Job stress and burnout in acute and nonacute pediatric nurses.

To identify predictors of burnout in pediatric nurses and to compare the incidence of burnout, job stress, anxiety and perceived social support in acute and nonacute care pediatric nurses. Prospective correlational-descriptive methodology was used to predict high, moderate or low burnout from length of work experience, perceived work stress and social support and anxiety. Registered nurses (n = 121) employed full-time in neonatal and pediatric intensive care units and pediatric intermediate care units. Measures of job stress, anxiety, experience, social support and burnout were compared in acute and nonacute care pediatric nurses. The overall mean incidence of burnout was in a moderate range for both acute and nonacute care pediatric nurses for the emotional exhaustion and depersonalization subscales and in the high range of personal accomplishment subscales of the Maslach Burnout Inventory. Analysis of variance revealed no differences between groups. However, when nurses were grouped by high, moderate and low burnout scores, chi-square analysis revealed significant differences. More acute care nurses reported high burnout and more nonacute care nurses reported low burnout. Discriminant function analysis revealed that job stress was the strongest significant predictor of burnout, followed by state anxiety, coworker support, trait anxiety and experience on the unit. Even though high burnout levels are more frequent in acute care pediatric nurses, burnout is a problem in both acute and nonacute care pediatric nurses. The pattern of results suggests that efforts directed toward reducing anxiety and job stress and increasing coworker support, particularly for less experienced nurses, might reduce burnout.


Survey of the degree to which critical care nurses are performing current procedural terminology-coded services.

To identify the degree to which current procedural terminology-coded services are provided by critical care nurses. Current procedural terminology codes are used by government and private insurers for reimbursement for office, home, hospital, nursing home and emergency department services. Out of 100 randomly selected registered nurses invited to participate in this national survey, 43 completed the survey questionnaire. The majority of respondents were 18 to 40 years old, had a bachelor's degree, had practiced nursing between 5 and 10 years, and were employed as staff or charge nurses in an intensive care or emergency room setting. More than 70% of the group were found to perform 28 codes. The codes performed by the greatest number (42) were blood or blood component transfusion and cardiopulmonary resuscitation. One-way analysis of variance applied to the amount of supervision the nurses received while performing the codes and the educational level of the nurses revealed a significant difference between the groups. Post hoc analysis of all possible group comparisons showed that diploma-prepared nurses reported significantly more supervision than nurses having a bachelor's or master's degree. This exploratory study indicates that critical care nurses frequently perform selected codes with little or no supervision by a physician.


Computerized clinical simulations: a strategy for staff development in critical care.

Identifying the learning needs of employees and evaluating the results of staff development offerings are essential elements of the responsibilities of the staff development educator. High patient acuity, the shortage of critical care nurses, and rapidly changing technology within the critical care environment demand the provision of staff development offerings that are appropriate for the learning needs of critical care nurses and the evaluation of the effect of programs on critical care nursing practice. The purposes of this descriptive, correlational study were to compare the ability of a knowledge test, a self-evaluation tool, and computerized clinical simulations to discriminate between nurses with varied levels of knowledge and experience, and to compare the learning needs identified from the three types of evaluative instruments. Each subject (n = 142) completed the Basic Knowledge Assessment Tool for Critical Care, Cardiovascular Self-Evaluation Tool, and four computerized clinical simulations. Both the Basic Knowledge Assessment Tool and the Cardiovascular Self-Evaluation Tool discriminated between experienced/inexperienced and Advanced Cardiac Life Support-certified/noncertified critical care nurses. The computerized clinical simulations discriminated according to Advanced Cardiac Life Support certification, but not between experienced and inexperienced critical care nurses. The computerized clinical simulations identified more specific learning needs than did the Basic Knowledge Assessment Tool or Cardiovascular Self-Evaluation Tool. The evidence for discriminant validity, adequate internal consistency reliability, and ease of administration supports the continued use of these two tools as methods for critical care staff development needs assessment and evaluation. In addition, the study findings support the use of computerized clinical simulations as an adjunct to other needs assessment and evaluation methods in nursing staff development.


Fluctuation in mixed venous oxygen saturation in critically ill medical patients: a pilot study.

To determine fluctuation in mixed venous oxygen saturation in critically ill medical patients during a period of rest. Nonexperimental, descriptive. The medical and coronary intensive care units in a large county hospital in south-central Texas. Twenty critically ill patients, aged 19 to 85, who had placement of a pulmonary artery catheter capable of continuous monitoring of mixed venous oxygen saturation. The majority had a diagnosis of respiratory failure and required mechanical ventilation. Mixed venous oxygen saturation was recorded each minute for a 2-hour period in either early morning or late afternoon hours. Minute-by-minute values obtained during a 30-minute period of rest were used to determine fluctuation. The lowest and highest mixed venous oxygen saturation values during the period were used to calculate percent changes from average values (fluctuation). The range of fluctuation was +/- 6% of the average mixed venous oxygen saturation value for 80% of the sample. Four patients had a greater range of fluctuation: however, their actual mixed venous oxygen saturation values were within a clinically acceptable range. No significant differences in percentage of low or high fluctuation were noted for the following variables: time of day, medication administration, oxygen delivery, oxygen consumption and average mixed venous oxygen saturation. The percentage of low fluctuation was significantly lower for four patients who were not mechanically ventilated. Knowledge of normal fluctuation enables the care giver to evaluate changes in mixed venous oxygen saturation in response to activities and/or treatments. Additional study of fluctuation in homogenous groups of critically ill patients is warranted.


Management of ventricular arrhythmias: then and now.

To review the changing environment of antiarrhythmic therapy. The majority of articles chosen were written by experts in the field of arrhythmia management. The references include a pilot study, abstracts, original articles and results of study groups. An equal number of sources used in this article were obtained from fellow healthcare professionals and MEDLINE searches. Large, controlled clinical trials in which patient populations had structural heart disease, prior myocardial infarction and/or frequent ventricular premature beats. All were treated with either antiarrhythmic therapy or devices. Past research in the field of arrhythmia management has indicated that ventricular premature beat suppression is the key to increasing patient survival. After reviewing the results of such pivotal trials as the Cardiac Arrhythmia Suppression Trial, however, the question of whether to initiate therapy remains. Several trials investigating the efficacy of antiarrhythmic drugs in decreasing sudden death have yielded disappointing results. These trials have been beneficial, however, in classifying arrhythmias and assessing patient risk. The outcomes of these trials, combined with advances in the treatment of heart disease, provide us with a framework for antiarrhythmic therapy. Additional controlled clinical trials are necessary if we are to learn the best means of increasing survival in ventricular arrhythmia patients.


Family-centered critical care: an option or obligation?

The patient was dying after undergoing aggressive treatment for a malignancy. Patient and family wanted "everything" to be done and the patient was transferred to the ICU for treatment of acute respiratory failure. The next day the patient's condition deteriorated further. The family decided against chest compressions or defibrillation; however, other aggressive treatment was continued. A "chemical code" was initiated and the patient was ventilated. The family was informed. As they stood in the hall outside the unit, the patient's wife asked if she could be with her husband. A nurse explained what she would see and accompanied her to the bedside. She stood at the head of the bed, stroked her husband's head and spoke softly in his ear. The patient's son came to the bedside and said his last words to his father. The wife was present when treatment was stopped and the patient was pronounced dead. She said to the nurse who had accompanied her, "You have given me the greatest gift possible--you allowed me to be with my husband at the end."


When weaning from mechanical ventilation fails.

To describe the etiologies and indicators of weaning failure and to provide a framework for planning interventions to facilitate weaning of long-term ventilation patients. A Medline search of human studies in English on weaning from mechanical ventilation. Articles were selected if they pertained to the assessment and management of weaning failure. Both research and review articles were included. All pertinent articles were described, along with their limitations. Weaning from mechanical ventilation is an emerging science. Caring for patients who are difficult to wean requires expert clinical decision making so patients do not feel defeated and have the best chances for success. Combining the limited research on weaning intervention with clinical expertise helps to build a scientific basis for care and can assist clinicians in tailoring interventions to specific problems that precipitate weaning failure. A scientific approach to care may promote weaning in difficult cases and provide directions for future research into the etiologies of weaning failure.


Myocardial ischemia during the weaning period.

To estimate the incidence of silent myocardial ischemia, its pattern over time and its relationship to the time and mode of weaning high-risk cardiac patients after noncardiac surgery. Prospective study with random assignment to one of three weaning modes. A surgical intensive care unit in a university hospital and a Veterans Administration hospital. Sixty-two patients meeting standard criteria for extubation were randomized to one of three modes of weaning: synchronized intermittent mandatory ventilation (n = 19), T-Bar (n = 21) or continuous positive airway pressure (n = 22). Ischemia was monitored with a continuous two-lead (V5, III) ST segment analyzer. Tracings were reviewed by a cardiologist. Ischemia was defined as greater than 1 mm ST segment depression 60 milliseconds after the J point. The monitoring period included a prewean (mean 654.0 minutes), wean (mean 46.5 minutes) and postwean (mean 1223.4 minutes) period. Of 62 patients, 12 (19.3%) experienced ischemia at some time during the monitoring period, most often during the weaning period. Ischemia during weaning was detected in 3 of 21 (14.3%) T-Bar patients and 2 of 22 (9.1%) continuous positive airway pressure patients but in no synchronized intermittent mandatory ventilation patients. This study demonstrates that silent myocardial ischemia occurs frequently in high-risk postoperative patients, with the highest incidence during weaning.


Job satisfaction among critical care nurses.

To develop a conceptual path model to explain the effects of a set of personal and work-related independent variables and the dependent variables of situational stress, job stress and job motivation on job satisfaction among critical care nurses. A prospective descriptive study using a conceptual path model. Nine hospitals licensed for at least 250 beds in the northeastern, northwestern, northcentral, and southern regions of Florida. Three hundred female critical care nurses employed in the nine hospitals who had worked full-time for at least 3 months. Subjects were administered a demographic and work survey questionnaire, Daily Hassles Instrument, Psychological Hardiness Test and the Job Diagnostic Inventory. A conceptual path model was constructed to illustrate the effects of a set of personal and work-related independent variables and the dependent variables of situational stress, job stress and job motivation on job satisfaction. Path analysis of a job satisfaction model resulted in a causal progression of situational stress leading to either job stress or job motivation, both affecting job satisfaction. The results showed that job stress, job motivation, job expectations, meaningful work, knowledge of work results, commitment to career, health difficulties, task identity, supervision, dealing with others at work, opportunity for advancement, pay and job security had a significant effect on job satisfaction. Thirteen variables had a significant effect on job satisfaction and explained 63% of the variance. The four most significant effects on job satisfaction were opportunities for advancement, meaningfulness of work, pay and supervision. Commitment to the career, task identity and job security had a modest effect on job satisfaction.


