Multiple-gated acquisition cardiac blood-pool isotope imaging. Evaluation of left ventricular function correlated with contrast angiography.

Thirty-one patients were assessed by the multiple-gated acquisition cardiac blood-pool isotope-imaging technique using radiolabeled albumin within 24 hours of biplane contrast ventriculography. Data from the imaging method were analyzed by a semiautomatic technique with computer-generated edge detection and background subtraction. An excellent correlation was observed between ejection fractions determined with multiple-gated isotope imaging and those obtained by biplane contrast ventriculography (r = 0.93), and the same was true for average ejection rates (r = 0.80). For assessment of wall motion with this imaging technique, the anterior and the left anterior oblique left ventricular views were divided into nine segments, and a score was assigned to each segment based on the degree of wall motion. The cumulative anterior and left anterior oblique scores correlated well with the score from biplane contrast ventriculography (r = 0.90), and in 94% of segments in the left anterior oblique projection the assessment with multiple-gated isotope imaging was the same as or varied by only one class from the assessment by biplane contrast ventriculography. The multiple-gated acquisition cardiac blood-pool isotope-imaging technique is thus a valuable noninvasive method for assessing left ventricular function as measured by ejection fraction, ejection rates, and wall motion.


Polymorphic reticulosis, lymphomatoid granulomatosis. Two diseases or one?

Clinical and pathologic data on 40 patients (31 men, 9 women) with polymorphic reticulosis are presented. The disease may involve the upper respiratory tract, notably the nose, paranasal sinuses, nasopharynx, or palate, as well as the lung, skin, gastrointestinal tract, and central nervous system. Polymorphic reticulosis is identical pathologically to lymphomatoid granulomatosis. Localized disease, particularly that in the upper airway, responds well to radiation therapy. Corticosteroids and cytotoxic agents appear to be ineffective with multisite involvement.


Pituitary adenoma in Olmsted County, Minnesota, 1935--1977. A report of an increasing incidence of diagnosis in women of childbearing age.

There has been a recent, rapid increase in the number of pituitary adenomas diagnosed in women of childbearing age in Olmsted County, Minnesota. The incidence rates in men of all ages and in women aged 45 and over have remained stable and are similar to rates reported from elsewhere. Since 1970 the mean annual incidence per 100,000 women aged 15 through 44 years has been 7.1, whereas it was 0.7 in the population of the same age and sex during the period 1935 through 1969.


Accuracy of antibody-coated-bacteria test in recurrent urinary tract infections.

Antibody coating of urinary bacteria was compared with results of ureteral catheterization studies in order to localize the site of recurrent urinary tract infections in 32 patients. The antibody-coated-bacteria test reliably detected infections in patients with upper urinary tract infection (16 of 17 patients), but false-positive results occurred frequently in patients with lower urinary tract infection (5 of 15 patients). The antibody-coated-bacteria test appears to be a useful screening test for localization of infection in patients with recurrent urinary tract infections.


Great-vessel switch operation without coronary relocation for transposition of great arteries.

Since its first successful clinical application in 1963, the Mustard operation has been the procedure of choice for most patients with transposition of the great arteries. Based on the principle of transposition of venous return, it produces a functional but not anatomic correction of the defect. Although the Mustard procedure has favorably changed the natural history of transposition, it is associated with various early and late complications that have led to a search for a more anatomic repair. Recently, transposition has been successfully corrected by switching the great vessels, with or without transplanting the coronary arteries. These are the first case reports of early postoperative hemodynamics in patients undergoing an arterial switch procedure without coronary relocation. The early hemodynamic and clinical results of this operation are excellent and they lend encouragement for its further application in suitable patients.


A syndrome of osteoporosis, increased serum immunoreactive parathyroid hormone, and inappropriately low serum 1,25-dihydroxyvitamin D.

Although most patients with postmenopausal osteoporosis have normal or low values for serum immunoreactive parathyroid hormone (iPTH), we have reported previously that a small subset (about 10% of the total group) have increased values. We studied three patients representative of this latter group. Serum iPTH was two to three times higher than the age-adjusted normal mean, serum ionized calcium and total calcium were in the lower half of the normal range, and serum 1,25-dihydroxyvitamin D [1,25(OH)2D] was in the low-normal range. Six months of treatment of one patient with 0.5 microgram/day of synthetic 1,25(OH)2D improved calcium absorption and balance; however, serum iPTH remained high. After surgical removal of 1,010 mg of hyperplastic parathyroid tissue, serum iPTH decreased to normal. These and other data suggest that increased serum iPTH in these patients was caused by secondary hyperparathyroidism, possibly because of inadequate conversion of 25-OH-D to 1,25(OH)2D.


Hematogenous osteomyelitis at uncommon sites in children.

The diagnosis of hematogenic osteomyelitis is often delayed in children if it involves uncommon sites such as the pelvis, clavicle, or calcaneus. Although parenterally administered antibiotics may control the disease process in the acute stage, abscess formation requires incision and drainage. Staphylococcus aureus was the most common organism in this series, and it usually was penicillin resistnat. When the condition is diagnosed early and is properly treated with at least 3 weeks of antibiotic therapy and judicious surgical intervention, recurrences are rare and morbidity is minimal.


Metabolism of uric acid in normal and toxemic pregnancy.

The formation, measurement, and excretion of uric acid are reviewed. Since fluctuations in serum uric acid may be as high as 40% over a 24-hour period, a single value must be evaluated with caution. Alterations in the renal handling of uric acid are responsible for the pronounced decrease in serum uric acid over the first 20 weeks of gestation, its gradual increase in the latter part of pregnancy, and its further increase with pregnancy-induced hypertension. Although there is a fair degree of overlap between a normotensive control and a preeclamptic group, the level of serum uric acid generally correlates with the severity of preeclampsia. Possible intrarenal mechanisms that could produce these changes are discussed.


Left atrial myxoma simulating peripheral vasculitis.

Left atrial myxoma remains a diagnostic challenge clinically. A brief review of previously reported cases and their individualistic clinical and laboratory features are described. The present case report documents an unusual clinical presentation, initially directing attention to the central nervous system as well as to the peripheral arterial system. Histologic evidence of peripheral arterial myxomatous emboli, associated with vasculitis but without other confirmatory immunologic evidence of collagen vascular disease, had predated for 14 months the subsequent echocardiographic diagnosis of left artrial myxoma. These findings further emphasize the importance of recognizing the enigmatic and variable clinical presentation of left atrial myxoma.


Comparison of the excitatory and anaesthetic effects of ethanol in C57BL/6 and BALB/c mice; relation to blood ethanol concentration.

Ethanol increased the exploratory locomotion of BALB/c mice over a wide dose range (1.15--3.1 g/kg orally), whereas only a 2.31 g/kg dose of ethanol increased the locomotion of C57BL/6 mice. After 1.15 g/kg of ethanol the blood concentrations in BALB/c and C57BL/6 mice were 65 +/- 11 and 68 +/- 13 mg %, respectively, and after 2.3 g/kg--the corresponding concentrations were 156 +/- 26 and 142 +/- 14 mg % (mean +/- SEM). Doses of 3.8 and 4.6 g/kg inhibited the exploratory locomotion of mice of both strains to an equal extent. The induction time and the duration of ethanol-induced anaesthesia, as well as the blood ethanol concentrations (428 +/- 40 and 446 +/- 40 mg %, respectively, at the onset of anaesthesia) were similar in mice of both strains after a 5.4 g/kg dose. However, motor excitement before anaesthesia was observed only in the BALB/c mice. It is suggested that the observed strain differences in response to ethanol are due to low responsivity of C57BL/6 mice to the excitatory action of ethanol and are not caused by differences in the rate of its metabolism. Apparently, the excitatory and anaesthetic effects of ethanol are under separate genetic control mechanisms.


1-methyl and 1-benzyl derivatives of tetrahydroisoquinoline inhibit 5-hydroxytryptamine uptake by human blood platelets.

The effect of 1-methyl (salsoline, salsolidine) and 1-benzyl (papaverine) derivatives of tetrahydroisoquinoline (TIQ) on 5-hydroxytryptamine (5-HT) uptake by human blood platelets was studied. The drugs tested inhibited 5-HT (3 X 10(-6)M 5 min incubation) uptake by 30--60 % at 10(-4)M concentration and by 20--25 % at 10(-5)M concentration.


Impact of patient perceptions on compliance with treatment for hypertension.

Patient noncompliance with medical regimens is a major obstacle in achieving hypertension control. In this study the relationships between patients' perceptions of health, disease and medical treatment and compliance were examined in personal interviews with 142 patients under treatment for hypertension. Compliance was measured in terms of blood pressure control,  self-reported medication-taking, and appointment keeping. A multivariate log linear technique was used to control confounding. Blood pressure control was found to be associated with the perceived effficacy of the antihypertensive regimen, having medications prescribed for other chronic conditions, a high level of anxiety when hypertension was first diagnosed, the impact of hypertension and its treatment on lifestyle, and a higher educational level. For self-reported medication-taking, the perceived severity of hypertension, having medications prescribed for other chronic conditions and older age were predictive. Blood pressure control and self-reported medication-taking were highly correlated with each other(p = .02). Older age and being employed were the only variables that contributed independently to improved appointment keeping behavior. From these findings, it might be expected that emphasis on the effectiveness of treatment and on the potential threat posed by hypertension would motivate improved blood pressure control.


Appendicitis: decreasing normal removals without increasing perforations.

There is wide interhospital variation in the removal rates of histologically normal appendices, and variation also in appendectomy rates among countries and among hospital catchment areas. Decision theory suggests that better patient workup and careful observation of doubtful cases result in improved discrimination between appendicitis patients and those with nonspecific abdominal pain. By improving the data base and weighing evidence with care, a surgeon can reduce his false-positives without risk of increasing his perforation rate. In some cases it may even be possible to reduce the false-positives while simultaneously reducing perforations. In a survey of New England hospitals there was no inevitable inverse relationship between normal removal rates and perforation rates. Two examples of improvement in performance are cited from the literature.


Temporal patterns in the use of health services leading to cholecystectomy: a process evaluation using insurance records.

