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Biomedical subjects

J A Acosta

Publications and source records attributed to J A Acosta.

18 recordsLinked to original sources

Foot temperature in diabetic polyneuropathy: innocent bystander or unrecognized accomplice?

AIM: To explore mechanisms by which temperature could influence the pathogenesis and symptoms of diabetic polyneuropathy. METHODS: We conducted a literature review attempting to identify mechanisms by which diabetic polyneuropathy could be affected by temperature. RESULTS: Cooling can theoretically hasten the progression of diabetic polyneuropathy through several different mechanisms. Specifically, cooling can enhance neuronal ischaemia, increase formation of reactive oxygen species, slow axonal transport, increase protein kinase C activity, and interfere with immune function. Short-term temperature fluctuations (both warming and cooling) can initiate and exacerbate neuropathic pain by causing neuronal hyperexcitability and functional deafferentation. Although normal fluctuations of distal extremity temperature may be sufficient for these effects, impaired thermoregulation may make the distal extremities more susceptible to temperature extremes. Eventually, a 'vicious cycle' may ensue, resulting in neuronal deterioration with further disruption of temperature regulation. Limited epidemiological data suggest a higher prevalence of diabetic polyneuropathy in populations living in colder locations, supporting our hypothesis. CONCLUSIONS: Variations in foot temperature may play an important but as yet unrecognized role in the development and symptoms of diabetic polyneuropathy. Further basic and clinical research exploring this concept could help elucidate the natural history of diabetic polyneuropathy and lead to novel therapeutic strategies.

Body Temperature↗

Production and biochemical characterization of the recombinant Boophilus microplus Bm95 antigen from Pichia pastoris.

The new antigen Bm95 from the cattle tick Boophilus microplus was recently isolated, cloned and expressed in the methylotrophic yeast Pichia pastoris. The recombinant protein has shown to induce protection in cattle against infestations of B. microplus under controlled and production conditions. In this paper we report the production and large-scale purification of the Bm95 protein, following a simple and cost-effective process. The antigen was obtained highly aggregated, forming particles ranging from 26 to 30 nm and with purity higher than 80%. The process yield was 0.55 g of pure Bm95 protein per liter of culture. The 98% of the primary structure of the recombinant protein was verified by mass spectrometry. Three amino acid changes in comparison with the sequence deduced from cDNA were detected by LC-MS/MS. The antigen was also obtained N-glycosylated, as previously reported for heterologous protein expression in P. pastoris.

Amino Acid Sequence↗

Neurotoxic, hemorrhagic and proteolytic activities of Duvernoy's gland secretion from Venezuelan opisthoglyphous colubrid snakes in mice.

Many colubrid snakes produce toxic oral secretions. We studied venom (Duvernoy's gland secretion) collected from Venezuelan opisthoglyphous (rear-fanged) colubrid snakes. Different proteins were present in Thamnodynastes stigilis Duvernoy's gland secretion and were characterized by 20% SDS-PAGE protein electrophoresis. The venom displayed proteolytic (gelatinase) activity that was partially purified on a chromatography ionic exchange mono Q2 column. We demonstrated hemorrhagic activity of Thamnodynastes stigilis Duvernoy's gland secretion on chicken embryos and mouse skin and peritoneum. Mice inoculated with Thamnodynastes stigilis Duvernoy's gland secretion presented signs of neurotoxicity. Thamnodynastes stigilis Duvernoy's gland secretion had proteolytic, hemorrhagic, and neurotoxic activities, not previously described in this species and identifies the presence of a new venomous colubrid in Venezuela.

Animals↗

Comparison of a high-protein disease-specific enteral formula with a high-protein enteral formula in hyperglycemic critically ill patients.

