Reaction-time differences between the left and right hemispheres for face and letter discrimination in children and adults. Twenty boys at each age level 7, 10, and 13 years and 20 adult males were tested for choice manual reaction times to photographs of faces or letter pairs tachistoscopically presented 3 1/2 degree to the left or 3 1/2 degree to the right of a central fixation point, in the left visual field (LVF) or the right visual field (RVF) respectively. All subjects were right-handed. Subjects were tested monocularly. They used a different hand and a different eye in the first and second half of trials. Eye order and hand order were randomized across subjects. Seven- and 10-year-olds were intermittently rewarded with a poker chip following fast correct responses. Analysis of correct reaction time scores indicated an overall LVF superiority for the speed of response to faces, but no significant field differences for responses to letter pairs. The interaction of these field-stimulus effects with age was not significant, suggesting that the obtained field effects with faces and letter pairs were consistent across the range of ages tested. The results of comparisons of field differences within individual subjects suggested a "switchover" from a left-field advantage with letter pairs at age 7  to a right-field advantage at the adult level; this tendency, however, was not significant. None of these results was influenced by the use of different hands or eyes or to frequencies of commission of errors. The results suggested that a left-field advantage in speed of response to familiarized faces is found as early as 7 years of age and does not change appreciably thereafter. The finding of a significant left-field advantage for faces in the 7-year-old  group represented an earlier age of left-field, right hemisphere lateralization for face stimuli than that previously obtained by other investigators. The failure to find over field differences with letter pairs was attributed to a possible tendency among subjects to process to letters visually (i.e., graphemically), a tendency which may have been more marked in the  7-year-old group due to the relative inexperience of children of this age with alphabetical material.


Paroxysmal alexia.

Paroxysmal alexia. This report describes a case of paroxysmal alexia which progressed to a persistent syndrome of alexia without agraphia. The sequence of symptoms beginning with a sensation of eyeball movement followed by blurred vision in the affected eye, alexia and diminished awareness strongly implicates an ictal mechanism. Anatomical, physiological and psychological considerations suggest that the syndrome arose from functional disruption between the visual cortex and the dominant inferior parietal cortex.


Depletion of awareness and double-simultaneous stimulation in split-brain man. To examine depletion of awareness in six total split-brain patients response to two tactual stimuli applied at the same time was studied. Losses as well as errors in reporting location to one of the pair are present in all patients. This disorder is not seen in callosal patients in whom the splenium is preserved. The results are interpreted to follow the transection of a general consciousness circuit which lies towards the back of the brain.


Differential finger movements and hand preference. In an attempt to replicate a study by Kimura and Vanderwolf (1970), normal left-handed and right-handed subjects were asked to flex a single finger or pairs of fingers at the middle joint. Both hands were found to be equally proficient at this task and no differences between right- and left-handers were found. When left-handers were divided into inverters and non-inverters according to hand-writing posture, a left hand superiority was a found for the right-handed and the left-inverted subjects, while the left-non-inverters showed a right hand superiority. Paired finger flexion was found to be more useful in discriminating between the handedness groups. These findings support the idea that the neural mechanism for hand preference is not based on an asymmetry in the control of fine movement. They also support the theory that two separate groups of left-handers exist, and the they can be differentiated by their handwriting postures.


Comparison of radionuclide and computed tomography scanning in non-neoplastic intracranial disease. In this comparison of computed tomography (CT) and radionuclide scanning (RN) in non-neoplastic disease, the CT and RN patterns in vascular occlusive disease, vascular anomalies, cerebral hemorrhage, cerebral infections, and trauma are described in detail. A retrospective evaluation of CT and RN findings in 514 patients provides a basis for determining which modality is more sensitive in a given disease entity. Illustrative cases demonstrate pertinent findings in both CT and RN scanning in the aforementioned disease categories.


Low attenuation lesions in the midline posterior fossa: differential diagnosis. A wide variety of cystic appearing or low attenuation lesions in the midline posterior fossa can so closely resemble one another as to render specific histologic diagnosis from CT scans alone fraught with error. Absorption coefficients often overlap and are too nonspecific to infer consistently accurate histologic diagnosis. It is virtually impossible to separate cystic from noncystic, benign from malignant, and neoplastic from non-neoplastic lesions by absorption coefficients alone.


Evaluation of renal masses by ultrasound and computed tomography: a preliminary study. Computed tomography (CT) and ultrasound were performed on fifty-two patients with renal masses. Both modalities were able to correctly demonstrate the renal mass with an equal degree of accuracy. Since renal ultrasound is a well established, economical and noninvasive technique, it should be the diagnostic procedure of choice to determine whether or not a mass demonstrated by intravenous urography is cystic or solid. However, if faster scanning times as well as lower patient cost could be accomplished, more widespread use of CT as a diagnostic modality for differentiation of renal masses could result.


Clinical usefulness of an enzyme strip for estimation of blood sugar ("Dextrostix") in a tropical medical practice: a 10-year experience. A series of studies were carried out to assess the usefulness and accuracy of measuring blood sugar levels in a tropical medical practice using an enzyme test strip ("Dextrostix"). The results showed that the method is simple, accurate and reproducible, especially when the colour changes on the strips are interpreted electronically by the reflectance meter or Eyetone instrument. The results are independent of packed cell volume. Sequestrene-containing blood samples maintain a constant level of glucose for 5 hours. The Eyetone can be used for approximate determination of blood glucose levels greater than 400 mg per 100 ml by exposing the strips to blood for only 30 seconds and multiplying the result by two. Where there is no mains supply, the instrument can be operated from a car battery.


Diagnosis of gout in general practice.

Diagnosis of gout in general practice. In a general practice survey of gout, an analysis was made of the criteria relating to the diagnosis in 604 patients. Approximately 60% of diagnoses were made within 1 month of the patient presenting with symptoms; in the remainder, there was often a considerable time lag before diagnosis and half of these patients had been wrongly diagnosed initially. Of the total cases, approximately 8% were diagnosed in hospital and only about 20% of cases were referred for diagnosis or subsequent management advice. Most diagnoses were based on the presentation by the patient of a typical acute arthritis, and a raised serum urate level was used as a confirmatory factor. Few patients presented with tophi and response to colchicine was infrequently used in diagnosis, as were diagnostic X-rays or synovial fluid examination for crystals.


The effects on normal skin of adhesives from stoma appliances. The irritancy of 7 adhesive plasters from different ostomy appliances was compared in 30 normal subjects. The adhesives were replaced both daily and weekly over a 21-day period. Using a clinical rating scale, the results slowed that "Stomahesive" had a significantly less irritating effect on the skin than the other plasters, both when removed daily and when removed weekly. The difference between daily and weekly removal reached statistical significance at the end of Weeks 2 and 3, and the results suggest that the nature of the adhesive is more important than the frequency of removal.


Diuretic effect of a combined preparation of frusemide and slow-release potassium chloride. An open randomized crossover study was carried out in 10 healthy volunteers to compare the diuretic effect of a single tablet combining 40 mg frusemide and a slow-release formulation of 600 mg potassium chloride with that of the two agents given in separate tablets. The results showed that both treatments had a similar effect on urinary volume and on sodium and potassium excretion, but the hourly urinary volumes during the first 6 hours suggested that the diuretic action of the combined formulation occurred slightly earlier after administration.


In vitro activity of oxolinic acid and nalidixic acid against common urinary pathogens: a comparative study. A study was carried out to compare the sensitivity of 500 bacterial strains, isolated from patients with urinary tract infections, to oxolinic acid and nalidixic acid. The results showed that whilst both antibacterial agents were similar in their bacterial spectrum they were not identical in terms of cross-sensitivity or resistance. Where there was a difference in sensitivity, this was always in flavour of oxolinic acid and was particularly evident in the case of Staphylococcus, Pseudomonas, Serratia, Klebsiella, Proteus (especially P. rettgeri), and to a lesser extent Citrobacter.


A simplified method to determine functional residual capacity during mechanical ventilation. We describe a nonrecirculating helium-rebreathing method providing rapid and simple measurement of the functional residual capacity (FRC) in spontaneously breathing subjects and patients receiving mechanical ventilation. Results of triplicate determinations in 24 normal subjects revealed a repeatability of +/- 5.2 percent of the measured FRC, results similar to those predicted for these subjects. Results in six additional subjects were not significantly different from those obtained with a standard method using helium equilibration in the pulmonary function laboratory. Triplicate determinations in eight patients after cardiac surgery demonstrated similar repeatability. In 22 other patients studied after open-heart surgery, the FRC fell more in those who could not be weaned than in those who could be weaned from the respirator. Since an increase in FRC is the goal of therapy with positive end-expiratory pressure, this method should be useful in determining the efficacy of a particular level of positive end-expiratory pressure.


Failure of disposable domes to prevent septicemia acquired from contaminated pressure transducers. Between January and June 1976, eight cases of primary bacteremia due to Enterobacter cloacae occurred in patients after open-heart surgery in a hospital in Connecticut. Epidemiologic studies implicated radial arterial catheters as the route of acquistion of E cloacae, and bacteriologic studies confirmed arterial pressure transducers as the sources of bacteria. Prospective studies indicated that the disposable domes from the pressure transducers did not prevent the spread of bacteria from contaminated transducers to the arterial catheters. This is the first report of transducer-acquired bacteremic infections occurring with the use of disposable domes. Although disposable domes may decrease the chances of cross-contamination of circuits for monitoring pressure, they do not, as previously thought, eliminate the risk of bacteremia from this source.