Characteristics and health service utilization patterns of ventilator-dependent patients cared for within a vertically integrated health system.

To describe the characteristics and service utilization patterns of long-term ventilator-dependent patients. Using medical records, a cohort of ventilator-dependent patients was identified and followed. A vertically integrated healthcare system in southwestern Pennsylvania. Forty-nine adults requiring prolonged ventilatory assistance. Demographics, admission date, admission diagnosis, discharge diagnosis, reason for ventilator dependency, level of care to which the patient was admitted, dates of all transfer orders, dates of all transfers between levels of care, discharge destination and subsequent readmissions. The major reason for long-term ventilator dependency was progressive debilitating disease of either a pulmonary or nonpulmonary nature. The mean length of stay within the system was 72.6 days +/- 42.55 (median = 59 days, range = 24 to 267 days). Patients had an average of 3.3 transfers +/- 2.53 within the system (median = 3, range = 0 to 10). No delays in transfer to lower levels of care were found. Health utilization variables were largely unrelated to reason for ventilator dependency. Almost half of the patients (n = 24 or 49.0%) died in the system. Patients who died in the system were significantly older than patients for whom discharge home was possible. Additional studies are necessary to describe the prevalence, etiology, health status and functional status of ventilator patients at all levels of care; the impact of different system approaches on patient well-being and cost of care; and the process of medical decision making. Economic analyses of costs and outcomes for ventilator-dependent patients using a cost-utility approach are also needed.


Terminal weaning from mechanical ventilation: ethical and practical considerations for patient management.

Decisions to withdraw life-sustaining therapy are being made more often as patients and healthcare providers increase their awareness of patient rights. The process of withdrawal of mechanical ventilation must be conducted in a humane fashion. An understanding of the ethical, legal and practical considerations for patient management during this type of intervention will enhance the ability of the healthcare provider to participate.


Effects of a closed tracheal suction system on ventilatory and cardiovascular parameters.

To determine whether patients ventilated in the assist-control mode experienced a change in oxygenation, respiratory rate, inspiratory:expiratory ratio, heart rate, blood pressure or acid-base balance when suctioned with a closed tracheal suction system. A quasi-experimental, within-subject, repeated-measures design was used. 18 patients ventilated on a fraction of inspired oxygen of 0.47 +/- 0.17 and 2.3 +/- 5.0 cm H2O positive end-expiratory pressure. Two suction passes were performed, with measurements at baseline, immediately after the first suction pass, immediately before the second suction pass, immediately after the second suction pass, 2 minutes after the second suction pass and 5 minutes after the second suction pass. No hyperoxygenation was used. Significant differences were seen over time for arterial oxygen saturation, respiratory rate and inspiratory:expiratory ratio. Arterial oxygen saturation decreased to less than 90% in four subjects (range 88% to 89%), with a maximum fall of 9%. No significant differences were seen for heart rate, blood pressure, partial pressure of carbon dioxide, bicarbonate, time to nadir (lowest arterial oxygen saturation) or recovery time. Subjects ventilated in the assist-control mode and suctioned with a closed tracheal suction system did not experience significant changes in cardiovascular or acid-base parameters when suctioned without hyperoxygenation. Although most subjects did not become desaturated, four subjects experienced desaturation at one or more intervals. To prevent desaturation, hyperoxygenation should be used before and after suctioning with a closed tracheal suction system.


Preventing hypoxemia and hemodynamic compromise related to endotracheal suctioning.

To help the clinician bridge the gap between research and practice in determining ways to minimize side effects of endotracheal suctioning. This article summarizes four previous reviews of research and studies published between 1984 and 1991 related to oxygenation techniques before, during and after endotracheal suctioning, and hemodynamic consequences of the suctioning procedure. Studies were reviewed by type of subject: animals, human subjects with normal lung function, and human subjects with abnormal lung function. Research of pediatric and head-injured populations was excluded from this review. Oxygenation protocol, endotracheal suction characteristics, outcomes and measurement times, sample and setting, and findings were presented. Conclusions relate to the effectiveness of various endotracheal suction protocols on prevention of hypoxemia and hemodynamic compromise in intubated patients. An algorithm to guide clinical decision making is presented based on the conclusions of this review of the research.


Characteristics of a child's critical illness and parents' reactions: preliminary report of a pilot study.

To explore the relationships between parents' reactions to the pediatric intensive care unit admission of a child and characteristics of the child's illness. A convenience sample, consisting of 16 mothers and 13 fathers of 16 children aged 5 years and younger, was used. The Pediatric Risk of Mortality scale was used to measure severity of illness. Parental reactions were measured at about 24 hours after the child's admission with the Parental Stressor Scale: PICU and the Parental Concerns Scale. Mothers' concerns and stressors were not related to the child's Pediatric Risk of Mortality score. However, fathers reported greater concern about the child's experience and about parenting as the child's Pediatric Risk of Mortality score increased. Parents' reactions to their child's critical illness and admission to the pediatric intensive care unit were not related to characteristics of the child's condition in this small sample. Future research needs are suggested.


An evaluation of interventions for meeting the information needs of families of critically ill patients.

To evaluate the effectiveness of two methods of meeting the information needs of families of critically ill patients: an open visiting hour policy and a family information booklet. Medical intensive care unit of a university medical center. Family members (N = 147) of patients admitted to the medical intensive care unit. Implementation of an open visiting hour policy and information booklet. Questionnaires were distributed to family members 24 to 48 hours after the patient's admission. The questionnaire addressed family satisfaction with having specific information needs met and posed questions that tested their knowledge of unit policies and personnel. The questionnaire was distributed to three groups: families who had restricted visiting hours and no booklet (group 1, n = 48), families who had open visiting hours but no booklet (group 2, n = 50), and families who had open visiting hours and an information booklet (Group 3, n = 49). Implementation of an open visiting hour policy increased family satisfaction. Families exposed to both the open visiting hours and the information booklet were more knowledgeable about specific details than were those exposed to only the open visiting hour policy. Flexible visiting hours and information booklets were two practical methods of meeting the information needs of families. Open visiting hours, as a singular intervention, significantly improved family satisfaction. The effectiveness of the booklet in assisting families to recall discrete pieces of information supports the further development and use of preprinted materials to assist in meeting family information needs.


Comparison of PT and aPTT values drawn by venipuncture and arterial line using three discard volumes.

Blood samples obtained through heparinized arterial catheters are used routinely for a variety of laboratory tests. Accuracy of coagulation studies performed from samples obtained in this fashion continues to be questioned, particularly in regard to the minimum discard volume necessary to clear the catheter of heparinized solution. To examine differences between prothrombin time and activated partial thromboplastin time values obtained from blood drawn by venipuncture and from an indwelling intra-arterial line using three discard volumes. Prothrombin time and activated partial thromboplastin time samples were drawn by venipuncture from 41 critically ill adult patients. Simultaneously, three consecutive blood samples of 2.3 mL were drawn from the arterial line after an initial discard volume of 3 mL (discard volumes of 3.0, 5.3 and 7.6 mL). Significant differences were found between arterial and venous prothrombin time values for the 3-mL discard volume group, as well as between arterial and venous activated partial thromboplastin time values for all three discard volume groups (paired t-test, Bonferroni correction). We recommend that when drawing prothrombin time and activated partial thromboplastin time samples from an arterial line, a 5.3-mL discard volume be used.


Mathematical model for agonist-induced oscillatory calcium waves in non-excitable mammalian cells.

Many non-excitable cells display cytosolic Ca2+ oscillations resulting from the periodic release of Ca2+ from intracellular stores. Recent observations in hepatocytes and some other cell types have shown that agonist-induced Ca2+ oscillations often display an intracellular spatial organization and do not occur synchronously within the cell. Ca2+ waves evoked by different agonists originate from the same subcellular locus and propagate through the cell with a constant rate of progress and amplitude. This indicates that Ca2+ waves are driven by a self-propagating mechanism and not by diffusion alone. We propose a simplified one-dimensional mathematical model to describe this phenomenon based on the mechanism of calcium-induced calcium release. The numerical solution of the system of two coupled non-linear partial differential equations reproduces many of the main features observed experimentally.


A rare synaptoid contact between gland cells in the anterior pituitary.

A rare type of cell-to-cell contact has been identified between the corticotropes in the anterior pituitary of the dog. It bears synaptoid features.


Implication of tryptophan in the stimulatory effect of delta-sleep-inducing peptide on indole secretion from perifused rat pineal glands.

We have recently demonstrated that delta-sleep-inducing peptide (DSIP) stimulates indolamine secretion from rat pineal glands. In the present study, we show that tryptophan (TRP), as well as DSIP, stimulate melatonin (MEL) and 5-methoxy-tryptophol (5-ML) secretion in a dose-dependent manner between 5 x 10(-6) and 10(-4) M. The kinetic characteristics of the MEL and 5-ML secretion and the response induced by the two substances were similar. The increase in MEL secretion in response to 10(-4) M DSIP was completely inhibited by pretreatment of the pineals with 10(-5) M phenanthroline (amino-peptidase inhibitor), suggesting that stimulatory effect of DSIP was due to TRP liberated by peptide degradation. This mechanism occurring in the pineal was confirmed using 10(-4) M para-chlorophenylalamine (TRP hydroxylase inhibitor), which reduced the pineal response to 10(-4) and 10(-5) M DSIP by 50 and 100%, respectively.


Antisense oligonucleotide-mediated inhibition of metallothionein protein synthesis in neuroblastoma IMR 32 and Chang liver cells in culture.

A synthetic antisense oligodeoxyribonucleotide with sequence complementary to the messenger RNA (mRNA) coding for human metallothionein (MT) II was prepared and tested for its ability to inhibit both constitutive- and cadmium-induced MT protein synthesis in neuroblastoma-IMR and Chang liver cells in culture. The sense oligonucleotide was also prepared and tested as a control for its sequence-specific effects. Oligonucleotide entry into cells was enhanced through the use of a polybrene carrier so that nearly 30% of a 10 microM dose of oligonucleotide was shown to be associated with cells. The antisense oligonucleotide inhibition of MT protein synthesis rendered both cell types more sensitive to cadmium toxicity. However, the sense oligonucleotide had no effects on either MT protein synthesis or sensitivity to cadmium toxicity.