Data from Saskatchewan's public medical and hospital insurance programs are used to estimate a multivariate model of health services utilization among cholecystectomy patients. A methodology is developed which partitions the care process into an assessment period, a waiting period, and a hospitalization period. The general hypothesis is that presurgical and surgical decisions of physicians are influenced by extra-medical factors, including the social condition of the patient and the availability of health resources. This hypothesis is only weakly supported by the data.


A new planning methodology to assess the impact of the health care system on health status.

This article summarizes a new methodology recently developed by the Rand Corporation which permits health planners to assess the impact of the local health care system on the health status of the population. The methodology, in algorithm form, should assist health planners in developing objectives and actions related to the occurrence of selected health status indicators and should be amenable to health care interventions. Emphasis has been placed on developing a simplified, approximate analysis that health planners will find both feasible and effective. No detailed mathematic analyses are called for. The data required are, in most instances, readily obtainable. The algorithm is a methodology by which HSAs can investigate determinants of health status, identify breakdowns in the health care system, and specify needed improvements in the system. The goal of these algorithms is to assist HSAs to obtain valid and sufficiently detailed data that will provide a basis for monitoring breakdowns in the health care system and to improve planning decisions aimed at preventing such breakdowns. This should, in turn, affect population health status in the planning area.


A survey of obstetrician-gynecologists' abortion attitudes and performances.

Attitudes toward general and repeat abortion are examined in a probability sample of board certified obstetrician-gynecologists in three Mid-Atlantic states. A mail-back questionnaire yielded seventy per cent response rate. A typology of abortion attitudes was developed by combining scores on two Guttman scales, one general acceptance and one repeat abortion acceptance scale. This resulted in six types varying from conservative to liberal. Personal and work setting characteristics were examined as correlates of abortion attitude. Personal characteristics are correlated; work setting characteristics are not. Obstetrician-gynecologists; abortion attitudes and performances are related.


Patient attitudes about two forms of printed oral contraceptive information.

The desired form and style of written drug information for patients were assessed in a national survey of oral contraceptive (OC) users. These women were queried about two forms of OC information: a short insert included with dispensed drugs and a longer brochure delivered by the physician upon patient request. Longer and more detailed information, especially concerning drug dangers and directions for use, was strongly preferred. Younger and more educated women were more likely to report receiving the OC brochure and to desire more comprehensive information. Most respondents found information in both the insert and the brochure clear and useful, and felt it was important to include written information with other prescription drugs. The longer brochure was preferred over the shorter insert as a model of drug information to be included with additional drugs.


The prospects for health services in the United States.

The enormous variety of diagnoses and prescriptions for dealing with the health care crisis in the United States can be simplified and clarified by reference to four logically distinct models of methods for organizing the production of health services. The assumptions of the free market model, the bureaucratic planning model, the professional model and the cooperative equalitarian model are described, as are the characteristic pathologies connected with the form those models take in reality. The intrinsically expansionist character of the manufacturing, service and consumer segments of the U.S. health system is described and the suggestion made that legislative attempts to contain costs will lead to increased bureaucratization primarily at the expense of the consumer.


Second opinion elective surgery programs: outcome status over time.

Given the increasing rate of surgery and the escalating costs of hospitalization, it seems appropriate to review the necessity of recommended elective surgery before the surgery is performed. The second opinion elective surgery program is designed to screen patients before they undergo surgery. Findings are based on all not confirmed for surgery cases and an equal number of confirmed for surgery cases who were evaluated one year after their second opinion consultation. Roughly 77.9% of those not confirmed had not had the surgery and, of this, 64.4% reported no medical treatment (potential surplus surgery). Of the 710 not confirmed cases, one third (34.9%) never reported receiving medical treatment. The majority of those individuals confirmed for surgery did have the operation; however, 25.4% had not had surgery one year from their consultation. Thirty-two per cent of the confirmed cases reported never receiving medical treatment. There were 77 individuals (11.1%) who were confirmed for surgery who neither reported having surgery nor any medical treatment (population at risk). Subsequent follow up studies will present a clearer assessment of the ability of the program to screen potential surplus surgery and to realize cost savings.


A comparison of fenestration of the horizontal canal and stapedectomy in the opposite ear.

The Lempert one stage horizontal semicircular canal fenestration was the surgical procedure of choice for otosclerosis from 1939 to 1954. Subsequently, mobilization and stapedectomy replaced fenestration. In the offices of Drs. Day, Jordan, and Caparosa, the horizontal semicircular canal fenestration was performed from 1940 to 1955; the mobilization, two years; and, thereafter, the stapedectomy. A significant number of patients have had fenestration on one side and stapedectomy on the opposite ear. Fifty patients seen consecutively were reviewed. Reliable office audiological testing has been available only in the more recent years; and, therefore, audiological statistical comparison has limited reliability. It is felt, however, that a review of these patients and the study of their surviving hearing results is a worthwhile inferential comparison.


Civilian air travel and the otolaryngologist.

Thousands of individuals fly commercial airlines and private aircraft daily. One airline boasts of serving more than 100,000 passengers each day. Of these individuals exposed to barometric alterations, an undocumented number will develop significant barotrauma and may seek help from an otolaryngologist. Although many otolaryngologists learn the mechanics and management of barotrauma as military flight surgeons, residents in otolaryngology usually receive no specific training in this area. Because private and commercial aviation are so common today, we believe that a basic knowledge of barometric changes experienced while flying is essential for the practicing otolaryngologist. These basic principles are covered in this presentation. Case histories will also be discussed. One patient, who presented with signs of perilymph fistula, including sensorineural deafness and abnormal ENG, recovered spontaneously.


Surgical approach to tumors of the nasal cavity.

In the past there has been a general reluctance among rhinologists to remove the entire lateral nasal wall for fear of causing drastic disturbances of nasal physiology. It has been our observation that the physiological disturbances are fairly minimal if the patient, following surgery, uses nasal saline irrigations daily. Sometimes a nasal siphon or water pik is required to prevent crusting. It has also been noted that when the septum is removed, a chronic antritis on the contralateral side will usually occur. It has been our practice to do an antrostomy on the uninvolved side when the septum has been removed for any reason. Ophthalmologists have shown some reticence to having the entire bony support of the medial wall of the orbit and half the floor removed. This does necessitate transecting the lacrimal duct at its neck. We have, however, seen no trouble with epiphora following this provided the sac was allowed to drain in to the open nasal cavity. The trochlea is by necessity deprived of its support; however, the periostium seems to provide adequate support here and we have noticed no troublesome permanent problems with function of this muscle. The periorbita, which has been robbed of its osseous support, quickly epithelializes with nasal mucosa and becomes a part of the nasal cavity. Requirements for intranasal douching with saline have varied; however, we have had no problems with bothersome crusting following b.i.d. nasal irrigations. In cases where a small portion of the inferior turbinate could be preserved, there was always extreme hypertrophy of this remnant which usually brings the nasal physiology back to a nearly normal state which seldom requires any special care whatever. This paper presents primarily a method of approaching tumors of the sinonasal area, especially when there is difficulty in determining whether the lesion arises from the septum or lateral wall of the nose.


Anatomical consequences of CO2 laser surgery of the guinea pig ear.

A modified American Optical (Model 100) CO2 laser was used to produce lesions in the tympanic membranes, ossicles, and cochlear capsules of guinea pigs. Even with the lowest available intensities and durations (0.4 watts, 50 msec), there was damage to the inner ear. Although laser surgery of the ear can avoid mechanical trauma and bleeding as well as increase accuracy, the use of commercial lasers in ear surgery should be avoided until a proven unit is available.


Drug therapy in otomycosis: an in vitro study.

Otomycosis represents a small percentage of clinical external otitis. This well documented entity is often a stubborn clinical problem and, in contrast to bacterial external otitis, there is no otic preparation with specific antifungal activity. In response to this lack of otic preparations, we have surveyed in vitro a variety of available preparations to determine the general spectrum of activity against appropriate bacterial and fungal species. An agar-disc diffusion system was used testing the drugs against (1.) bacteria common in external otitis, and (2.) a variety of yeast and filamentous fungi. Aqueous Merthiolate and Cresylate demonstrated good non-specific antimicrobial activity, while nystatin and clotrimazole demonstrated specific antifungal activity. Otic preparations can now be used which have demonstrated in vitro effectiveness and give an alternate means of therapy to the now empirically selected otic preparation used for otomycosis.


Otospongiosis (otosclerosis): polytomographic and histologic correlation.

The Temporal Bone Laboratory of Northwestern University Medical School has three sets of temporal bones from patients who had antemortem polytomographic examinations resulting in a diagnosis of otospongiotic involvement of the cochlea. One of these cases was thought to have been an example of pure cochlear otospongiosis. The other two cases were patients with clinical (stapedial) otospongiosis, and their polytomograms were interpreted as unilateral otospongiosis with involvement of the basal turn of the cochlea. In the first set of temporal bones, no otospongiosis was present. In the other two sets, the otospongiotic lesion did not involve the cochlea, and a contralateral otospongiotic lesion was present that had not been seen on the polytomograms. Caution must be exercised in the interpretation of subtle polytomographic changes noted in the cochlear capsule and restraint used in the X-ray diagnosis of pure cochlear otospongiosis until there is evidence of correlation with pathological material.


Respiratory rate and ATP content of stria vascularis of guinea pig in vitro.

Stria vascularis from guinea pig cochleae was incubated in vitro to determine its metabolic response to variations in substrate and ion composition of the incubation medium. The respiratory rate at 37 degrees C in a medium containing glucose and pyruvate as substrate was 17.3 +/- 1.33 (SEM, n = 51) microliter O2/mg dry weight-hour. The stria could not maintain constant respiration by relying solely upon endogenous fuel stores. With substrate supplied, the ATP level could be maintained at about 73% of that existing in vivo. Glucose appears to be an adequate substrate for stria in vitro since glutamate, pyruvate, and fumarate did not increase the respiratory rate. Succinate increased respiration markedly but did not increase the ATP level. Ouabain (10(-4) M) caused a 48% decrease in the respiratory rate. Incubation in Na+-free and K"-free medium, each resulted in irreversible decrease of respiratory rate comparable to (or greater than) that caused by ouabain. These data are in accord with the high activity of Na+-K+-ATPase in the stria and the pronounced sensitivity of the endolymphatic potential to ouabain.