AIMS: To determine whether a specific high-protein enteral formula with a similar caloric percentage of fat and carbohydrates achieves greater control over glycemic levels and reduces insulin requirements in hyperglycemic critically ill patients when compared to a control high-protein enteral formula. DESIGN: A prospective, randomized, controlled, single-blind trial in two University Hospital Intensive Care Units in Spain. METHODS: We enrolled 50 patients with diabetes mellitus or stress hyperglycemia with basal glycemia > or =160 mg/dl and indication for enteral nutrition > or =5 days. Patients with severe kidney failure, liver failure or obesity were excluded from the study. In the first 48 h of admission, after randomization, 26 patients received the study diet and 24 patients received the control diet. The variables were monitored for 14 days. The Harris-Benedict formula with a fixed stress factor of 1.2 was used to calculate caloric needs. Insulin was administered by continuous infusion. An intention-to-treat analysis was performed. RESULTS: On admission, there were no differences between the study and control group in plasma glucose levels (mg/dl) (190.9+/-45 vs 210.3+/-63) and capillary glucose levels (mg/dl) (226.1+/-73 vs 213.8+/-67). After the feeding trial, there were differences between the study and control group in plasma glucose levels (mg/dl) (176.8+/-44 vs 222.8+/-47, P=0.001), capillary glucose levels (mg/dl) (163.1+/-45 vs 216.4+/-56, P=0.001), insulin requirements/day (IU) 8.73 (2.3-27.5) vs 30.2 (21.5-57.1) (P=0.001), insulin/received carbohydrates (UI/g) 0.07 (0.02-0.22) vs 0.18 (0.11-0.35) (P=0.02) and insulin/received carbohydrates/kg 0.98 (0.26-3.59) vs 2.13 (1.44-4.58) (P=0.04). These differences remain in a day-to-day comparison. There were no differences in the analytical tests, or in digestive or infectious complications. Intensive Care Unit length of stay, mechanical ventilation and mortality were similar in both groups. CONCLUSIONS: Hyperglycemic critically ill patients fed with a high-protein diet with a similar caloric percentage of fat and carbohydrates show a significant reduction in plasma glucose levels, capillary glucose levels and insulin requirements in comparison to patients on a conventional high-protein diet. This better glycemic control do not modify Intensive Care Unit length of stay, infectious complications, mechanical ventilation and mortality.

APACHE↗

Penetrating colon injuries requiring resection: diversion or primary anastomosis? An AAST prospective multicenter study.

BACKGROUND: The management of colon injuries that require resection is an unresolved issue because the existing practices are derived mainly from class III evidence. Because of the inability of any single trauma center to accumulate enough cases for meaningful statistical analysis, a multicenter prospective study was performed to compare primary anastomosis with diversion and identify the risk factors for colon-related abdominal complications. METHODS: This was a prospective study from 19 trauma centers and included patients with colon resection because of penetrating trauma, who survived at least 72 hours. Multivariate logistic regression analysis was used to compare outcomes in patients with primary anastomosis or diversion and identify independent risk factors for the development of abdominal complications. RESULTS: Two hundred ninety-seven patients fulfilled the criteria for inclusion and analysis. Overall, 197 patients (66.3%) were managed by primary anastomosis and 100 (33.7%) by diversion. The overall colon-related mortality was 1.3% (four deaths in the diversion group, no deaths in the primary anastomosis group, p = 0.012). Colon-related abdominal complications occurred in 24% of all patients (primary repair, 22%; diversion, 27%; p = 0.373). Multivariate analysis including all potential risk factors with p values < 0.2 identified three independent risk factors for abdominal complications: severe fecal contamination, transfusion of > or = 4 units of blood within the first 24 hours, and single-agent antibiotic prophylaxis. The type of colon management was not found to be a risk factor. Comparison of primary anastomosis with diversion using multivariate analysis adjusting for the above three identified risk factors or the risk factors previously described in the literature (shock at admission, delay > 6 hours to operating room, penetrating abdominal trauma index > 25, severe fecal contamination, and transfusion of > 6 units blood) showed no statistically significant difference in outcome. Similarly, multivariate analysis and comparison of the two methods of colon management in high-risk patients showed no difference in outcome. CONCLUSION: The surgical method of colon management after resection for penetrating trauma does not affect the incidence of abdominal complications, irrespective of associated risk factors. Severe fecal contamination, transfusion of > or = 4 units of blood within the first 24 hours, and single-agent antibiotic prophylaxis are independent risk factors for abdominal complications. In view of these findings, the reduced quality of life, and the need for a subsequent operation in colostomy patients, primary anastomosis should be considered in all such patients.

Adult↗

Analysis of motor vehicle ejection victims admitted to a level I trauma center.