Isomorphism, task dependence, and the multiple meaning theory of neural coding.

The neural coding problem is defined and several possible answers to it are reviewed. A widely accepted answer descends from early suggestions that neural activity, in general, is isomorphic with sensation and that the biological signals resident in the axons of neurons, in particular, are given by their frequency of firing. More recent data are reviewed which indicate that the pattern of neural responses may also be informative. Such data led to the formulation of the multiple meaning theory which suggests the neural pattern may encode different information features in single responses. After a period in which attention turned elsewhere, the multiple meaning theory has quite recently been revived and has stimulated novel and careful experimental investigations. A corollary theory, the task dependence hypothesis, suggests that these information-bearing multiple response features are accessed differentially in different behavioral tasks. These theories place stringent temporal requirements on the generation and analysis of neural responses. Recent data are examined indicating that both requirements may indeed be satisfied by the nervous system. Finally, several methods of experimentally testing such coding theories are described; they involve manipulating the biological signals of neurons and observing the effect of these manipulations on behavior.


Flight effects on plasma levels of neurohypophysial hormones in homing pigeons.

A significant increase in the circulating levels of arginine vasotocin (AVT), without change in plasma osmolality, was observed in homing pigeons immediately after a flight of 48 km, lasting 60-80 min. This increase in plasma AVT is perceived as part of an overall homeostatic mechanism of mobilizing lipid as fuel for the flight muscles, of water conservation and temperature regulation in the body during the homing flight within the specific distance and duration of flight and under normal weather conditions. However, there was no change in plasma levels of mesotocin (MT) which suggests that the birds were under no significant stress during the flight.


Nicotinic versus muscarinic binding sites in cat and rabbit carotid bodies.

It has been suggested that acetylcholine (ACh) might play an important role in carotid body chemoreception. However, a unified explanation of the actions of ACh in this organ has been lacking, due in part to the opposite pharmacological effects of this agent on carotid sinus nerve discharge in different animal species, most notably the cat, where ACh is excitatory, versus the rabbit, where it is inhibitory. In the present study, we utilized receptor binding techniques to compare the nicotinic and muscarinic receptor populations in the carotid bodies of these two species. Our results with the nicotinic ligand 125I-alpha-bungarotoxin and the muscarinic ligand 3H-quinuclidinyl benzilate suggest that nicotinic receptors predominate in the cat by a ratio of 2:1, while in the rabbit, a 12:1 ratio favors muscarinic receptors. Our data suggest that the relative numbers of muscarinic and nicotinic receptors in the carotid bodies of these two species determine the excitatory or inhibitory actions of exogenously administered ACh in this chemoreceptor organ.


Inhibitory action of peptide YY on pancreatic secretion is independent of secretin.

The purpose of this study was to characterize the effect of peptide YY (PYY) on acid-stimulated pancreatic bicarbonate secretion and to determine whether PYY affects the release of secretin in response to intraduodenal infusion of acid. Six dogs were prepared with gastric and pancreatic cannulas. In study 1, graded doses of hydrochloric acid (HCl) (3, 6, 12, and 24 mEq/h) were given intraduodenally alone or in combination with intravenous PYY (400 pmol/kg.h). In study II, and ED50 of intraduodenal HCl (6 mEq/h) was given alone or in combination with graded doses of PYY (12.5, 25, 50, 100, 200, and 400 pmol/kg.h, i.v.). Bicarbonate output was significantly inhibited during PYY infusion at 200 and 400 pmol/kg.h, but plasma secretin levels were unchanged. The calculated maximal response for bicarbonate secretion (5.1 +/- 1.3 mEq/15 min) was significantly reduced by PYY (2.1 +/- 0.7 mEq/15 min). We concluded that PYY can inhibit acid-stimulated pancreatic bicarbonate secretion without affecting the release of secretin. The mechanism of the inhibitory effect of PYY on acid-stimulated pancreatic bicarbonate secretion is compatible with a noncompetitive type of inhibition.


Effects of anticoagulants and incubation time on neutrophil nitroblue tetrazolium score.

We studied the effect of anticoagulants and incubation time on neutrophil nitroblue tetrazolium (NBT) scores. Heparin (10 IU/ml) and EDTA (1.5 mg/ml) were used, and the preparations were incubated for periods ranging from 20 to 180 min. Heparin, in contrast to EDTA, was found to be associated with cell destruction, cell aggregates and higher NBT scores; the effects were more profound with endotoxin stimulation. The duration of incubation significantly affects NBT scores in both the heparin- and EDTA-anticoagulated samples, and the effect is more marked with heparin. Cell destruction and cell clumping are both enhanced with incubation, again more so with heparin. It is concluded that when performing NBT tests, blood samples would best be anticoagulated with EDTA to ensure more consistent results.


Effect of a cholecystokinin antagonist, proglumide, on cholecystokinin-8-induced gallbladder contraction in conscious dogs.

The objective of this study was to characterize the effect of proglumide, a cholecystokinin (CCK) antagonist, on gallbladder contraction stimulated by CCK in conscious dogs. The gallbladder contraction was monitored by a strain-gauge force transducer that was chronically sutured onto the serosal surface of the gallbladder. The results of this study show that proglumide, given as an intravenous bolus (2.5, 5, 10, 20, and 40 mg/kg) or as a continuous intravenous infusion (150 or 300 mg/kg/h, 10 min), can block the stimulatory action of CCK in a dose-related manner. Bolus administration of proglumide resulted in a transient inhibition, whereas continuous infusion of proglumide resulted in a prolonged antagonism of CCK-stimulated gallbladder contraction. Review of the data leads to the conclusion that the antagonistic action of intravenously administered proglumide on CCK-stimulated gallbladder contraction may be characterized as rapid and reversible.


Light-related melatonin changes in pituitary response to gonadotropin-releasing hormone during sexual development in the female rabbit.

Melatonin levels in the blood of female rabbits were determined from the time of weaning to adulthood in a longitudinal study. Blood samples were taken at 3 h after light onset and 1 h after dark onset and plasma was analysed for melatonin, LH and FSH by radioimmunoassay procedures. The animals were sacrificed on days 25, 32, 39, 51, 72, 91 and 120 days of life and pituitaries removed for in vitro incubation of slices to determine their response to GnRH. Circulating melatonin levels were significantly higher in the dark compared to the light phase and peaked on days 72 and 91 when gonadotropin levels were at a nadir. Melatonin levels on day 120 were lower than those on any other day examined. Basal secretion of LH and FSH by pituitary slices in vitro increased several-fold from day 25 of age to days 51-91 and then decreased by day 120. The pituitary gonadotropin responsiveness to GnRH in vitro was also different: while LH generally increased, FHS accumulation remained constant after GnRH stimulation. These data suggest that the female rabbit pituitary undergoes changes in sensitivity to GnRH during sexual maturation and that the pineal gland may play a role in this process.


Insulin-like growth factors.

The insulin-like growth factors (IGF-I and IGF-II) play important roles in the regulation of growth and metabolism. While the liver is the main source of circulating IGFs, their production by numerous extrahepatic tissues suggests the existence of autocrine and paracrine modes of action in addition to typical endocrine mechanisms. The actions of the IGFs are mediated through their activation of specific cell surface receptors, primarily the IGF-I receptor, although some effects may be mediated through the IGF-II receptor and the insulin receptor. The stability of the IGFs and their interaction with their receptors are mediated by specific IGF binding proteins (IGF-BPs) which are found in the circulation and in extracellular fluids. Thus, the overall biological actions of the IGFs can be regulated by control of ligand biosynthesis, modulation of receptor levels and postreceptor signalling pathways, and changes in the levels and activity of IGF-BPs.


Genistein inhibits DNA synthesis but has no effect on levels of DAG and IP3, cell rounding and alkalinization in sulphate-treated Chang liver cells.

Agonist-activated phosphoinositide (PI)-specific phospholipase C initiates PI hydrolysis to produce signals implicated in mitogenic signaling in which the cyclin-dependent cdc2-protein kinase of the maturation-promoting factor is a major protein-tyrosine kinase (PTK) substrate. It has been suggested that PI mitogenic signals are separable into PTK-dependent and non-PTK-dependent by genistein, a tyrosine-specific protein kinase inhibitor. However, we show here that DNA synthesis was abolished in human Chang liver cells although the sulphate-induced PI second messengers, i.e. inositol 1,4,5-trisphosphate and sn-1,2,diacylglycerol, were at equivalent dose-response levels with or without genistein (0.5 mM, 135 microgram/ml). This genistein dosage had been demonstrated to be effective in suppressing tyrosyl phosphorylation in cells. There was no increase in the trypan blue dead cell index. We have shown previously that human Chang cells stimulated by this 'non-growth-factor' agonist, i.e. sulphate, as well as extracellular ATP, became rounded with raised intracellular pH. ATP-induced cell rounding and intracellular alkalinization were not affected by the presence of genistein (0.5 mM). In the present investigation, that genistein dosage had also no effect on these cellular responses when initiated by added sulphate. It seems that the mitogenic signaling function of PI second messengers is dissociable and requires unsuppressed PTK activity.


Localization of GTP-binding protein Go in the enteric nervous system in rat ileum.

The localization of a GTP-binding protein G(o) was examined immunohistochemically in rat ileum using antibodies against the alpha-subunit of G(o) (G(o) alpha). G(o) alpha-positive fibers clearly demonstrated the topography and structure of the enteric nervous system of the ileum. G(o) alpha was present only in the nervous system and was generally distributed both in synapse-rich and in nonsynaptic areas. The distribution of G(o) alpha in a nonsynaptic area suggests the possibility that G(o) may be involved not only in neurotransmission mechanisms but also in other functions.


Extraction, discrimination and analysis of single-neuron signals by a personal-computer-based algorithm.

We communicated a computer algorithm that is capable of concurrently extracting, discriminating and analyzing single-neuron signals from adjacent neurons, particularly those with poor signal-to-noise ratio or contaminated by 60-Hz noise and/or baseline drift. Based on a continuous process of differentiation and peak-to-peak amplitude discrimination, our algorithm provided a two-dimensional amplitude histogram that readily distinguishes the clusters of spike signals representing different neurons. The inclusion of a time domain in our three-dimensional amplitude histogram further allowed us to simultaneously evaluate the temporal responses of neighboring cells to the same experimental manipulation. In addition to retaining many of the advanced features of existing extraction and discrimination procedures, this method offered the benefits of being efficient, requires minimal supervision and operates in real time even during long-term recording. Above all, it is cost effective because it is purely software based and only requires a PC-AT compatible general purpose computer.