Serum dopamine beta-hydroxylase activity in acute cardiac disease. The activity of dopamine beta-hydroxylase in the serum was measured in patients with acute cardiac disorders who were admitted to a coronary care unit. The activity of the enzyme on admission was similar in patients with acute myocardial infarction and in those with other conditions; on discharge, the activity was reduced significantly. Patients with myocardial infarction had the greatest fall in the activity of dopamine beta-hydroxylase. Patients with multiple signs of sympathetic hyperactivity had significantly higher values for the activity of dopamine beta-hydroxylase on admission. Pain was found to significantly increase the activity of the enzyme. These data confirm findings that the activity of dopamine beta-hydroxylase in the serum reflects the intensity of sympathetic activity. The factors contributing to the elevated sympathetic activity in some patients with acute myocardial infarction seem to be nonspecific, but because of the ominous nature of increased sympathetic tone in this condition, it could be advantageous to identify these patients.


The esophageal obturator airway: a clinical comparison to ventilation with a mask and oropharyngeal airway. We compared controlled ventilation with the esophageal obturator airway to ventilation with a conventional rubber mask and oropharyngeal airway in ten anesthetized patients. Measurements of exhaled tidal volume, mask-to-face fit (leakage of mask), supraglottic obstruction, and the operator's effort were all inferior using the esophageal obturator airway. No consistent peak airway pressure could be obtained with the esophageal obturator airway. Placement of the device was difficult in three of ten patients, and two of ten had inadvertent tracheal intubations. Edentulous patients were difficult to impossible to ventilate using the esophageal obturator airway.


Changes in pulmonary mechanics and gas exchange following thoracocentesis. In nine patients with large pleural effusions, we studied the changes in pulmonary mechanics and gas exchange that occurred in the first three hours following removal of 600 to 1,800 ml of fluid by thoracocentesis. There was a small but significant increase in the functional residual capacity and total lung capacity but no change in residual volume and vital capacity. Calculated pulmonary shunt fraction did not change. We could not relate the subjective improvements noted by patients after thoracocentesis to the changes in pulmonary volumes or blood gas levels.


Changes in ventilation and perfusion in anesthetized dogs following lobar lavage with saline solution. The therapeutic application of endobronchial lavage has been inhibited by concern regarding alterations in the exchange of gases, particularly hypoxemia, and by the technical complexity of the procedure. Using a cuffed fiberoptic bronchoscope with which lavage could be restricted to one lobe, we studied the sequence of alterations in the exchange of gases after lavage and the attendant disturbances in ventilation and perfusion in ten mongrel dogs following lobar lavage with 1,850 ml of physiologic saline solution. Sequential scintiphotographs of ventilation and perfusion and sequential measurements of arterial blood gas levels were obtained. Linkage of the computer to the scintillation camera allowed quantification of data on ventilation and perfusion from the lobar area of interest. Lavage induced a reduction in regional ventilation and perfusion in all dogs. The decline in ventilation preceded that in perfusion, and the computed ratio of ventilation over perfusion reached its lowest point during the first 30 minutes after lavage. The arterial oxygen pressure (PaO2) declined in all dogs from a mean baseline value of 87 mm Hg to a mean value of 76 mm Hg at 30 minutes after lavage and gradually returned to a mean of 85 mm Hg by six hours after lavage. The lowest value for PaO2 occurred after balloon occlusion prior to lavage. Calculations of shunt showed a minimal increment in the intrapulmonary shunt (Qs/Qt). In the normal dog, lobar lavage induces mild hypoxemia due to an imbalance of ventilation and perfusion that resolves within six hours.


Pulmonary edema: physiologic approaches to management. The integrity of the normal endothelial barrier is responsible for two of the three major safety factors preventing pulmonary edema. This is why edema due to increased pressure is usually not as severe as edema due to increased permeability. Management ought to follow sound physiologic principles. These principles are to lower microvascular hydrostatic pressure and to provide adequate supportive therapy. Positive end-expiratory pressure may improve arterial oxygen transport, but there is no evidence that it improves the balance of pulmonary fluid in edema. Raising the microvascular protein osmotic pressure may be beneficial in edema due to increased pressure but has no demonstrated rationale in edema due to increased permeability.


A-V nodal reentrant tachycardia vs accelerated A-V junctional rhythm in acute inferior myocardial infarction. This report described initiation of A-V nodal reentrant tachyycardia in a patient with acute inferior myocardial infarction. The onset of tachycardia was preceded by an abortive A-V nodal Wenckebach periodicity. A-V nodal ischemia with or without vagotonia was implicated as the cause of induction of critical functional dissociation between the two A-V nodal conduction pathways. Since the tachycardia manifested its rate between 95-110 beats/min during the evolutionary phase of acute inferior myocardial infarction, it simulated, electrocardiographically, an accelerated A-V junctional rhythm. Analysis of the onset of tachcardia was of diagnostic importance.


Knotting of central venous catheters: nonsurgical correction. A complete knot occurred in a central venous catheter inserted through the subclavian vein. By passing a spring guidewire into the catheter under fluoroscopic control, the knot was easily untied leaving the catheter correctly in place.


Late bronchopleural fistula and Hemophilus influenzae empyema complicating longstanding oleothorax: report of two cases. Bronchopleural fistula and Hemophilus influenzae empyema developed in two patients with longstanding oleothorax. The first patient died after drainage with a pleurocutaneous flap, and a seven-rib thoracoplasty failed to resolve her infection. In the second, resection of the oleothorax cavity and left upper lobe resulted in cure.


Simulation of pleural disease by disk space infection. A young woman presented with the acute onset of pleuritic chest pain ahd pleural effusion which eventually proved to be secondary to an infected disk space. This complication most likely resulted from a paraspinal extension of the infection. Disk-space infection must be added to the differential diagnosis of acute pleural disease.


Cross-sectional echocardiographic detection of aortic ring abscess in bacterial endocarditis. The diagnosis of aortic ring abscess by cross-sectional echocardiography has not been reported. In this paper, a case of bacterial endocarditis of the aortic valve extending to the aortic ring and the mitral valve is reported. The role of cross-sectional echocardiography in defining the anatomic distortion of the aortic valve in bacterial endocarditis and its complications is emphasized. This study would indicate that early diagnosis of aortic ring abscess is feasible by cross-sectional echocardiography.


Idiopathic perforation of a porcine aortic bioprosthesis in the aortic position. The report of a failure of glutaraldehyde-preserved porcine aortic xenograft bioprosthesis in the aortic position after 13 months is presented. Severe aortic regurgitation resulted from three "idiopathic" perforations in one of the cusps, and a linear tear in another cusp. Light and electron microscopy showed generalized degeneration of collagen thoughout the faulty valve. The absence of a platelet-fibrin coat on edges of the tear suggested a recent origin, compatible with cardiac catheter manipulation during unsuccessful attempts to cross the valve. The histopathologic data from this valve correlate with previously reported failures with formaldehyde preserved xenograft valves.


Myocardial infarction due to tumor embolization following pulmonary resection. A fatal case of massive systemic tumor embolization, with involvement of the coronary arteries, which occurred following resection of a metastatic pulmonary fibroliposarcoma, is presented. Elevation of the cardiac specific creatine kinase isoenzyme (MB-CK) documented myocardial damage due to obstruction of the coronary arteries by tumor emboli. The preoperative computed tomography scan demonstrated contiguity between the pulmonary mass, the inferior pulmonary vein and left atrium. In future cases this finding should alert the surgeon that cardiopulmonary bypass and removal of the left artial extension of the tumor under direct vision may be required to prevent embolization during pulmonary resection.


Left stellectomy in the long QT syndrome. Recent investigations have reaffirmed the role of autonomic innervation of the heart in the genesis of certain cardiac arrhythmias. The long QT syndrome (LQTS) has been described for years, but only recently has evidence of its link to autonomic imbalance been established. A case of LQTS is presented with intraoperative evidence at the time of left stellectomy of life-threatening arrhythmias triggered by stimulation of this neural body. Removal of the left stellate ganglion normalized the electrocardiographic (ECG) abnormalities and has rendered the patient asymptomatic since surgery. Left stellectomy may become definitive therapy for selected patients with the LQTS.


Correlation of phono- and apexcardiographic findings with tumor motion in left atrial myxoma. We have analyzed the genesis of physical signs in a case of prolapsing left atrial myxoma by simultaneous phono-, apex- and M-mode echocardiography. Our findings confirm a direct relationship of tumor movements with notching in the upstroke of the apexcardiogram and with the protodiastolic "tumor plop."


Left ventricular outflow obstruction produced by a pedunculated fibroma in a newborn: clinical, angiographic, echocardiographic and surgical observations. An unusual case of a one-day-old infant with significant left ventricular outflow obstruction produced by a pedunculated fibroma is described. The clinical findings were indistinguishable from severe valvular or subvalvular aortic stenosis. The tumor was difficult to detect by echocardiography. It produced an echo-free widening of the left ventricular outflow tract. Left ventricular cineangiography clearly demonstrated a mobile mass beneath the aortic valve.


Double ventricular response to an extrastimulus in a patient with triple atrioventricular pathways. A patient with the Wolff-Parkinson-White Syndrome was studied through recordings of the intracardiac potentials and programmed atrial stimulation. During programmed atrial stimulation at progressively shorter coupling intervals (A1-A2 intervals), the His deflection was always recorded after the ventricular complex. Thus, at coupling intervals between 295 and 250 msec, there was a double ventricular response, one through the accessory pathway (QRS complex of the Wolff-Parkinson-White morphologic pattern) and the other by the normal atrioventricular pathway (normal QRS complex or with pattern of left bundle-branch block). At a coupling interval of 295 msec, the atrio-His (A-H) interval increased from 200 to 350 msec. This fact and the presence of two distinct A2-H2 intervals are suggestive of the existence of dual atrioventricular pathways, coexisting functionally with a lateral accessory bypass (Kent's bundle).


Cyanosis in uncomplicated atrial septal defect with normal right cardiac and pulmonary arterial pressures. A patient with cyanosis in an uncomplicated ostium secundum atrial septal defect without pulmonary hypertension is described. There were no anatomic abnormalities in right-sided cardiac valves or venous return and no evidence of right ventricular hypoplasia or hypertrophy; however, the diastolic pressure curve suggested a decreased compliance. We suggest that this unusual finding may be a result of intrinsically abnormal right ventricular compliance.


