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Biomedical subjects

C E Lucas

Publications and source records attributed to C E Lucas.

At least 37 records · Page 2Linked to original sources
PubMed1997

The role of rectosigmoid neocolporrhaphy.

BACKGROUND: Vaginoplasty for congenital vaginal atresia, a component of the Mayer-Rokitansky-Kuster syndrome, or for gender confirmation, may be achieved by several techniques. This report focuses on the efficacy of rectosigmoid neocolporrhaphy (RSNC) performed either primarily or secondarily after failure of another procedure. METHODS: Sixty patients underwent isoperistaltic RSNC, three primarily and 57 secondarily. The indication was vaginal atresia in 1 patient and gender dysphoria in 59 patients. RESULTS: All 60 patients survived and have a functional neovagina. One major complication, an anastomotic leak with colovaginal fistula, was treated by a temporary colostomy and later reconstruction through a combined anterior and posterior approach. Late complications were reversible stomal stenosis (six patients), reversible conduit narrowing (five patients), transient rhabdomyoblastosis (one patient), and temporary mucosal bleeding from hyperplasia (three patients). Thirty patients have regular intercourse, 12 patients have occasional intercourse, and the others feel "whole," with their intact desired sexual anatomy awaiting a suitable partner. CONCLUSIONS: The number of patients seeking vaginoplasty is increasing. Primary or secondary RSNC is a safe and effective method.

Abnormalities, Multiple↗
PubMed1997

Neurosurgical trauma call: use of a mathematical simulation program to define manpower needs.

Resource criteria for trauma centers (TC) mandate a first plus backup neurosurgeon (NS) coverage, an unnecessary expense for TC treating few neurosurgery patients. This report uses a mathematical modeling system to define optimal NS trauma coverage. Random data from 749 patients treated with emergency neurosurgery operations (OR) within 24 hours of admission at 97 TC were used to create a 1-year profile of admission by month, day, and hour, operation times, and operation duration. These data were entered into a simulation program to define the frequency that a patient needing a NS consult would wait beyond 30 minutes because the NS was in the operating room at a trauma center with one, two, or three neurosurgeons on-call. One thousand iterations were done for each sample size of 25 to 300 patients in 25-patient increments. The probability that a patient could not be seen promptly by one NS in a trauma center operating on 25, 50, 75, or 100 patients per year is 0.23, 0.9, 1.6, and 3.66 patients per year. Fewer than one patient (0.75) per year will wait more than 30 min in a trauma center doing 225 emergency ORs when two neurosurgeons are on-call. One patient in 10 years would wait more than 30 min in a trauma center doing 300 ORs with a third NS on-call. Mathematical modeling of patient data helps define optimal hospital resources. Mandatory NS backup for TC performing fewer than 25 neurosurgery procedures is unneeded.

Computer Simulation↗
PubMed1997

The MtrR repressor binds the DNA sequence between the mtrR and mtrC genes of Neisseria gonorrhoeae.

Gonococcal resistance to antimicrobial hydrophobic agents (HAs) is due to energy-dependent removal of HAs from the bacterial cell by the MtrCDE membrane-associated efflux pump. The mtrR (multiple transferrable resistance Regulator) gene encodes a putative transcriptional repressor protein (MtrR) believed to be responsible for regulation of mtrCDE gene expression. Gel mobility shift and DNase I footprint assays that used a maltose-binding protein (MBP)-MtrR fusion protein demonstrated that the MtrR repressor is capable of specifically binding the DNA sequence between the mtrR and mtrC genes. This binding site was localized to a 26-nucleotide stretch that includes the promoter utilized for mtrCDE transcription and, on the complementary strand, a 22-nucleotide stretch that contains the -35 region of the mtrR promoter. A single transition mutation (A-->G) within the MtrR-binding site decreased the affinity of the target DNA for MtrR and enhanced gonococcal resistance to HAs when introduced into HA-susceptible strain FA19 by transformation. Since this mutation enhanced expression of the mtrCDE gene complex but decreased expression of the mtrR gene, the data are consistent with the notion that MtrR acts as a transcriptional repressor of the mtrCDE efflux pump protein genes.