Role of stroma in oestrogen-induced epithelial proliferation.

To examine the role of stromal-epithelial interactions in the response of epithelial cells to oestrogens, tissue recombinations were prepared with epithelium (E) and stroma (S) from the vagina (V) and urinary bladder (BL), that is between oestrogen target tissues (VS and VE) and non-target tissues (BLS and BLE). Following 3 weeks of growth in intact female hosts, ovariectomy was performed and 1 week later the hosts subjected to various hormonal treatments. Whereas homotypic vaginal tissue recombinations (VS+VE) exhibited epithelial cornification and mucification (cycling), this activity was not observed in homotypic bladder recombinants (BLS+BLE) or in heterotypic tissue recombinants between vaginal and bladder tissues (VS+BLE and BLS+VE). In BLS+VE recombinants the epithelium remained atrophic and failed to respond to exogenous oestrogen alone or in combination with progesterone. This lack of hormonal responsiveness of vaginal epithelium was completely reconstituted when the epithelium of BLS+VE recombinants was recovered and reassociated with fresh vaginal stroma (VS). Examination of epithelial proliferative activity ([3H]thymidine labelling index) demonstrated a marked oestrogen-induced increase in epithelial proliferation in VS+VE recombinants. BLS+BLE recombinants were unresponsive to oestrogen as were recombinants composed of BLS+VE. However, when bladder epithelium was grown in association with vaginal stroma (VS+BLE) the epithelium exhibited an 8-fold oestrogen-induced increase in labelling index over oil-treated specimens. The lack of an oestrogen-induced proliferative response of vaginal epithelium in BLS+VE recombinants was reversed when the vaginal epithelium of these recombinants was recovered and reassociated with fresh vaginal stroma. These results indicate that the effects of oestrogen and progesterone on both epithelial differentiation and proliferation are critically dependent upon the appropriate stromal environment.


Neurotensin secretion in response to intraduodenal and intraileal administration of fat in dogs.

Release of neurotensin from the small intestine in response to administration of fat directly into the duodenum and ileum was examined in conscious dogs. The present results show that: (1) intraduodenal administration of fat causes a diphasic release of neurotensin which is mediated, at least in part, by cholinergic mechanisms, and (2) both a fatty acid (sodium oleate) and a triglyceride, when infused directly into an isolated ileal loop, stimulate a significant release of neurotensin. Our findings indicate that release of neurotensin is triggered by mechanisms originating in the proximal small intestine and by a direct contact of nutrients with the ileal mucosa.


Synthetic antisense oligonucleotide probes the essentiality of metallothionein gene.

The metallothionein II gene, whose structure is highly conserved throughout the animal kingdom, is composed of three exons and two introns. Synthetic antisense oligonucleotides (ODN), with sequence complementary to the messenger RNA coding for human metallothionein II, were prepared and tested for their ability to inhibit both constitutive- and cadmium-induced metallothionein protein synthesis in human Chang liver cells and hamster lung V79 cells in culture. The property of sense ODN was also examined as a measure of sequence specificity. The antisense inhibition of metallothionein protein synthesis rendered all cell lines more susceptible to the toxic effects of cadmium. However, the sense ODN had no effects on either metallothionein protein synthesis or sensitivity to cadmium. Phosphorothioate oligonucleotides were more potent in enhancing the toxicity of cadmium than phosphodiester oligonucleotides. The antisense oligonucleotides targeted to the splice donor region between exon 1 and intron 1 was significantly more effective as an inhibitor than those targeted to either the 5' end of the mRNA or within exon 3. Therefore, not all antisense oligonucleotide sequences are equally efficient as inhibitors of metallothionein synthesis. Therefore, the delineation of an obvious mechanism for predicting the most potent sequence is not apparent at this time. The results of this study are interpreted to indicate that (a) metallothionein is endowed with an essential gene, (b) modifications in oligonucleotide structures show specificity in inhibiting metallothionein synthesis, and (c) antisense inhibition of metallothionein gene expression may provide a useful tool in studying the action and perhaps the function(s) of metallothionein.


Circadian variations in cell cycle phase progression of mouse epidermal cells measured directly by bivariate BrdUrd/DNA flow cytometry.

Circadian stage-dependent variations in cell cycle traverse of mouse epidermal cells in vivo were investigated. The fate of cohorts of basal cells pulse-labelled with bromodeoxyuridine (BrdUrd) at different times of the day were studied by bivariate BrdUrd/DNA flow cytometry of isolated epidermal basal cells. Basal cells were tracked through the cell cycle up to 96 h after intraperitoneal injection of BrdUrd at 0800 and 2000, or followed for 6 h after BrdUrd injection at 0400, 1200, 1600 and 2400. The results confirmed our previous assumption that the cell cycle progression through S phase and G2 phase is considerably delayed at night, i.e. from 1600 to 0400, compared with daytime. The results indicate variations in G1 phase as well. The data strongly support the hypothesis that the main parameters responsible for circadian fluctuations in mitotic activity are variations in the S and G2 phase durations. The data are also consistent with the notion of proliferative heterogeneity among basal cells as described by a hierarchical proliferation model.


Clinical applications of cultured epithelium.

Techniques that allowed the successful serial subcultivation of human keratinocytes into sheets of epithelium suitable for grafting have made possible a variety of clinical applications for cultured epithelium. Following the first description of this technique in 1981 to treat third-degree burns, cultured keratinocytes derived from a small biopsy of the patient's normal skin (autografts) have been used in centres throughout the world to provide permanent wound coverage for extensive burns. Over the years, applications have expanded to include the treatment of leg ulcers and blistering skin disorders. A further development in this field has been the use of cultured epithelium derived not from the patients own skin, but from an allogeneic donor (cultured allograft). Cultured allografts have also been widely used in the treatment of burns, leg ulcers, the donor sites for split-thickness grafts, and other dermatological disorders. These allografts seem to act as a potent stimulus to wound healing, but do not survive permanently on the wound bed. Their postulated mechanism of action is through release of multiple cytokines that stimulate epithelialization from the wound periphery as well as from adnexal elements within the wound bed. Allograft application is a simple outpatient procedure which involves no discomfort for the patient. No skin biopsy is necessary and cryo-preservation of grafts for future use is possible.


[125I]iodomelatonin-binding sites in the chicken kidney: characterization and comparison to other avian species.

The existence of [125I]iodomelatonin-binding sites in the kidney of the chicken and other avian species has been demonstrated in the present study. [125I]Iodomelatonin-binding sites in membrane preparations of the chicken kidney were reversible, saturable, specific and of high affinity. Scatchard analysis of the specific binding revealed an equilibrium binding constant (Kd) of 30.3 +/- 5.1 pmol/l (n = 5) and a total number of binding sites (Bmax) of 2.89 +/- 0.24 fmol/mg protein (n = 5) at the middle of the light period (mid-light). The Hill coefficient approached 1.0, suggesting a single class of [125I]iodomelatonin-binding sites in the chicken kidney. The diurnal variation study showed that the Bmax was 52% higher at mid-light than that in the middle of dark period (1.90 +/- 0.33 fmol/mg protein, n = 4; p < 0.05), with no significant variation in Kd. The Kd value determined from kinetic analysis was 10.8 pmol/l in the mid-light birds, which was comparable to values determined from equilibrium studies. The competition inhibitor experiments demonstrated that [125I]iodomelatonin-binding sites were highly specific for melatonin with the following order of potency: 2-iodomelatonin > melatonin, 6-chloromelatonin > 6-hydroxymelatonin N-acetylserotonin >> 5-methoxytryptamine, 5-methoxytryptophol, 5-hydroxyindole-3-acetic acid, 5-hydroxytryptamine, 1-acetylindole-3-carboxaldehyde, 3-acetylindole, tryptamine, 5-methoxyindole-3-acetic acid, L-tryptophan, harmaline, acetylcholine, epinephrine and norepinephrine. Studies on the relative binding density of [125I]iodomelatonin to the kidney in different species of birds showed the following descending order: duck > chicken > pigeon > quail.(ABSTRACT TRUNCATED AT 250 WORDS)


Binding of [125I]-labelled iodomelatonin in the duck thymus.

[125I]-labelled iodomelatonin binding sites in membrane preparations of duck thymus were studied. The specific binding of [125I]-labelled iodomelatonin in the duck thymus was stable, saturable, reversible and of high affinity. Scatchard analysis of the binding of [125I]-labelled iodomelatonin in the duck thymus collected at midlight had an equilibrium dissociation constant (Kd) of 34.8 +/- 9.4 pmol/l and a maximum number of binding sites (Bmax) of 0.98 +/- 0.07 fmol/mg protein. Two-point diurnal study demonstrated that the Bmax in samples collected at midlight was 42.0% higher (p < 0.05) than that at middark, but there was no significant difference (p > 0.05) between the midlight and middark Kd values. Competition inhibition studies showed that only melatonin, 2-iodomelatonin, 6-chloromelatonin, 6-hydroxymelatonin, N-acetylserotonin, 5-methoxytryptophol, and 5-hydroxytryptamine showed significant inhibition of the [125I]iodomelatonin binding in duck thymus membrane preparations, while the other compounds had no significant inhibition. Our results suggested a direct action of melatonin on the thymus and, thus, the cellular immune system.


Identification of an 85-100 kDa glycoprotein as a cell surface marker for an advanced stage of urothelial differentiation: association with the inter-plaque ('hinge') area.

