteworthy that the techniques described are performed with only a minimum of equipment and demand no special training on the part of the radiologic technician. Emergency center arteriography can be beneficial for ruling out suspected peripheral vascular injury in the massively injured patient who will require other extensive procedures. However, the procedure described is probably most beneficial for excluding potential injury in the patient who has no sign of arterial injury other than anatomic proximity of a blunt or penetrating injury to a peripheral vessel. It is true that many surgeons will not order formal arteriograms on an emergency basis for the asymptomatic patient with normal distal pulses, yet we have found that 13 percent of such patients require operative intervention for an arterial injury. It is in precisely this setting that the surgeon can perform a rapid arteriogram in the emergency center. After a negative arteriogram is obtained, the patient can be discharged from the emergency center or admitted for observation with the assurance that arterial injury is absent.

Angiography↗
PubMed1986

Correlation of immunologic and nutritional status with infectious complications after major abdominal trauma.

Examination of the response of injured patients' lymphocytes to the mitogen phytohemagglutin in a defined medium provides a mechanism to define the relationship between alteration in immune function and septic complications. Lymphocytes from 30 victims of gunshot wounds to the abdomen were examined. Response to mitogen was measured by incorporation of [3H]-thymidine as a function of lymphocyte concentration, with a constant amount of mitogen phytohemagglutinin and a standard incubation period. A saturation curve was obtained, and lymphocyte response was expressed as the concentration necessary for half-maximal incorporation of radioactive label, L1/2. Lymphocyte transformation was compared with that found in a group of 50 healthy volunteers. On arrival in the emergency center, the in vitro lymphocyte response of patients was markedly diminished. There were seven patients for whom a lymphocyte curve could not be generated, i.e., L1/2 greater than 1 X 10(6). For the other 23 patients, L1/2 = 4.75 X 10(5) (SEM - 7.5 X 10(4)) compared with L1/2 = 1.5 X 10(5) (SEM - 5 X 10(4)) for normal volunteers (p less than 0.01). Measurement of skin test response, white blood cell count, anthropometric measurements, and albumin level were not predictive of patient course. In contrast the in vitro lymphocyte viability corresponded to the degree of injury, and recovery of lymphocyte function was associated with improvement in the patient's clinical course.

Abdominal Injuries↗
PubMed1984

Emergency center arteriography in the evaluation of suspected peripheral vascular injuries.

From January 1982 through June 1983, 488 patients with suspected peripheral vascular injuries were examined with the use of 515 emergency center arteriograms performed by surgical residents via hand injection of contrast material using a single roentgenographic film. A total of 130 (25%) abnormal arteriograms resulted, including vascular spasm in nine instances and occlusion of noncritical arteries in 19 instances. One hundred two (20%) operations resulted from these abnormal emergency center arteriograms. A diminished pulse rate was the indication for performing 76 arteriograms, 52 (68%) of which were abnormal; however, only 43 patients from this group required surgery. Anatomic proximity to a major vessel was the sole indication for performing 352 arteriograms, 59 (17%) of which were abnormal. There was one false-normal arteriogram, one delayed development of an arteriovenous fistula, and four false-abnormal arteriograms. No complications of arteriography occurred during examination or at the time of clinic follow-up. Single-injection arteriography in the emergency center is a simple, sensitive, accurate, and cost-effective technique for the examination of patients with potential peripheral vascular injuries.

Angiography↗
PubMed1984

Cholelithiasis and cholecystitis in childhood.

In this review of 50 children with gallbladder disease in Houston, Texas, there were an equal number of patients with and without hemolytic disease and a slight predominance of males in both groups. Nearly all had been symptomatic for a prolonged period before diagnosis and cholecystectomy. Common early diagnoses were hemolytic crisis and appendicitis. Ultrasonography has become a very accurate tool for the preoperative evaluation of these children. Once the diagnosis of cholelithiasis is established, elective cholecystectomy is the treatment of choice.

Adolescent↗
PubMed1981

Determination of the ligand-binding characteristics of several tight-binding mutants of the lactose repressor protein.