Procedures for preparation of otological and audiological data for computer analysis.

Extensive amounts of clinical data exist in the files of facilities providing otological and audiological services. Because of the considerable time involved in manual analysis, some departments are beginning to consider the use of computers for analyzing the data. It is often assumed that this data can simply be submitted to a computer center for analysis. This, however, is not the case. A careful series of planned procedures must be undertaken before information can be submitted and analyzed. This paper illustrates the procedural steps necessary to permit the utilization of a computer system for analysis of clinical data. The feasibility of the use of these procedures in the examination of otological and audiological data is considered.


Recurrence as a mode of determining efficacy in treatment of carcinoma of the larynx.

A study population of 374 patients with cancer of the larynx was evaluated, treated, and followed at yearly intervals up to a maximum of 18 years post-diagnosis. Of these, 348 received definitive therapy to attempt to eradicate their disease and were followed for recurrence and presence of cancer at death. In Stages I, II, and III recurrence of disease appears to be a very good indicator of therapeutic efficacy. Stage I carcinomas of the larynx should be treated with radiation as the proportions of patients with recurrences were the same for both primary surgical or radiation therapy. In Stages II and III, primary surgical therapy significantly lowered the proportion recurring when compared with primary radiation therapy. In Stage IV carcinomas of the larynx, both survival and recurrence accurately reflect therapeutic efficacy since most patients suffer recurrence of their carcinoma and die of the disease.


The relationship between adience-abience scale scores and judged communication proficiency of alaryngeal speakers.

Fifteen esophageal speakers and 15 artificial larynx speakers were administered the Hutt Adaptation of the Bender-Gestalt Test (HABGT): Adience-Abience Scale. Adience was defined as the individual's tendency to be motivated to adapt to new experiences that effect his physical functioning. Conversely, abience was defined as the individual's tendency to avoid or be inhibited from adapting to new experiences that effect his physical functioning. Audio-tape recordings were made of each speaker and used to determine verbal communication proficiency by six speech pathologists. Results indicated that the HABGT: Adience-Abience Scale was able to differentiate between the two groups of alaryngeal speakers, as well as relate to their verbal communication proficiency.


Altered bacterial flora and clinical course with intraoral cancer.

Nineteen consecutive patients with intraoral cancer were cultured and tested for cell-mediated immunity. They were then treated and followed for three years. The recurrence rate for those patients with normal flora was similar to that reported for dinitrochlorobenzene (DNCB) reactors; and the recurrence rate for those patients with abnormal microorganisms was similar to that reported for DNCB non-reactors.


Antitumor Plants. V. Constituents of Cinchona pubescens.

The stem bark and stem wood of Cinchona pubescens were found to owe their weak cytotoxic activity to the presence of quinovic acid. This acid and its 3-rhamnoside were isolated and characterized through several derivatives, all of which were assayed for their cytotoxicity.


Polyenoic acid metabolism in cultured human skin fibroblasts.

The incorporation of [1-14C]linoleic acid, and [1-14C]linolenic acid into cellular lipids of cultured human skin fibroblasts was studied. Cultured cells took up both labeled fatty acids at nearly the same rate and incorporated them into a variety of lipid classes. At the end of 1 hr incubation with [1-14C]linoleic acid, radioactivity was found in the triacylglycerol (TG) and choline phosphoglyceride (CPG) pools preferentially. Incorporation into the TG fraction decreased rapidly, while the uptake into CPG, serine phosphoglyceride (SPG), and ethanolamine phosphoglyceride (EPG) fractions increased progressively with longer incubation times. Similar results were obtained with [1-14C]linolenic acid as precursor. At the end of 24 hr, desaturation and chain elongation of 18:3 n-3 was more extensive than conversion of 18:2 n-6 to higher polyenoic acids. During pulse-chase experiments with either fatty acid precursor, the incorporated radioactivity was progressively lost from cellular lipids, particularly from the TG and CPG fractions, but continued to increase in the SPG and EPG pools. The similar labeling pattern of cellular phospholipids with linoleic or linolenic acids, and data from pulse-chase studies suggest that a direct transfer of fatty acids from CPG to EPG is a likely pathway in fibroblast cultures. Incorporation into the EPG pool during the pulse-chase experiments paralleled extensive desaturation and elongation of linoleic acid to 20:4 n-6, and 22:4 n-6; and of linolenic acid into 22.5 n-3 and 22:6 n-3.


Arachidonic acid intestinal absorption: mechanism of transport and influence of luminal factors of absorption in vitro.

The mechanism and characteristics of intestinal absorption of arachidonic acid were studied in vitro using everted intestinal sacs of the rat. Arachidonic acid absorption was studied at concentrations of 5 micron to 8.36 mM. The plot of absorption rate vs. concentration fitted best to a rectangular hyperbola at low micron concentrations and to a straight linear relationship in the mM range of concentrations. Metabolic inhibitors and uncouplers did not change absorption in either range of concentrations. The absorption of arachidonic acid increased with thinning of the unstirred water-layer, decrease in the pH, or the substitution of sodium taurocholate by Pluronic F 68 OR Tween 80. Absorption decreased following the equimolar additions of oleic, linoleic, and linolenic acids. Absorption rate did not change when the taurocholate concentration was varied from 5-15 mM or following the additions of butyric or glutamic acids, leucine, lysine, or dextrose. It was concluded that arachidonic acid is absorbed by a concentration-dependent dual mechanism of transport which is not energy dependent. At the low micron range of concentrations, facilitated diffusion is predominant, while at mM concentrations, simple diffusion is the dominant mechanism of absorption. Changes in the intestinal fluid composition, flow rate, and pH can modify the rate of absorption of arachidonic acid.


The behavior of rat bile phospholipids in the intestine and in incubation media containing pancreatic juice.

Samples of radioactive bile were collected from rats after intravenous injection of potassium soaps ([9-10 3H2] or [1 14C] oleate, [1 14C] linoleate or [9-10 3H2] palmitate). These radioactive acids were chosen because it is well established that, in natural phosphatidyl cholines, palmitic acid is located chiefly at the 1 position and linoleic and oleic acids at the 2 position. After incubation of bile with pancreatic juice, the labeling of unchanged biliary phospholipids was higher when native bile was labeled with oleic acid than with palmitic or linoleic acids. These data suggest that monounsaturated molecular species of biliary phospholipids are more resistant than the diunsaturated ones to in vitro hydrolysis by phospholipase A2. Ninety min after introduction of the radioactive bile into the upper part of the rat duodenum, high labeling of luminal phospholipids was observed regardless of the bile sample used, although labeling of free fatty acids was always low. The passage of intact biliary phospholipids through the intestinal epithelium is discussed.


Screening of higher plants for biological activities. II. Antiviral activity.

Extracts prepared from 100 samples of higher plants were evaluated for antiviral activity against several viruses, including Semliki forest, coxsackie, measles, poliomyelitis, herpes, and adeno viruses. The plants were chosen from 73 genera and 43 families on the basis of literature data and medicinal reports on antimicrobial activity. The results of the antiviral testing showed that eight of these extracts exhibited a pronounced activity against one or more of the test viruses. Another three plant extracts showed a moderate level of antiviral activity against some of the test viruses.


In vitro and in vivo effects of exogenous lipids on the enzymatic hydrolysis of rat bile phospholipids.

The addition of total phospholipids, phosphatidylcholines, triglycerides, cholesterol or glycerol to incubation media containing rat pancreatic juice and bile labeled with [9, 10 3H2] oleic acid (90% of the radioactivity present as phospholipids) had no effect on the hydrolysis of bile endogenous phospholipids. The introduction of 2 or 10 mg of phosphatidylcholines and 0.5 ml of bile (approximately 1.5 mg of phospholipids) into the rat upper duodenum decreased the rate absorption of native bile phospholipids. It was not followed by an increase of free fatty acids released from biliary phospholipids in the intestinal lumen. The introduction of bile (0.5 ml) and small amounts of triolein (1.4--3.5 mg) into the duodenum had little effect on the rate of hydrolysis and absorption of native bile phospholipids, but caused a reduced absorption of the free fatty acids released or those coming from initial nonphosphorus biliary lipids. The introduction of bile (0.5 ml) and large amounts of triolein (30 mg) into the duodenum increased the rates of hydrolysis and absorption of endogenous bile phospholipids. These observations suggest that luminal lipid components can modify the organization of luminal micelles and, consequently, the action of the pancreatic phospholipase A2 and the absorption of bile lipids.


The incorporation of orally administered radiolabeled dihomo gamma-linolenic acid (20 : 3 omega 6) into rat tissue lipids and its conversion of arachidonic acid.

Radioactivity from orally administered radiolabeled dihomo-gamma-linolenic acid (20 : 3 omega 6) was recovered from the liver, plasma and brain lipid fractions. After administration the fatty acid was metabolized to arachidonic acid, the 22 carbon chain length fatty acid, and was also beta-oxidized. However, 22 hr after administration of [1-14C] 20 : 3 between one-third and one-half of the recovered radioactivity was still associated with dihomo-gamma-linolenic acid in the liver and plasma lipid fractions. Orally administered dihomo-gamma-linolenic acid is incorporated into lipid fractions and is, therefore, available in the metabolic pool for  PGE1 synthesis.


Effects of feeding ethyl-dihomo-gamma-linolenate on rabbit renomedullary lipid composition and prostaglandin production in vitro.