Bacterial Proteins↗
PubMed1996

Plasma supplementation is beneficial for coagulation during severe hemorrhagic shock.

BACKGROUND: Hemorrhagic shock (HS) often causes coagulopathy due, in part, to decreased coagulation proteins. This study assessed the efficacy of fresh frozen plasma (FFP) in preventing this coagulopathy following a canine model of HS designed to mimic bleeding with shock as seen in the emergency department followed by bleeding without shock as seen during operation for control of bleeding. METHODS: Twenty-two dogs had acute HS for 2 hours followed by resuscitation with red blood cells (RBC) plus lactated ringers (LR) or RBC and LR with FFP. After resuscitation, bleeding was continued for 1 hour while intravenous replacement of RBC and LR with or without FFP was provided. Baseline, postshock, postresuscitation, post-1 hour exchange, postoperative day one and day two measurements included coagulation Factors I, II, V, VII, VIII, and X, and the prothrombin (PT), partial thromboplastin (PTT), and thrombin times (TT). RESULTS: Baseline, postshock, and postresuscitation hemodynamic responses, coagulation factor levels, and coagulation times were similar for both groups. By contrast, the 1-hour postexchange factors were depleted in the LR dogs compared to the FFP dogs. This depletion correlated with prolonged PT, PTT, and TT in the LR dogs (mean 14, 35, and 8 seconds) compared to FFP dogs (9, 24, and 6 seconds). CONCLUSIONS: Severe HS beyond one blood volume exceeds the interstitial stores of coagulation protein, thus necessitating FFP supplementation.

Animals↗
PubMed1996

Hemodynamic, plasma volume, and prenodal skin lymph responses to varied resuscitation regimens.

The theoretical efficacy of hypertonic saline (HS) resuscitation for hemorrhagic shock purportedly stems from the osmolar extraction of intracellular fluid into the plasma. This hypothesis presumes a concomitant expansion of the interstitial fluid space. Colloid resuscitation, in theory, expands the plasma volume by extracting interstitial fluid. These hypotheses were tested in a canine-modified Wigger's model of hemorrhagic shock. Forty, male, splenectomized dogs were anesthetized and instrumented. Animals underwent a baseline equilibration period followed by shock for 120 minutes. Each animal was randomized to one of four groups and received equal amounts of Na+ either as lactated Ringer's (LR) solution, 10% dextran 40 (Dex) in normal saline, 7.5% saline (HS), or 7.5% saline plus Dex (HSD). Parameters measured at baseline, shock, and at postresuscitation 30 minutes, 60 minutes, 90 minutes, and 120 minutes, included: mean pressure (MAP), output, pulmonary capillary wedge pressure, prenodal skin lymph flow, serum and lymph albumin, wet-to-dry skin ratios, and plasma volume. MAP, cardiac output, and plasma volume were most quickly restored with LR and Dex resuscitation (MAP = 106 and 118 mm Hg) compared to HS and HSD (MAP = 98 and 92 mm Hg). Lymph flow and lymph albumin flux were best restored with LR and HSD (mean = 85 and 48 microL/min) compared to Dex and HS (mean = 36 and 37 microL/min). Wet/dry skin ratios were greatest at 60 minutes in the LR group but similar at 120 minutes in all four groups. These data suggest that interstitial fluid space remains contracted during the first hour after HS, HSD, and Dex resuscitation compared with LR resuscitation, even though the restoration of plasma volume, MAP, and cardiac output is greatest with the Dex regimen. Further studies with total body water and intracellular water are needed in this model.

Animals↗
PubMed1995

Retrograde gastroesophageal intussusception complicating chronic achalasia.

We treated a patient with retrograde gastroesophageal intussusception complicating chronic achalasia. Operation consisted of diaphragmatic division in the median plane to facilitate reduction, followed by Heller myotomy and fundoplication for the achalasia. The patient was able to eat normally after recovery.

Adult↗
PubMed1995

Prediction of rib fracture injury outcome by an artificial neural network.