Disopyramide in patients with the Wolff-Parkinson-White syndrome and atrial fibrillation. The effect of administration of disopyramide on the ventricular response to atrial fibrillation was studied in six patients with the Wolff-Parkinson-White syndrome. The drug was given intravenously to five patients during intracardiac electrophysiologic studies and to a sixth patient during electrocardiographic monitoring in a coronary care unit. One patient with a very rapid ventricular response to atrial fibrillation underwent a second electrophysiologic study after oral treatment for four weeks with disopyramide. In all cases, administration of disopyramide reduced the mean ventricular rate and increased the shortest interval between consecutive preexcited ventricular complexes during atrial fibrillation. Therapy with disopyramide should therefore be useful in preventing ventricular fibrillation which can result from a rapid ventricular response to atrial fibrillation in patients with an accessory atrioventricular pathway. There has been no recurrence of paroxysmal tachycardia in the four patients who have been maintained on oral therapy with disopyramide.


Systolic time intervals in atrial fibrillation. Forty patients with atrial fibrillation and 20 patients with congestive heart failure and sinus rhythm were studied. Patients were divided into two groups. Group A consisted of 20 patients with atrial fibrillation in whom systolic time intervals were measured. Twenty to 50 beats were analyzed. Five of the patients had high-fidelity measurements of left ventricular pressure simultaneous with determination of systolic time intervals. Analysis of the systolic time intervals for the entire group showed that the preejection period lengthened at faster heart rates and that the left ventricular ejection time was relatively constant at slower heart rates. This resulted in a progressive increase in the ratio of preejection period over left ventricular ejection time (PEP/LVET) as the heart rate increased. The rate of increase in PEP/LVET was minimal below a heart rate of 75 beats per minute. The increase in preejection period at faster heart rates is due to greater isovolumic developed pressure without a corresponding increase in left ventricular dp/dt. Group B consisted of 40 additional patients (20 with atrial fibrillation and 20 with sinus rhythm). In group B, the total electromechanical systole corrected for heart rate (QS2I) and the levels of digoxin in the blood were compared. The QS2I was significantly shorter in atrial fibrillation (497 +/- 5 msec vs 528 +/- 4 msec; P less than 0.01), while the levels of digoxin in the blood were identical (0.9 +/- 0.1 vs 1.0 +/- 0.1 ng/ml). The results of this study must be considered when systolic time intervals are to be employed in patients with atrial fibrillation.


Quantitative tracheal bacteriologic and cytologic studies in patients with long-term tracheostomies. Quantitative aerobic and anaerobic cultures were performed on 28 tracheal aspirates from 16 clinically stable patients with tracheostomies. There were an average of six isolates per specimen, and the mean bacterial concentration was 106.9 organisms per milliliter. The numerically dominant bacteria were aerobic and facultative gramnegative bacilli. Anaerobic bacteria were recovered from just nine specimens (32 percent); and, when present, these organisms were found in relatively low concentrations. Repeat cultures obtained 30 to 60 days later from the same patients showed substantial changes in flora, but the numerically dominant species tended to persist. Cultures of saliva and throat swabs collected at the time of tracheal aspiration showed that there was little correlation between the bacteriologic findings from the upper and lower airways. Cytologic studies indicated a mean of 12,900 cells per cubic millimeter of tracheal aspirate, with polymorphonuclear leukocytes being the predominant forms. No correlation could be found between the concentrations of polymorphonuclear leukocytes and quantitative bacterial counts. These studies indicate that tracheal aspirates from patients with stable tracheostomies harbor a complex, predominantly aerobic flora which is subject to change and bears little relationship to the flora of the adjacent upper airways. Our results also suggest that neither quantitative bacterial cultures nor cytologic analysis of these specimens would be helpful in distinguishing colonization from overt infection requiring antibiotic treatment.


Platelet-mediated pulmonary hypertension and hypoxia during pulmonary microembolism: reduction by platelet inhibition. The literature indicates that vasoactive substances released from platelets contribute to the pulmonary pressor response and hypoxemia during pulmonary microembolism. Hence, removal of the platelets or inhibition of their function should reduce these effects. The purpose of this study was, therefore, to investigate the pulmonary effects of experimental embolism with glass beads in dogs rendered thrombocytopenic with platelet antiserum and to compare these effects to the effects in dogs pretreated with sulfinpyrazone (Anturane) or heparin, both substances that affect the function of platelets, probably by inhibiting the release of platelets. In all three groups the pulmonary hypertension was reduced by more than half, and hypoxemia was lessened or abolished. The results of this study indicate the platelets contribute to the effects of pulmonary microembolism and that administration of sulfinpyrazone or heparin reduces the embolism-induced pulmonary hypertension to the same extent as the depletion of platelets. Platelet-inhibiting drugs might therefore be useful prophylactically in human pulmonary microembolism.


Fracture of pacing electrode mimicking failure of pulse generator. To our knowledge, this is the first reported case of spontaneous fracture of a pacing electrode with decreased amplitude of the pacing artifact, failure to capture, and intact sensing. We postulate that the difference in impedance of the pacemaker for sensing and stimulation may account for this phenomenon.


The alveolar air equation abbreviated.

The alveolar air equation abbreviated. The alveolar air equation is not widely used in clinical medicine, probably because of the complicated appearance of its classic forms. The following shorter form has been derived: formula: see text (where PAO2, PEO2, and PIO2 are the partial pressures of oxygen in alveolar, expired, and inspired, gas, respectively, and VD/VT is the ratio of physiologic dead space over tidal volume). This shorter form is an algebraic identity of the classic equation. The shorter form involves the same assumptions and requires the same measurements as the traditional expressions but is more compact and easier to use in circumstances where VD/VT is measured routinely.


Tricuspid atresia with double-outlet left ventricle and bilateral conus. The first case of tricuspid atresia with a double-outlet left ventricle, l-transposition of the great arteries [S,D,L], and bilateral conus in levocardia diagnosed correctly during life is reported. This case is unique and differs from the classic double-outlet left ventricle in that there is a bilateral conus.


"Contarini's condition:" bilateral pleural effusions with markedly different characteristics. A leukemic patient presented with bilateral pleural effusions. The effusions were markedly different in their characteristics; left-sided staphylococcal empyema and right-sided lymphocytic effusion. To our knowledge, there are no cases of this type reported in the modern literature. The importance of bilateral diagnostic thoracocentesis in patients on immunosuppressant therapy is emphasized.


Systemic-pulmonary arterial supply in pulmonary atresia with ventricular septal defect: postmortem angiograms and histologic survey. Postmortem angiographic and histologic studies of the pulmonary arterial circulation were performed in a patient with pulmonary atresia and a ventricular septal defect. While the left lung was supplied by a closing ductus arteriosus, the right lung was supplied by two systemic pulmonary arteries arising from the descending aorta. The examination disclosed that systemic pulmonary arteries lead into the pulmonary vascular bed and the capillaries of the alveolar walls. According to these observations, such collateral circulation is to be considered functional. The pulmonary vascular bed, supplied by the ductus arteriosus and the stenotic systemic pulmonary artery, showed a thin muscular layer in the small arteries and arterioles. On the contrary, medial hypertrophy and severe intimal proliferation were observed in the pulmonary segments perfused by the other large unobstructed systemic pulmonary artery, thus proving that asymmetric pulmonary vascular disease may complicate the natural history of this malformation.


Varying ejection fractions of both ventricles in paradoxical pulses: demonstration by radionuclide study. A noninvasive radionuclide study of the paradoxical pulse in pericardial effusion is described. The study shows complementary changes of the right and left ventricular ejection fractions in a patient with paradoxical pulse, supporting the theory that the inspiratory reduction of the left ventricular stroke volume is an immediate and direct result of the inspiratory increase of the right ventricular filling. The technique may be sensitive to detect early paradoxical pulse and cardiac tamponade.


Idiopathic bronchial stenosis in a young woman. An 18-year-old white woman presented with a severe obstructive ventilatory defect. An evaluation revealed a stenotic lesion of the right bronchus intermedius and the left mainstem bronchus. Treatment with prednisone followed by beclomethasone resulted in a marked improvement in her condition.


Interdisciplinary training for child welfare and health. Recognition of the symbiotic relationship of the child welfare and child health disciplines led to a project that developed and tested health concepts and methods curricula for child welfare administrators and research staff.


Father-daughter incest: a clinical view from the corrections field. Effective handling of court cases of incest involving a child calls for an understanding of the dynamics of the child's family. This paper outlines characteristics of the parents involved.


Infant antecedents of cognitive functioning: a longitudinal study. A follow-up investigation of 35 boys and 33 girls 10 years old who had been assessed originally at 4, 8, 13, and 27 months old did not reveal strong relations between infant variables such as attentiveness, vocal excitability, irritability or activity, on the one hand, and reflection-implusivity, intelligence quotient, or reading ability at age 10. A suggestive relation was found between assimilative smiling during infancy and a reflective attitude on the Matching Familiar Figures Test and between a slow tempo of play during infancy and longer response time on a specially constructed Embedded Figures Test at age 10. Although attentiveness during infancy predicted IQ and reading ability at age 10, both infancy and childhood variables were positively correlated with social class, suggesting that experiences associated with the social class of the parents, rather than particular infant qualities, were the more important predictors of the cognitive variables at age 10. Children with high EMG levels from the flexor forearm tended to be slightly more impulsive at age 10 and less attentive at 27 months, even when the effect of social class was removed.


Facilitation of infants' recognition memory. Infant's recognition memory, defined by novelty preferences, was found to be improved by providing 5--7-month-old infants with discriminable but related targets during the familiarization period. Facilitation of recognition was found for both photos of faces and for abstract patterns. It was necessary to present only 1 associated stimulus along with the to-be-remembered target in order to aid recognition. Such facilitation was dependent upon the kind of related target shown for study and was more likely to be demonstrated when simultaneous rather than successive exposure to related instances was allowed.