Feeding the ethyl ester of dihomo-gamma-linolenic acid for 25 days to rabbits resulted in increased PGE1 (20 to 30-fold) and PGE2 (1.5-fold) output by a hormone responsive, in vitro, renal papilla preparation. The relative amount of PGE1 increased from less than 5% of PGE2 in controls to 25-35% of PGE2 in the papillae of 20 : 3 omega 6-supplemented animals. During the study renomedullary tri glycerides in the 20 : 3 omega 6-supplemented animals increased 2.8-fold compared to animals fed an equal amount of a control fatty acid mixture, and in addition to a marked enrichment in 20 : 3 omega 6, also contained increased proportions of 20 : 4 omega 6 and longer chain polyenes. The increase in triglyceride content found in the renal medulla was not seen in the renal cortex or liver. There was no increase in renomedullary phospholipid content during the study, and phopholipids of treated animals contained increased proportions of 20 : 3 omega 6 and 20 : 4 omega 6, but not longer chain polyenes. The results indicate that enriching the prostaglandin precursor pool by feeding 20 : 3 omega 6 can alter the type and amount of prostaglandin released by the renal papilla, at least in vitro. Also, the selective changes in amount and long chain polyene content of renomedullary triglycerides during the study suggest some special functions for this lipid class in prostaglandin precursor metabolism.


Uptake and utilization of 1-14C palmitic acid by heart cells treated with fresh or thermally oxidized fats.

The effects of fractions isolated from thermally oxidized corn oil or olive oil on the metabolic activity of heart endothelial and muscle cells were studied. Rat heart cells in culture, exposed to thermally oxidized fat components, took up more exogenous 1-14C-palmitic acid and incorporated more of it into the cell triacylglycerol fraction than when the cells were treated with fresh fats. Particularly with the heated corn oil compared to fresh corn oil, much less of the radioactivity from the labeled palmitic acid was deposited in the  phospholipid fraction. Also, with heated corn oil when the incubation period was extended beyond 12 hr, there was a decline in the radioactivity retained in the triacylglycerol fraction of the heart muscle cells. When the fresh fats were compared for 14C-radioactivity incorporation into the heart cells, the olive oil gave much higher values, indicating a distinct difference in response to the proportion of fatty acids supplied.


Effect of feeding protected cholesterol on ruminant milk fat secretion.

Feeding 1-2 g/day of cholesterol protected against ruminal hydrogenation caused a 20-30% drop in the secretion of milk fat by goats and cows. The effect was observed with goats fed conventional rations or with goats and cows fed rations supplemented with protected lipids, but was not observed with cows fed conventional rations, or when unprotected cholesterol and protected beta-sitosterol was fed to these animals. The results suggest that this depression in milk fat is due to a decreased uptake of plasma triacylglycerol fatty acids by the mammary gland, induced by dietary cholesterol.


Fatty acid composition of unfertilized and fertilized eggs of the sea urchin, Arbacia punctulata.

Fatty acid compositions of polar lipids and triacylglycerols isolated from eggs of the sea urchin, Arbacia punctulata, were examined before and 15 min after insemination. The main fatty acids present in polar lipids and triacylglycerols were palmitate, palmitoleate, eicosaenoate, arachidonate and eicosapentaenoate, while palmitate and palmitoleate predominated in triacylglycerols. There were no significant changes in weight percentage of individual fatty acids of either polar lipids or triglycerides of eggs after insemination.


15-Methyl-1,2-hexadecanediol, a major constituent of hamster surface wax.

Long chain 1,2-alkanediol diesters comprise about 15-20% of the acetone soluble skin surface wax of golden Syrian hamsters. The constituent 1,2-alkanediols, obtained through acidic methanolysis, were fractionated by preparative gas liquid chromatography of their isopropylidene derivatives. The major component (57%) was identified by nuclear magnetic resonance and mass spectrometry as 15-methyl-1,2-hexadecanediol.


Alpha tocopherol levels in various regions of the central nervous systems of the rat and guinea pig.

The alpha tocopherol contents of various discrete anatomical regions in the central nervous system of adult rats and guinea pigs were assayed using a liquid chromatographic method. All parts of the guinea pig nervous system had lower alpha tocopherol contents per gram wet, dry orlipid weights than the corresponding areas in the rat. In both animals the distribution of alpha tocopherol did not correspond to the distribution pattern of total lipid. There was also a rostral to caudal concentration gradient with respect to alpha tocopherol content; gray matter from cerebral hemisphere has the highest concentration and cervical spinal cord the least. In both animals alpha tocopherol content per gram dry weight or lipid weight were higher in gray matter areas when compared with white matter areas. The low concentration of alpha tocopherol in spinal cord could make this region more susceptible to damage from deficiency than the rest of the central nervous system.


Models for lipid organization in cholesterol-phospholipid bilayers including cholesterol dimer formation.

Three new structural models, which account for abrupt changes in physical properties observed at several molar concentrations of cholesterol in phospholipid bilayers, are described. Cholesterol monomers, each surrounded by its own envelope of unshared acyl hydrocarbon chains of the phospholipid, can accommodate 22% cholesterol. Cholesterol dimers, each surrounded by its envelope of unshared acyl hydrocarbon chains, can accommodate 31% cholesterol. When surrounded by shared acyl hydrocarbon chains, cholesterol dimmers can accommodate about 47% cholesterol. At greater concentrations, cholesterol aggregation occurs, the system is unstable, and cholesterol forms a separate phase.


Acid triacylglycerol lipase from bovine thyroid gland.

An acid lipase has been detected in bovine thyroid tissue using triolein as a substrate. The activity, probably associated with the lysosomes, displays a rather broad pH-optimum in the pH 4 to pH 6.5 range. The lipase activity can be partially purified by cosedimentation with lysosomes followed by solubilization through detergent and chromatography on Sephadex G-200 and carboxymethyl cellulose. The elution profile on Sephadex G-200 shows one peak (moleculare weight 67,000 +/- 2,000). In the final CM-cellulose step, two lipase peaks (lipase LA and lipase LB) are found. Sulhydryl reagents (iodoacetate, iodoacetamide, and N-ethylmaleimide) as well as mercuric ions markedly reduce both enzyme activities. Calcium ions, EDTA, and heparin have no effect. Sodium fluoride and diisopropylfluorophosphate are only slightly inhibitory. Sodium chloride causes a slight increase in both lipase activities. Anionic phospholipids such as cardiolipin and phosphatidylserine are not essential for enzyme activity.


[Gas volume stabilization in the pneumatic transmission unit of the assisted circulation apparatus].

A compensator connected to the section consisting of the pump-main line-operating member and including a pneumatic resistance and a flaxid non-elastic container enables it in combination with the feedback to maintain through the volumetric displacement of the gas, or changing the pump diaphragm position, the stability of the gas volume in the pneumatic transmission element of the assisted circulation apparatus. The stabilization of the gas volume in the pneumatic transmission element creates favourable conditions of exploitation and heightens the effect of the cardiac insufficiency treatment, expecially in cases of protracted assisted circulation.


[Feasibility of increasing the high-speed response of the electromechanical drive in assisted circulation devices].

The conditions in assisted circulation, especially with ballooned aorta, place high demands on the speed of the intraortal pump-balloon response. The salient feature of the described assisted circulation unit consists in that the intraortal pump-balloon is connected to the pneumotract via a commutative air-operated valve. A block diagram of the assisted circulation unit "Biopulso-4" based on the use of the electric drive, designed at the All-Union Scientific-Research Institute of Medical Equipment and Instruments, stress diagrams and a scheme explaining the operation of the apparatus, are described. The results obtained show the possibility of the balloon's resetting and opening in 70 ms, with the triggering synchronous pulse delay of 10 ms prior to response (with air use as power gas). These results are not any worse than those obtained with the pneumatic drive-based assisted circulation apparatus.


[Analysis of control systems for artificial circulation devices].

A variant of a complex approach to solving the problem of ensuring the optimal perfusion, based on the separation of the ECA-organism system parameters into 4 subsystems, is proposed. An automatic control of the entire set of the extracorporeal circulation parameters is accomplished in the hierarchial order, with due consideration for the necessity to provide a fast response and physiological significance for the organism of the characteristics and factors subject to correction. The criteria for the adequacy of the extracorporeal circulation should be brought into a dynamic relation to the actual state of the organism. The composition of the blocks making up the system of the extracorporeal circulation regulation is discussed.


[Artificial heart control system].

To develop a system for the artificial heart control the algorhythm of the latter, with the blood pressure in the aorta acting as a regulation parameter, was analyzed on its mathematical model. The results of the algorhythm operation in three model situation describing transitional processes under physical efforts, stress and resuscitation are reported. The technical implemetation of the described algorhythm is set forth and a comparison of the obtained experimental data versus the design curves is made.


[Perfusion system for assisted blood oxygenation during treatment of children with acute respiratory insufficiency].

To conduct an auxiliary extracorporeal oxygenation in acute respiratory incompetence in young children a perfusion system with a small primary charging volume is proposed. The system was tested in an experiment and clinically in an infant with mass of 4.5 kg. The auxiliary oxygenation lasted for 73 1/2 hours. The operating characteristics of the perfusion system with a "Lande-Edwards" diaphragmatic oxygenator and its schematic diagram are described.


[Ergonomics and improvements in efficiency in stomatology].

The ergonometric methods used in the organization of the medical personnel of stomatological establishments and in designing technical facilities of stomatological rooms help raise the effectiveness of the therapeutic processes and to improve conditions of work of the physician-stomatologist and medical nurses. At the basis of modern ergonomic facilities and principles in stomatology there are the concepts: recumbent patient, sitting medical personnel, invariable presence of an assisting nurse, "long-term" treatment and centralization of the ancillary service.


[Means of improving the operational safety of balloon-pump counter-pulsation apparatus].

The apparatus of assisted circulation, in particular those intended for counter-pulsation with the pump-balloon, as concerns their reliability and safety to units whose failure presents immediate danger for the patient's life. An analysis of modern batch manufactured apparatus revealed a tendency toward widening the scope and complicating the signallization means of automatic protection and preventing failures. It is shown that the reliability of the units for counter-pulsation with the pump-balloon is not only a technical, but also a biomedicocybernetic problem. Substance is given to the need for introduction into the system of the apparatus for assisted circulation of sand-by actuating mechanisms for secure a purposeful influence on the physiological parameters of the organism.


[Improving interference freedom of asynchronous cardiostimulators].

In their every day life the patients with implanted cardiostimulators are infrequently undergo the effects of electromagnetic interference sources that might seriously disrupt the normal performance of cardiostimulators (CS). For the asynchronous CS (EKC-2, EKC-4, EKC-8) the dependence of the CS pulse repetition period on the the frequency and amplitude of interferences is given. The interference resistance and stability of these apparatus is shown to be materially increased if a condenser of 10 nF capacity is to the CS output terminals connected.