Although bladder cancers account for almost 5% of all human cancer deaths, little is known about the biochemistry of urothelial differentiation. We have recently identified three major protein subunits ('uroplakins') of asymmetric unit membranes (AUM), which form rigid-looking plaques covering up to 70% of the apical surface of urothelial superficial (umbrella) cells. The ordinary-looking plasma membranes that interconnect these plaques are believed to be functionally specialized, serving as flexible but durable 'hinges'. Whether these hinge membranes are biochemically unique is unknown. Using a new monoclonal antibody (AE32) we have identified an 85-100 kDa glycoprotein (UGP85) which appears to be urothelium-specific. In both normal urothelium and cultured urothelial colonies this cell surface protein is associated mainly with superficial cells, suggesting that its expression is differentiation dependent. Results from in vitro translation experiments indicated that this glycoprotein contains a core polypeptide of about 55 kDa. Using immunogold localization techniques, we showed that in cultured urothelial colonies--which are known to lack mature AUM plaques--UGP85 is distributed relatively uniformly on the apical surface of some differentiated cells. However, in superficial cells of normal urothelium UGP85 is mainly associated with the hinge areas. These results raise the possibility that UGP85 is a plasma membrane component which can be excluded, to varying extents, from the plaque region as 12 nm protein particles are assembled into a tightly packed paracrystalline AUM structure. The identification of UGP85 provides the first evidence that the hinge areas interconnecting the urothelial plaques are biochemically distinguishable from the plasma membranes of the relatively undifferentiated urothelial cells of the lower cell layers.(ABSTRACT TRUNCATED AT 250 WORDS)


Changing patterns in incidence of non-melanoma skin cancer.

Surveillance of skin cancer is important to evaluate prevention programmes and to monitor the effect of stratospheric ozone depletion. Evidence available from a limited number of studies suggests that incidence rates of basal cell carcinoma and squamous cell carcinoma have been increasing for at least two decades. In white populations in the United States, Canada and Australia, average annual increases of 3%-7% for basal cell carcinoma and 2%-8% for squamous cell carcinoma have been observed, though variation in ascertainment levels or changes in treatment practices during the study periods may have contributed to these apparent changes in incidence patterns.


Nonendothelial aortic source of nitric oxide in Wistar-Kyoto normotensive and spontaneous hypertensive rats.

Using a recognized inhibitor of nitric oxide (NO) synthesis, Nw-nitro L-arginine methyl ester (L-NAME), we tested the hypothesis of the existence of a nonendothelial source of NO in vascular tissue using rings of rat thoracic aorta in which endothelial cells have been removed by mechanical abrasion and have totally lost their endothelium-dependent relaxation. Contractility of the muscle was tested by recording the concentration-dependent contraction of the preparations induced by an alpha-adrenergic agonist, phenylephrine. Contractility in aortas from Wistar-Kyoto normotensive rats (WKY) and spontaneous hypertensive rats (SHR) was not significantly affected by a 30-min to 2-hour incubation with L-NAME prior to agonist stimulation. However, preparations incubated for 30 min with 1 mM L-arginine (L-ARG) and then washed for 1 h in standard Krebs solution had a significantly reduced contraction to phenylephrine in both WKY and SHR. In these preparations pretreated with L-ARG, L-NAME significantly increased contractility in both WKY and SHR; this effect was prevented by L-ARG but not by D-arginine. Responses to phenylephrine were not inhibited by L-ARG when preparations were incubated from the beginning of the experiment with 1 mM cycloheximide, thus suggesting a dependence on protein synthesis of the attenuation of contraction seen with L-ARG. Intact aortic rings processed for NADPH diaphorase histochemistry, a putative marker for NO synthase, showed NADPH diaphorase reactivity only in the endothelial layer and in the adventitia.(ABSTRACT TRUNCATED AT 250 WORDS)


The migration pathway of epithelial cells on human duodenal villi: the origin and fate of 'gastric metaplastic' cells in duodenal mucosa.

The specific migration pathways which epithelial cells take as they migrate through the human villus is unknown, although there have been several speculations. The well-known phenomenon of 'gastric metaplasia' in the human duodenum is readily demonstrable by the diastase periodic acid Schiff (dPAS) method. However, there is no general agreement on whether the origin of this cell lineage is the villus epithelial cells or proliferative crypt cells. Using serial sections, model building and computer-aided three-dimensional reconstruction we have followed the pathway of migration of these metaplastic cells in human duodenal villi and report: (1) that these cells migrate in straight lines; (2) that migration is in relatively tight cohorts or migration streams; (3) that a single vestibule can supply cells to more than one villus; and (4) that the cell lineage has a complex origin, deriving either from Brunner's gland duct epithelium or from basal buds growing out of the crypts of Lieberkühn.


Characteristics of (-)-stepholidine on the firing activity of substantia nigral dopamine neurons after repeated reserpine treatment.

Although (-)-stepholidine [(-)-SPD] exhibits antagonistic effects to normosensitive dopamine (DA) receptors, it shows agonistic effect (probably D1) on rotational behavior in rats with unilateral 6-OHDA lesions of substantia nigra pars compacta (SNC). In this study, another supersensitive model, reserpinized rats (1 mg/kg x 6 days, s.c.), were used to investigate the properties of (-)-SPD. In reserpinized rats, (-)-SPD reversed and/or significantly attenuated the firing inhibition caused by the mixed DA receptor agonist apomorphine (APO). After reserpinization, the selective D1 and D2 receptor agonists separately inhibited the firing rate of SNC DA neurons, and (-)-SPD reversed both D2 receptor agonist N-0437- and D1 receptor agonist SKF 38393-induced inhibition of the SNC DA cell firing. These results suggest that (-)-SPD shows D1 and D2 receptor antagonistic action and does not possess the same DA receptor agonistic effect on SNC DA cell firing activity in reserpinized supersensitive rats as it does in unilateral 6-OHDA-lesioned rotational behavior. Also, large doses of (-)-SPD inhibited the firing rate of SNC DA cells in reserpinized rats, but the inhibition was not reversed by D1 receptor antagonist SCH 23390 but was reversed by N-0437 or APO. This inhibition, thus, could be interpreted as depolarization inactivation (DI) due to blockade of DA receptors. Interestingly, in control (nonreserpinized) rats, (-)-SPD did not produce DI of SNC DA cells as it did on ventral tegmental area DA cells. These results imply that reserpinization modulates the onset of DI of SNC DA cells and that (-)-SPD may serve as a leading compound for exploring new types of atypical neuroleptics.


Possible non-functional crypts in small intestine defined using mouse aggregation chimaeras.

We have identified a minor population of crypts in small intestine which do not appear to export cells to villi. These crypts can be observed in whole-mounts of small intestine prepared from C57BL/6J<-->SWR mouse aggregation chimaeras stained with a peroxidase conjugate of the lectin Dolichos biflorus agglutinin (DBA-Px). In preparations where by chance the C57BL/6J epithelium (positive staining) forms only a minor component of the chimaera, occasional crypts occur which are isolated from larger patches of C57BL/6J epithelium and are surrounded by SWR (non-staining) epithelium. Fifty-one of 383 isolated C57BL/6J crypts (13%) did not appear to export cells to villi, although the crypt mouth is surrounded by a small patch of C57BL/6J epithelium on the intervillus gut floor.


Role of epithelial-mesenchymal interactions in the differentiation and spatial organization of visceral smooth muscle.

Uterine mesenchyme from newborn (0-day) rats was grown in association with epithelia from the adult cornea, urinary bladder, oesophagus, mammary gland, 1-day skin, and 1-day uterus. Following 1 month of growth, the differentiation of uterine mesenchyme into actin-positive smooth muscle cells was assessed immunocytochemically with antibodies to smooth muscle actin. Whereas grafts of uterine mesenchyme produced only small amounts of myometrium, all types of epithelia induced extensive myometrial differentiation in the uterine mesenchyme, which indicates that this effect is non-specific. The role of cell-cell interactions in the morphological patterning of smooth muscle layers was assessed by analysing tissue recombinants composed of adult prostatic epithelium (PRE) plus mesenchyme of the urogenital sinus (UGM), or seminal vesicle (SVM), or adult bladder epithelium (BLE) plus UGM or SVM. Prostatic ducts developed in all of these tissue recombinants (UGM + BLE, SVM + BLE, UGM + PRE and SVM + PRE). When UGM was used (UGM + PRE and UGM + BLE recombinants), actin-positive smooth muscle cells became organized into thin sheaths resembling the prostatic pattern. Conversely, when SVM was grown in association with PRE or BLE, the induced prostatic ducts were surrounded by thick layers of smooth muscle cells exhibiting the seminal vesicle pattern of organization. Smooth muscle cells were unorganized in grafts of SVM or UGM alone. These observations suggest that in male urogenital glands the mesenchyme dictates the spatial organization of the smooth muscle layers.(ABSTRACT TRUNCATED AT 250 WORDS)


Developmental response of adult mammary epithelial cells to various fetal and neonatal mesenchymes.

Adult mouse mammary epithelial cells were isolated and grown in combination with mesenchyme from the following sources: embryonic preputial gland, foot skin, tail skin, genital tubercle skin, mammary gland, and neonatal uterus, vagina and urinary bladder. Following 1 month of in vivo cultivation of the tissue recombinants as grafts underneath the renal capsule of normal female or hyperprolactinaemic (pituitary-grafted) hosts, the specimens were analysed histologically and immunocytochemically for the expression of milk proteins, smooth muscle actin, and cytokeratins. Mesenchymal effects on adult mammary epithelium varied with the source of the mesenchyme and the hormonal status of the host. In normal female hosts preputial gland mesenchyme induced extensive mammary epithelial growth and ductal branching morphogenesis with epithelial differentiation and ductal pattern being comparable to that observed in homotypic recombinants composed of mammary gland mesenchyme plus adult mammary epithelium. Other mesenchymes (from foot, tail, genital tubercle and uterus) preserved ductal morphology and normal epithelial differentiation, but elicited minimal epithelial growth and branching morphogenesis in adult mammary epithelium. In association with urogenital sinus, vaginal or bladder mesenchymes ductal branching morphogenesis of the mammary epithelium was absent or greatly distorted and the epithelium exhibited a stratified cuboidal phenotype even though considerable epithelial growth had occurred. In hyperprolactinaemic hosts (which received a pituitary graft) epithelial growth, alveolar morphogenesis, and synthesis of casein and milk fat globule protein was stimulated in all tissue recombinants although to different extents. Alveolar morphogenesis and milk protein expression were extensive in tissue recombinants prepared with mesenchyme from embryonic mammary gland, preputial gland, tail skin and urinary bladder, but were minimal in tissue recombinants prepared with foot or genital tubercle skin. Few milk-protein-positive alveoli formed in tissue recombinants composed of mammary epithelium combined with urogenital sinus or vaginal mesenchyme, even following growth in pituitary-grafted hosts. These findings demonstrate: (1) that adult mammary epithelial cells are responsive to the growth-promoting influences of heterotypic embryonic and neonatal mesenchymes; (2) that mammary growth and branching morphogenesis are induced to variable extents by different mesenchymes; (3) that fibrous (non-adipose) mesenchymes are effective inducers of mammary epithelial development; and (4) that the ability to form alveoli and produce milk proteins in adult mammary epithelial cells is critically dependent upon the nature of the connective tissue environment.


