Energy conversion theorems for some linear steady states.

One of the main issues that real energy converters present, when they produce effective work, is the inevitable entropy production. Within the context of nonequilibrium thermodynamics, entropy production tends to energetically degrade human-made or living systems. On the other hand, it is not useful to think about designing an energy converter that works in the so-called minimum entropy production regime since the effective power output and efficiency are zero. In this paper we establish some energy conversion theorems similar to Prigogine's theorem with constrained forces. The purpose of these theorems is to reveal trade-offs between design and the so-called operation modes for (2×2)-linear isothermal energy converters. The objective functions that give rise to those thermodynamic constraints show stability. A two-mesh electric circuit was built as an example to demonstrate the theorems' validity. Likewise, we reveal a type of energetic hierarchy for power output, efficiency, and dissipation function when the circuit is tuned to any of the operating regimes studied here. These are maximum power output (MPO), maximum efficient power (MPη), maximum omega function (MΩ), maximum ecological function (MEF), maximum efficiency (Mη), and minimum dissipation function (mdf).

Glenoid track ''off-track'' as a risk factor for recurrence of anterior glenohumeral instability in postoperative patients.

INTRODUCTION: Glenoid track is used to assess the engagement of Hill-Sachs lesions. The objective of this study was to identify if off-track glenoid track was a risk factor for recurrence of anterior glenohumeral instability in postoperative patients with arthroscopic anterior labrum repair. MATERIAL AND METHODS: Sixty patients with glenohumeral instability who underwent arthroscopic repair of the anterior labrum were studied. Study group (patients with recurrence of postoperative dislocation) and control (no dislocation). Radiographic measurements were made on magnetic resonance imaging and computed tomography. Measurements of glenoid diameter, glenoid bone loss, as well as the presence and size of Hill-Sachs lesions were obtained. Later they were classified as "on-track" or "off-track". RESULTS: Seven (11.67%) patients suffered recurrence, of which six (10%) were carriers of an off-track injury and 1 (1.67%) on-Track. 53 (88.33%) patients did not experience recurrence, of which 11 (18.33%) were carriers of an off-track injury and 42 (70%) on track. A 23.47 increased risk of recurrence of instability was interpreted in patients with "off-track" lesions compared to patients with "On track" lesions. CONCLUSIONS: Off-track injuries were a risk factor for recurrence of instability in patients who underwent Bankart-type arthroscopic repair. This allows us to recommend that the presence of lesions be routinely studied and classified as "on-track" or "off-track" to provide a better therapeutic approach.

INTRODUCCIÓN: El encarrilamiento glenoideo se emplea para valorar el enganche de lesiones Hill-Sachs. El objetivo de este estudio fue identificar si el encarrilamiento glenoideo. MATERIAL Y MÉTODOS: off-track fue un factor de riesgo de recidiva de inestabilidad glenohumeral anterior en pacientes postoperados de reparación de labrum anterior por vía artroscópica. Se estudiaron 60 pacientes sometidos a reparación artroscópica del labrum anterior. Grupo de estudio (pacientes con recidiva de luxación postoperatoria) y control (sin luxación). Las mediciones radiográficas se realizaron en resonancia magnética y en tomografía axial computarizada. Se obtuvieron mediciones del diámetro glenoideo, pérdida ósea glenoidea así como la presencia y tamaño de lesiones de Hill-Sachs. Posteriormente se clasificaron como. RESULTADOS: on-track u off-track. Siete (11.67%) pacientes sufrieron recidiva, de los cuales seis (10%) eran portadores de lesión. CONCLUSIONES: off-track y uno (1.67%) on-track. 53 (88.33%) pacientes sin recidiva, de los cuales 11 (18.33%) eran portadores de lesión off-track y 42 (70%) on-track. Se interpretó un aumento de riesgo de recidiva de inestabilidad de 23.47 en los pacientes portadores de lesión de tipo off-track en comparación con los pacientes portadores de lesiones on-track. Las lesiones.