[Experience with a comparative study of several adsorbents].

A comparative study of adsorbents with respect to their capability to absorb low- and medium-molecular metabolites was effected. The adsorbents displaying high activity in regard to low-molecular metabolites are shown to be insufficiently effective with respect to the medium-molecular ones and vice versa. The results thus obtained bear proof to the advisability of a preliminary selection of adsorbents for clinical application in hemocorption according to their activity as concerns low- and medium-molecular substances.


[Evaluation of distortions in clinical thermography].

Distortions appearing on the thermograms can depend on a number of factors, including the radiation coefficient, the ambient temperature, the angle between the sighting direction of the thermograph and the normal of the study surface. A quantitative assessment made of distortions conditioned by these factors during registration of thermograms of flat and curvilinear surfaces helped to recommend the most expedient manipulations in conducting thermographic examinations.


[Feasibility of constructing thermoelectric thermoregulatory units for artificial circulation devices].

The prospects for the use of thermoelectric systems to regulate the blood temperature in extracorporeal circulation apparatus are outlined. The temperature and electric conditions in the thermoelectric thermoregulating system were optimized, which enabled extremal values of their basic parameters to be obtained. A conclusion is drawn on the expediency of using these systems for the purpose in view.


[Device for studying muscle tonus].

A portable device for studying the muscular tone can be constructed on the principle of registering displacements of a metal rod accomplished by means of the bridge network. The indicating instrument is calibrated with reference to the steel rod, whose density (tightness) is taken as an ultimate one, while the tightness of the muscle tissue is determined in per cent of the ultimate tightness.


[Mechanization of the work of the personnel of the sterilization service of therapeutic-preventive institutions].

The presently functioning service of central sterilization departments at medical institutions has presented itself in a good light. The home industry already puts out the necessary basic facilities and is putting into production the ancillary ones to equip them. Further development of the sterilization service centralization follows the way of setting up sterilization centres organized on the principle of highly mechanized and automated industrial enterprises.


[Nomograms for calculating the parameters of a system of recording intracavitary pressure through sounds].

The signal of the intracavitary pressure registered through a probe is, as a rule, distorted by fluctuations of the liquid column in the probe. Nomograms enabling the velocity of the sound wave and the own frequency oscillations of the measuring system to be found from the size of the probe, elastic modulus of its material and elasticity of the bulk of the guage are described. In this way a selection of probes to secure high-quality recording of the signal is facilitated. An example of a calculation with the use of the nomograms is given.


Congenital failure of automatic control of ventilation, gastrointestinal motility and heart rate.

A new congenital syndrome characterized by the simultaneous failure of control of ventilation (Ondine's curse) and intestinal motility (Hirschsprung's disease) is reported in three infants, all of whom died in the first few months of life; two were siblings. Detailed studies in one also revealed markedly decreased esophageal motility and abnormal control of heart rate. In one infant, minute ventilation was lower in quiet than in REM sleep and lower in both states of sleep than in wakefulness. Although the mean inspiratory flow was decreased in quiet sleep, the hypoventilation resulted primarily from a decrease in respiratory frequency. Intravenous doxapram increased ventilation but did not reverse respiratory failure. Aminophyllin, progesterone, physostigmine and chlorpromazine did not change ventilation significantly; imipramine resulted in a significant decrease. Both long and short-term variability of the heart rate were markedly decreased when compared with the normal infant. Although neuropathologic studies postmorten did not reveal an anatomic defect, we postulate that a developmental abnormality in serotonergic neurons is responsible for this new syndrome.


Considerations on a laser-scanning-microscope with high resolution and depth of field.

In conventional light microscopy, the depth of focus is severely limited. This limitation might be overcome by a light optical scanning procedure. In this procedure, the specimen surface is scanned point for point by a focused laser beam. The image of the specimen surface is generated by an electronic system, similar to the procedure used in the scanning electron microscope. Possibilities to develop a "laser-scanning-microscope" on the basis of available techniques (laser microirradiation, miniprocessors, light detecting systems, automatic focusing, holographic focusing etc.) are discussed. On account of its possibility to form images of high resolution and depth of focus, a laser-scanning-microscope might become a valuable tool in addition to conventional light microscopy and scanning electron microscopy.


Plasmid-mediated sulfanilamide resistance.

Dihydropteroate synthetase (DHPS) is specified by a substrain of Escherichia coli K12, ML1410. This enzyme activity is inhibited by sulfanilamides (Sa) and is known to be heat-stable, i.e., an Sa-sensitive normal enzyme. Another DHPS activity specified by E. coli ML1410 carrying drug resistance plasmids is Sa-resistant but heat-sensitive, i.e., an Sa-resistant enzyme. Most plasmids encoding single Sa or double (Sa. Tc or Sa. Sm) (Tc, tetracycline; Sm, streptomycin) resistance mediate the formation of this type of DHPS. Therefore, E. coli carrying these plasmids becomes diploid for DHPS, i.e., an Sa-resistant and an Sa-sensitive normal enzyme. The biochemical mechanism of Sa resistance mediated by plasmids encoding triple (Cm.Sm.Sa; Tc.Sm.Sa) and quadruple (Cm.Tc.Sm.Sa) resistance is not due to the formation of an altered DHPS but probably due to the decrease in permeation of the drug into the cell. The evolutionary process of the formation of Sa-resistance determinants on plasmids is discussed based on the presence of two types of Sa resistance mechanism.


[Functional significance of bivalent iron and manganese oxidation in Leptothrix pseudoochraceae].

The effect of oxidation of bivalent compounds of iron and manganese was studied on the growth of filamentous iron bacteria. The stimulating action of these metals could not be attributed to utilization of the energy of their oxidation in the assimilation of carbon dioxide or in lithoheterotrophic processes. The cells yield increased because the metal ions removed the toxic metabolite, hydrogen peroxide, which was formed in the respiratory chain upon oxidation of an organic substrate. This function of bivalent metals in detoxication of hydrogen peroxide accounts for the ecological confinement of iron bacteria to certain environment.


[Comparative study of the dynamics of carbohydrate metabolism in the growth of Candida tropicalis yeasts on n-octadecane and glucose].

The dynamics of carbon metabolism was studied in Candida tropicalis growing on 14C-labeled n-octadecane and glucose by means of the technique of radioactive indicators. The kinetics of incorporation of 14C into the main groups of organic substances in the cell (proteins, nucleic acids+polysaccharides, lipids, free amino acids, organic acids, free carbohydrates+nucleotides) revealed differences in the rate of their synthesis and accumulation. The general features and the major differences in the pathways of carbon metabolism depended on the nature of a carbon substrate. If the yeast used n-octadecane as a source of carbon, the rate of synthesis of the lipid fraction was higher, and the ratio between its components changed as well as the rates of their synthesis.


[Luminescence and growth of Photobacterium mandapamensis in periodic culture].

The luminescent Photobacterium mandapamensis, strain 54 (the collection of the Institute of Physics, Siberian Branch of the USSR Academy of Sciences), was isolated from the water of the Pacific Ocean in the equatorial zone and studied in the course of periodic cultivation. The dynamics of changes in the main parameters of the culture, such as luminescence, growth, respiration, heat emission etc., was investigated. The data obtained were used to establish a correlation between changes in these parameters and in the cell metabolism when one energy substrate was substituted by another.


[Systematic place of the act nomycetes of the Albidus Krassilnikov, 1970 group].

Detailed studies of the taxonomical characteristics and the complex of produced antibiotics made it possible to establish the identity of Actinomyces albus var. fungatus, Solovieva et Rudaya, 1959 and Actinomyces tumemacerans, Krassilnikov et Koveshnikov, 1962. Both organisms produce a complex of antibiotics comprising albofungin, albonursin, and a polyene antibiotic belonging to the group of tetraenes. The cultures do not belong to the group of verticillate actinomycetes as was believed earlier (Krassilnikov, 1970). The later name, Actinomyces tumemacerans, is more appropriate since the organism described under the name of Act. albus var. fungatus differs sharply from other representatives of Act. albus and therefore cannot be regarded as its variety (nomen confusum). Actinomyces sp. RIA-248 producing albofungin differs from Act. tumemacerans P-42 as well as from Act. albus var. fungatus RIA-247 by the complex of produced antibiotics and other taxonomic properties. Apparently, it should be classed as a new species.


[Nitrogenase activity of Rhizobium meliloti and Rhizobium vigna in a root tisse culture of leguminous and nonleguminous plants].

As was shown using the acetylene technique, the nitrogenase activity of Rhizobium meliloti and Rhizobium vigna increased when they were cultivated with the root tissue cultures of legumes (lucerne, sweetclover) and non-legumes (tobacco, glasswort, carrot), particularly in the case of the former. The maximum activity of nitrogenase was found in R. meliloti. The tissue cultures of legumes had no effect on the growth of Rhizobium whereas the tissues of non-legumes stimulated their biomass accumulation though the activity of nitrogenase in both Rhizobium cultures was low in this case. Therefore, the metabolites of legumes produced a specific action on the nitrogenase of nodule bacteria.


[Microorganisms of the genus Nocardia and the "rhodochrous" group in the soils of the Ukrainian SSR].

Nocardioform bacteria characterized by the IV type of the cell wall and by lipid LCN-A are widely distributed in various soils of the Ukrainian SSR. The acetamidase-negative forms of Nocardia asteroides were found in 24.4% of soil samples, and the acetamidase-positive forms of this organism, in 4% of soil samples. The "rhodochrous" group was most often represented by the species N. erythropolis and N. rubropertincta, and less often, by Nocardia (Rhodococcus) rhodochrous, N. opaca and N. flava. The greatest amount of different species was detected in chernozem and dark chestnut soils of the waste zone. Chernozem soils impregnated with petroleum were particularly abundant in N. asteroides, N. rubropertincta, N. corallina and N. erythropolis. The best medium for isolation of most species was the Münz medium containing n-alkanes.


[Significance of the ability of Candida Berhout to assimilate D-glucuronic acid, D-glucono-delta-lactone and 5-keto-D-gluconate for systematics].

