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Biomedical subjects

L C Martin

Publications and source records attributed to L C Martin.

At least 19 recordsLinked to original sources
PubMed2006

Is 44-hour better than 24-hour ambulatory blood pressure monitoring in hemodialysis?

The aim of this study is to evaluate if hemodialysis (HD) patients with similar blood pressure (BP) in the whole inter-HD period could have different target organ lesions and survival if the behavior of BP differs from the first to the second day of the inter-HD period. The present study compares 44-hour ambulatory BP monitoring (ABPM) patterns in 45 HD patients. Three BP patterns emerged: group A (n = 15) had similar BPs throughout (138 +/- 11/88 +/- 12 in the first 22 h vs. 140 +/- 11/87 +/- 12 mm Hg in the second 22-hour period); group B (n = 15) had a significant systolic BP rise from the first to the second period (132 +/- 15/80 +/- 12 vs. 147 +/- 12/86 +/- 13 mm Hg, p < 0.05); group C (n = 15) had significantly higher BPs (p < 0.05) than the other 2 groups throughout the whole inter-HD period, with no significant change between the 2 halves (172 +/- 14/108 +/- 12 vs. 173 +/- 18/109 +/- 14 mm Hg). Ventricular mass and survival during the 30-month follow-up period were statistically significantly better in group A, intermediate in group B and worse in group C. The data suggest that a 44-hour ABPM is more accurate than a 24-hour one in evaluating organ lesion and prognosis in HD patients.

Adult↗
PubMed2005

Using information theory to search for co-evolving residues in proteins.

MOTIVATION: Some functionally important protein residues are easily detected since they correspond to conserved columns in a multiple sequence alignment (MSA). However important residues may also mutate, with compensatory mutations occurring elsewhere in the protein, which serve to preserve or restore functionality. It is difficult to distinguish these co-evolving sites from other non-conserved sites. RESULTS: We used Mutual Information (MI) to identify co-evolving positions. Using in silico evolved MSAs, we examined the effects of the number of sequences, the size of amino acid alphabet and the mutation rate on two sources of background MI: finite sample size effects and phylogenetic influence. We then assessed the performance of various normalizations of MI in enhancing detection of co-evolving positions and found that normalization by the pair entropy was optimal. Real protein alignments were analyzed and co-evolving isolated pairs were often found to be in contact with each other. AVAILABILITY: All data and program files can be found at http://www.biochem.uwo.ca/cgi-bin/CDD/index.cgi

Amino Acid Sequence↗
PubMed2005

Acquisition of resistance to extended-spectrum cephalosporins by Salmonella enterica subsp. enterica serovar Newport and Escherichia coli in the turkey poult intestinal tract.

Salmonella enterica subsp. enterica serovar Newport resistant to the extended-spectrum cephalosporins (ESCs) and other antimicrobials causes septicemic salmonellosis in humans and animals and is increasingly isolated from humans, animals, foods, and environmental sources. Mechanisms whereby serovar Newport bacteria become resistant to ESCs and other classes of antimicrobials while inhabiting the intestinal tract are not well understood. The present study shows that 25.3% of serovar Newport strains isolated from the turkey poult intestinal tract after the animals were dosed with Escherichia coli harboring a large conjugative plasmid encoding the CMY-2 beta-lactamase and other drug resistance determinants acquired the plasmid and its associated drug resistance genes. The conjugative plasmid containing the cmy-2 gene was transferred not only from the donor E. coli to Salmonella serovar Newport but also to another E. coli serotype present in the intestinal tract. Laboratory studies showed that the plasmid could be readily transferred between serovar Newport and E. coli intestinal isolates. Administration of a single dose of ceftiofur, used to prevent septicemic colibacillosis, to 1-day-old turkeys did not result in the isolation of ceftiofur-resistant E. coli or Salmonella serovar Newport. There was a remarkable association between serotype, drug resistance, and plasmid profile among the E. coli strains isolated from the poults. This study shows that Salmonella serovar Newport can become resistant to ESCs and other antibiotics by acquiring a conjugative drug resistance plasmid from E. coli in the intestines.

Animals↗
PubMed2004

Association between hypervolemia and ventricular hypertrophy in hemodialysis patients.