Comprehensive Review of Cranial Chordomas Using National Databases in the USA.

AIMS: The management of cranial chordomas is controversial. We provide a comprehensive review of the evolving patterns of care of cranial chordomas in the USA. MATERIALS AND METHODS: We analysed the National Cancer Database (NCDB) and the Surveillance, Epidemiology, and End Results (SEER) database between 2004 and 2014 for clinical characteristics and long-term survival, and the National Surgical Quality Improvement Program (NSQIP) dataset between 2005 and 2016 for perioperative characteristics and surgical morbidity. RESULTS: In total, 936 patients were identified from the NCDB, 405 patients from SEER and 64 patients from the NSQIP. Most patients were men (56.2, 54.8 and 57.8% in NCDB, SEER and NSQIP, respectively) and White (80.9 and 83.2% in NCDB and SEER, respectively). Surgery was the preferred treatment modality (87.3% in NCDB and 86.2% in SEER). Surgery was carried out alone (41.8% in NCDB and 40.7% in SEER) or in combination with radiation (42.1% in NCDB and 45.4% in SEER). Proton therapy was the most common type of radiation (32.2% in NCDB), particularly after 2011. The median operative time, median hospital length and postoperative morbidity were significantly higher in chordoma patients compared with patients who underwent other skull-base procedures. The 5-year survival rate was 79.8% in NCDB and 76.9% in SEER. There was a trend towards longer survival in patients receiving surgery and radiation, which has been increasingly used since 2004. Patients younger than 60 years had a decreased risk of mortality. CONCLUSIONS: Our analysis reflects patterns of care in the USA. The use of surgery and radiation is increasing, with a trend towards longer survival. Surgery is complicated with long operative time, hospital stay and a higher rate of complications.

Activation of a P2Y4-like purinoceptor triggers an increase in cytosolic [Ca2+] in the red blood cells of the lizard Ameiva ameiva (Squamata, Teiidae).

An increasing number of pathophysiological roles for purinoceptors are emerging, some of which have therapeutic potential. Erythrocytes are an important source of purines, which can be released under physiological and physiopathological conditions, acting on purinergic receptors associated with the same cell or with neighboring cells. Few studies have been conducted on lizards, and have been limited to ATP agonist itself. We have previously shown that the red blood cells (RBCs) of the lizard Ameiva ameiva store Ca2+ in the endoplasmic reticulum (ER) and that the purinergic agonist ATP triggers a rapid and transient increase of [Ca2+]c by mobilization of the cation from internal stores. We also reported the ability of the second messenger IP3 to discharge the ER calcium pool of the ER. Here we characterize the purinoceptor present in the cytoplasmic membrane of the RBCs of the lizard Ameiva ameiva by the selective use of ATP analogues and pyrimidine nucleotides. The nucleotides UTP, UDP, GTP, and ATPgammaS triggered a dose-dependent response, while interestingly 2MeSATP, 2ClATP, alpha, ss-ATP, and ADP failed to do so in a 1- to 200-microm con- centration. The EC50 obtained for the compounds tested was 41.77 microM for UTP, 48.11 microM for GTP, 53.11 microM for UDP, and 30.78 microM for ATPgammaS. The present data indicate that the receptor within the RBCs of Ameiva ameiva is a P2Y4-like receptor due to its pharmacological similarity to the mammalian P2Y4 receptor.

Tertian and quartan fevers: temporal regulation in malarial infection.

The periodicity in the development of Plasmodium parasites in infected animals, including man, has been known for almost 100 years. In turn, this periodicity is a consequence of the synchronous maturation of the parasite during its intracellular development. The cyclic fever that characterizes malarial infections is the outward manifestation of the parasite development. Until recently, little was known about the mechanisms by which parasite synchronicity is established and maintained. This review surveys the recent literature bearing on two main questions. (1) What are the mechanisms involved in the process of parasite synchronicity? (2) Do the circadian rhythms of the host interfere with the parasite cycle?