117 Candida strains representing 76 species and varieties were studied. Most of them readily assimilated glucono-delta-lactone with an exception of species which were imperfect analogues of Pichia spp. with round ascospores, Saccharomyces spp. and Kluyveromyces spp. The test for assimilation of 5-keto-D-gluconate can be used to differentiate varieties of C. guilliermondii, C. pelliculosa, and species C. zeylanoides and C. vinaria. The group of glucuronate-positive species belonging to the genus Candida comprises both ascomycetous and basidiomycetous organisms. The former lack the urease activity. Among the latter, C. curvata, C. humicola, C. marina and C. podzolica produce extracellular polysaccharides identical in the monosaccharide composition to polysaccharides of cryptococci. These four species should be included into the genus Cryptococcus.


[Comparative study of the action of different antibiotics on the membrane dehydrogenase activity in Micrococcus lysodeikticus].

The object of this work was to study the effect of antibiotics belonging to the groups of penicillin, tetracycline and aminoglycosides on the activity of lactate dehydrogenase, alcohol dehydrogenase and malate dehydrogenase in the membranes of Micrococcus lysodeikticus. Streptomycin, benzylpenicillin, carbenicillin and phenoxymethylpenicillin decreased the activity of the above dehydrogenases. Tetracycline and oxytetracycline activated lactate dehydrogenase and alcohol dehydrogenase in the membranes, but decreased their activity in the supernatant fraction of disintegrated membranes. The enzyme activity in the membranes was particularly inhibited by neomycin.


[Continuous cultivation of Penicillium brevicompactum that forms extracellular ribonucleases].

Conditions for continuous cultivation of Penicillium brevi-compactum producing extra-cellular ribonucleases were studied. The two-step process of fermentation in the course of which the flow of the medium in the first fermenter was maintained at 0.054 hr-1, and in the second fermenter at 0.0527 hr-1, made it possible to produce 3--4 times more enzymes as compared to the batch culture.


[Population dynamics study of Streptomyces olivocinereus in soil].

The dynamics of the population of the soil actinomycetes Streptomyces olivocinereus can be studied in its natural habitat using a conventional technique of inoculation at a level of the population density close to the natural one. The colonies are registered and counted in UV where they are clearly visible due to their bright orange luminescence. Techniques employed for obtaining information about the population structure (spores--mycellium) are described. The dynamics of the population has been studied within a year. The population introduced into soil is stabilized at a relatively high level.


[Fine structure of Bifidobacterium bifidum].

Cultures of Bifidobacterium bifidum 1 were grown in liquid and semisolid nutrient media for 14 hours to 6 days. Their preparations were then studied by electron microscopy on ultra-thin sections after a routine chemical fixation or on replicas after rapid freezing-fracturing and etching. This procedure made it possible to obtain new data about the structural organization of cells in the course of growth of cultures which were characterized by desynchronization of growth and division processes. The growth was inhibited later when populations reached the highest number of cells in the given set of conditions. The zone of nuclear vacuoles contained peculiar membrane structures which appeared and underwent certain changes related, apparently, to the mode of growth of this bacterium.


[Electron microscopic study of the action of submicroscopic levorin structures on Candida guillermondii].

In the course of preparation of aqueous solutions of the polyene antibiotic levorin, the latter is recovered in the solid phase forming granular submicroscopic structures. If the cells of Candida guilliermondii are treated with submicroscopic granular structures (SMGS) of levorin, the structures are adsorbed on the surface of the yeast cell walls. Some visible changes occur in the ultrastructure of the yeast cells incubated with SMGS of levorin for 5 min: the inner layer of the cell wall becomes loose, the periplasmic space appears, the cytoplasmic membrane becomes thicker, the mitochondria swell, and fragmentation of the mitochondrial cristae takes place. Dense round alien bodies 20--40 mn in size can be discerned in the periplasmic space of such cells. If the yeast cells are treated with the levorin structures for a longer period of time (15--60 min), the cell ultrastructure is entirely disorganized.


[Radial growth rate of fungal colonies in respect of their ecology].

Indices of the radial growth rate of colonies were determined for Circinella circinans and Mortierella ramanniana as well as for the complex of fungi in soil in the course of microbial succession. The maximum of growth (Kr = 0.053 cm/hr) for C. circinans was observed at a high concentration of glucose (10%) in the medium, whereas for M. ramanniana the maximum (Kr = 0.0054 cm/hr) was detected at a low glucose concentration (0.005%) in the medium. These data account for the position of C. circinans and M. ramanniana in the course of microbial succession in the natural habitat. Kr was used to establish the origin of successional changes in the complex of soil fungi in serozem upon the introduction of glucose.


[Phenomenon of temperate phage restriction and modification in a lysogenic culture of Streptomyces hygroscopicus].

Temperate phages were isolated from the lysogenic culture of Streptomyces hygroscopicus 0485 in the indicator cultures of Str. hygroscopicus 0477 and Str. levoris 1331. The phages were found to be identical in the morphology of particles and serological properties. The phenomenon of cross limitation, by the culture of Str. hygroscopicus 0477, of the phage growing on the culture of Str. levoris 1331, and vice versa, was established. At the same time, the phages were shown to be modified by the host cell.


[Effect of carbon dioxide on the methylotrophic metabolism of Candida boidinii].

The activity of enzymes involved in carbon metabolism of Candida boidinii KDI was compared on media containing methanol with bicarbonate and without it. The presence of carbon dioxide stimulated the activity of methanol oxidase, formaldehyde dehydrogenase, hexulose phosphate synthase and particularly carboxylases of pyruvate and phosphoenol pyruvate. At the same time, the activity of formate dehydrogenase, citrate synthase and isocitrate lyase decreased. Therefore, carbon dioxide produces a significant effect on methylotrophic metabolism of Candida boidinii KDI and is actively involved in biosynthetic processes.


Nelson-Town anti virus theory.

For any virus that causes a biological change in the body, there is a substance that will prevent this virus from causing this biological change. We will call this substance an anti virus substance. Reasons for proposing this theory along with reasons for the prediction of 3 properties of an anti virus will be presented. Also to be presented is an anti virus circular diagram, a mechanism where when vitamin C is present the body can more easily manufacture the anti virus, other mechanisms, and the comparison of properties of humoral antibodies and interferon with suspected properties of anti viruses.


The anatomy of emotion.

Emotion is seen as a function of an autonomic system which pervades the cerebrum as much as the rest of the body. An emotional centre, or organ of mood, seems to exist in the hypothalamus, at the upper end of a reticular core rising through the brainstem, which initiates and co-ordinates vital impulses. The reticular formation (which may be identical with the centrencephalic integrating system) appears to contain adrenergic and cholinergic fibres and these may be central nervous elements of the autonomic system. Supporting evidence for this whole concept is presented from findings in brain self stimulation reward, the syndrome of central pain, posture and movement accompanying mood change, epileptic convulsions and progressive refinements in pre-frontal leucotomy. The limbic system is considered to subserve "on going" memory rather than mood, which appears to reach consciousness in the lateral temporal convexity, as a rule independently of awareness of peripheral somatic accompaniments of emotion.


An innovative, rational approach to rural health care.

Parts of rural, southern Illinois, like many rural areas throughout the world, are medically underserved. An innovative, rational solution to the physician shortage in those parts of rural, southern Illinois, which may be applied to other medically underserved areas, rural or urban, is proposed in this manuscript. To attract physicians to or near medically underserved, rural areas in southern Illinois it is proposed that Primary Care and Referral Centers be set up in southern Illinois. This could be done by adding well trained general practitioners, family physicians, or general internists to the staff of each emergency center of the Total Emergency Medical Service System for (southern) Illinois that is located in or near an otherwise medically underserved, rural area of southern Illinois. These additional physicians would diagnose and treat within their capabilities all non-emergency cases coming to the primary care centers and refer non-emergency cases needing referrals. Referrals would be either for secondary or tertiary health care. The Primary Care and Referral Centers should be self-supporting from pre-paid patient fees. For almost ten years a health center like a Primary Care and Referral Center has been operating at SIU/Edwardsville.


Lipid peroxidation in the hemolytic uremic syndrome.

Based on recent evidence of a genetic influence on prognosis (1) and the existence of red cell membrane phospholipid depletion with low or absent serum alpha-tocopherol (2) levels in three children with the Hemolytic Uremic Syndrome (H.U.S.), we wish to suggest the existence of an inborn error of antioxident capacity as the basic pathogenetic mechanism in the development of the hemolytic uremic syndrome (H.U.S.).


The mechanism of intimal thickening in arteriosclerosis.

The limitations of current theories of the mechanism of intimal thickening in arteriosclerosis are briefly reviewed. The suggestion is advanced that this change is due to intimal oedema, arising from failure of the lymphatic system of the surrounding tissue to remove adequately, protein-containing fluid filtering outwards through the vascular endothelium. It is postulated that such local environmental influences account for the variability in the degree of arterial degeneration seen in different arteries, and in different portions of the same artery.


The importance of trophozoites in transmission of toxoplasmosis: survival and pathogenity of Toxoplasma gondii trophozoites in liquid media.

It has been generally assumed that Toxoplasma gondii trophozoites cannot survive long outside the body, and that toxoplasmosis is transmitted by transplacental infection, cysts and oocysts. We tested the survival and pathogenicity of separated Toxoplasma trophozoites in saline, colostrum, and solutions of albumen and serum, and the penetration of Toxoplasma trophozoites from infected secretions through mucous membranes of nose, conjunctiva, and mouth. The trophozoites survived 24 h in saline, 3 days in 3.5% serum albumen, 3 days in colostrum, and 17-43 days in serum solutions. The infectivity of the trophozoites was highest after nasal instillation, second highest after instillation into conjunctiva, and lowest after instillation into the mouth. The infective dose was calculated. The results show that Toxoplasma trophozoites survive and remain infectious for a relatively long time in biological liquid media and can easily penetrate mucous membranes, and suggest a revised hypothesis for the transmission of Toxoplasmosis with the trophozoites as one important source of infection.


The surgeon's responsibility for asepsis.