Intermodal relationships in children's perception. Since judgment of geographical slant requires the use of both optical and postural information, such judgments were used to determine whether intermodal relationships affect children's perception. First, third, and fifth graders made judgments of geographical slant of surfaces depicted in photographs either with or without postural inclination. The results indicate the existence of a linear mechanism which compensates for the effect of postural inclination. Compensation was about 50% of that expected from an ideal perceptual system and did not change with age. The present data are similar to those previously reported for adults and suggest that the compensation process develops early in childhood.


Mother-child interaction in high-risk and contrast preschoolers of low socioeconomic status. Children's activities with their mothers and the techniques used by mothers while interacting with their child were examined in older (30--46 months) and younger (12--27 months) low SES preschool children from high-risk (in terms of cultural-familial retardation) and contrast homes. Older high-risk children interacted less often with their mothers and spent less time in "highly intellectual" activities than did the contrast children. The mothers of older high-risk children, in comparison with the contrast group, engaged less often in didactic teaching, showed less encouragement of their child's activities, and their attempts to control their child's activities more often resulted in failure. The differences between younger high-risk and contrast groups however were nonsignificant. Implications for future home intervention programs for high-risk low SES children are discussed.


Fetal malnutrition: an experimental study of its consequences on infant development in two caregiving environments. Infants from low socioeconomic status families were randomly assigned to an instructional day-care program designed to prevent socioculturally caused mental retardation or to a nonintervention control group. This assignment procedure resulted in an equal distribution of full-term, full-birth-weight, fetally malnourished babies in 2 environments varying in intellectually supportive characteristics. The condition of fetal malnourishment was defined by infants having low ponderal indices (PI). At 3 months of age low-PI infants showed lower Bayley Mental Development Index (MDI) scores than normal-PI infants, independent of the environment. In the control group low-PI infants still had lower MDI scores than normal-PI infants at 18 months of age. However, at that time in the day-care group, low-PI infants scored as well as normal-PI infants. These findings were replicated when the infants were 24 months of age with Stanford-Binet intelligence tests. Observations of mothers' involvement with their infants showed that, although all groups had similar amounts of maternal involvement when the babies were 6 months of age, the mothers of low-PI infants in the control group showed less involvement with their infants at 18 months of age than the other mothers. We suggest that this longitudinal study provides experimental evidence for a transactional model of development which emphasizes both newborn infant characteristics and environmental quality as cocontributors to the process of development.


Family interaction in abusive, neglectful, and normal families. This study represents an attempt to discover whether there are distinctive patterns of day-to-day interactions that distinguish abusive and neglectful families from families with no known history of abusing or neglecting their children. Observational data collected in the homes of 17 abuse, 17 neglect, and 19 control families indicated that the abusive and neglectful parents demonstrated lower rates of interaction, overall, and were more likely to emphasize the negative in their relationships with their children. The implications of these data for further research and for intervention efforts are discussed.


Sex differences in responsiveness to infants: a developmental study of psychophysiological and behavioral responses. Sex differences in responsiveness to infants were investigated by comparing physiological responses to infants with overt behavioral reactions. The former were assumed to be more biologically determined than the latter whereas overt behavioral responsiveness was presumed to be more affected by societal norms than were psychophysiological indices. The subjects were boys and girls in middle childhood and early adolescence. Psychophysiological indices showed that children, like parents, responded differentially to infant smiles and cries. As predicted, there were no sex differences on psychophysiological measures of responsiveness to babies. When permitted to interact with a baby, however, girls interacted more and ignored less than boys did. The results suggest that sex differences in overt responsiveness to babies are attributable to societal pressures rather than innate factors. Sex differences appear to wax and wane depending on the salience of sex stereotypy in differing developmental phases.


The development of sibling relationships in infancy: a short-term longitudinal study. 24 infants and their preschool-aged siblings were observed in a laboratory playroom in the presence of their parents. Observations took place when the infants were 12 months old and again 6 months later. Analysis of the social behavior revealed that, at both ages, the children assumed differentiable roles in their interactions: The infants "followed" by observing and imitating while the preschoolers "led" by drawing the infants' attention and by assertive dominance. Over time, infants became increasingly willing to direct social behaviors toward their siblings. There was remarkable behavioral stability across time, with the infants' early propensities seemingly causally related to later pre-schoolers' behavior. Older girls directed more social behaviors to siblings than boys did. The amount of parent-directed behavior was affected by the number of adults present, whereas the amount of sibling-directed behavior was unaffected.


Young children's knowledge about visual perception: hiding objects from others. Children of ages 2 1/2, 3, and 3 1/2 years were tested for their understanding of object hiding, believed to reflect an early developmental level of knowledge about visual perception. Even the youngest subjects could nonegocentrically hide an object by placing it on the opposite side of a screen from another person, even though placing it there necessarily left it unhidden from themselves. In contrast, there was a significant increase with age in the ability to achieve the same physical end state by placing the screen between the other person and the object. Most subjects at each age level correctly indicated that the other person could see the object when the experimenter interposed the screen between the child and the object but that the other person could not see the object when she placed the screen between the other person and the object. These and other recent findings indicate that children of this age can be both nonegocentric and skillful at estimating what other people do and do not see under various viewing conditions.


Spatial strategies in the counting of young children. 3--6-year-old children counted 7, 10, and 14 items arranged in columns or in rows. Developmental changes in spatial strategy and the relation of strategy to accuracy were examined. Increases with age in the organization of children's counting sequences were observed as they progressed from (a) a counting sequence based on the proximity of an item to the one previously counted, to (b) a sequence based on the exterior form of the array, to (c) a sequence based on the linear arrangement of items. The column or row arrangement of items did not affect strategy choice, but increasing the number of items caused some children to revert to a less organized count. Fewer errors were associated with more mature strategies at all ages.


Operativity and reversibility in children's understanding of pictorial sequences. The role of reversibility in children's comprehension and memory for sequences of pictures was investigated. Bidirectionality in the ability to remember and infer antecedents and consequences was assessed. Preschoolers were significantly more accurate at identifying consequences of portrayed events than the antecedents. Kindergartners and older children correctly identified beginnings and endings of sequences with equal proficiency. This developmental shift from relatively unidirectional to reversible comprehension was observed both on trials involving figurative memory and operative inference judgments.


A developmental study of the category effect in visual search. Several studies have demonstrated that adults display a category effect in visual search paradigms. That is, when searching an array for the presence of a target letter, subjects detect the letter faster when the array is composed of numbers rather than letters, and vice versa. Groups of 8-year-olds, 10-year-olds, and adults searched for the presence of a target in fields of items that were either of the same or a different category (letter or number) than the target. Highly significant category effects were evident in the search times of all 3 age groups. While search times were found to decrease with development, there was no evidence of an increasing effect of category with age. It was concluded that the feature extraction process that mediates the category effect is fully automated by age 8.


Early cognitive development and its relation to maternal physiologic and behavioral responsiveness. Data are presented which support the hypothesis that infant cognitive development is a function of maternal responsiveness to infant cues. 22 mothers whose physiologic responses to infant signals had been recorded at an earlier date participated in the follow-up study reported here. Mother-infant dyads were videotaped during a feeding session when the infant was 9 months of age. Behavioral data collected were the mother's responses to her infant's facial orientation. The statistic developed to index maternal sensitivity was the rate of maternal responding during infant gaze/the rate of responding during infant looking away. Development of the object concept was assessed at 15 months using the Uzgiris and Hunt scale. The data indicated that the development of the concept of the object is positively related to maternal behavioral sensitivity and that mothers who were behaviorally sensitive to infant cues earlier had exhibited physiologic responses to infant signals.


The stability of children's fears.

The stability of children's fears. The stability of fears in a group of 27 fourth-grade children over a 1-year period was investigated. The fears were obtained by individual interview and were coded according to the categories of Jersild and Holmes. The kinds of fears expressed by the children were similar to those found in other surveys. These fears were also found to be highly stable both in number and in kind. The implications of this high stability were discussed.


Life cycle variation and regulation of macronuclear DNA content in Tetrahymena thermophila. The mean DNA content of G2 macronuclei varies during the life cycle of the ciliate Tetrahymena thermophila. Early in the life cycle the mean is about 130 C; later it is about 94 C. In hybrids between strains A and B the decrease from 130 C to 94 C usually began after 60 fissions after conjugation. In B X B clones the decrease was complete by 50 fissions. The data suggest that there may be a genetic difference between strains A and B with respect to the onset of the decrease in DNA content. The downward regulation of the mean DNA content appears to be related to the mechanism which removes the variance in macronuclear DNA content which is added to macronuclei by unequal macronuclear division. Unequal macronuclear division regularly occurs at all stages of the life cycle, with larger macronuclei tending to divide more unequally. In the absence of regulation, unequal macronuclear division would constantly add variance to G1 macronuclei and their range would continue to increase. Analysis of the variances of G1 and G2 macronuclei suggests that at all stages of the life cycle the added variance is removed by acting upon nuclei which become too small or too large. According to this model, macronuclei with smaller amounts of DNA are regulated upward by an extra macronuclear S phase, while larger amounts are regulated downward by chromatin extrusion and the skipping of macronuclear S. The mean DNA content appears to change during the life cycle because  the thresholds at which macronuclei become too small or too large are readjusted. It is postulated that these thresholds are a function of gene dosage.