Signal transduction in red blood cells of the lizards Ameiva ameiva and Tupinambis merianae (Squamata, Teiidae).

The fluorescent calcium probe, Fluo-3, AM was used to measure the intracellular calcium concentration in red blood cells (RBCs) of the teiid lizards Ameiva ameiva and Tupinambis merianae. The cytosolic [Ca2+] is maintained around 20 nM and the cells contain membrane-bound Ca2+ pools. One pool appears to be identifiable with the endoplasmic reticulum (ER) inasmuch as addition of the sarco-endoplasmic reticulum Ca2+ ATPase, SERCA, inhibitor thapsigargin induces an increase in cytosolic [Ca2+ both in the presence and in the absence of extracellular Ca2+. In addition to the ER, an acidic compartment appears to be involved in Ca2+ storage, as collapse of intracellular pHgradients by monensin, a Na+ -H+ exchanger, and nigericin, a K+ -H+ exchanger, induce the release of Ca2+ from internal pools. A vacuolar H+ pump, sensitive to NBD-Cl and bafilomycin appears to be necessary to load the acidic Ca2+ pools. Finally, the purinergic agonist ATP triggers a rapid and transient increase of [Ca2+]c in the cells from both lizard species, mostly by mobilization of the cation from internal stores.

Red blood cells of the lizards Ameiva ameiva (Squamata, Teiidae) display multiple mechanisms to control cytosolic calcium.

We have previously reported that lizard red blood cells control their cytosolic calcium concentration by sequestering calcium ions in pools, which could be discharged by thapsigargin, by the Na+/H+ ionophore, monensin, by the K+/H+ ionophore, nigericin and by the proton pump inhibitor, bafilomycin A1 [1]. We have now demonstrated, with the aid of confocal microscopy, the presence in these cells of organelles, which accumulate the dye acridine orange and are thus by inference the sites of proton pools. We have found, moreover, that monensin, nigericin and bafilomycin all act to discharge these pools. We further show that calcium release ensues when the calcium ionophore, ionomycin, is added after thapsigargin and monensin; this implies the existence of a third pool, besides the acidic pool and the Endoplasmic Reticulum (ER), which participates in calcium homeostasis. The ER calcium pool can de discharged by the addition of the second messenger, IP3, and we present evidence, based on confocal microscopy, that the IP3 receptors are located in or close to the nucleus.

Calcium homeostasis in intraerythrocytic malaria parasites.

The fluorescent indicator, fura-2, AM, was used to measure free calcium concentrations in the intraerythrocytic malaria parasites of Plasmodium chabaudi and Plasmodium falciparum. In both species the free cytosolic calcium concentration was maintained at low levels (between 40 and 100 nM throughout the maturation process. Digital image analysis of the indicator fluorescence was performed on parasites and evaluated with the aid of a calibration of the calcium response, based on permeabilized parasites, exposed to calcium buffers. This again revealed that free calcium concentrations in the intact parasite are maintained at a predetermined level, regardless of the free calcium in the surrounding milieu. Both species of parasites are thus capable of regulating their internal free calcium levels with high precision, presumably by means of calcium pump ATPases. A small but significant elevation of the cytosolic free calcium concentration by the tumor promoter, thapsigargin, may be taken to reflect the presence of calcium stores in the endoplasmic reticulum in P. falciparum.

Acidic calcium pools in intraerythrocytic malaria parasites.

Calcium uptake by permeabilized P. chabaudi malaria parasites was measured at the trophozoite stage to assess calcium accumulation by the parasite organelles. As determined with 45Ca2+, the total calcium in the parasite was found to be 11 pmoles/10(7) cells. When the K+/H+ uncoupling agent, nigericin was present, this level fell to 6.5 pmoles/10(7) cells. A similar regulatory mechanism operates in P. falciparum, since addition of nigericin to intact parasites in calcium free-medium resulted in a transient elevation of free calcium in the parasite cytosol, as judged by fluorescent imaging of single cells loaded with the calcium indicator fluo-3,AM. 7-Chloro-4-nitrobenz-2-oxa-1,3-diazole (NBD-Cl) and monensin, inhibitors of H+ ATPases and K+/H+ ionophore respectively, induced calcium elevation in fluo-3, AM-labeled intact P. chabaudi parasites. We conclude that malaria parasites utilize acidic intracellular compartments to regulate their cytosolic free calcium concentration.