OBJECTIVES: The objective of this study was to compare the injuries and outcomes of ejected victims who reached a Level I trauma center with nonejected MVC occupants. METHODS: Data from 6,909 MVC victims admitted to a Level I trauma center, over a 91/2-year period, were retrospectively reviewed. Three mutually exclusive groups were studied: ejected, nonejected nonrestrained, and nonejected restrained. RESULTS: The patient distribution was as follows: ejected 6.4% (n = 443), nonrestrained 50.1% (n = 3,461), and restrained 43.5% (n = 3,005). Ejected patients were younger, required ICU care more frequently, and a higher percentage were males compared with nonrestrained or restrained patients. Injury Severity Score (ISS) and length of stay (LOS) were significantly higher in ejected patients. Ejected patients suffered more injuries per anatomic region, and had a higher number of severe injuries in the head and neck region. The overall in-hospital mortality was 3.9% (272/6,909), and 10.8% (48/443) for the ejected group. The incidence of restrained patients increased during the study period but was not associated with a change in the incidence of ejected patients. CONCLUSION: Patients who were ejected after motor vehicle collisions were more severely injured and had a worse outcome than those not ejected. Efforts should be concentrated on enforcement and enactment of better seat belt laws, as well as the development of new strategies that will prevent ejection regardless of occupant behavior.

Accidents, Traffic↗

Nose muscular dynamics: the tip trigonum.

In 1995, the senior author (E.E.F.) published an article in which he described the musculus digastricus septi nasi labialis. In the article presented here, work carried out by anatomists and other researchers who, over the last two centuries, studied nose muscular dynamics is described. The present study is based on Gray's Anatomy, which, in 1858, first described the nasal tip muscles, along with the other nasal muscles. Later works not only used different terminology for these muscles but also ignored some, creating tremendous confusion. The study presented here provides an update of the exact terms, location, insertions, and muscle functions of the muscles of the nose. Each nose muscle is described with regard to the two portions able to produce separate contractions. In this study, the term "dual function" is used and characterizes the nasal mimetic muscles that do not have well-defined fascia. Therefore, there is doubt about the existence of a real nasal superficial muscle aponeurotic system. The musculus myrtiformis seems to have a dual function, inserting in the canine fosse and in the periosteum of the central incisors, forming two portions-one to the septum and the other to the nostril-each of which has specific functions. This study has been based on research in physiognomy, the science of expression. With regard to the basis for nose expressions, common anatomical research is excluded because it provides a different view of the dynamics studied to date. The term trigonum musculare apicis nasi defines the interaction of the musculi compressor narium minor and dilator naris anterior, connecting with the columellar bundle of the musculus digastricus and levering the nasal spine. This muscular trigone creates circular concentric and eccentric movements of the nasal tip.

Facial Muscles↗

Depletion of intracellular Ca2+ stores, phosphorylation of eIF2alpha, and sustained inhibition of translation initiation mediate the anticancer effects of clotrimazole.

Regulation of translation initiation plays a critical role in the control of cell growth and division in eukaryotic cells. Translation of many growth regulatory proteins including cyclins depends critically on translation initiation factors because their mRNAs are translated inefficiently. We report that clotrimazole, a potent antiproliferative agent both in vitro and in vivo, inhibits cell growth by interfering with translation initiation. In particular, clotrimazole causes a sustained depletion of intracellular Ca2+ stores, which results in activation of PKR, phosphorylation of eIF2alpha, and thereby in inhibition of protein synthesis at the level of translation initiation. Consequently, clotrimazole preferentially decreases the expression of the growth promoting proteins cyclin A, E and D1, resulting in inhibition of cyclin-dependent kinase activity and blockage of cell cycle in G1.

3T3 Cells↗

Validation of selective cardiac evaluation prior to aortic aneurysm repair.

