Selective inhibition of cholera toxin- and catecholamine-stimulated lipolysis by blocking agents.

Vibrio cholerae enterotoxin stimulates lipolysis in rat epididymal fat cell suspensions. Like hormones this toxin increases adenylate cyclase activity, raising levels of cyclic adenosine 3',5'-monophosphate (cAMP), which activates a cellular lipase. Using specific blocking agents, we studied the responses to the adrenergic lipolytic hormones epinephrine, norepinephrine, and isoproterenol, and to cholera toxin. All stimulators were used at 100 x threshold dose. Propranolol (34 muM), a beta blocking agent, inhibited epinephrine stimulation (P less than 0.001) but not that of toxin (P greater than 0.2). Choleragenoid (25 mug/ml), a natural toxoid of cholera toxin, blocked stimulation by toxin (P less than 0.001) but not that of the adrenergic agents (P greater than 0.2). A beta blocker, practolol (3 mM), inhibited stimulation by the catecholamines tested (P less than 0.005) but not that of toxin (P greater than 0.05). Higher concentrations of propranolol (340 muM) and the alpha blocking agents phenoxybenzamine (3 mM) and phentolamine (1.6 mM) inhibited all agonists (P less than 0.001). The response to theophylline was inhibited by all blockers (P less than 0.05) except propranolol at the lower concentration (34 muM). A combined beta and alpha blockade using propranolol and epinephrine together did not inhibit toxin-mediated lipolysis. It appears that stimulation by cholera toxin is independent of beta adrenergic receptors. A major inhibition of theophylline-mediated lipolysis by alpha blocking drugs indicated a nonspecific effect of these agents at the concentrations used. The uninhibited response to toxin in the presence of propranolol and epinephrine suggests a lack of relationship of the toxin receptor to either alpha or beta receptors.


Endotoxin-binding substances from human leukocytes and platelets.

We have found whole human platelets, granulocytes, and mononuclear leukocytes to possess high affinity for the toxic lipopolysaccharide from all gram-negative bacteria tested. We have extracted these cells and platelets with n-butanol-water; all endotoxin-binding activity resided in the organic phase. These endotoxin-binding extracts did not block serologically active groupings on  endotoxins or receptors on the erythrocytes. The specificity of these still crude materials was less that that of the highly purified erythrocyte lipopolysaccharide receptor previously described by us, since they bound some bacterial antigens not related to endotoxins. Depending on source, the n-butanol extracts contained 40 to 52% glycerophosphatides (most active), 15 to 22% sphingomyelin, 17% cholesterol, less than 2 to 5% triglycerides, and 7 to 13% inactive peptide. The most active substances in the n-butanol extract were soluble in petroleum ether, whereas the peptide and sphingomyelin were not. Thus, no constituent protein, carbohydrate, or nucleic acid was present in the most highly active material. Polyacrylamide gel electrophoresis of the petroleum ether-soluble material showed for each extract one lipid band only, which was well defined and migrated similarly to phosphatidyllipids. Because of the lipidic nature of the inhibitory substances from leukocytes and platelets we also tested the lipid A component of bacterial endotoxins and some of its derivatives. Lipid A inhibited endotoxin coating of erythrocytes. De-O-acylation of lipid A left amide-linked 3-D-hydroxymyristic acid intact and increased the inhibitory activity of lipid A 20-fold. Complete de-O- and de-N-acylation destroyed its inhibitory effect.


Murine model for study of cell-mediated immunity: protection against death from fully virulent Francisella tularensis infection.

To assess cell-mediated immunity in terms of host protection, an experimental model was developed in which passively transferred spleen cells from immunized AKR/J mice enabled nonimmume syngeneic recipients to survive an otherwise fatal infection with fully virulent Francisella tularensis. Donor immunization was achieved by administering live attenuted tularemia vaccine and, subsequently, the virulent streptomycin-sensitive SCHU S4 strain of F. tularensis. At selected intervals after immunization, donor spleen cells were transferred to streptomycin-treated recipients challenged subcutaneously, intravenously, or intraperitoneally with 25 to 50 minimal lethal doses of virulent streptomycin-resistant F. tularensis SCHU S5. The protection afforded by immune spleen cells was maximal (essentially 100%) 12 days after the SCHU S4 secondary immunization.