BACKGROUND: Left ventricular hypertrophy (LVH) is a well-known predictor of cardiovascular mortality in patients who have end-stage renal disease and are maintained on hemodialysis (HD), and LVH is not always correlated with the severity of hypertension in these patients. The purpose of this study was to investigate the role of other factors contributing to LVH. METHODS: A total of 50 patients with HD were classified in three groups according to whether their LV mass index (LVMI) was higher than (n = 15), equal to (n = 20), or lower than (n = 15) that predicted by a formula based on their ambulatory blood pressure monitoring (ABPM). RESULTS: Subjects with higher LVMI than predicted had significantly greater inter-HD weight gain (3.4 +/- 0.8 v 2.7 +/- 0.8 and 2.6 +/- 05 kg, respectively, in the other two groups, P < .05), and subjects with lower LVMI than predicted had a tendency toward a more pronounced nocturnal dipping pattern of BP (P = .07 v the other two groups), although daytime and night-time average BP levels did not differ between groups. All other clinical and laboratory parameters were similar among the three groups except higher cardiac output and various indices of LVH, which were more pronounced in the group with higher LVMI by ABPM. This group had also the lowest survival rate over the 2 to 3 years of follow-up, with five deaths versus two in each of the other two groups. CONCLUSIONS: The data suggest that correct management of inter-HD weight gain by nutritional counseling and shorter inter-HD intervals may prevent LVH and improve survival independently of BP control.

Adult↗
PubMed2001

Reducing overtriage without compromising outcomes in trauma patients.

HYPOTHESIS: Changing category 1 criteria to include primarily physiologic and anatomic indicators of injury, eliminating mechanism of injury criteria, decreases the rate of overtriage without compromising outcomes. METHODS: Retrospective review of our American College of Surgeons-verified level I trauma registry from January 1, 1996, to December 31, 1998, comparing patients before and after trauma alert criteria changes. RESULTS: There was a significant decrease in category 1 alerts, representing a reduction in overtriage. There was a concomitant increase in injury severity and mortality in category 1 patients. There was no significant change in injury severity or mortality for category 2 patients. CONCLUSIONS: There was a significant reduction in overtriage of trauma patients demonstrated without an appreciable impact on patient outcome. Changing trauma response criteria to more physiologic and anatomic indicators allowed improved triage of trauma patients, which improves resource allocation.

Adult↗
PubMed2000

Focused abdominal sonography for trauma (FAST) in children with blunt abdominal trauma.

BACKGROUND: Focused abdominal sonography for trauma (FAST) has been well reported in adults, but its applicability in children is less well established. We decided to test the hypothesis that FAST and computed tomography (CT) are equivalent imaging studies in the setting of pediatric blunt abdominal trauma. METHODS: One hundred seven hemodynamically stable children undergoing CT for blunt abdominal trauma were prospectively investigated using FAST. The ability of FAST to predict injury by detecting free intraperitoneal fluid was compared with CT as the imaging standard. RESULTS: Thirty-two patients had CT documented injuries. There were no late injuries missed by CT. FAST detected free fluid in 12 patients. Ten patients had solid organ injury but no free fluid and, thus, were not detected by FAST. The sensitivity of FAST relative to CT was only 0.55 and the negative predictive value was only 0.50. CONCLUSION: FAST has insufficient sensitivity and negative predictive value to be used as a screening imaging test in hemodynamically stable children with blunt abdominal trauma.

Abdominal Injuries↗
PubMed1999

Survival of critically ill surgical patients discharged to extended care facilities.

BACKGROUND: Rates of discharge of surgical ICU (SICU) patients to extended care facilities (ECF) increase as SICU length of stay (LOS) increases. Increased SICU LOS and APACHE II scores have been related to increased hospital mortality. This study evaluated factors influencing ECF survival after SICU patient discharge. STUDY DESIGN: We did a longitudinal followup study of patients admitted to our tertiary care SICU during a 2-year period who were eventually discharged to ECF Demographic data, SICU admission APACHE II score, and LOS data were obtained prospectively. Patient followup was obtained 2 years after discharge by telephone interviews with patients themselves or next of kin to ascertain current status or date of demise. RESULTS: Of 1,799 SICU patients admitted during the study period, 160 patients (9%) were discharged to an ECF Telephone followup was obtained from 150 patients (94%). Mean length of followup was 21 months after hospital discharge (range 7 to 34 months), mean patient age 64 years (range 16 to 96 years), mean SICU admission APACHE II score 13 (range 2 to 29), and mean SICU LOS 11 days (range 1 to 146 days). At followup, 45% of patients had died, 37% had been discharged home, and 18% still resided in an ECF or hospital. Elderly patients (above age 65) had significantly worse 1-year (p < 0.001) and 2-year (p < 0.001) ECF survival than nonelderly patients. Patients admitted to the SICU after otolaryngologic procedures also had significantly worse 1- and 2-year ECF survival than all other patients. Severity of illness as estimated by admission APACHE II scores or SICU LOS does not seem to influence survival. CONCLUSIONS: Outcomes of ECF discharge after SICU admission is poor, with nearly 50% 2-year mortality. ECF mortality seems significantly higher for the elderly, with patients undergoing otolaryngologic procedures being at highest risk. Severity of illness at the time of SICU admission and SICU LOS does not seem to influence ECF outcomes.