Mouse embryonic palatal epithelial sheets in culture: an immunocytochemical study of proliferative activity using bromodeoxyuridine.

Mouse secondary palate morphogenesis is accompanied by distinctive patterns of proliferation in the palatal epithelium which latterly reflect its region-specific differentiation into oral, nasal and medial edge phenotypes. Isolated intact embryonic palatal epithelial sheets were cultured prior to, and during, the critical period of epithelial differentiation in chemically defined culture medium with, and without, 10% donor calf serum. The spatial and temporal patterns of proliferative activity were investigated by immunocytochemistry in 'pulse' and 'continuous' labelling experiments using bromodeoxyuridine (BrdUrd). Continuously labelled cultures exhibited extensive proliferation throughout the oral, nasal and medial edge regions. Pulse labelled cultures demonstrated a shift in mitotic activity from nasal to oral epithelial cells probably representing the cell turnover associated with the respective differentiated phenotypes. Medial edge cells became post-mitotic within the first 19 h of culture. Our defined culture system coupled with the immunocytochemical detection of cell proliferation using BrdUrd offers a rapid and precise method for the further investigation of palatal epithelial proliferation and its regulation by extrinsic factors.


Beta actin expression and organization of actin filaments in colorectal neoplasia.

Several studies have linked abnormal actin cytoskeletal organization and mutant actin genes with neoplastic transformation. Using in situ hybridization techniques we looked at expression of beta actin mRNA at a cellular level in normal, benign and neoplastic human colorectal tissues and correlated the level of expression with the extent of actin cytoskeletal organization in sequential sections. Normal tissues showed light labelling with the actin riboprobe, but non-neoplastic crypts, with evidence of regeneration and repair, showed greater levels. Higher levels of actin mRNA expression were found in adenomas and metaplastic polyps, but the highest levels were found in carcinomas, particularly those that were poorly differentiated. Cytoskeletal actin organization was, however, reduced in colorectal neoplasia. Normal mucosa showed the highest level of cytoskeletal actin organization, as assessed by phalloidin binding, and adenomas and metaplastic polyps also stained strongly. In contrast, phalloidin binding to poorly differentiated carcinomas was absent or very weak. The inverse relationship between actin mRNA expression and actin filament organization was confined to the carcinomas studied and may indicate defects in actin binding proteins or in post-transcriptional or translational events.


A comparison of in vivo cell proliferation measurements in the intestine of mouse and man.

Using tritiated thymidine (3HTdR) labelling in vivo in the mouse we have determined the labelling index (LI%) at each cell position along the sides of sections of crypts in the small and large bowel. We have compared LI versus cell position frequency plots obtained in this way with those obtained using bromodeoxyuridine (BrdUrd) in vivo in the small intestine. Both thymidine analogues give identical patterns and similar levels of labelling: for example, the overall LI is 29.1% after 3HTdR and 34.7% after BrdUrd in the mouse ileum. Similar data have been obtained following in vivo labelling in humans with BrdUrd prior to gastrointestinal surgery for cancer and in mouse colon following 3HTdR labelling. Comparisons between the mouse and human data show that the spatial distribution of label within the crypts occurs at the same relative positions in the two species. However, the intestinal crypts are between 2-fold and 4-fold larger, particularly in their length, in the human: for example, 250 and 450 cells per crypt for ileum and 590 and 2000 cells per crypt for the colon in mouse and human respectively. The absolute value of the maximum LI in the mouse small intestine (56.5%) is higher than it is in the human (26.3%). However, the patterns of proliferation are similar in the two species under steady-state conditions.


Differential adhesion of rat colon carcinoma cells to fibronectin in relation to their tumorigenicity.

We examined the fibronectin-adhesive properties of clones from a rat colonic cell line exhibiting distinct tumorigenicity in a syngeneic host. These cells were originally selected on the basis of differential adhesion to plastic surfaces. The TR cell line, when injected subcutaneously, forms a tumour which grows progressively and gives off metastases, whereas the TS cell line forms a small tumour which regresses within a few weeks. The regression is largely mediated by immunological factors and involves a fibroblastic reaction. REGb, a clone from the TS subline, adhered better to fibronectin or RGDS tetrapeptide than did PROb, a clone from the TR subline. However, there was little binding to the RGD tripeptide with either clone. The degree of adhesion was dependent on time and substrate concentration. After 6 h of incubation, 38% and 55% respectively of PROb and REGb cells bound to plates coated with 10 micrograms/ml fibronectin. Adhesion of both clones to fibronectin was inhibited to various degrees when cells were preincubated with RGDS, GRGDS or GRADSPK peptides, whereas other synthetic peptides such as RGD, GRGD or GRGFSPK were ineffective. Binding experiments using 125I-labelled fibronectin showed 39,000 fibronectin receptor sites on REGb cells but only 17,000 on PROb cells. Flow cytometry analysis using both anti-alpha 5 and anti-beta 1 integrins showed more fibronectin receptor sites on REGb than on PROb cells. Both approaches were in accordance with the higher adhesiveness of the REGb clone to fibronectin.(ABSTRACT TRUNCATED AT 250 WORDS)


[Digital image processing of radiography of 32 cases with mandible sarcomas].

The radiographys of 32 cases with mandible sarcoma were analysed with digital image processing. The processed image of fibrosarcoma showed many scattered fine grains after the X-ray film were edge detected. In the same processing, the image of chondrosarcoma showed many little rings or arc structures. For osteosarcoma, the processed image showed very irregular veins. These digital processing pictures can help us to differentiate mandible sarcomas.


[Detection of DNA G+C mol% in taxonomy of Streptococcus mutans by means of high performance liquid chromatography].

In the present study, DNA G+C mol% of 9 strains of bacteria (including 7 international standard strain, Ingbritt, and 2 other strains extracted in our Lab) were detected with application of High Performance Liquid Chromatograph. The results showed that DNA G+C content of S. mutans was 35-40%, S. sobrinus was 45-46%, S. cricetus was 38%, and S. rattus was 41%. The difference between S sobrinus and S. mutans was higher than 5%, which suggested that S. sobrinus should be identified as an independent classification unit of bacterial species from S. mutans.


[Quantitative analysis of blood flow changes measured by radioactive microsphere technique after segmental anterior maxillary osteotomy in dogs].

The radioactive microsphere technique was used to study quantitatively the blood flow changes after segmental anterior maxillary osteotomy in dog. The results of experiment indicated that the blood flow of gingiva and alveolar bone in segmental side has not significantly changed compared with that of the control side after anterior maxillary osteotomy with intact labial and palatal soft tissue flaps. The blood flow of alveolar bone in segmental side was significantly lower than that of the control side (P < 0.01) when only the labial flap was kept intact, the blood flow of labial and palatal alveolar bone in segmental side was 55.5% and 60.28% lower than that of the control tissue respectively.


[The distribution and significance of collagen type III and fibronectin in human gingiva].

Immunohistochemical methods were used to study the distribution and patterns of collagen type III and fibronectin (FN) in human gingiva, their appearance in normal and several periodontal diseases were compared and discussed. It is found that type III collagen and FN are distributed consistently throughout the connective tissue. In inflamed gingiva, both of them are greatly diminished (P < 0.01). It is suggested that they should be in coordination with each other in the maintenance of normal gingiva and the decrease in amount may play a role in the development of periodontal disease.


[Determination of contents of glycosaminoglycans in temporomandibular joint discs in dogs].

Glycosaminoglycans (GAGs) are one of the important components of articular cartilage. The present study had determined the contents of uronic acid, galactomine, glucosamine, and hexosamine of temporomandibular joint discs in 10 dogs by Bitter's carbozole reaction method and derivative spectrophotometry. The data indicated that the contents of these components in different bands of the disc are not significantly different and that the discs of dogs contained averagely 0.6%, 0.987%, 0.4% and 1.4% of uronic acid, galactomine, glucosamine, and hexosamine respectively. The data also suggested that the discs contained keratan sulfate and chondroitin sulfate in some degree. This study is significant for analysing TMJ disc functions and its biomechanical properties in the future.


[A comprehensive analysis of osteosarcoma, fibrosarcoma and chondrosarcoma of the jaws].

The clinical, pathological and radiographic materials of 99 cases with osteosarcoma, fibrosarcoma and chondrosarcoma of the jaws were analyzed comprehensively. Neither obvious differences of age, sex, duration, location of tumor, clinical symptoms and five-year survivals nor radiographic characteristics were found between these three types of sarcoma. The tumor stage and destruction of cortical bone by the tumor are the important factors influencing the prognosis of the patients. The radiographic findings are valuable for the estimation of prognosis.


[Changes in the mandibular growth after ramus osteotomy in rats].

A comparison is made between mandibular growth of the operated side and the unoperated side after vertical ramus osteotomy by measurements of the area and linear distances of bilateral mandibles, and digital image processing technique from the radiographs. The results show that slightly retarded growth of the mandible of the experimental side in growing Wistar rats occurs after osteotomy in the mandibular ramus, but obvious asymmetry is not found Deficiencies of mandibular growth in the operated side are similar in both groups of upward and downward repositioning of the proximal segment.


[A computerized system for image cephalometrics].

This system is composed of: (1) a perspective table, (2) TV camera, (3) a high-resolution image displayer, (4) a computer, (5) a laser printer The functions of this system are as follows: (1) It can perform cephalometries directly from image of X-ray film, (2) it can diagnose and analyse the deformity and provide treatment plan. This system is valuable for orthodontics and surgical orthodontics.


[A preliminary approach of the malocclusion of second permanent molar].

We examined 2183 cases of orodental malocclusion in our clinic. 420 cases of deep-overjet of second permanent molar were found. In this paper we discussed the sex and age of the patients, distribution of tooth position, ratio, degree of overjet, causes of malocclusion, malocclusion condition, endangerment, prevention and treatment.


[Straight wire appliance in orthodontic practice].

This paper is a preliminary report of using Straight Wire Appliance (SWA) in orthodontic practice in our school since 1989. Thirty finished cases including malocclusion, extraction mode, treatment sequence and time and the outcome, of treatment were analysed. Discussion of the problems concerning arch wire and correction of deep overbite was made. The authors confirm that SWA is a simple and effective type of appliance and it is easily to popularize in orthodontic practice in our country.