Eighty percent of postoperative wound infections result from bacteria acquired elsewhere than in the operating room. Concomitant infections--such as dermatitis; periodontitis; infections of the respiratory, gastrointestinal, or urinary tracts--are not identified preoperatively, despite a threat to the patient greater than that of anesthesia and surgery combined. Isolation of overt infection is neglected. The entire hospital becomes a reservoir of bacterial debris that is reflected in the carriage of pathogens by personnel and patients. Infections are often initiated by medical devices that invade the vascular system, respiratory tract, or urinary bladder. Professional leadership at the bedside is the key to detecting and correcting breaches in technique and setting an example of a philosophy of total patient care.


Apparatus for measuring zones of inhibition.

The apparatus described is a device allowing rapid measurement of susceptibility zone diameters obtained by the Kirby-Bauer method. The device consists of a series of radially arranged strips upon the lid of a microbiologic plate. The strips are transparent, labeled with the antibiotic tested, and slightly movable circumferentially. The strips being as wide as the diameter separating susceptible from resistant organisms, the device allows rapid classification of zone diameters into those indicating susceptibiltiy as well as resistance of orgainisms to the antibiotic tested.


The operating room and the ultraviolet environment.

Clean surgical wounds may be contaminated from three separate sources: endogenously from the patient himself; exogenously from direct contamination by unsterile instruments, drapes, gowns, hands, or gloves; and by bacteria settling from that final common pathway, the air over the operative field. The advent of total joint replacement precipitated a renewed consciousness in the orthopedic community of the disastrous consequences a wound infection can have upon the orthopedic patient. Deep infection around a total joint replacement can convert a procedure with a 95 percent probability of success to a total disaster, leaving the patient worse than prior to operation. Most orthopedists use at least two accepted methods of preventing deep wound infection in the postoperative period: the application of topical antibiotics during surgery, and the intravenous infusion of systemic antibiotics during and after surgery for a brief period. In addition, many orthopedic surgeons are operating in clean air rooms with body exhaust systems; others are operating in an ultraviolet environment. Orthopedic surgery in the ultraviolet environment has been used at the brigham hospitals since 1973. The infection rate has dropped from 3.8 percent to 1.04 percent in a series of 2000 patients. However, inconveniences and hazards have been experienced in the use of ultraviolet radiation in the operating room.


Metastatic neck nodes of unknown primary origin.

The patient who presents with a metastatic node in the neck should first have a thorough examination of the upper part of the respiratory tract and then a needle aspiration biopsy of the neck mass to confirm the diagnosis of cancer. Biopsy excision or incision of the neck tumour is unnecessary and can prejudice the patient's survival. In approximately 85% of cases, the occult primary tumour will be discovered after endoscopic examination with biopsies of appropriate areas. At the Prince of Wales Hospital, 43 patients received treatment for metastatic neck lesions where no primary tumour was found before definitive treatment. These patients were divided into three groups. Seventeen patients had potentially curable neck tumours, while the remaining two groups were divided into those with incurable neck masses and those with supraclavicular nodes. The three-year survival rate for the potentially curable group was 64%. However, only one patient in the other two groups survived. Radiotherapy to the neck node and likely primary site is recommended as the main form of therapy for nodes up to 3 cm in diameter. For nodes greater than 3 cm, a combination of surgery and radiotherapy gives the best results.


Improved waveform generator and cardiac simulator for sensitivity testing of ventricular programmed pulse generator.

The need for an easily generated, simulated QRS complex to facilitate preimplantation sensitivity testing of ventricular programmed pacemakers has led to the adoption of the sine squared waveform as the standard test pulse, by the Pacemaker Standards Subcommitte of the Association for the Advancement of Medical Instrumentation (AAMI). A simple circuit is presented that provides an accurate sine squared pulse with easily adjustable pulse width (base frequency). A suggested circuit for incorporating this sine squared pulse generator into a complete pacemaker test waveform generator/cardiac simulator is also presented.


Automation of antimicrobial susceptibility testing.

Laboratory services lag significantly behind the time demands of the clinician in determining the appropriate antimicrobic drug to treat a bacterial infection. The authors discuss several new automated optical systems that promise to shorten the time lag for results, as well as lead to improved precision and standardization. The advantages of expressing antimicrobic susceptibility results as Minimum Inhibitory Concentration (MIC) over the three classifications of sensitive, intermediate, or resistant commonly determined by the Kirby-Bauer disc diffusion method are discussed. Computerization is a central feature of emerging instrumentation for antimicrobic susceptibility testin, and it will be potentially useful in providing interpretive data relating the MIC to specific dose-site combinations. The paper is concluded by short descriptions of nonoptical techniques that investigators have used to measure bacterial growth.


Sinus arrhythmia in acute myocardial infarction.

Sinus arrhythmia, defined by means of a calculation of variance of the R-R interval on admission to hospital, was present in 73 of 176 patients admitted to a coronary care unit with acute myocardial infarction. These patients had a lower hospital mortality. They tended to have a higher incidence of inferior infarction, and a lower incidence of anterior infarction, and to have smaller infarcts as measured by the Norris index. The main difference between patients with sinus arrhythmia and without sinus arrhythmia related to heart rates on admission to hospital, the patients with the former having slower heart rates at that time.


Digital range-gated echocardiographic tracking.

Many applications of standard echocardiography require velocity computation which is usually determined by manually measuring slopes on an echocardiogram. However, manual techniques are limited by the inaccuracy with which slopes may be drawn and measured, the large amount of time required for detailed analysis, and the lack of real time information. A system is described which automatically provides real time and continuous and essentially instantaneous position and velocity measurements on selected heart structures. The system is designed with digital electronics wherever possible to facilitate data processing and the transfer of information to a computer. The system has advantages over continuous wave ultrasonic Doppler techniques and a range-gated ultrasonic Doppler system because dynamic, range-gated digital tracking allows target isolation and identification. Also, because range gate size may be kept small, noise susceptibility is minimized.


Systemic griseofulvin therapy of monilethrix.

After a report of clinical effectiveness, four adult patients with monilethrix were treated with griseofulvin for six months at an orally administered dose of 500 mg (microsize) per day. No objective or subjective improvement was observed.


Manual record-keeping and statistical records for the operating room.

Surveys have shown that handwritten anesthesia and circulating records kept in hospital operating rooms may be inadequately maintained and analyzed. Online, fully automated data processing techniques have been applied to reduce the anesthesiologist's recordkeeping workload, but with limited receptivity. An off-line data processing system has been developed using handwritten records to provide both anesthesia and operating room utilization statistics. Evaluation of the system indicates that an online, semiautomated approach applied only to charting vital signs and recording utilization statistics is an appropriate one for future development.


Cardiac electrodes and safe voltage limits.

The 5-mV safe voltage limit that has been proposed for hospital safety codes is shown to be based on incorrect assumptions. The actual voltage threshold for 60-Hz current is of the order of 100 mV or greater, because of the effects of electrode interface impedance and cell membrane characteristics. AK value of 50 mV is proposed as the safe voltage limit for 60 Hz current for the purposes of safety standards. The medical community is requested to consider this value.


Queensland's rural practitioners: background and motivations.

In view of the continuing maldistribution of medical manpower, this study was undertaken in order to delineate the backgrounds and motivating factors influencing choice of practice by rural practitioners in Queensland. Of those doctors in rural practice 38% had spent more than 10 years of their childhood in a rural environment. Interest of work and variety of practice were most consistently designated as attractions of rural practice, while the factor designated as the greatest attraction of rural practice was the variety of practice. The major disadvantages of rural practice were: (i) restricted opportunities for continuing education; (ii) difficulty obtaining adequate locum assistance for holidays and continuing education; and (iii) professional isolation. The prime reasons doctors had for choosing their present practice were the practice conditions (31.3%), and geographical location (20.9%).


Single-dose therapy in management of urinary tract infection.

A study was undertaken to determine whether single dose therapy for urinary infection can identify those patients who are likely to have underlying pathological changes of the renal tract, and, thus, those patients who need further investigation. Fifty-three patients (50 females, three males) with documented recurrent urinary tract infection, in whom the present infection was confirmed in two consecutive urine specimens, were studied. Patients received a single dose of 0.5 g kanamycin intramuscularly (or another antibiotic for kanamycin-resistant organisms), and urine was cultured daily over the following week. The original infecting organism was eradicated in 22 of the 37 patients (60%) who completed the study (urine clear at one week), but persisted or relapsed in 15. Bacteriuria disappeared within 24 hours in all but four patients, but both relapses and new infections were seen as early as 48 hours after treatment. Fifteen of 18 patients (83%) with radiologically normal renal tracts were successfully treated compared with only 6 of 16 patients (37%) with a radiological abnormality. Failure of single dose therapy to eradicate urinary infection is thus an indication for further investigation.


Functional pelviureteric junction obstruction.

A case of functional pelviureteric junction obstruction is reported and a radiological method for detecting this entity is described. The causes of this condition are described and the reasons for the appropriate treatment are given.


Oral administration of erythromycin stearate: effect of dosage form on plasma levels.

The clinical effectiveness of three different oral dose forms of erythromycin stearate was assessed by following plasma levels during continued dosage. The assessment was carried out in 12 volunteers who took 250 mg of the drug every six hours in a cross-over design with intravenous administration of erythromycin lactobionate as a reference. While in some patients levels which were obtained after the initial dose were low, plasma levels sufficient to inhibit the majority of bacterial pathogens which cause acute respiratory tract infections were obtained and maintained after the second dose.


An open study of the antihypertensive efficacy of metoprolol.

An open study of the effectiveness of metoprolol in reducing the blood pressures of 13 hypertensive patients was conducted. It was found that metoprolol reduced the patients' blood pressure satisfactorily, and is well tolerated within the dose range of 100 mg to 400 mg daily.


Rhabdomyolysis and renal failure in acute mercuric chloride poisoning.

A case of acute renal failure after mercuric chloride poisoning is reported. Laboratory data revealed markedly elevated serum concentrations of aldolase and creatine phosphokinase, and the presence of pigment granular casts and myoglobin in the urine. The patient went into a diuretic phase after 12 days of oliguria and renal function returned to normal during the next 10 days. Besides direct nephrotoxicity, the contributory role of rhabdomyolysis in the pathogenesis of renal failure after mercuric chloride poisoning, has been stressed.