Experimental hybridization within the genus Triturus (Urodela: Salamandridae). I. Spermatogenesis of F1 species hybrids, Triturus cristatus carnifex female x T. vulgaris meridionalis male. The spermatogenesis of 9 F1 hybrids of Triturus cristatus carnifex female x T. vulgaris meridionalis male was studied in squash preparations of testicular fragments, treated by the C-staining method. The chromosome number of these hybrids was examined in spermatogonial metaphases and found to be diploid. The two parental sets were always recognized, which means that a regular, although heterospecific, amphimixis occurred (2n = nfemale + nmale). Meiotic prophase I is greatly altered owing to a failure of typical chromosome pairing and chiasma formation. At metaphase I and/or meta-anaphase I, the effects of the hybrid combination of the 2 specific parental sets are clearly visable. Most primary spermatocytes contain only univalents. A few show chromosome associations (bivalents, trivalents and, more rarely, quadrivalent chains) besides univalents. Such associations are of 2 types: (a) intragenomal associations = associations of 2 chromosomes by a terminal (a1) or subterminal chiasma (a2); (b) intergenomal associations = associations of 2 chromosomes by a terminal (b1) or subterminal chiasma (b2). Univalents segregate at random while the associations often lag on the equatorial plane or migrate entire to a spindle pole. Primary spermatocytes with chromosome multivalents can encounter greater difficulties in accomplishing the first cytokinesis. Secondary spermatocytes are numerically and qualitatively unbalanced; however, some of them undergo spermiogenesis and can give rise to a small number of sperms, generally abnormal and never united in bundles. --Problems related to the occurrence of "anomalous" chiasmata and of intra- and inter-genomal homologies are discussed.


Induction of triploidy in the newt Pleurodeles waltlii by heat shock or hydrostatic pressure: interpretation of the different types of ploidy using a chromosomal marker. Eggs of diploid females of Pleurodeles waltii, fertilized artificially by waltlii sperm, have been submitted to increased temperature of hydrostatic pressure during the first hour of development. Of the resulting viable individuals about 95% were triploid, the remainder diploid or tetraploid. Other types of ploidy have been observed in abnormal embryos (n, 2n/4n, 5n, n/5n, 6n). Some of the treated eggs came from females with a marker chromosome (pericentric inversion). The karyotypes of the animals developing from such eggs confirm that triploidy results from retention of the second polar body and make it possible to interpret the origin of the other types of ploidy. From the results it can be envisaged how gynogenetic animals can be obtained from eggs inseminated by inactivated sperm and shock-treated to restore diploidy.


Experimental gynogenesis in the newt species Pleurodeles waltlii and P. poireti. Eggs of diploid females of Pleurodeles waltlii, inseminated by genetically inactivated sperm of Salamandra salamandra, have been treated by heat-shock or increased hydrostatic pressure during the first hour of their development. The resulting viable gynogenetic individuals show different degrees of ploidy although they mostly are diploid. The use of females with a pericentric inversion as a marker chromosome allow the chromosomal constitution to be clarified. Eggs of females heterozygous for a recessive semilethal mutation (ascite caudale, ac) subjected to the same experimental treatment gave 50% ac/ac embryos. Experiments with Pleurodeles poireti gave the same results as those with P. waltlii. These observations prove that gynogenetic Urodeles can be produced in large numbers. In their offspring the detection of inherent or spontaneous recessive mutations is greatly facilitated.


"Nodules" in the achiasmatic meiosis of Bithynia (Mollusca, Prosobranchia). In spermatocytes of Bithynia leachi and B. tentaculata, synaptonemal complexes with nodules in an achiasmatic meiosis were demonstrated for the first time by means of the spreading technique. The number and position of the nodules are different in each species and are independent of the length of the chromosomes. Although no crossing over occurs in Bithynia chiasma-like terminal connections of the chromosomes are preserved in diakinesis by the presence of the nodules. --Enzymatic treatments revealed information regarding their composition of alkaline proteins, RNA and DNA. In all proteolytic digestions the nodules more of less retain their position in the central region, while they disappear immediately if SCs are exposed to DNase. On the basis of the results a model of the composition and the function of nodules can be developed considering the concept of a lampbrush-organization of the chromosomes in early meiotic prophase.


Effect of galactose treatment in the puffing pattern of Chironomus thummi Balbiani rings. Galactose feeding of Chironomus thummi larvae induces the regression of Balbiani ring c (BRc) and the full expansion of BRb, both localized in the IV salivary gland chromosome. This effect coincides with that described on BR2 and BR1 of Ch. pallidivittatus and Ch. tentans. The puffing changes of BRb and BRc throughout develoment have been studied and also show identical variations as in BR1 and BR2 of Ch. pallidivittatus and Ch. tentans. The similar behaviour of BRb and BR1, and of BRc and BR2 respectively after galactose treatment and throughout development strongly suggests that these BRs play the same physiological role in the three Chironomus species, with BRb = BR1 and BRc= BR2.


Dictyostelium rDNA consists of non-chromosomal palindromic dimers containing 5S and 36S coding regions. Restriction enzyme mapping of snap-back DNA has been used to show that the ribosomal DNA (rRNA genes and spacers) from Dictyostelium discoideum exists as 88 kb (kb=1,000 base pairs) linear palindromic dimers. Analysis of the mobility of total cell DNA in 0.15% agarose gels indicates that the majority of the rDNA is not covalently attached to chromosomal DNA.


Localization of Drosophila nasutoides satellite DNAs in metaphase chromosomes. Metaphase chromosomes of D. nasutoides were hybridized in situ with 3H-cRNA synthesized from the four satellites which make up 50--60% of the total DNA of this species. All four satellites were localized in the large, metacentric, heterochromatic chromosome four. They did not, however, appear to hybridize to centromeric or other constitutive heterochromatin, nor did they, with the exception of satellite I, seem to hybridize in the specific regions of chromosome four which, on the basis of C, Q, and H banding and AT contents, were predicted to contain some of these satellites.--Comparison of grain patterns with the results of fluorescent staining indicated that satellite-bearing heterochromatin was not always associated with other fractions of constitutive heterochromatin in interphase nuclei and was, at least partially, decondensed in some larger nuclei.


An artificial sphincter: a preliminary report. A new method of providing continence to patients with fecal stomas is presented. The device, used as an artificial sphincter, consists of an inflatable Silastic balloon, which is implanted in the subcutaneous tissue around the stoma; it is easily handled by the patient. The artificial sphincter was used in six patients with colostomies. In all cases, satisfactory continence of the stoma was achieved, obviating the need to use enemas, bags or other appliances. In three patients subcutaneous infections developed around the prosthesis. In two cases, this was readily controlled; in one case, the prosthesis had to be removed. The other five patients are well and continent. None of the patients experienced pain or discomfort during use of the prosthesis. There has been no stomal ischemia.


Wound infections after colectomy.

Wound infections after colectomy. The records of 650 patients were analyzed to determine factors predisposing the patients to wound infections. Statistically significant increases in infections were found in association with Crohn's disease, stomas present preoperatively, serum albumin levels of less than 2.9 g/dl, operative blood losses greater than 1,200 ml or operative times longer than two hours, preoperative irradiation, and bowel preparations other than mechanical preparation and nonabsorbable antibiotics. Wound infection did not occur in patients who were prepared for the operation with the neomycin-erythromycin antibiotic regimen.


Conservative treatment of anal fissure: an unselected, retrospective and continuous study. Three hundred and ninety-three patients who had anal fissures were followed continuously for approximately five years. More than 44 per cent of them were cured nonsurgically within a four-to-eight-week period. There was an 8 per cent complication rate, consisting of abscesses and fistulas, necessitating surgical treatment. The recurrence rate following healing was 27 per cent, but a third of these patients had recurrent fistulas that healed in response to further conservative treatment. The authors feel that conservative treatment of anal fissure is justified unless there is advanced anal stenosis.


Lateral internal sphincterotomy.

Lateral internal sphincterotomy. Lateral internal sphincterotomy proved to be effective in 99 per cent of the 418 procedures in which it was performed. The complication rate of 5 per cent was an improvement over most of the rates reported in the medical literature and over our previous experience with posterior sphincterotomy and anoplasty. Anal wounds and fissures healed faster than with previous procedures. It is encouraging that this simple and rapid procedure has such great efficacy with a minimum of complications.


Colorectal infarction following resection of abdominal aortic aneurysms. Infarctions of the colon and rectum (incidences approximately 1 and 0.5 per cent, respectively) are caused by compromised collateral circulation to the colon and rectum, usually as a result of arteriosclerotic disease of the superior and inferior mesenteric arterial systems, as well as the hypogastric arteries. Patients who have colorectal ischemia after operations for abdominal aortic aneurysms have diarrhea (sometimes bloody), abdominal pain, and distention. The diagnosis may be established by sigmoidoscopic examination. Treatment includes surgical removal of the compromised bowel and creation of a temporary or permanent end colostomy. Prevention of this complication is aided by preservation of primary and collateral circulation, avoidance of hypotension, and preoperative bowel preparation.


Management of benign villous adenomas of the entire rectum. While villous adenomas of the rectum are common, they rarely encompass the entire rectum to the dentate line. It is even more unusual to find a tumor of this size to be benign. Fluid and electrolyte deficits associated with this tumor add to the difficulty in management. The experienced surgeon should be aware of the various modes of treatment and be able safely to use the appropriate operation. It is as grave an injustice to the patient to treat a benign lesion as a malignancy as it is to remove the rectum for a benign villous adenoma.


Nonspecific ulcers of the colon.

Nonspecific ulcers of the colon. Two cases of nonspecific cecal ulceration are presented. The lesions tend to occur in the right colon, produce pain or bleeding, and generally are best managed surgically. Etiology of the ulcers is unknown, but a vascular theory of origin is favored.


[Contribution of Antioquia University to Latin American Dentistry]. The School of Dentistry of Antioquia University is one of the first institutions in Latin America to have developed and disseminated the ideas of integral clinical instruction and the delegation of functions to auxillary personnel. This article narrates some of the more important events that took place when these propositions were first advanced and put to the test. It also describes a few distinctive features of current clinical instruction at this School, including an evaluation system developed by members of the institution. The article comments on the trainig of auxiliary personnel and the scope of their functions. A brief review is given of the research on salt fluoridation that staff of Antioquia University have been conducting for several years in a number of Colombian towns. The results of this research to date are discussed.