OBJECTIVE: To evaluate perioperative and long-term morbidity in patients undergoing selective evaluation of coronary artery disease prior to abdominal aortic aneurysm (AAA) repair. DESIGN: Case series. SETTING: University and Veterans' Administration medical centers. PATIENTS: One hundred eighty-nine consecutive patients undergoing AAA repair between January 1989 and September 1996 were selectively evaluated for coronary artery disease and assigned to 1 of 3 groups: group 1, no abnormal cardiac history, normal electrocardiogram; group 2, minimal symptoms, history of myocardial infarction (MI), older than 70 years, diabetes mellitus, or congestive heart failure; or group 3, severe or unstable angina, ventricular dysfunction. INTERVENTIONS: Group 1 patients proceeded to AAA repair without further workup. Group 2 patients underwent pharmacologic or exercise stress testing followed by coronary angiography and intervention as required. Group 3 patients went directly to coronary angiography and intervention as needed. MAIN OUTCOME MEASURES: Perioperative MI, arrhythmias, or death. Long-term follow-up measures included MI and death. RESULTS: Adequate documentation was available on 171 patients. Twenty-four patients (14%) were in group 1. Of 136 patients (79.5%) in group 2, coronary angiography was performed in 36 (26%), followed by percutaneous transluminal coronary angioplasty (PTCA) in 9 (7%) and coronary artery bypass (CAB) in 5 (4%). Of 11 patients in group 3, 3 (27%) each received PTCA and CAB. Remote CAB or PTCA had been performed in 32 (19%) and 12 (7%) patients, respectively. Two perioperative deaths (1.1%) occurred in the 189 patients, one due to MI in a group 2 patient. There were 2 (1%) nonfatal MIs, both in group 2 patients who had no preoperative intervention. Arrhythmias and/or congestive heart failure occurred in 17 (9%) cases, 7 (39%) having had recent coronary revascularization (P = .001). By univariate analysis, only preoperative renal dysfunction predicted perioperative complications (P = .03) Overall survival by lifetable analysis was 87.9% and 69.7% at 3 and 5 years, respectively. CONCLUSION: Coronary artery disease is common in patients undergoing AAA repair, with 35.7% having preoperative coronary revascularization at some point. Selective preoperative coronary artery disease screening achieves excellent perioperative and late results in this population.

Aged↗

Lethal injuries and time to death in a level I trauma center.

BACKGROUND: The purpose of this study was to identify the causes and time to death of all trauma victims who died at a level I trauma center during an 11-year period. STUDY DESIGN: Autopsies were performed on all patients who died secondary to trauma. Retrospective review of these autopsies was carried out and appended to existing trauma registry data. Standard definitions were used to attribute the cause of death in each case. Preventable deaths were determined by a standardized peer review process. RESULTS: Between January 1985 and December 1995, a total of 900 trauma patients died. This represented 7.3% of all major trauma admissions (12,320). Seventy percent of these patients died within the first 24 hours of admission. Thoracic vascular and central nervous system (CNS) injuries were the most common causes of death in the first hour after admission to the hospital. CNS injuries were the most common causes of death within the 72 deaths after admission. Acute inflammatory processes (multiple organ failure, acute respiratory distress syndrome, and pneumonia) and pulmonary emboli were the leading causes of death after the first 72 hours. Overall, 43.6% (393 of 900) of all trauma deaths were caused by CNS injuries, making this the most common cause of death in our study. The preventable death rate was 1%. CONCLUSIONS: The first 24 hours after trauma are the deadliest for these patients. Primary and secondary CNS injuries are the leading causes of death. Prevention, early identification, and treatment of potentially lethal injuries should remain the focus of those who treat trauma patients.

Accidents, Traffic↗

Angiodysplasia as the cause of massive lower gastrointestinal hemorrhage in a young adult. Report of a case.

PURPOSE: This study was undertaken to clarify the importance of bleeding vascular ectasia of the colon as the etiology of massive lower gastrointestinal hemorrhage in patients 40 years of age or younger. METHODS: An otherwise healthy 21-year-old male was admitted to a tertiary medical center with massive lower gastrointestinal hemorrhage. Technetium-labeled red blood cell scan, selective visceral angiography, and colonoscopy identified the source of bleeding as vascular abnormality of the descending colon. Segmental colonic resection was performed. RESULTS: Histologic review of the specimen demonstrated a vascular ectasia. The patient recovered uneventfully and has had no further stigmata of hemorrhage. A review of the literature was undertaken to make clear the significance of vascular ectasia as the source for massive colonic hemorrhage in the young adult. CONCLUSION: This is the first report that documents histologically a vascular ectasia as the source of massive lower gastrointestinal hemorrhage in an otherwise healthy patient less than 40 years of age. Vascular ectasia is an uncommon cause of lower gastrointestinal hemorrhage in the young adult.