APACHE↗
PubMed1998

The role of computed tomography in selective management of gunshot wounds to the abdomen and flank.

OBJECTIVE: To determine whether computed tomography (CT) is an accurate diagnostic modality for the triage of hemodynamically stable patients with gunshot wounds of the abdomen and flank. METHODS: A chart review of 83 trauma patients for whom abdominal CT was used as initial screening. RESULTS: In 53 patients, CT revealed no evidence of peritoneal penetration, and in 15 patients, there was evidence of either peritoneal penetration or liver injury. There were no false results in these patients. Among 15 patients with questionable peritoneal penetration, cavitary endoscopy was performed in 11 and exploratory laparotomy was performed in 3, and 1 patient was initially observed and subsequently underwent exploratory surgery for a missed colonic injury. CONCLUSION: In selected centers and in hemodynamically stable patients with abdominal and flank gunshot wounds, abdominal CT can be an effective and safe initial screening modality to document the presence or absence of peritoneal penetration and to manage nonoperatively stable patients with liver injuries. If there is any question of peritoneal penetration, cavitary endoscopy should be part of the protocol of nonoperative management.

Abdominal Injuries↗
PubMed1998

Electrogenic bicarbonate secretion in mouse gallbladder.

Mouse gallbladders (4 mm2) were investigated using the short-circuit current (Isc) technique. Responses of 50 microA/cm2 were obtained in response to forskolin and agents that stimulated the adenylate cyclase system (IBMX and dibutyryl-cAMP). The calcium ionophore ionomycin increased Isc to 30% of the forskolin-stimulated increase. The forskolin-dependent current was inhibited 40% by acetazolamide but was insensitive to furosemide. Forskolin responses were dependent on the presence of bicarbonate ions; removal from both sides of the membrane or the basolateral side alone caused a significant reduction in responses. Removal of chloride ions from the basolateral side had no effect, while removal from the apical side caused a significant reduction in the forskolin responses, but only by 30%. It is argued that the remaining current (70%) cannot result from a parallel arrangement of a chloride channel and a chloride-bicarbonate exchanger and that bicarbonate is secreted through the apical membrane by a predominantly conductive mechanism. Apparently, forskolin converts a near electrically silent epithelium to an electrogenically secreting tissue.

1-Methyl-3-isobutylxanthine↗
PubMed1998

Restoration by intratracheal gene transfer of bicarbonate secretion in cystic fibrosis mouse gallbladder.

Gallbladders from cystic fibrosis (CF) mice (Cftrtm1Cam and Cftrtm2Cam) were examined with the short-circuit current technique. The tissues failed to show any electrogenic anion transport in response to forskolin (cAMP stimulus) but responded to the Ca2+ ionophore ionomycin. Administration of the plasmid pTrial10-CFTR2 complexed with cationic liposomes (3beta-[N-(dimethylaminoethane)-carbamoyl]cholesterol and L-alpha-phosphatidylethanolamine dioleolyl) to the airways restored the phenotype of CF gallbladders to that of the wild type, but did not do so when given orally. Formation of human CFTR mRNA in gallbladders of transfected CF null mice was demonstrated. Using the reporter genes pCMV-luc and pCMV-LacZ, we showed that 1) the intratracheal route was more effective than the oral,intravenous, intramuscular, subcutaneous, or intraperitoneal routes in expressing luciferase activity in the gallbladder and 2) beta-galactosidase staining after pCMV-LacZ was confined to the columnar epithelium lining the gallbladder without any discernible activity in it smooth muscle. The discovery of an unusual route for gene transfer to the biliary system may give useful insight into counteracting the consequences of biliary fibrosis in human CF patients.

Animals↗
PubMed1998

A comparative study of p53 immunoexpression in parathyroid hyperplasias secondary to uremia, primary hyperplasias, adenomas and carcinomas.