[The mechanism of topical applied ion supplemented acidulated phosphate fluoride gel effects on dental enamel demineralization: an in vitro study].

The present study was carried out on dental enamel to describe surface changes in the scanning electron microscope and crystallites changes in the high-resolution transmitted electron microscope as related to treatments of topical applied ion supplemented acidulated phosphate fluoride (APFI) gel and artificial caries agent demineralization in vitro, which imitated in vivo with pH- cycling condition. Our data suggest that topical application of APFI gel produce some CaF2 spheres on the surface of enamel and some fluoride-containing apatites in dental enamel. The latter are considered as result of F- and CaHPO4 or hydroxyapatites. The essence of chemical reactions are discussed. The results confirm that enamel treated with APFI gel becomes more resistant to artificial caries agent and electron radiation damage.


[Hemodynamic evaluation of GK and Medtronic-Hall prosthetic mitral valves by exercise Doppler echocardiography].

Hemodynamic alterations were studied in 42 patients with GK and Medtronic-Hall (M-H) prosthetic valves by stress Doppler echocardiography after submaximal supine exercise. In the GK group, peak and mean gradients increased from 10.1 +/- 1.7 and 3.4 +/- 1.3 mmHg respectively, at rest to 15.3 +/- 3.1 and 5.4 +/- 1.5 mmHg at peak exercise (mean +/- s), mitral valve area increased from 2.61 +/- 0.34 cm2 at rest to 2.86 +/- 0.45 cm2 at peak exercise (P < 0.05). In the M-H group, peak and mean gradients increased from 11.3 +/- 1.8 and 4.3 +/- 1.0 mmHg respectively, at rest to 15.0 +/- 1.9 and 5.8 +/- 1.5 mmHg at peak exercise. Mitral valve area increased from 2.66 +/- 0.43 cm2 at rest to 2.94 +/- 0.38 cm2 at peak exercise (P < 0.05). The results showed that peak and mean gradients at rest in patients with GK prosthetic valve were lower than those of M-H group. But after exercise, the two prosthetic valves showed similar characteristics in hemodynamics. Exercise Doppler echocardiography is a simple, noninvasive and reliable method for the evaluation of the function of mechanical mitral prostheses.


[Measurement of the right ventricular systolic pressure in ventricular septal defect--a simultaneous correlative study with Doppler echocardiography and dual cardiac catheterization].

To assess the reliability of Doppler echocardiography (DE) in measuring the right ventricular systolic pressure (RVSP) in ventricular septal defect (VSD), both left and right heart catheterization (Cath) and DE were performed simultaneously in 59 cases with VSD. Systolic shunt velocities through VSD were recorded by DE and converted into the peak instantaneous (delta P-PD) and mid-systolic (delta P-MD) pressure gradients using the simplified Bernoulli equation RVSP was estimated by subtracting delta P-PD from the brachial artery systolic pressure (BASP) measured by a cuff sphygmomanometer (method A) and by subtracting delta P-MD from BASP (method B). The left ventricular systolic pressure (LVSP), RVSP, and the peak instantaneous (delta P-PC) and the peak-to-peak (delta P-PP) pressure gradients were measured from pressure c rves. The comparison between BASP and LVSP yielded a good correlation (r = 0.90, SEE = 0.76 kPa). There were also good correlation of interventricular pressure gradients measured by two techniques (r = 0.98, SEE = 0.83-0.93 kPa). Although RVSP estimated by method A correlated well with that measured by Cath, there was a significant underestimation (P < 0.05). On the other hand, RVSP estimated by method B agreed highly with that measured by Cath and there was no significant difference between the two means. We conclude that DE offers a reliable technique for estimating RVSP in VSD noninvasively.


[The effect of indapamide on plasma prostaglandins in hypertensive patients].

After two weeks' treatment of indapamide (2.5 mg/d) in 30 cases of mild to moderate hypertensive patients, there was a significant decline of systolic and diastolic blood pressure. And 8 weeks after indapamide administration, 2/3 of the total treated patients achieved complete control of hypertension. During the treatment period, there were no changes of serum cholesterol, triglyceride and renal function, except a slight, but still in the normal range, decrease of serum potassium and sodium. Concurrently, plasma vasoconstrictive prostaglandins TXB2 (metabolite of TXA2) and PGF2 alpha reduced significantly (P < 0.01 and P < 0.001 respectively), whereas plasma vasodilative prostaglandins 6-keto-PGF1 alpha (metabolite of PGI2) and PGE2 increased significantly (P < 0.02 and P < 0.05 respectively). The results support the theory that prostaglandins system may play an important role in the hypotensive process of indapamide. The influence of indapamide on prostaglandin system may favour the improvement of platelet function and the maintenance of the homeostasis.


[Clinical observation on pause-dependent long QT syndrome and torsade de pointes ventricular tachycardia].

Ten patients with long QT syndromes (LQTs) and torsade de pointes (Tdp) were evaluated. The following features were noticed: (1) Serum potassium concentration was reduced in 5 of 10 patients (50.0%, mean value 3.0 mmol/L); (2) The QT interval (mean value 0.50s) was significantly prolonged in all patients; (3) A flat and wide T wave, an abnormal increase in U wave amplitude close to the end or the peak of the T wave and these changes were accentuated by pause or a sudden deceleration in ventricular rhythm; (4) The critical beat of Tdp inevitably started after the peak of the T wave of a markedly prolonged QT interval. Cycle lengths preceding torsade de pointes were shown in a pattern of short cycle-long QT-"late premature ventricular contraction" initiating sequence changes.


[Clinical and pathological analysis of sudden coronary death in hospitalized elderly patients].

Forty-five hospitalized elderly patients with coronary heart disease who died suddenly within 6 hours after the onset of symptoms were analyzed clinically and pathologically and summarized as following. (1) All the cases showed abnormal ST segments or T waves on ECG. (2) Various degrees of cardiac dysfunction were found clinically in all the patients. (3) Pathological examination of 31 cases revealed serious coronary atherosclerosis. New myocardial necrosis and/or multiple myocardial scars existed in about two-thirds of the patients. Based on these findings and characteristics, it is speculated that sudden coronary death in the elderly patients is caused by imbalance between oxygen supply and demand in the myocardium or deterioration of the cardiac function, which may result in fatal ventricular arrhythmia. Therefore, the prevention of sudden coronary death in the elderly patients should be focusing on reduction of myocardial ischemia, improvement of myocardial metabolism and protection of cardiac function.


[The clinical relevant factors of the myocardial ischemic threshold].

The myocardial ischemic threshold (heart rate at the onset of ischemia) was assessed in 92 patients with coronary heart disease. The highest myocardial ischemic threshold (HMIT) ranged from 83 to 163 (122 +/- 18) beats/min usually happened during activities at the daytime. The lowest myocardial ischemic threshold (LMIT) ranged from 45 to 115 (82 +/- 17) beats/min usually happened when awaken early morning or asleep at night. The differences were statistically significant (P < 0.01). The mean variability of myocardial ischemic threshold (VMIT) was 30.22% (range from 8.2 to 51.2%). The variability was correlated positively with the number of ischemic episodes, negatively with LMIT, and larger in senior-aged group than in middle-aged group (P < 0.001). The authors suggest that LMIT and VMIT may be related to the severity of coronary lesions, coronary tonus, and the patients' prognosis, etc.


[Surgical treatment of trilogy of Fallot].

Two hundred and thirty-four patients with trilogy of Fallot including 102 cases of severe type were operated in our hospital in the last 15 years. Right ventricular outflow patching was done in 117 cases, Devega tricuspid annuloplasty in 7 cases. Total operative mortality rate was 2.6%. The pathological anatomy and the surgical treatment of the severe type cases were discussed.


[The value of CT in diagnosing abdominal aortic aneurysm].

The CT scanning findings in 30 cases of the abdominal aortic aneurysm were analysed. The value of CT in diagnosing and following up of the abdominal aortic aneurysms was discussed. CT is recommended in comparison with other imaging technics. Thin slices and enhancement were made in order to show the relationship between aneurysm and the origin of the renal arteries when suspected.


[Phenotype analysis of mononuclear cells from endomyocardial biopsy specimens in patients with viral myocarditis and dilated cardiomyopathy].

The distribution and phenotype of mononuclear cells from endomyocardial biopsy (EMB) specimens in patients with viral myocarditis (VMC, 25 cases) and dilated cardiomyopathy (DCM, 10 cases) were studied. T-lymphocytes, including T-h/i (T-helper/induced) cells in VMC and T-c/s (T-cytotoxic/suppressor) cells in DCM, were predominated in the infiltrating mononuclear cells within these specimens. The morphological relationship between infiltration of T-lymphocytes and pathological changes of myocardium was also observed, but both macrophages and B-lymphocytes were absent.


[Early afterdepolarization and cesium chloride induced ventricular arrhythmias].

This study is to demonstrate the role of early afterdepolarization (EAD) in the cesium chloride induced long QT interval and ventricular arrhythmias by recording monophasic action potential (MAP) of right ventricular endocardium with contact electrode in 12 closed chest dogs. The results suggested that EAD could produce triggered premature ventricular beats and ventricular tachycardias (VT) in situ. The first ectopic ventricular beat of EAD induced VT usually appears close to the peak of the U wave. Short-long-short interval sequence preceding episodes of VT occurred in 89.6% of VT.


[Fever of unknown origin. A study of cases seen at the third level].

Clinical records of 160 patients admitted with fever of unclear origin were reviewed. Of them, all cases with fever of obscure origin (FOO) were selected based on the following criteria: at least two weeks with fever, with an oral temperature of 37.5 degrees C or more during hospitalization and whose clinical history, physical examination, hemocytologic data, erithrosedimentation rate, urinalysis, febrile tests, glutamic-piruvic transaminase, chest and abdomen radiographies were not suggestive of any specific diagnosis. 32 cases of FOO were found, but only the 30 which had been studied previously in another hospital were considered for analysis. Of these 30 patients, 18 were men and 12 women, with a mean age of 36.3 (range 19-64). Infectious diseases caused 40 percent and neoplastic disease 27 percent of cases. The single most frequent cause was non-Hodgkin lymphoma in four cases, followed by tuberculosis and Hodgkin's disease in three patients each. In four cases the cause of fever was not identified. Eleven patients required exploratory laparotomy; in nine of them it was usefull for diagnosis. Our results show a high proportion of neoplastic diseases, probably related with patient's selection and with intrinsic diagnostic difficulty of these kind of diseases.