Production and secretion of complement component 3 by endometriotic tissue.

Many investigators have described a variety of immune phenomena associated with endometriosis. Among these are elevated titers of activated macrophages, monokines, and lymphokines in the peritoneal fluid of patients with endometriosis. In 1980, Weed and Arquembourg first described the deposition of complement component C3 in epithelial cells of endometrial glands in patients with endometriosis. In this study our objective was to examine the synthesis and secretion of proteins by endometriotic tissue. Tissues were incubated in Minimal Essential Medium without methionine containing 50 microCi/mL [35S]methionine for 12-16 h at 37 C in 5% CO2-95% air. Twenty thousand trichloroacetic acid-precipitable counts were placed on a 7.5% sodium dodecyl sulfate-polyacrylamide gel, and the radiolabeled proteins were detected by fluorography. We examined the radiolabeled secretory proteins obtained from 17 endometriotic implants and/or endometrioma cyst walls as well as 8 control tissues. A 180 kDa protein was produced in much greater quantities by endometriotic tissue than by control tissues. In the presence of reducing agent this protein dissociated into 113- and 69-kDa subunits. To identify and quantitate this protein we performed immunoprecipitations on the incubated medium using antihuman C3 immunoglobulin G. Up to 16% of the precipitable counts were recovered with this antibody from endometriotic tissue, while a maximum of only 4.6% was recovered from control tissue. In addition, we isolated and incubated the epithelial glandular cells, stromal cells, and remaining cells from two endometriomas. The great majority of the newly synthesized and secreted C3 was found in the glandular epithelial cell incubation. Up to 60% of the total precipitable counts were recovered from the glandular cells using this antibody. Only one protein was immunoprecipitated. The immunoprecipitated protein had a mol wt of 180 kDa under nonreducing conditions and dissociated into two subunits of 113 and 69 kDa in the presence of dithiothreitol. We conclude that the glandular epithelial cells found in endometriotic implants produce and secrete complement component, C3 which could be responsible for many of the immunological phenomena now well described in endometriosis.

Intravenous catheter-associated Malassezia furfur fungemia.

Malassezia furfur, a lipophilic yeast that is the etiologic agent of tinea versicolor, has not been considered as a cause of serious illness in adults in the past. Two adults are described in whom Malassezia furfur fungemia developed while receiving total parenteral nutrition supplemented with lipids. The organism was identified in blood cultures from both patients only after isolation media were supplemented with a source of fatty acids. Because M. furfur will grow only in media supplemented with fatty acids, clinicians should alert the laboratory whenever a lipophilic organism is suspected to be present in blood cultures.

The psychoneuroendocrinology of the ovulatory cycle of woman: a review.

PIP: This review has as its objective to show that the mammalian, specifically human, ovulatory cycle is subject to many influences which can alter its inherent rhythmicity. This cyclicity is, in essence, a displaying of a pattern that is endogenously driven but which is also subjected to, and subject to, exogenous influences that alter the basic endogenous rhythm. This literature review is in 2 sections. The first discusses 7 major aspects of the endogenous nature of the primate ovulatory cycle: 1) natural rhythmicity of the ovaries; 2) steroid production and control; 3) gonadotropin production and control; 4) prolactin production, effects, and control; 5) monoamine control of the gonadotropins; 6) autonomic innervation of ovarian tissue; and 7) metabolic influence on ovarian cyclicity. This section concludes with a summary of the endogenous aspects of the ovulatory rhythm. Secton 2 reviews 3 exogenous influences of fertility: 1) nutritional influences; 2) geophysical influences; and 3) childbearing and lactation influences on subsequent ovulation.^ieng

Acquired immunodeficiency syndrome-related intraocular B-cell lymphoma.