OBJECTIVE: To investigate immunoexpression of p53 in parathyroid tumors and hyperplasias and correlate it with the histopathological diagnosis and severity of hyperparathyroidism. DESIGN: A total of 102 parathyroid tissues from archival paraffin-embedded specimens or obtained at surgery between 1988 and 1997 from 65 consecutive individuals with hyperparathyroidism were studied. METHODS: p53 immunoexpression, gland mass, preoperative serum calcium and intact parathyroid hormone (PTH) were analyzed; 14 normal parathyroid glands were used as controls. RESULTS: The histopathological findings were: adenomas (n = 28), primary hyperplasias (n = 12), secondary nodular and diffuse hyperplasias (patients with uremia, n = 57), carcinomas (n = 4) and carcinomatous metastatic tissue (n = 1). Nuclear p53 was detected in 36% of the adenomas, 42% of the primary hyperplastic glands, 72% of the diffuse hyperplasias, 44% of nodular hyperplasias and 40% of the carcinomatous tissues, and was absent from normal glands. p53 expression was significantly more frequent in diffuse hyperplasias than in adenomas (P = 0.037). Serum ionized calcium tended to be higher in p53-positive glands in all histopathological groups; however, the difference was only significant in nodular hyperplasias (P = 0.018). The same trend was observed for serum intact PTH levels of adenomas and nodular hyperplastic glands. Gland mass was not significantly different according to p53 staining. CONCLUSIONS: p53 immunoexpression was not useful in differentiating between the histopathological parathyroid subgroups. p53 immunodetection was particularly frequent in secondary hyperplastic glands of uremic patients. Our study suggests that p53, whether wild-type or mutant, is regulated in parathyroid tumors and hyperplasias. Changes in wild-type p53 may be part of a cellular response to a hyperproliferative condition.

Adenoma↗
PubMed1997

Pyloric exclusion in the management of duodenal trauma: is concomitant gastrojejunostomy necessary?

Pyloric exclusion with gastrojejunostomy (PE-GJ) has been recommended in patients with severe injuries to the pancreatoduodenal complex. Recently, the management philosophy for pancreatoduodenal injuries has been that less treatment is probably the best treatment. But whether gastrojejunostomy (GJ) should be used routinely with pyloric exclusion (PE) remains controversial. A retrospective review was conducted of patients who underwent PE at a Level I trauma center during a 36-month period. Forty-five patients had duodenal injuries and 12 of these (27%) underwent PE for management of complex duodenal injuries. Gunshot wounds were the cause of the injuries in 10 of the 12 patients (83%). Eight patients (67%) underwent PE-GJ and had a mean hospital stay of 25 days. Four patients (33%) underwent PE alone and had a mean hospital stay of 29 days. All 12 patients had spontaneous opening of the PE, regardless of the technique used. One patient (12.5%) in the PE-GJ group developed marginal ulceration and significant hemorrhage, and one patient died in the PE-GJ group. The reported incidence of marginal ulceration in the PE-GJ group, the spontaneous opening of the pylorus, and the need to limit the extent of surgical repair to focus on all other associated lesions present in these patients, suggest that GJ should not be used routinely in patients undergoing PE for the management of severe pancreatoduodenal injuries.

Adult↗
PubMed1996

Hydrocele of the spermatic cord: embryology and ultrasonographic appearance.

Five cases of hydrocele of the spermatic cord are presented. All five patients had a firm inguinal mass, and ultrasonography, performed to exclude adenopathy, incarcerated hernia, and paratesticular tumor, showed an avascular cystic mass superior to and separate from the testicle. A testicular hydrocele did not coexist. This typical appearance should lead to a confident diagnosis of this benign but rare anomaly. Elective surgery may prevent the development of an acquired indirect hernia.

Diagnosis, Differential↗
PubMed1996

Utility of admission chemistry and coagulation profiles in trauma patients: a reappraisal of traditional practice.

To determine whether abnormal results of admission serum chemistry profiles (P7: sodium (Na), potassium (K), chloride (Cl), carbon dioxide content (CO2), blood urea nitrogen (BUN), creatinine (Cr), and glucose (GLU), amylase (AMY), and coagulation profiles (CP: prothrombin time (PT) and partial thromboplastin time (PTT) in trauma patients lead to clinical interventions, and to characterize frequency of abnormal results, we prospectively gathered laboratory data on 500 consecutive patients seen in our Level 1 trauma center. Clinicians were blinded to the study. Abnormal results were found in 93% of P7s, 7% of AMYs, and 59% of CPs. Interventions were made for < 1% of abnormal P7s, 0% of abnormal amylase, and 5% of patients with abnormal CP. We conclude that information provided by routine admission chemistry and coagulation profiles in trauma patients seldom lead to clinical interventions. These tests should not be ordered routinely on admission in trauma patients.

Adolescent↗
PubMed1996

Blunt traumatic injuries to the colon and rectum.