[Programs for supervised professional practice and for rural oral health promoters in Guatemala]. The experiences of the programs of Supervised Professional Practice and for Rural Oral Health Promoters conducted by the School of Dentistry of San Carlos University in Guatemala are described. The first of these programs was designed to have students practice the profession during an eight-month academic period in hinterland towns under periodical supervision by their professors, and the second resulted as an unexpected offshoot during the initial stages of the program of Supervised Professional Practice in a northwestern district of Guatemala. The history and progress of both programs are described, some results are presented, and the salient features of university-community interaction, as exemplified by these programs, are discussed in terms of a theoretical model designed by one of the authors.


[Community laboratories as tools of scientific research on health society in Venezuela]. The School of Dentistry of Zulia University, Maracaibo, Venezuela, set up "community laboratories" to investigate alternative solutions to Venezuelan oral health problems. These academic-administrative units were used to make trial of different arrangements for the provision of dental care in different community situations. The purposes of the community laboratories were to design, develop, and compare comprehensive dental care systems, delegate functions to auxiliary personnel selected in the communities themselves, use simplified equipment, design techniques for reducing costs while maintaining quality, generate a methodology for community motivation, apply preventive techniques on a mass scale, offer the experience so acquired to the public services and to the profession at large, and supply information on the community essential for the design of curricula. The result has been highly encouraging because of the degree of community participation obtained and the salutary effect on student training and attitudes.


[Dental education oriented to various socioeconomic conditions in Panama]. The current system of instruction in the School of Dentistry of the University of Panama is described. The object of the system is to prepare professional people capable of blending biological, techological, and social principles and applying them in different models of dental care for the solution of individual and collective oral health problems. The students take their clinical training in the metropolitan area (clinics on campus and in Santo Tomás Hospital) in the heavily populated rural area (the community hospital and primary schools), and in the sparsely populated countryside (where they work with teams of three auxiliaries in prevention programs for schoolchildren and programs of care for teachers and lend support to community activities).


[The experience in dental education of Cayetano Heredia University of Peru]. This article describes the educational experience gained in the dentistry program of Cayetano Heredia University in Peru. The programs for professional and auxiliary personnel training were drawn up after analyzing the health needs of the population and the services required to meet them, which resulted in the elaboration of an original methodology and taxonomy. Learning is an integral experience, one that takes place in the dental clinic, the hospital, and the community. The curriculum includes the following components: units for the intensive learning of clinical functions, fewer preclinical activities, clinical training with the ongoing assistance of auxiliary staff, extended interaction with marginal urban communities, rural internships, and hospital externships. A summary account is given of the gains made, the difficulties encountered, and plans for devising in-service teaching approaches that more effectively meet the needs of the community.


[Training and use of dental manpower resources in Mexico]. The introductory section describes the general situation of dental care in Mexico, analyzes the prevailing service model (including the kind of work done by the dental professional and the technology he employs), and briefly reviews the evolution of dentistry in the country. There follows an account of a series of new approaches to service and manpower training in experimental implementation since 1972 in the stomatology curriculum at the Xochimilco campus of the Metropolitan Autonomous University, at the National School of Professional Studies at Zaragoza, in the School of Dentistry of Nuevo León Autonomous University, Monterrey, and in the Dental Services at Ciudad Netzahualcóyotl. In each case, the background, characteristics, and objectives of the programs, and their evolution and prospects are described.


[The Ecuadorean experience: rural work as an axis for the provision of dental services]. This article discusses dental practice up to 1972 and the oral-dental epidemiologic profile in Ecuador. It is then proposed that the indices of oral-dental morbidity can be lowered by establishing a technical unit of national scope, shifting the orientation in the year of compulsory rural service required of dnetal school graduates, training and employing auxiliaries from the communities, adding research to the regular functions of the dentist, and centering the performance of dental services on rural work. Lastly, a detailed description is given of the national rural dentistry program and its operation from 1972 to 1976, and the gains made in the oral-dental care of population are reviewed.


[Inhibition of rat liver delta 4-3-ketosteroid-5 alpha-reductase by steroids in vitro]. The inhibition of the hydrogenation of testerone to 5alpha-dihydrotestosterone in microsomes of female rat liver has been studied by progesterone-, testosterone- and estradiol derivatives. In the pregnane series, progesterone, 17alpha-OH-progesterone and its acetate were the strongest inhibitors. In the estradiol series, 3-hydroxy-compounds with a CH2X-substituent at 17alpha-position were stronger inhibitors than the respective 3-methoxy derivatives. The most potent inhibitor till now is an estradiol derivative with a SeCN group in 16alpha-position.


Abnormal growth hormone response in obesity with normal carbohydrate tolerance and normal thyroid function. Growth hormone (HGH) response to glucose-induced hyperglycemia and insulin-induced hypoglycemia in 13 obese adults without carbohydrate intolerance and with normal thyroid function were compared with 16 normal weight subjects. HGH levels measured 30 min after placing an indwelling needle in an antecubital vein were significantly lower in obese than in the non-obese controls. HGH concentrations were inversely related to the body weight in all subjects. In the obese group a suppression of serum HGH level was lacking during glucose-induced hyperglycemia and furthermore it was recorded that HGH response to insulin was significantly less as compared with controls. These data indicate that abnormal HGH response is a characteristic in obesity with normal carbohydrate tolerance and normal thyroid function. HGH is a potent physiological stimulatory of lipolysis and it is thus tempting to speculate that an impaired HGH secretion leads to a diminished lipolysis and further deposition of excessive fat in obesity.


Some disturbances related to iodination and utilisation of thyroglobulin and 27 S iodoprotein in non-toxic multinodular goitre. The relationships among the thyroid iodoproteins, their biosynthesis in vitro in thyroid slices and the histological structure of a multinodular, sporadic goitre was examined after strumectomy from a euthyroid 51-year-old woman. Using sedimentation methods 27S, thyroglobulin (TG), 12S and 3--8S proteins were found. Besides these, 4 to 5 other proteins with molecular weights between 165,000 and 36,000 daltons were detected by polyacrylamide gel electrophoresis. The concentration of soluble proteins was very low (3 mg/100 mg wet tissue), particularly TG (0.69 MG/100 MG). The sedimentation constant (18.3S) of goitrous TG was lower than mature 19S-TG and it was poorly iodinated (0.06% w/w). 27S iodoprotein was present in the goitre extract. Thyroid slices of goitre tissue incorporated 14C-leucine into proteins and synthesized TG and its subunits. Newly synthesized proteins were rapidly released from the microsomes. Pathohistologically, struma colloido-microfolliculare  with dystrophic-proliferative changes was noted. In the large follicles which were filled with colloid, dystrophic alterations in thyrocytes and desquamation of the follicular epithelium were observed. In conclusion, it is suggested that the presence of poorly iodinated, immature TG in nontoxic multinodular, sporadic goitre, in the absence of iodine deficiency, probably results in disturbances in the utilization of TG from the follicular lumen. In the follicular lumen under these conditions it is possible that 27S protein is formed from pre-existing poorly iodinated TG. These findings suggest that inability to resorb colloid may be a cause of nodule formation.


[Changed body composition by increased total body fat content in experimentally hypothyroid rats]. Total body fat content was determined in growing normal male Wistar rats and hypothyroidized animals 7 weeks after feeding with Methimazol (group MMI-HT), Methyl-thiouracil (group MTU-HT), and performance of radiothyroidectomy by 131-iodine (group R-HT), respectively. At the end of experiments there was an extreme hypothyroid state in all treated groups, verified by external signs, growth kinetics, serum cholesterol estimation and evaluation of the iodothyrosine pattern of the thyroid glands. Changed body composition resulted in all HT-groups from significant increase of total body fat content. The relation of constituents fat : protein : water of 1 : 2 : 6 in the KT-group was changed into 1 : 1 : 3 in the HT-groups. No differences were found between the different HT-groups. Our findings are in good agreement with altered metabolism of plasma lipids described by other authors showing the existence of a highly disturbed lipid metabolism in thyroid hormone deficiency.


The effect of lactation on thyroid activity of women. The study comprised 12 lactating (L) women, 26 women who interruped the lactating during study (IL) and 6 women failing to lactate (NL). All women gave birth to normal fullterm infants after uneventfull pregnancy and vaginal delivery. Sampling was done during the 2nd day and 10th week after parturition. Lactating women showed more pronounced decrease of thyroxine, decreased thyroxine: triiodothyronine ratio and increased TSH level during the 10th week after parturition in comparison to IL group. The women on NL group showed similar changes as L women, but without increased level of TSH in comparison to IL ones. Results suggest the effect of lactation on the thyroid activity. This effect could be due to the loss of iodine and thyroid hormones to the milk.


Ten-year experience with DDAVP in treatment of diabetes insipidus. Thirty patients with central diabetes insipidus were treated with 1-deamino-9-D-arginine vasopressin (DDAVP) during the period of 3--10 years. DDAVP was applicated in 1--3 intranasal doses daily. The dosage varied between 7--42 microgram/24 h. The diuresis before the treatment ranged between 28,000--7,600 ml/24 h (mean 13,883 ml/24 h) and was decreased by DDAVP below 2000 ml/24 h in 21 patients (70%) and to 2000--4000 ml/24 h in 8 patients (26.6%). In a single case it was not possible to reduce the diuresis from 20,000 ml below 8,000 ml/24 h. Favourable properties of DDAVP: absence of reduction of potency, lack of important side-effects and prolonged action were not lost even in the course of the long term treatment. No harmful effects of DDAVP were noted. Blood count as well as renal function tests were not affected by the treatment. All the patients preferred DDAVP to their previous therapy.