Rubella vaccination in Australia: 1. A five-year follow-up of vaccinated schoolgirls.

Schoolgirl rubella vaccination commenced in New South Wales in 1971. Serological follow up of 242 girls, four to five years after vaccination, showed that 9% of girls had missed the vaccination programme. Only 5% of vaccinees were still susceptible to rubella in comparison with 27% of unvaccinated male controls. The efficacy of the programme is thus well demonstrated. Screening for vaccine failures at the time of prescribing contraceptives is suggested as a means of detecting schoolgirl vaccine failures. It is noted that the first cohort of schoolgirl vaccinees has not yet reached the peak childbearing age range.


Combined microwave therapy.

Fifty-two cases of advanced head and neck cancer were treated by 434-MHz radiowave hyperthermia which was combined with cobalt radiotherapy and/or radioactive gold grain implant. Complete resolution of primary and secondary lesions occurred in 94% of cases, and the survival rate after three years was 54%. Retrospective study of comparable series revealed 62.5% resolution rate, and 29% survival after treatment with hyperbaric oxygen and cobalt, while after conventional supervoltage therapy, the resolution rate was 36.5%, and only 19% survived for three years.


[Symmetric cerebral calcification associated with disturbed parathyroid function (author's transl)].

Alteration of the metabolism of calcium and phosphate may be associated with symmetric cerebral calcification. Detailed investigations of the function of parathyroid glands including computer tomography of the brain are so far missing. In 6 patients with clinical and biochemical signs of altered function of the parathyroid glands symmetric cerebral calcification could be demonstrated by computer tomography. They are also visible by X-ray examination in one patient. Consequently, functional disturbances of the brain, cerebellum and of the extrapyramidal system may occur. Moreover, the combination of hypoparathyroidism and hypothyroidism also appears to result in the development of symmetric cerebral calcification. The pathogenesis of the calcification as well as therapeutic approaches will be discussed.


[Successful gastric ulcer treatment of a patient with primary hyperparathyroidism with cimetidine (author's transl)].

Case report on the successful gastric ulcer treatment of a patient with primary hyperparathyroidism with the H2-receptor antagonist cimetidine. After four weeks of therapy with 0.8 g/d cimetidine stomal ulcerations were seen by x-rays and endoscopy to be healed. The patient was discharged on a regimen of 400 mg daily of oral cimetidine. Peptic ulcer did not recur after 1/2 year of treatment with this H2-receptor antagonist, although the signs of primary hyperparathyroidism were still present.


[Treatment of rheumatoid arthritis with biarison. Results of a double-blind study with placebo (author's transl)].

The effectiveness of Biarison vs. placebo was compared in an inter-individual double-blind study on 30 hospitalized patients with possible, definitive and classical rheumatoid arthritis. The time of comparison was 3 weeks; the dose used 900 mg (up to maximally 1500 mg)/day. The clinical index and the index of activity according to Lansbury were improved with Biarison and with placebo. The superiority of Biarison could be confirmed statistically (p less than 0,01). The effectiveness of Biarison was shown in reference to parameters of pain (number of painful joints and intensity of joint pain, pain on motion and at rest). Biarison was essentially well tolerated. Side effects were all gastro-intestinal. In 3 patients adverse reactions were slight and subsided spontaneously when treatment was continued. In 2 individuals Biarison had to be withdrawn in the 3rd week of treatment. In the placebo group 3 patients were taken off treatment due to no therapeutic effectiveness.


Evaluation of observer performance in detecting blood vessels on simulated angiographic images.

This paper presents methods for evaluating the effects of technical factors on observers' detection of small blood vessels in angiographic images. A fixed set of physical parameters was used to generate computer-simulated angiographs that contained blood vessels of various diameters. Observers' judgments about each set of images permitted estimation of the receiver operating characteristic (ROC) curves for vessel detection and of the probability of correctly locating the vessels. Both parametric and nonparametric methods were used to characterize the ROC curves. Three different, but theoretically related, measures of vessel detectability varied systematically with changes in the blood vessel's diameter, reflecting changes in observer performance.


Tissue mimicking materials for ultrasound phantoms.

Up until now, no material has been found whose attenuation and speed of sound properties not only mimic those of human soft tissue, but are controllable in magnitude. We have discovered such a material in the form of water-based pharmaceutical gels containing uniform distributions of graphite powder and known concentrations of alcohol. The magnitude of the attenuation coefficient can be controlled easily between 0.2 and 1.5 dB/cm at 1 MHz, by varying the concentration of graphite. These attenuation coefficients are nearly proportional to the frequency. The speed of sound varies between 1520 and 1650 m/s at room temperature, depending primarily upon the concentration of alcohol. Bacterial invasion has been prevented by sterilization procedures and the introduction of appropriate preservatives. The ultrasonic properties exhibit temporal stability and change little over the range of room temperatures.


Thermal conductivity and diffusivity of neuroblastoma tumor.

In the application of hyperthermia to cancer management, it would be useful to know the temperature/tim profile of heated tissues, including the tumor and surrounding normal structures. To obtain this information, knowledge of thermal conductivity and diffusivity of the tissues is required. The thermal conductivity of neuroblastoma was determined by a transient technique to be 89% of the thermal conductivity of water at 25 degrees, 37 degrees, and 44 degrees C. From the latter measurements, the thermal diffusivity of neuroblastoma cells was estimated as 93% of the thermal diffusivity for water. Further, in this study of neuroblastoma cells, the water content was measured as 87.4 g/100 ml of cells, a rather high value not atypical of tumor cells. From literature values of density, specific heat, and thermal conductivity, values for the thermal diffusivity of a variety of normal tissues were estimated. The thermal diffusivity values of normal tissues and neuroblastoma cells exhibit an excellent correlation with water content.


Dynamic nuclear-medicine image display system using standard multiformatter images.

There is much interest in visualizing dynamic physiological function using nuclear-medicine techniques. In particular, these methods are used in cardiac studies, but it is likely that many other functions will be better visualized with cinematographic-type displays. A new instrument is described which takes a sequence of images, records on a single sheet of film by standard formatting devices and, by means of digitally controlled mirrors, projects them in rapid sequence onto a screen to produce the dynamic movie display.


Monte Carlo calculation of the wall correction factors for ionization chambers and Aeq for 60Co gamma rays.

The application of cavity-ionization chambers to the standadization of 60Co gamma-ray beams, in terms of exposure, requires that the specific ionization of air Jg, be corrected for the attenuation and scatter of the incident rays by the wall, central electrode, and supporting stem of the chamber. A Monte Carlo photon-electron transport code has been developed for the purpose of calculating this correction for spherical and cylindrical chambers. The code has been applied to a spherical graphite chamber having dimensions typical of the chambers used by the NBS, the calculated wall-correction factor is in close agreement with the average of the NBS factors which were determined experimentally. The code was also used to calculate Aeq, which is central to the determination of tissue-air ratios. The calculated value, 0.989 +/- 0.003, is very close to the generally accepted value, 0.985.


Importance of geometry in biological sample analysis by x-ray fluorescence.

The determining factors of a good analysis by x-ray fluorescence are discussed, emphasizing the importance of the geometrical arrangement, especially the excitation-source to analysis-material distance. The variation of the peak area of the Kalpha x-ray of Fe is evaluated as a function of the distance. Precautions are given for the analysis of low concentration samples as well as for obtaining the relative concentration of an element in a specific material or organ.


Relation between tolerance dose and treatment field size in radiotherapy.

A relation is developed between tolerance dose and field size from an analysis of available clinical data on skin-tolerance doses for various treatment field sizes in radiotherapy. It is shown that plots of log-dose against log-field-size for various fractionation schedules give isoeffect lines all having approximately the same slope. This suggests a power law relation between tolerance dose and field size. A generalized form of NSD equation, incorporating the field-size dependence of tolerance dose, is shown to follow naturally when this new relation is combined with Ellis' NSD relation. Certain discrepancies between the sets of data used in the present analysis are pointed out and it is suggested that more data are needed before the generalized NSD relation can be applied under varying conditions of dose, time, fractionation, and field size.


Nationwide evaluation of 60Co teletherapy calibrations.

As a result of a reported incident which resulted in the unintended overexposure of several hundred patients, teletherapy installations throughout the United States were evaluated to verify the accuracy of teletherapy equipment calibrations. Selected licensees received TLDs for exposure under specified conditions. Site visits were made to each licensee showing an apparent discrepancy greater than +/- 5% and intercomparison measurements made. This paper describes results of a sampling of 373 teletherapy licensees and the success of site visits in reducing final discrepancies to less than +/- 5%. TLD and site visit measurement techniques, results, comparison with data from other studies, and possible sources of uncertainty in the management of a large-scale screening program are discussed.


Determination of radiographic screen-film system characteristic curve and its gradient by use of a curve-smoothing technique.

One of the important factors affecting radiographic image quality is the film contrast of the recording system, which may be expressed by the gradient of its H & D curve. Experimental determinations of H & D curves are subject to relatively small error, which can nevertheless cause large fluctuations and uncertainties in the calculated gradient. To reduce this fluctuation, we wrote a computer program for orthogonal-polynomial (discrete  Legendre polynomials) curve fitting by means of least-squares estimation of parameters. This procedure facilitates curve smoothing and gradient computation following sensitometric measurements. The program was tested against a large number of measured characteristic curves. A brief description of the program is given, with examples which illustrate its applications.


Cryotherapy for animals.

The advisability of using cold depends on the character and stage of the pathologic change, the therapist's knowledge of the patient's condition, and an understanding of how cold affects tissues. Cold is simple to use, requires no expensive special equipment, relieves pain, and helps to control acute and chronic stages of inflammation. Combined with other therapeutic procedures, it is a valuable addition to the treatment regimen.


Restriction endonuclease mapping of pSC101 and pMB9.

A restriction endonuclease analysis of the plasmids pSC101 and pMB9 has allowed a determination of the alterations that occurred in the tetracycline resistance locus during the construction of pMB9 from pSC101. The genes for four of the polypeptides involved in tetracycline resistance have been positioned on the restriction endonuclease map of pSC101.