Several tight-binding mutants of the lactose repressor protein have been characterized with respect to their fluorescence properties and their inducer, operator and nonspecific DNA-binding constants. The tryptophan fluorescence emission spectra for the mutants and the wild-type repressor are quite similar. However, alterations in the Stern-Volmer constants for iodide quenching of the tryptophans in the mutant proteins compared to wild-type suggest differences in the local environment or solvent accessibility for these amino acids in the tight-binding repressors. The inducer-binding affinities and association rate constants of the mutant proteins and protein-operator DNA fragment complexes are also altered compared to wild-type. The extents of these changes vary among the different mutant repressors. The nonspecific DNA-binding affinities of the mutant proteins are 2--3-fold greater than the wild-type repressor, and the affinities of the tight-binding proteins for a 29 base-pair operator DNA fragment are also increased, though to a varying extent depending upon the mutant. The phenotypic behavior of these proteins in vivo can be partially explained by these results obtained in vitro; however, it is likely that there are additional factors responsible for the tight-binding behavior of the proteins that were not detectable in these experiments.

Alleles↗
PubMed1980

DNA binding characteristics of lactose repressor and the trypsin-resistant core repressor.

The nonspecific DNA binding capacity of repressor protein has been assessed by boundary sedimentation of repressor and calf thymus DNA fragmented by shearing and by nitrocellulose ultrafiltration employing labeled lambdaplac DNA in the presence of inducer concentrations sufficient to insure dissociation of repressor from the operator region of the DNA. These methods gave values in good agreement with values previously reported in the literature. The association constants for the interaction of repressor with operator DNA fragments and lambdaplac DNA have been measured and found to differ by approximately 100-fold at low salt concentrations, but the difference decreases to 4-fold at salt concentrations near the physiological value. The equilibrium association constant for the repressor-operator DNA fragment is significantly less sensitive to salt concentration than the corresponding constant for lambdaplac DNA. Inducer decreases the salt concentration dependence of repressor-operator DNA fragment only slightly. Measurement of the association constants for the interaction of the trypsin-resistant core protein with operator DNA fragment and lambdaplac DNA indicate that the core protein binds to the two DNA's with the same affinity. This result contrasts with the differential affinity of intact repressor for these two DNA's. In addition, the core protein association constants for operator DNA fragment and lambdaplac DNA display minimal dependence on the salt concentration. These results suggest a role for nonionic interactions in the binding of core protein to operator DNA.

Animals↗
PubMed1980

Equilibrium binding of inducer to lac repressor.operator DNA complex.

The characteristics of inducer binding to lactose repressor protein in the presence of a small (29 base pair) operator DNA fragment have been examined. The presence of operator DNA fragments decreases the affinity of the protein for inducer molecules. The maximum change observed is a 20-fold increase in the concentration of inducer necessary for half-saturation of the protein. The non-linearity of the Scatchard type plots and slopes of the Hill plots of the binding data indicate that inducer binding exhibits cooperative behavior in the presence of operator DNA fragments, while free repressor binds inducer in a noncooperative fashion. The experimental data for the binding of inducer to repressor both in the presence and absence of saturating amounts of operator DNA fragments were compared to curves predicted by several different models. Using the limits placed by the measured values for repressor-operator DNA-inducer interaction, it was possible to discriminate between the various models. The models which accurately predicted the inducer binding curves and conformed to the measured values for the other parameters were Monod-Wyman-Changeux and Koshland type models with the following features: 1) positive cooperativity in the binding of inducer to the repressor . operator DNA complex; 2) two sites for the binding of the operator DNA fragment to repressor protein; 3) effect of binding of each operator DNA fragment on all four subunits of the repressor. These models are consistent with all of the available data, and they indicate that the binding of the first two inducer molecules accounts for greater than or equal to 60% of the difference in affinities between free and induced repressor for operator DNA; in vivo this difference should be sufficient for induction to occur.

DNA, Bacterial↗