Vasopressin release from incubated in situ posterior pituitary lobe after intraventricular injection of carbachol or atropine. The vasopressin release rate from incubated in situ rats posterior pituitary lobe as observed following intracarotid infusions of hypertonic solutions (3 x 0.1 ml/100 g b.w. contained 1.0 mmol NaCl and 0.1 mmol CaCl2 per 1 ml) was studied when influenced by intraventricular injections of 0.6 microgram carbachol or 240 microgram atropine sulphate, respectively. The increase in the release of vasopressin following intracarotid infusions of hypertonic solution augmented by intraventricular injection of carbachol was found. Atropine was shown to be effective in preventing the vasopressin release caused by hypertonic solution. The effects of carbachol and atropine indicate that mediation at synapses in the nucleus supraopticus involved in the release of vasopressin induced by osmotic stimulation is cholinergic.


Correlation among foetal number, corpora lutea and plasma progesterone in Rockland-Swiss mice. The relationship among plasma progesterone, number of corpora lutea, and foetal number was assessed in Rockland-Swiss albino mice. While number of corpora lutea and foetal number were significantly correlated, neither was related to plasma progesterone level. This finding in the mouse is similar to results reported in the rabbit.


Endoscopy of the nose and nasopharynx.

Endoscopy of the nose and nasopharynx. Endoscopy of the nose and nasopharynx using rigid endoscopes and the zoom-laryngoscope-epipharyngoscope after v. Stuckrad enhances the diagnostics in these regions considerably. These "inaccessible" regions, remote structures and niches can easily be visualized by angle-endoscopes with magnification. Not only diagnostic procedures are facilitated but also some therapeutical manipulations. Especially for the early detection of cancer as for follow-up control and photo-documentation the endoscopes are of particular importance.


Therapeutic endoscopy of the paranasal sinuses. This paper is mainly concerned with describing and demonstrating the technique of paranasal endoscopies--maxillary, frontal, sphenoidal--, illustrated by diagrams. The improvement of technique in diagnosis and therapy of the paranasal sinuses has proved essentially successful. Indications for therapeutic endoscopy of paranasal sinuses are: 1. Purulent sinusitis. 2. Polypous and purulent sinusitis in children. 3. The so-called "mucosinus". 4. Removal of solitary cysts. 5. Removal of tooth fillings and roots. The different procedures are described.


Endonasal sinus surgery with endoscopical control: from radical operation to rehabilitation of the mucosa. The radical operations of the paranasal sinuses with total removal of the diseased mucosa very often produced postoperative disability due to scar formation and nerve irritation. A new concept of endonasal sinus surgery is based on the reestablishment of paranasal draining, reventilation, and preservation of the lining mucosa. This became possible by a strictly endonasal approach using angle-optic endoscopes for the optical control of manipulations. The principles of endonasal antrostomy, ethmoidectomy, and infundibulotomy are outlined, and their preliminary results are given. The importance of long-range postoperative local treatment is emphasized.


Magnifying endoscopic observation of the gastric mucosa, particularly in patients with atrophic gastritis. The gastric mucosal surface was observed using the magnifying fibergastroscope (FGS-ML), and the fine gastric mucosal patterns, which were even smaller than one unit of gastric area, were examined at a magnification of about 30. For simplicification, we classified these patterns by magnifying endoscopy in the following ways; FP, FIP, FSP, SP and MP, modifying Yoshii's classification under the dissecting microscope. The FIP, which was found to have round and long elliptical gastric pits, is a new addition to our endoscopic classification. The relationship between the FIP and the intermediate zone was evaluated by superficial and histological studies of surgical and biopsy specimens. The width of the band of FIP seems to be related to the severity of atrophic gastritis. Also, the transformation of FP to FIP was assessed by comparing specimens taken from the resected and residual parts of the stomach, respectively. Moreover, it appears that severe gastritis occurs in the gastric mucosa which shows a FIP. Therefore, we consider that the FIP indicates the position of the atrophic border.


Significance of intraoperative fibercholangioscopy in the diagnosis of biliary tract disorders. Intraoperative fibercholangioscopy allows direct inspection of the entire biliary tree up to the secondary distributaries. In 100 patients with suspected biliary tract pathology on account of endoscopic retrograde cholangiography the following findings were obtained: choledocholithiasis (solitary or multiple) in 66, biliary mud in 4, stricutres in 15, common bile duct carcinoma in 8, choledochal cyst in 1 and extrinsic lesions in 6. Peroral direct transpapillary cholangioscopy is still in an experimental stage but its results are promising.


Flexible rectosigmoidoscopy in the detection of tumoral colonic lesions. The fibrorectosigmoidocope Olympus TCF I S, has been systematically applied to the exploration of the distal colon (rectum and sigmoid) in patients with intestinal or digestive extra intestinal symptoms. In the first 300 patients the technical parameters of the method were tested: the fleet enema preparation was found excellent or satisfactory in 95% of examinations. The tolerance was good in 96% of examinations--the mean length of operation was 5.15 min--the mean length of colon examined was 48.5 cm, the distance of 50 cm being surpassed in 50% of patients. The efficacy in the detection of the lesions was tested in 476 patients. Tumoral colonic lesions were detected in 105 patients with a total of 125 adenomas and 31 cancers. In the area that could have been explored by a rigid rectosigmoidoscope (0-19 cm) we found 71 lesions (50 adenoma and 10 carcinoma), whereas beyond this limit (25-60 cm) 85 lesions (50 adenoma and 10 carcinoma).


Endoscopic fistulotomy (EFT) for parapapillary choledochoduodenal fistula. Up to now, surgery was the only possible treatment for choledochoduodenal fistulas, which are seen more often in Japan than in Europe. This paper presents the value and effect of endoscopic fistulotomy (EFT) as an alternative treatment in those cases. Parapapillary choledochoduodenal fistulas are abserved usually on the longitudinal fold of the papilla or on its oral side. The papillotome is inserted into the common bile duct through the orifice of the duodenal papilla, then the wall between its orifice and the fistula is cut to open widely the distal portion of the choledochus. EFT was performed successfully in 7 cases. The procedure led to a wide open stoma of the distal common bile duct with free bile outflow. Residual stones, a common occurrence in cases of parapapillary choledochoduodenal fistulas, may pass spontaneously after EFT or can be removed with a basket catheter. In cases of parapapillary choledochoduodenal fistula, EFT is a reliable method, especially in high-risk patients, and an alternative to surgical treatment.


Right colon loop: a potential pitfall for total colonoscopy. A right colon loop can occur during total colonoscopy. A light on the anterior abdominal wall in the right lower quadrant and a fluoroscopic view may imply that the tip of the colonoscope is in the cecum. The right colon loop can be documented by roentgenograms and the injection of a radioopaque solution. An arrest in embryological development with overdistension with air accounts for the right colon loop. An unrecognized right colon loop could account for a failure to see a cecal carcinoma.


Boerhaave's syndrome: description of a case with endoscopic confirmation. A rare case of spontaneous oesophageal rupture is reported. The clinical, radiological and endoscopic aspects of that specific syndrome are described, and possible pathogenetic factors are also considered.  Subsequently, appropriate radiological methods are reviewed and compared with the fiberendoscopic technique, the importance of which is outlined for diagnosis confirmation, right positioning of the rupture and correct surgical approach, Wherever possible,, immediate surgery is the proper therapy, as confirmed by literature.


Kindling effect in the reptilian brain: motor and electrographic manifestations. The extension of the kindling effect to the reptilian brain is reported with two experimental groups of lizards Lacerta galloti. The first group received daily stimulation in the telencephalic cortex at a current level sufficient to produce motor responses. These motor responses occurred only when the stimulus was applied, and disappeared when it was terminated. However, the threshold for evoking these motor responses decreased in 20 days of stimulation, and the responses evolved to stimulus-bound convulsions. In the second group, the stimulus was too low to produce motor responses, but it developed afterdischarges and spontaneous recurrent electrographic seizures that increased their duration with each stimulation. Reptilia are discussed as useful experimental animals for studying the kindling phenomenon.


A neuropsychological battery for epilepsy. The development of the Neuropsychological Battery for Epilepsy is presented. The tests are designed to be helpful in the evaluation of adult epileptics. The battery consists of General Measures which include tests in the areas of intellectual functioning, emotional status, and lateral dominance. The development of a series of 16 Discriminative Measures is presented in detail through the discussion of a pilot study, the principal investigation, and a cross-validational effort. In the principal study, 50 epileptics were individually paired with individuals having no history of neurological disease, and their performances on a wide range of ability measures were compared. Tests were eliminated if they did not appear sensitive to the brain-related problems of epileptics, if they demonstrated excessive duplication with other measures, or if they did not cross-validate with a new sample of 25 epileptic--normal pairs. The advantages of the battery were discussed, including coverage of areas previously not adequately assessed, elimination of tests with limited utility, greater uniformity and accuracy in the classification of individual subjects, and standardization of the tests with epileptics.


Effects of antiepileptics on both behavioral and electrographic seizure patterns induced by maximal electroshock in rats. Effects of antiepileptics on both behavioral (TE) and electrographic seizure patterns induced by maximal electroshock were studied simultaneously in the same animal. The results obtained are as follows. All the antiepileptics used in this study depressed the TE seizure. Imipramine, biperiden, and lidocaine also depressed TE seizure, although they are not classified as antiepileptics. Phenobarbital, primidone, trimethadione, carbamazepine, ethosuximide, diazepam, clozapine, and imipramine had a depressant effect on electrographic seizures. However, phenytoin, ethotoin, phenacemide, and acetazolamide did not influence the electrographic seizure, in spite of having a strong effect on TE seizure. The present procedure, i.e., that of simultaneous observation of both behavioral and electrographic seizure patterns induced by maximal electroshock in the same animal, provides information which cannot be obtained from either behavior or EEG observation alone.