BACKGROUND: Experience in the treatment of patients with blunt colonic injuries is based on isolated case reports, and it is unclear whether the principles that guide the management of penetrating colonic injuries should be applied to these patients. Reviews of patients with these injuries suggest that such injuries present unique problems for diagnosis and treatment and are accompanied by excessive morbidity and mortality. STUDY DESIGN: A 42-month retrospective case series was analyzed. RESULTS: Data from 27 patients were analyzed, accounting for 8.5 percent of all colon and rectal injuries and for 0.5 percent of total blunt trauma admissions. Automobile crashes were the cause of injuries in 20 patients (74 percent). The mean Injury Severity Score was 28. All but 2 patients were operated on within 3 hours after admission. No significant difference was found in the morbidity and mortality rates based on the operation performed to manage the colonic injury. Indications for early exploration included a positive diagnostic peritoneal lavage in 23 patients, abnormal radiologic findings in 2, and positive clinical abdominal findings in the remaining 2 patients. CONCLUSIONS: Blunt colonic and rectal injuries are uncommon and pose problems for diagnosis and treatment. Associated injuries are common, and steering wheel compression of the upper abdomen as well as lap belts seem to predispose to colonic injuries. Initial diagnosis is made at the time of operation, and a thorough exploration of the abdominal cavity is important to diagnose associated injuries. Treatment must be individualized; however, based on our observations, the creation of ostomies is not mandatory for the treatment of these injuries.

Accidents, Traffic↗
PubMed1995

Open versus laparoscopic appendectomy. A prospective randomized comparison.

OBJECTIVE: The authors compare open and laparoscopic appendectomy in a randomized fashion with regard to length of operation, complications, hospital stay, and recovery time. METHODS: Adult patients (older than 14 years of age) with the diagnosis of acute appendicitis were randomized to either open or laparoscopic appendectomy over a 9-month period. All patients received preoperative antibiotics. The operative time was calculated as beginning with the incision and ending when the wound was fully closed. Patients that were converted from laparoscopic to open appendectomy were considered a separate group. Return to normal activity and work were determined by questioning during postoperative clinic, telephone, or mailed questionnaire. RESULTS: There was a total of 169 patients randomized, 88 to the open and 81 to the laparoscopic group. The groups were similar demographically. Of the 81 laparoscopic patients, 13 (16%) were converted to open. In the open group, 70 patients (79.5%) had acute appendicitis and 21 (23.9%) had perforative appendicitis. In the laparoscopic group, 62 patients (76.5%) had acute appendicitis and 10 (12.3%) had perforative appendicitis. There was no statistical difference in the return to activity or work between the laparoscopic and open groups. The operative time was significantly longer in the laparoscopic group (102.2 minutes vs. 81.7 minutes, p < 0.01). The hospital stay of 2.2 days in the laparoscopic group and 4.3 days in the open group was statistically (p = 0.007). There was no difference in the hospital stay for those with acute appendicitis (1.89 days vs. 2.61 days, p = 0.067) compared with those with a normal appendix but with pelvic inflammatory disease (1.1 days vs. 2.3 days, p = 0.11). There was a significant difference in patients with perforative appendicitis (1.5 days vs. 9.5 days, p < 0.01). The hospital cost for patients having laparoscopic appendectomy was $6077 and for an open appendectomy $7227 (p = 0.164). There were no increased complications associated with the laparoscopic technique. CONCLUSION: Laparoscopic appendectomy is comparable to open appendectomy with regard to complications, hospital stay, cost, return to activity, and return to work. There was a greater operative time involved with the laparoscopic technique. Laparoscopic appendectomy does not offer any significant benefit over the open approach for the routine patient with appendicitis.

Adult↗
PubMed1995

The need for aggressive nutritional intervention in the injured patient: the development of a predictive model.

Early nutritional intervention has been advocated in trauma patients. We have developed a model to identify those patients who will most benefit from the invasive and costly measures that are required to provide injured patients with early enteral feedings. Four hundred forty-two patients admitted to a level I trauma center during a 2-month period were evaluated using 21 clinical variables. Time to tolerance of a regular diet was used as the dependent variable in a step-wise regression, and then the selected variables were used to build a classification and regression tree to predict tolerance of a regular diet within 5 days. Our findings demonstrate that intensive care unit disposition, Injury Severity Score, Abdominal Trauma Index, and the need for early surgical intervention are important predictors regarding the need for early nutritional intervention. When the model was applied to the study population, it had a sensitivity of 83%, a specificity of 84%, and an accuracy of 84%.

Adolescent↗