OBJECTIVES: To present the full clinical spectrum of the acquired immunodeficiency syndrome-related intraocular lymphoma as manifested in the eye, specifically retinal lymphoma associated with primary central nervous system lymphoma, isolated ocular lymphoma, and choroidal lymphoma associated with systemic lymphoma. METHODS: Three patients with acquired immunodeficiency syndrome were noted to have atypical retinal lesions. Diagnostic retinal biopsy in 2 patients and postmortem examination of the eyes in the third case were performed. RESULTS: Diagnostic retinal biopsy in the first 2 patients revealed retinal B-cell lymphoma. Initial systemic evaluation showed the eyes to be the sole site of disease. Later, in 1 of these patients, the lymphoma spread to the brain. The third patient developed an acute abdomen 4 months after the development of his ocular findings. The histological evaluation of the resected bowel revealed high-grade B-cell lymphoma. The patient died 1 week later and postmortem analysis of the eyes disclosed the presence of lymphoma in the choroid of both eyes. CONCLUSIONS: This is the most complete series of patients with acquired immunodeficiency syndrome-related intraocular B-cell lymphoma and, to our knowledge, provides the first 2 cases diagnosed by retinal biopsy. These 3 cases present the full clinical spectrum of the disease as manifested in the eye.

Uterine müllerian adenosarcoma with histiocytic (xanthomatous) mesenchymal component.

We present an endometrial Müllerian adenosarcoma in which the sarcomatous component showed prominent nests of foamy cells that accounted for 50% of the neoplastic mesenchyma. Such foamy cells showed occasional cytological atypias and immunohistochemical features of histiocytic (macrophagic differentiation in the absence of changes that could substantiate the presence of an inflammatory infiltration of foamy histiocytes. These facts suggest histiocytic differentiation from neoplastic mesenchymal cells. Such differentiation has been reported in association with malignant mixed mesodermal tumor, but not in Müllerian adenosarcoma.

Perioperative complications arising after transvaginal oocyte retrieval.

OBJECTIVE: To determine the incidence of perioperative morbidity in patients undergoing transvaginal oocyte retrieval and to identify those patients at greatest risk for complications. METHODS: A retrospective analysis was performed on 674 patients of reproductive age who underwent transvaginal retrieval of oocytes for assisted reproduction technologies during a 3-year period. All procedures were performed by surgeons with extensive experience with transvaginal retrieval. Patients were entered into the program with a primary diagnosis of unexplained infertility (16%), endometriosis (32%), pelvic adhesions and/or tubal occlusion (38%), or infertility from male or immunologic factors (14%). RESULTS: Of the 674 patients studied, ten (1.5%) required hospital admission because of perioperative complications. Nine of these patients needed intravenous antibiotics and one required admission and observation for an expanding broad-ligament hematoma. Six of nine women admitted for antibiotic therapy had a history of extensive pelvic adhesions with or without a history of salpingitis. Five of nine patients had a history of salpingitis. In addition, two patients experienced impressive vaginal arterial bleeding during the procedure. CONCLUSION: This study suggests that transvaginal retrieval may not be as innocuous as is often expressed and that the primary factor predisposing to perioperative morbidity is a history of previous pelvic inflammatory disease and/or adnexal adhesions.

Management of sexually assaulted females.

PIP: The victim of sexual assault has 5 needs: 1) care of injuries, 2) prevention of venereal disease, 3) prevention/alleviation of psychologic damage, 4) medicolegal examination with documentation for law enforcement authorities, and 5) prevention of pregnancy. The staff of Philadelphia General Hospital, in a program designed to meet these needs, treated 480 (24.6 per 100,000 population) victims of sexual assault in 1968. 70% were ages 14-44, 24% below 14 years of age. In this program, serologic testing and cultures are followed by intramuscular injection of penicillin, 2,400,000 units. Both pediatric and adult victims are treated with reassurance, close follow-up and psychiatric referral as indicated. Detection of motile spermatozoa by examination of vaginal aspirate by a qualified experienced laboratory technician is of utmost importance. Postcoital contraceptive therapy revealed a high incidence of gastrointestinal side effects and 4 pregnancies were established in the treated cycle.^ieng

Emotional distress patterns among women having first or repeat abortions.