Chronically isolated cerebral hemisphere in the cat: effects of parenteral administration of penicillin. Brain electrical activity (EEG) of cats with chronic, complete, neural isolation of the cortex of an entire cerebral hemisphere was studied prior to and following intramuscular administration of penicillin (250,000--300,000 units/kg). The most prominent feature of the isolated hemisphere's EEG during base-line recordings was irregular, aperiodic, slow-wave activity with intermittent sharp waves and occasional spike discharges. Following penicillin administration there was an increase in the number of spikes and sharp waves in the isolated hemisphere and an increase in amplitude of the background activity. Simultaneously recorded EEG activity of the intact hemisphere demonstrated the paroxysmal burts of sharp waves or spike-wave complexes that have been described previously in normal animals. There was complete independence of the electrical activity recorded from intact and isolated hemispheres. These results indicate that intramuscularly administered penicillin can exert a convulsant effect on cortical structures in the absence of subcortical connections, but the generalized epileptiform activity seen in normal animals is dependent on thalamocortical connections.


Plants as bioassay systems for monitoring atmospheric pollutants. Plant species act as natural bioindicators of atmospheric pollutants. Plants can be used as bioassay systems for monitoring atmospheric pollutants. Plant injury symptoms, altered growth and reproductive pattern, changes in yield and/or productivity, and changes in species distribution can be used singly or in combination as monitoring devices. The results must be accepted as semiquantitative, but within that constraint, air quality can be sufficiently well defined to enable the setting of air quality standards. Genetic variability of higher plant species has yielded cultivars which display a range of tolerance to gaseous and particulate atmospheric pollutants. Asexual propagation of these cultivars provides pollutant-sensitive and pollutant-tolerant plant material which can be grown on selected sites for observation. Gymnosperm and Angiosperm species as well as species of lichens and mosses have been used to establish field monitoring networks in Europe, Canada, and the United States. White pine, shade tobacco, mosses, and lichens have proven particularly useful as bioassay tools. Pollen from pollutant-sensitive and pollutant-tolerant plant cultivars has also been used as a sensitive laboratory bioassay tool for studying air quality. Epiphytic mosses are particularly efficient as monitors of particulate pollutants, especially heavy metals, some of which may act as chemical mutagens. The cost, complexity, and lack of reliability of instrumented systems for air quality monitoring make imperative the need to develop successful plant bioassay systems for monitoring air quality.


Bioaccumulation and detection of trace levels of cadmium in aquatic systems by Eichhornia crassipes. The water hyacinth (Eichhornia crassipes) may be used as a sensitive biological indicator for continuously monitoring trace quantities of toxic heavy metals in aquatic systems. A river water system polluted with cadmium was simulated while other factors of temperature, day-night cycle, water quality, and light intensity remained constant. When the water hyacinth is maintained in river water containing 0.001 mg/l. of cadmium chloride, the plant's root system will concentrate this element at an average rate of 0.9, 1.4, and 3.0 mug Cd/g root dry weight after 24, 48, and 72 hr exposure periods, respectively. At a higher cadmium concentration of 0.01 mg/l., cadmium was concentrated in the roots much faster to levels of 6.8, 13.6, and 39.1 mug/g root after 4, 8, and 24 hr exposure periods, respectively. At initial concentrations of 0.05 mg/l. cadmium, the roots contained 29.5, 48.8, and 156 mug/g root following 4, 8, and 24 hr exposure periods, respectively. During these same time intervals, the water hyacinth sorbed 56.7, 153, and 281 mug/g root when the initial cadmium concentration was increased to 0.10 mg/l. The water hyacinth tops can also assist in the monitoring process when cadmium contamination levels are 0.10 mg/l. and greater. At this initial cadmium concentration, cadmium is translocated into the tops. After 8 hr, the tops averaged 1.1 mug/g top. After 24 hr, this concentration was increased to 6.1 mug/g top.


EMIC: a centralized source of chemical mutagenesis information. In 1969, a group of scientists concerned with the health hazards posed by environmental mutagens formed the Environmental Mutagen Society to encourage interest in and the study of mutagens in the human environment. In order to deal effectively with this potential health problem, these scientists saw the need for a centralized source of published information on chemicals tested for mutagenicity and, therefore, set down as one of the immediate functions of the Society, the formation of a registry of chemicals tested for mutagenicity. The Environmental Mutagen Information Center (EMIC) was established at Oak Ridge National Laboratory to fill this information need by collecting, organizing, and making available the international literature on chemical mutagenesis. EMIC is now sponsored by the National Institute of Environmental Health Sciences and the National Cancer Institute. From a simple registry of chemicals tested for mutagenicity, the scope and activities of EMIC have increased greatly. EMIC now processes all publications from the open literature dealing with the genetic effects of any environmental agent except those publications dealing exclusively with ultraviolet light or ionizing radiation.Growing concern for the long-term effects of chemical exposure on human health and interest in the relation between mutagenicity and carcinogenicity are placing ever-increasing demands on this Center. As a result of the early realization of the need for literature control, a modern, specialized information center now serves the information needs of mutagenesis workers and other interested persons around the world.


The current status of hazardous solid waste management. Growth of the population and of industrialization, and substandard disposal of the increased waste products thus generated, have resulted in numerous documented cases of harm to human, plant, and animal health. The Resource Conservation and Recovery Act (1976), its stated goals, and its intended means of implementation, are discussed relative to hazardous waste problems. Subtitle C of this Act, and the authority granted by it to the U.S. Environmental Protection Agency, are explained. Standards and regulations have been imposed upon those responsible for generating and transporting hazardous wastes, to ensure the ultimate safe disposal of such wastes in environmentally suitable, properly licensed facilities.


Hazards of solid waste management: bioethical problems, principles, and priorities. The putative hazards of solid waste management cannot be evaluated without placing the problem within a cultural climate of crisis where some persons consider such by-products of "high, hard technology" to have raised unresolved moral and ethical issues. In order to assist scientific and technical efforts to protect public health and safety, a bioethical perspective requires us to examine three controversial aspects of policy-making about public safety. Failure to recognize the qualitative difference between two cognitive activities-risk-measurements (objective, scientific probabilities) and safety-judgments (subjective, shifting value priorities)-has had three unfortunate consequences. Sophisticated methods of risk analysis have been applied in a piecemeal, haphazard, ad hoc fashion within traditional institutions with the false expectation that incremental risk-reducing programs automatically ensure public health and safety. Ethical priorities require, first and foremost, a whole new field of data arranged for comparable risk-analyses. Critics of cost/risk/benefit quantifications attack the absurdity of "putting a price on human life" but have not been confronted with its threefold ethical justification. The widening discrepancy in risk-perceptions and loss of mutual confidence between scientific experts and ordinary citizens has placed a burden of social responsibility on members of the scientific and technical community to engage in more effective public education through the political process, notwithstanding advocates of a nonscientific adversary process. The urgency of effective public education has been demonstrated by the extent to which we have lost our historically balanced judgment about the alleged environmental hazards posed by advanced technology.


Hazardous solid waste from domestic wastewater treatment plants. The treatment of liquid wastes in municipal sewage treatment plants creates significant quantities of solid residue for disposal. The potential hazard from these wastes requires that their characteristics be determined accurately to develop environmentally sound management criteria. It is readily recognized that the sludge characteristics vary with the type and degree of industrial activity within a wastewater collection system and that these characteristics play a significant role in determining whether the material has potential for beneficial reuse or if it must be directed to final disposal. This paper offers an overview of past and present practices of sewage sludge disposal, an indication of quantities produced, and experience with beneficial reuse. An estimated range of costs involved, expected environmental effects and potential for continued use is offered for each disposal or reuse system discussed.


Municipal solid wastes and their disposal. A brief overview is given of the sources, characteristics, and toxic constituents of municipal solid wastes. Several methods are presented for handling, treating, and disposal of solid wastes. Monitoring the landfill site is necessary; there has been a trend to recognize that municipal solid wastes may be hazardous and to provide separate secure handling, treatment, and disposal for their dangerous constituents. Under current state and Federal regulations, permits are being required to assure that proper handling of conventional solid wastes and more hazardous constituents are carefully managed.


Minnesota Mining and Manufacturing Company's hazardous waste program. This paper discusses the present hazardous waste program of 3M Company (Minnesota Mining and Manufacturing Company). 3M's definition of hazardous waste and the company's position on hazardous waste disposal are first considered. The company position is that wherever and whenever the disposal of a waste material threatens the environment or public safety, then that waste should be considered a hazardous waste and treated accordingly in terms of its handling and ultimate disposal. The generation of hazardous wastes and the differentiation of "hazardous" and "nonhazardous" wastes are described next. Handling of hazardous wastes from their generation to their disposal is then covered. This includes a definition of internal 3M terminology and a description of the hazard rating system used by the company. Finally, 3M disposal practices are presented. It is 3M's position that thermal destruction of hazardous wastes, where appropriate, is the best method for their disposal. With this in mind, 3M has constructed incineration facilities throughout the country. The rotary kiln incinerator at the 3M Chemolite plant in Cottage Grove, Minnesota is briefly described. Disposal of certain hazardous wastes in controlled secure land disposal sites is then briefly discussed.


Hazardous solid waste from metallurgical industries. Types of land disposed residuals from selected metal smelting and refining industries are described, as are the origin and disposition of land disposed residuals from the primary copper industry as an example. Quantities of land-disposed or stored residuals, including slags, sludges, and dusts, are given per unit of metal production for most primary and secondary metal smelting and refining industries. Assessments of the hazard potential of residuals are given. Present treatment and disposal of residuals are discussed and assessed for health and environmental protection. Possible technologies for protection of ground and surface water contamination are presented. These include lined lagoons, chemical fixation of sludge, and ground sealing. Possibilities of resource recovery from residuals are discussed. Data are presented showing attenuation of heavy metal ions and fluorides in selected soils. The leachability and mobility of smelting and refining residuals constituents, including heavy metals and fluorides, and other potential toxicants in specific soil, geologic, and hydrologic disposal environments must be carefully considered in setting disposal requirements.