Outcome-based therapy is becoming the standard for assessing patient care efficacy. This study examines the ability of an artificial neural network to predict rib fracture injury outcome based on 20 intake variables determined within 1 hour of admission. The data base contained 580 patient records with four outcome variables: Length of hospital stay (LOS), ICU days, Lived, and Died. A 522-patient training set and a 58-patient test set were randomly selected. Nine networks were set up in a feed-forward, back-propagating design with each trained under different initial conditions. These networks predicted the test set outcome variables with an accuracy as high as 98% at the 80% testing level. Internal weight matrix examination indicated that age, ventilatory support, and high trauma scores were strongly associated with both ICU days and mortality. Being female, injury severity, and injury type were associated with increased LOS. Smoking and rib fracture number were low-level predictors of the four outcome variables.

Adolescent↗
PubMed1995

The value of the medical examiner as a member of the multidisciplinary trauma morbidity-mortality committee.

The multidisciplinary trauma peer review process collects, reviews, discusses, and collates all morbidities and mortalities of injured patients to institute corrective action in a timely manner. The resultant remedial activity may include professional education, physician counseling, restriction of privileges, or changes in the trauma care system. Effective corrective action necessitates timely data input from the postmortem examination. Faced with an inordinate delay, skimpy reports, and expense in obtaining such reports from the medical examiner's office, the chief medical examiner was invited to become a member of the peer review committee. During a 12-month interval as a full-fledged member of the peer review process, the medical examiner was able to provide complete verbal reports on all deaths resulting in a synergistic benefit to the peer review process and to the medical examiner office. Two of 53 nonpreventable deaths were reclassified as possibly preventable in one and preventable in the other. Four of 15 possibly preventable deaths were reclassified based on the medical examiner report. In turn, the physician members of the team were able to augment the medical examiner's knowledge in certain areas that were critical for his analysis of accidents or homicide. Based on these findings, the medical examiner is recommended as a participating member of the trauma peer review committee.

Autopsy↗
PubMed1995

Importance of lipooligosaccharide structure in determining gonococcal resistance to hydrophobic antimicrobial agents resulting from the mtr efflux system.

Levels of gonococcal resistance to antimicrobial hydrophobic agents (HAs) are controlled by the mtr (multiple transferrable resistance) system, composed of the mtrRCDE genes. The mtrR gene encodes a transcriptional repressor that appears to regulate expression of the upstream and divergent mtrCDE operon. The mtrCDE genes encode membrane proteins analogous to the MexABOprK proteins of Pseudomonas aeruginosa that mediate export of structurally diverse antimicrobial agents. In this study we found that a single base pair deletion in a 13 bp inverted repeat sequence within the mtrR promoter resulted in increased resistance of gonococci to both crystal violet (CV) and erythromycin (ERY) as well as to the more lipophilic non-ionic detergent Triton X-100 (TX-100). However, this cross-resistance was contingent on the production of a full-length lipooligosaccharide (LOS) by the recipient strain used in transformation experiments. Introduction of this mutation (mtrR-171) into three chemically distinct deep-rough LOS mutants by transformation resulted in a fourfold increase in resistance to TX-100 compared with a 160-fold increase in an isogenic strain producing a full-length LOS. However, both wild-type and deep-rough LOS strains exhibited an eightfold increase in resistance to CV and ERY as a result of the mtrR-171 mutation. This suggests that gonococci have different LOS structural requirements for mtr-mediated resistance to HAs that differ in their lipophilic properties. Evidence is presented that gonococci exclude HAs by an energy-dependent efflux process mediated by the mtr system.

Bacterial Proteins↗
PubMed1994

Antrectomy. A safe and effective bypass for unresectable pancreatic cancer.

BACKGROUND: Pancreatic cancer is most often diagnosed too late for curative resection. Operative therapy, therefore, involves relief of biliary obstruction and relief or prevention of gastric outlet obstruction. Previous studies show that gastrojejunostomy done either therapeutically or prophylactically often causes delayed gastric emptying. OBJECTIVE: To describe the results of antrectomy with Billroth II reconstruction (A/BII) as the palliative operation for gastric outlet obstruction. SUBJECTS: Fifty patients with unresectable pancreatic cancer underwent A/BII without vagotomy from 1987 through 1993. Of these patients, 42 underwent simultaneous biliary bypass; six had undergone biliary bypass from 3 weeks to 34 months previously; and two with cancer originating in the uncinate process had no biliary bypass. RESULTS: One 87-year-old patient died on day 12 of azotemia and pulmonary insufficiency. The other 49 patients were discharged tolerating an oral diet an average of 11.3 days (range, 5 to 29 days) after A/BII. The length of stay following A/BII was not related to the extent of disease or to preoperative weight loss but was increased in older patients. CONCLUSION: The A/BII is a safe and effective bypass in patients with unresectable pancreatic cancer.