[Necrosectomy and retroperitoneal lavage in necrotic pancreatitis].

Necrotic pancreatitis is the most severe of all acute pancreatitis and treatment with various surgical procedures has had a high mortality. A retrospective study of 37 patients treated by necrosectomy and postoperative lavage-drainage from January 1987 to December 1990 was made. The most frequent etiologies were alcoholic (21 patients) and biliary (15 patients). Eight patients had moderate pancreatitis according to Ranson's classification when they entered the hospital (one died) and in 28 it was severe (eight died). The mean time between entrance to the hospital and surgery was 15.1 days. Twenty five were reoperated, twelve for residual abscesses and eight of these died. The mean hospitalization time was 56.7 (+/- 32.8) days and overall mortality was 24.3%, smaller than that observed in our hospital with other various procedures. It is concluded that necrosectomy and lavage-drainage is a good surgical alternative for patients with necrotic pancreatitis.


[Histamine as modulator of potassium currents in ventricular cells isolated from heart of guinea pig. A possible regulator effect of ventricular electric activity].

Histamine is present in cardiac tissues in considerable amount, but its physiological role is not well understood. There are two kinds of histamine receptors on the cardiac cells (H1 and H2). Whereas the H2 actions are very well studied little is known about H1 effects. It has been reported that stimulation of H1 receptors induce a shortening of the action potential as a decrease in excitability, but the ionic mechanisms responsible for these are not known. The aim of the present paper is to explore the possible ionic mechanisms related to these effects on isolated ventricular myocytes by means of voltage clamp technique. Histamine induced a shift in the current-voltage relationship of the potassium background current to the right. This shift implies an increase in outward current at the plateau level, responsible for the shortening, as well as for the decrease in excitability. This is, as far as we know, the first report in potassium background channel modulation by an endogenous substance and firmly support the hypothesis that histamine is playing a role in cardiac modulation.


[Pancreatic beta cells and cytokines].

Over the past decade the study of Interleukins and Interferons has advanced from functional descriptions to detailed structural understanding. The ability of these growth factors to act, directly or through immune mechanisms on the pancreatic beta-cell and to affect in vitro and in vivo both its morphology and physiology, indicate that they may play a role in the pathogenesis and prevention of insulin-dependent diabetes mellitus. Also, the relation between these cytokines-constitutive or upon stimulation maybe useful to predict the development of diabetes mellitus.


[Increase in neuroendocrine secretion granules in submaxillary and parotid glands in patients with non-insulin dependent diabetes mellitus].

The amount of neuroendocrine granules in microgranular cells of salivary glands were investigated in necropsies of 20 non-insulin dependent diabetics (NIDDM) and in 20 non-diabetic subjects with Grimelius and Fontana-Masson stainings. Granules in serous acini, and intercalated ducts were observed in both groups; however, a significant higher number of granules and microgranular cells were observed in NIDDM subjects as compared with non-diabetics. Both parotid and submaxillary glands were significantly heavier in NIDDM than in the non-diabetic group. These granules may be related to immunoreactive glucagon which has been found in submaxillary glands of rodents and might play a role in the pathogenesis of NIDDM. Further investigations should be performed to clarify whether these cells are the site of glucagon synthesis and also clarify the pathogenesis of NIDDM.


[Fever of unknown origin. Presentation of 180 pediatric cases].

Fever of unknown origin (FUO) is a frequent disorder in pediatric age. FUO is defined as the presence of fever over 38.4 centigrades in a patient for more than three weeks in which the etiology remains undetermined. From 30.736 consecutive admittances into our hospital, 180 patients with FUO were detected, and studied in a systematized way and according to a predetermined protocol. FUO was commonly found in children under six years of age. Our patients presented fever from three weeks to six and a half years of evolution; however, in the vast majority of the cases (n = 115) fever had a three weeks course. Several symptoms and physical manifestations other than fever were observed in our patients but they were widely variable and nonspecific. Infectious diseases were the commonest etiological factor encountered; among them, thyroid fever, and urinary tract infections were the most frequent infectious disorder found; in four children fever was associated to ampicillin administration; in 19 patients, fever was no demonstrated. A large number of laboratory investigations were done in the diagnosis of neoplastic diseases. We think that the study of a patient with FUO requires of a systematized approach.


[Lymphoblastic lymphoma in the adult].

We report a series of 57 adults patients with lymphoblastic lymphoma treated at our Institution between 1975 and 1987. Mediastinal involvement was seen in 74% (42 cases); extranodal involvement (not including bone marrow) in 24% (14 cases); stage IV in 84% (48 patients) and leukemic phase in 19% (11 patients). In 15 cases immunologic studies were performed 14 proved to be of T type and the other one lack both T and B markers. Survival and duration of remission was better when the patients were treated with aggressive chemotherapy that included maintenance and central nervous system prophylaxis. In the multivariable analysis we observed that mediastinal mass, attainment of a complete remission and high levels of lactic dehidrogenase were associated with a worse prognosis. We believe that patients with lymphoblastic lymphoma have an aggressive disease and that the treatment should be more aggressive than in other non-Hodgkin's lymphomas, and include central nervous system prophylaxis.


[Evaluation of nopal capsules in diabetes mellitus].

To find out if commercial capsules with dried nopal (prickle-pear cactus, Opuntia ficus indica may have a role in the management of diabetes mellitus, three experiments were performed: 30 capsules where given in fasting condition to 10 diabetic subjects and serum glucose was measured through out 3 hours; a control test was performed with 30 placebo capsules. OGTT with previous intake of 30 nopal or placebo capsules was performed in ten healthy individuals. In a crossover and single blinded study 14 diabetic patients withdrew the oral hypoglycemic treatment and received 10 nopal or placebo capsules t.i.d. during one week; serum glucose, cholesterol and tryglycerides levels were measured before and after each one-week period. Five healthy subjects were also studied in the same fashion. Opuntia capsules did not show acute hypoglycemic effect and did not influence OGTT. In diabetic patients serum glucose, cholesterol and tryglycerides levels did not change with Opuntia, but they increased with placebo (P < 0.01 glucose and cholesterol, P = NS triglycerides). In healthy individuals glycemia did not change with nopal, while cholesterol and triglycerides decreased (P < 0.01 vs. placebo). The intake of 30 Opuntia capsules daily in patients with diabetes mellitus had a discrete beneficial effect on glucose and cholesterol. However this dose is unpractical and at present it is not recommended in the management of diabetes mellitus.


[Preservation of the pancreas for the simultaneous transplantation of kidney-pancreas].

This paper studies the advances that have participated in the development of preservation solutions for the combined kidney-pancreas transplantation. These developments have been associated most importantly with hypothermia, the use of colloid solutions with high oncotic pressure, and the maintenance of near-intracellular ionic concentration. At the present time, the more effective solutions are the plasma-like modified Silica Gel Fraction and the starch and lactobionate based solution such as, the UW. Further advances in this area, would allow for improved results in the combined kidney-pancreas transplant preparation.


Antigenic and genomic differences of two Jasper strains of infectious pancreatic necrosis virus.

Strains of infectious pancreatic necrosis virus (IPNV-Jasper) obtained from two different laboratories were compared serologically with polyclonal and monoclonal antibodies. Nucleotide sequence and restriction endonuclease patterns of 359-bp fragment of genome segment A cDNA were also compared. Substantial differences were found in both analyses that will support the fact that the two Jasper strains are not identical.


Inefficient transmission of HTLV-I to MOLT-4 cells by cell-free virus and cocultivation.

Transmission of human T cell leukemia virus type I (HTLV-I) to a T cell line (MOLT-4#8) was studied using cell-free virus infection or cocultivation with an HTLV-I-transformed T cell line (MT-2). Immunofluorescence and FACS analyses showed that HTLV-I was efficiently adsorbed onto MOLT-4#8 cells. However, after adsorption, no extrachromosomal viral DNA in the cells was detected by the Southern blot method. In contrast, when MT-2 cells were cocultured with MOLT-4#8 cells, generation of extrachromosomal DNA was clearly observed. These data suggest that the cell-free HTLV-I may have difficulties in penetration, uncoating or reverse transcription. After cocultivation, MOLT-4#8 cells chronically infected with HTLV-I were cloned and analyzed. Only four provirus-positive cell lines were obtained. The transmission rate of the virus by cocultivation seemed to be low in our experimental system, although marked cell fusion was observed. Moreover, none of the cloned cell lines which harbored HTLV-I provirus expressed any viral protein. Inefficient integration and expression of the provirus might be hypothesized as compared with human immunodeficiency virus type 1 transmission.


[Corneal autograft, an additional alternative in corneal transplantation].

Corneal autotransplantation is a process in practice for various years. This procedure has the advantage of providing corneal tissue which will not be immunologically rejected in the host. This paper reports five cases in which this procedure was undertaken by changing a transparent cornea from a blind eye on the other side.


Bacterial luciferase produced with rapid-screening baculovirus vectors is a sensitive reporter for infection of insect cells and larvae.

Bacterial luciferase, derived from a fusion of the luxA and luxB genes of Vibrio harveyi, has been expressed at very high levels in caterpillars and insect cells. The coding sequence for luciferase was inserted into vectors developed in our laboratory which were designed to expedite screening of recombinant virus. These vectors contained the beta-galactosidase indicator gene under control of immediate early (IE1), early (ETL), or very late (P10) promoters and a cloning site for inserting the fused luciferase gene next to the polyhedrin promoter. Recombinant baculoviruses containing the luciferase gene as well as the beta-galactosidase gene could be easily selected when Bluo-gal (beta-galactosidase indicator) was included in the plaque assays. Using cells derived from the fall armyworm (Spodoptera frugiperda), luciferase was strongly expressed very late in infection (48-72 h). The bacterial luciferase assay was sufficiently sensitive that light production could be detected from an extract of a single cell. In addition, live insects, including the cabbage looper (Trichoplusia ni) and saltmarsh caterpillar (Estigmene acrea) were infected by mixing recombinant baculovirus into their diet. Cabbage loopers (with an average wet weight of 223 mg) produced at least 195 micrograms of active luciferase and levels of synthesis peaked between 96-120 h. The results indicate that bacterial luciferase may be used as a reporter of gene expression in insects.