Adult↗

T1 breast carcinoma in women 70 years of age and older may not require axillary lymph node dissection.

BACKGROUND: The current trend in breast cancer treatment is toward breast conservation and selective use of axillary lymph node dissection. Patient eligibility criteria for treatment without axillary dissection are evolving. METHODS: We retrospectively reviewed the tumor registry over a 10-year period at Naval Medical Center San Diego and included all women aged 70 and older with T1 breast carcinoma (n = 78). Data included tumor size, surgical therapy, post-operative therapy, recurrence, and survival. The women were divided into groups by the approach taken toward the axilla. RESULTS: No patient was given adjuvant chemotherapy. There were no axillary cancer recurrences in our patients. No statistically significant difference existed, regardless of the approach to the axilla, in recurrence or survival between groups. CONCLUSION: Axillary dissection in this population did not influence postoperative treatment, decrease recurrence, or improve survival. Our study suggests breast cancer treatment in this population should not include axillary dissection.

Age Factors↗

The transient pore formed by homologous terminal complement complexes functions as a bidirectional route for the transport of autocrine and paracrine signals across human cell membranes.

BACKGROUND: We have previously shown that the membrane attack complex (MAC) of complement stimulates cell proliferation and that insertion of homologous MAC into the membranes of endothelial cells results in the release of potent mitogens, including basic fibroblast growth factor (bFGF). The mechanism of secretion of bFGF and other polypeptides devoid of signal peptides, such as interleukin 1 (IL-1) is still an open problem in cell biology. We have hypothesized that the homologous MAC pore itself could constitute a transient route for the diffusion of biologically active macromolecules in and out of the target cells. MATERIALS AND METHODS: Human red blood cell ghosts and artificial lipid vesicles were loaded with labeled growth factors, cytokines and IgG, and exposed to homologous MAC. The release of the 125I-macromolecules was followed as a function of time. The incorporation of labeled polypeptides and fluorescent dextran (MW: 10,000) was measured in MAC-impacted human red blood cells and human umbilical endothelial cells (HUVEC), respectively. RESULTS: Homologous MAC insertion into HUVEC resulted in the massive uptake of 10-kD dextran and induced the release of bFGF, in the absence of any measurable lysis. Red blood cell ghosts preloaded with bFGF, IL-1 beta, and the alpha-chain of interferon-gamma (IFN-gamma) released the polypeptides upon MAC insertion, but they did not release preloaded IgG. MAC-impacted ghosts took up radioactive IFN-gamma from the extracellular medium. Vesicles loaded with IL-I released the polypeptide when exposed to MAC. CONCLUSIONS: The homologous MAC pore in its nonlytic form allows for the export of cytosolic proteins devoid of signal peptides that are not secreted through the classical endoplasmic reticulum/Golgi exocytotic pathways. Our results suggest that the release, and perhaps the uptake, of biologically active macromolecules through the homologous MAC pore is a novel biological function of the complement system in mammals.

Biological Transport↗

Surgical margins after needle-localization breast biopsy.

BACKGROUND: The use of needle-localization breast biopsy (NLBB) for the early diagnosis of breast cancer is common. The therapeutic adequacy of tumor-free margins following NLBB is unknown. We hypothesized that the presence of residual tumor after reexcision (mastectomy, tylectomy, or quadrantectomy) does not depend on the margin status following NLBB. PATIENTS AND METHODS: Retrospective cohort analysis was performed on 890 consecutive NLBBs executed between January 1990 and June 1994. Patients with invasive breast neoplasia were divided into two groups based on the tumor margins after NLBB. Group 1 were the women with positive margins, and group 2 had negative margins. Breast specimens after reexcision were reviewed for evidence of residual invasive carcinoma. RESULTS: Invasive neoplasia was present in 107 patients (12%). Surgical margins and definitive records of care were available for 96 of them (90%). All 45 patients in group 1 and 38 (75%) of 51 patients in group 2 underwent reexcision of the initial biopsy site (P = 0.36). Residual invasive carcinoma was present in 10 patients (22%) in group 1 and 3 (8%) in group 2 (P = 0.13). CONCLUSION: Invasive breast neoplasia diagnosed by NLBB requires reexcision regardless of tumor margins to achieve complete local surgical eradication of tumor.