Aged↗
PubMed1994

Regionalization of critical care medicine: task force report of the American College of Critical Care Medicine.

OBJECTIVES: To review the existing literature and task force opinions on regionalization of critical care services, and to synthesize a judgement on possible costs, benefits, disadvantages, and strategies. DATA SOURCES: Pertinent literature in the English language. STUDY SELECTION: One hundred forty-six English language papers were studied to determine possible ramifications of regionalization of critical care or other similar services. DATA EXTRACTION: Information on possible influence on the care of the critically ill was sought and integrated with the opinions of task force members. Possible costs, benefits, as well as disadvantages to the patient, transferring and receiving institutions, and region as a whole were sought. DATA SYNTHESIS: Regionalization of critical care services was thought to be advantageous to the patient. The larger academic institutions tend to have more resources, better subspecialty availability, and expertise in the care of the critically ill. Efficiency and safety during transport need to be in place. Disadvantages of overutilization, possible costliness to both the referring institution as well as to the receiving institution were outlined. It was agreed that pediatric critical care medicine was a separate issue. CONCLUSIONS: Regionalization of critical care medicine probably is beneficial and the concept should be explored.

Adult↗
PubMed1994

Massive steroids do not reduce the zone of injury after penetrating spinal cord injury.

The National Acute Spinal Cord Injury Study II concluded in 1990 that high-dose methylprednisolone (MP) improved neurologic recovery after acute spinal cord injury (ASCI). We tested this conclusion by analysis of 54 patients with ASCI; 25 patients were treated without MP before 1990 whereas 29 patients were treated with MP after 1990. Neurologic deficit was assessed regularly, in most cases daily. Motor and sensory scores on admission, and best results at one-half week (days 2 to 4), 1 week (days 6 to 10), 2 weeks (days 11 to 21), 1 month, and 2 months were noted for both groups. Motor assessment was recorded in 22 muscle segments on a scale of 0 (complete deficit) to 5 (normal); the range, thus, was 0 to 110. The 23 patients with closed injuries demonstrated no difference in improvement with or without MP. In contrast, MP was associated with impaired improvement in the patients with penetrating wounds; the 15 patients with no MP therapy had an admission motor score of 49, which increased by 6.9 at one-half week, whereas the 16 patients treated with MP had an admission motor score of 48, which decreased by 0.3 at one-half week (p = 0.03). The neural status seen by day 4 persisted throughout the next 2 months. Changes in sensation paralleled the changes in motor function. We conclude that MP therapy for penetrating ASCI may impair recovery of neurologic function.

Adolescent↗
PubMed1994

Lower esophageal sphincter dysfunction precludes safe gastric feeding after head injury.

Early nutrition is advocated for patients with head injury to counter the postinjury hypermetabolic state. The gastric route of feeding often leads to vomiting and aspiration pneumonitis. This study was designed to identify the role of lower esophageal sphincter (LES) function in this complication. The LES function was assessed within 72 hours of admission in 16 patients with a head injury and a Glasgow Coma Scale (GCS) score less than 12 (range, 3-11). Other admission assessments included an APACHE II score of 11.7, Injury Severity Score (ISS) of 30.5, and a Revised Trauma Score (RTS) of 6.4. These studies were repeated 1 week postinjury in five patients. Dysfunction of the LES was present in all 16 patients; the average gastric-to-esophageal pressure difference was -0.49 mm Hg (range, -0.59 to 2.5) compared with a normal value of greater than 20 mm Hg. The five patients restudied at 1 week had a gastric-to-esophageal pressure difference of 13.3 mm Hg (range, -3.4 to 36.6 mm Hg). The single patient with a GCS score below 12 at 1 week had a low LES tone. These data show that LES dysfunction accompanies acute head injury and contributes to aspiration pneumonitis after early gastric feeding. Nutrition in patients with low GCS scores should be parenteral or via the jejunum.