Thirty-five percent of a sample of 413 women undergoing first-trimester abortions were repeating abortions. All patients rated their emotional symptoms on an SCL-90 scale and completed a brief demographic questionnaire. Preabortion and postabortion emotional distress factors and associated demographic characteristics were compared for women having first and those undergoing repeat abortions. Elevated distress levels were similar in both groups prior to abortion procedures, particularly depression, anxiety, and somatization. After abortion, repeat aborters continued to have significantly higher emotional distress scores in dimensions relating to interpersonal relationships. The variables that discriminated most between first and repeat abortion groups were number of living children, race, and phobic anxiety.

Effect of anovulatory drugs on the human urinary tract and urinary tract infections.

PIP: Over a 1-year period, 44 women using either Demulen, Deladroxate or the Lippes loop were studied at the University of Pennsylvania for urinary tract disorders. Monthly catheterized urine specimens were cultured and examined cytologically. Excretory urograms and serum creatinine examinations were performed 1 month prior to and 6 and 12 months after contraceptive initiation. No effect on the urinary tract was observed by X-ray studies. All serum creatinines remained normal. Urine sediments showed cytologic patterns consistent with phase of cycle. Incidence of asymptomatic bacteriuria was 6.8% initially and 11% during the course of study. Only 1 Demulen patient developed asymptomatic tract infection. Urographic abnormalities were found in a certain percentage of women of reproductive age irrespective of contraceptive use. Study results, are confirmed by urograms of family planning clinic patients, indicate that estrogen-progestogen contraceptives appear to have little significant effect on human tract anatomy or infection rate.^ieng

Episodic secretion of LH and FSH after ovariectomy. Secretory patterns in response to estrogen and progesterone.

PIP: Patterns of LH and FSH secretion were studied in menopausal and ovariectomized subjects by frequent sampling and the influence of ovarian steroids upon these patterns was observed. Subjects were 5 women who had been subjected to bilateral oophorectomy. At 8:00 AM of Study Day 1 (control day), after fasting since midnight, 5 ml of venous blood was drawn and samples were taken at 20 minute intervals thereafter for a period of 8 hours. Patency of the needle was maintained by a slow infusion of normal saline. Blood serum was stored at - 20 degrees C. The next day blood samples were similarly collected for 2 hours. Then, in 2 patients, at 10:00 AM estradiol benzoate 1 mg was administered in a single dose, after which blood samples were collected at 20 minute intervals for an additional 6 hours. On Day 3 the same procedure was followed, except that at 10:00 AM progesterone 100 mg was given in a single intravenous dose. In 3 other patients the order of steroid administration was reversed so that progesterone was given on Study day 2 and estradiol on Day 3. Serum LH and FSH concentrations were determined by double antibody radioimmunoassays. Serum LH and FSH concentrations were increased in all patients. During control periods serum LH levels fluctuated periodically in all subjects. Serum FSH concentration varied episodically in 2 patients. No synchronous pattern was noted either before or after the administration of the drugs. After estradiol was administered on Day 2 to 2 patients, serum LH concentrations declined 39-55% from pretreatment levels and serum FSH levels decreased 15-20%. In these patients episodic increases in both LH and FSH values were observed even after estradiol injection. When progesterone was given on Day 2 and estradiol on Day 3, serum LH concentrations declined promptly. Fluctuation of LH levels were apparent in 2 of the 3 patients. FSH levels declined in only 1. Progesterone alone had no effect on FSH levels. Steroids seem to modify release of gonadotrophin rather than exert sole control over gonadotrophin release.^ieng