Adult↗

Precholecystectomy esophagogastroduodenoscopy: is it of value?

Patients with cholelithiasis and history of atypical abdominal pain present the surgeon with a challenging clinical problem. We hypothesized that preoperative esophagogastroduodenoscopy before cholecystectomy would identify patients with concomitant upper gastrointestinal pathology. Retrospective review of 143 patients who presented with atypical abdominal pain, gallstones, and underwent EGD before their cholecystectomy between July 1989 and March 1994. A total of 1162 cholecystectomies were performed during the study period; 143 patients (12 per cent) underwent a preoperative EGD because of atypical abdominal pain. One hundred ten patients (77 per cent) had normal endoscopies. Thirty-three patients (23 per cent) had abnormal findings. Gastric polyps were found in three patients and esophageal varices in one patient. There were 36 findings in 29 patients, which included peptic ulcer disease, esophagitis, gastritis, and duodenitis. Seven patients had two abnormal findings. Moderate to severe disease was found in a total of 13 (9 per cent) patients. We recommend that patients who present with cholelithiasis and atypical abdominal pain undergo preoperative esophagogastroduodenoscopy, as we have found that at least 9 per cent of the patient population will have significant findings that may alter their management.

Abdominal Pain↗

Colonoscopic evaluation of rectal bleeding in young adults.

The role of colonoscopy in the evaluation of blood loss per rectum has been studied extensively in older patients but not in the younger adult population. The objective of this study was to review the diagnostic yield of colonoscopy in patients 40 years of age or younger with passage of minimal amounts of bright red blood per rectum or occult blood positive stools. Retrospectively, 5924 colonoscopic examinations were reviewed. All patients, 40 years of age or younger, with rectal bleeding as the only indication for colonoscopy were selected. A total of 280 patients met these criteria and 59 (21%) had significant findings. Polyps were present in 25 (8.9%) of patients. Other findings included colitis, diverticular disease, and angiodysplastic lesions present in 8.6 per cent, 2.1 per cent, and 1.1 per cent, respectively. Adenocarcinoma was present in one patient (0.03%). These results suggest that colonoscopy in patients 40 years of age or younger with rectal bleeding may be justified because significant findings may be present in up to 21 per cent of patients.

Adenocarcinoma↗

Colonic diverticular disease in patients 40 years old or younger.

Diverticular disease in patients 40 years of age or younger has been described as rare but virulent. Previous studies, based on age, on diverticular disease are often confusing because of inexact definitions of the disease status. With these criticisms in mind, the authors studied 322 clinical records on patients admitted with a diagnosis of colonic diverticulosis or diverticulitis to the University of New Mexico Hospital and the Lovelace Medical Center. Of these patients, 285 had documented evidence of colonic diverticula with only 6 per cent of these being 40 years of age or younger. The criteria for acute diverticulitis were met by 86 patients, 17 of whom were 40 years of age or younger. The younger group had disproportionately more men, particularly Hispanics. The authors conclude that acute diverticulitis is more common in the young than suggested by previous reports, but the behavior of the disease is not distinctive.

Acute Disease↗

Barotrauma associated with high-frequency jet ventilation for hypoxic salvage.

Most reports describe reduction in proximal airway pressures with high-frequency jet ventilation. This led us to speculate that high-frequency jet ventilation might reduce barotrauma by providing alveolar ventilation at lower airway pressures. We describe a group of patients in whom a high incidence of barotrauma was observed after institution of high-frequency jet ventilation despite reduction in measured airway pressures. Fifteen hypoxic patients who could not be treated with conventional ventilation and who had no roentgenographic evidence of barotrauma were entered into the study. Airway pressures were measured during conventional ventilation and at 2 and 24 hours after high-frequency jet ventilation. Despite significant reduction in peak inspiratory and mean airway pressures, pneumothorax developed in seven of the 15 patients, an average of 21 hours after initiation of high-frequency jet ventilation. Five patients had bilateral pneumothorax and three developed tension pneumothorax. Despite reductions in proximal airway pressures, barotrauma is a significant potential complication of high-frequency jet ventilation in patients with noncompliant lungs. We currently place bilateral prophylactic thoracostomy tubes in patients with adult respiratory distress syndrome prior to initiation of high-frequency jet ventilation.

Adult↗