Adolescent↗
PubMed1994

Duodenal organ injury severity (OIS) and outcome.

The effect of organ injury severity on outcome was assessed in 101 patients treated for duodenal trauma. Most patients were men (89%) and victims of penetrating wounds (93%). Grade I is minor hematoma or incomplete perforation; Grade II is major hematoma or small complete perforation; Grade III is large perforation excluding ampulla; Grade IV is large perforation at ampulla; Grade V is duodenopancreatic crunch. The injuries were as follows: Grade I (5 patients), Grade II (31), Grade III (40), Grade IV (12), and Grade V (13). Fourteen patients exsanguinated from associated vessel injury; each had Grade IV or Grade V injury. All 36 patients with Grade I and Grade II injury had primary repair; the single death was due to liver necrosis. Most (31 patients) Grade III injuries and three Grade IV injuries were treated by primary repair alone; the three deaths were unrelated to the duodenal injury. Other major injuries were treated by duodenal exclusion (4 patients), duodenal diverticulization (6), or resection (4); the single death was unrelated to the duodenum. Primary closure is favored for minor injuries and most Grade III injuries. Severe injuries may require exclusion, diverticulization, or resection.

Adolescent↗
PubMed1994

Splenic reimplantation does not affect outcome in chronic canine model.

The effects of septic insult were compared in a canine model of splenic reimplantation. Sequential changes in hematologic, hepatic, and immunologic function were monitored biweekly in 18 dogs during 10 months after splenectomy, splenectomy with reimplantation, or sham operation. There was no significant difference in these measures between the two groups. At the end of the 10-month period, spleen scans with technetium (99Tc) labeled, heat-damaged RBCs were obtained on the reimplanted dogs. 99Tc scanning revealed no active splenic implants at 10 months. All dogs were then infected with intravenous Type III pneumococcus for 9 consecutive days. There were no measurable hematologic, hepatic, or immunologic differences between groups before or after the septic insult. These animals were then sacrificed for histologic analysis of the splenic reimplants. Reimplant histology showed active germinal centers, but the surrounding pulp was fibrotic and lymphocyte-depleted. Splenic reimplantation in this canine model yields no apparent benefit.

Analysis of Variance↗
PubMed1994

The technique of visceral packing: recommended management of difficult fascial closure in trauma patients.

Since 1986, we have cared for 17 patients whose abdomen could not be closed because of bowel edema and loss of abdominal wall compliance. These patients were managed by a technique of visceral packing with the intestines kept in place by a combination of rayon cloth, gauze packs, and retention sutures. This packing was changed in the operating room under general anesthesia until the edema was sufficiently resolved to allow for closure. Two patients died within 24 hours of operation from irreversible shock. The remaining 15 patients had their fascia successfully closed with an average of two additional anesthetics. There was one case of fasciitis associated with the development of an intra-abdominal abscess and one patient died of late sepsis. There was no early postoperative ventilatory compromise or acute oliguric renal failure. Other direct complications have been minor with no enterocutaneous fistulae, dehiscence, or incisional hernia. Visceral packing of posttraumatic abdominal wounds circumvents expected complications of intraperitoneal hypertension and enhances the chance for survival. Its ease and low morbidity also lends itself to a wide variety of other uses.

Abdominal Injuries↗
PubMed1993

Management of the difficult abdominal closure.

Hemorrhagic shock and multiple trunk injuries, especially severe pelvic fracture, may cause massive swelling of intra-abdominal viscera and the abdominal wall, thereby precluding safe, primary abdominal wall closure. Primary closure, under tension in such patients, causes a multitude of problems including respiratory compromise, reduced cardiac output, oliguria, enterocutaneous fistulae, impaired abdominal wall nutrient blood supply, necrotizing fasciitis, evisceration, and death of the patient. Multiple methods have been described to aid the surgeon in circumventing these problems. The authors advocate the abdominal wall pack technique, which has the advantages of ease of implementation and a low rate of wound complications.

Abdominal Injuries↗