Superego processes in a collective society: the Israeli kibbutz.

An attempt has been made to examine some aspects of cultural conformity and superego development in the Israeli Kibbutz. The basic premise has been that in a collective society, such as the kibbutz, with its multiple child-caretakers, we find a superego based on internalized values rather than introjected specific figures--a collective superego. The result is a shame- as opposed to a guilt-oriented conscience, with resulting emphasis on the need for the presence of others as controlling forces.


Problems of a temporary adolescent psychiatrist.

I have tried to describe just less than one year of learning experience on my part in one type of adolescent unit. Only 16 inpatients were treated at a time while I was there: there were only 25 discharges and 19 admissions in my time. We knew we were making little inroad into our whole regional problem of adolescent disturbance; but we believe that as a team, able to work closely with each other and with our patients and their relatives, in a therapeutic community of undogmatic ideology, we were able to give a little to almost all and, to those who did best, a great deal. Very few ex-inpatients lost all touch with us. Nearly all came back from scattered homes for our Christmas discotheque. Even our very modest aim, to reset and then foster the natural development of the personalities of our patients, rather than break them down in deep analysis and radically reconstruct them, required an intensity of psychotherapeutic effort which engaged all we had to offer, and often drained us at the end of the day. Yet those who joined us transiently, particularly student nurses and medical students, seemed to find the experience significant--occasionally deeply so--and came back to visit us. Our social worker has now departed to have a baby. Our three senior nurses have left, two to university as mature students, one to prepare for a no. 7 post. Possibly the intensity of the demand upon them would have made them leave, anyway. For myself, it was a year of development of my psychotherapeutic sensitivity and of close working with a valued team of colleagues in a setting new to me, which I shall never forget.


Reestablishing duodenal continuity after previous gastrectomy for peptic ulcer.

Gastroduodenal anastomosis is not routine during reoperation for stomal ulcers after primary Billroth II gastrectomy. It nevertheless is a sure way to prevent an increased peptic potential which is brought about by a duodenal bypass. We have reviewed the published cases and added three more, bringing the total to 47. We analyzed the modalities, indications and results of this method. Gastroduodenal anastomosis can be accomplished more often than is thought, despite the often necessary large gastric resections. Separation of the duodenopancreatic block and liberation of the fundus allows suturing without traction. End-to-side anastomosis of the stomach on the anterior wall of the second portion of the duodenum avoids dissection of the duodenal stump. Vagotomy is required when basal acidity is greater than 20 mEq/liter. Reestablishing a physiologic alimentary tract is particularly indicated in chronic obstruction due to stenosis associated with a proximal loop syndrome in young patients. Jejunal interposition becomes necessary when total gastrectomy is the result of repeated surgery. Such a method is the best solution for agastria. The excellent results obtained by gastroduodenal anastomosis after repeat gastrectomy should encourage wider use.


Blood coagulation studies in children with surface hemangiomas.

Thirty patients with surface hemangiomas were investigated for any latent coagulopathy. Whole blood clotting time, kaolin cephalin clotting time, prothrombin time, thrombin time and platelet counts did not differ significantly from the control group values. The values of plasma fibrinogen, euglobulin lysis time and serum levels of fibrinogen degradation products remained within the normal ranges but their mean values were significantly different from those of healthy children. The findings may be attributed to a chronic incipient type of "consumption coagulopathy" occurring locally in the hemangiomas.


Thyroid nodules and thyroid carcinoma.

Seventy carcinomas of the thyroid gland were found in 1300 thyroidectomies for an incidence of 5.4%. The incidence of malignancy in single nodules was 9.7% and in multinodular nontoxic goiter 4.3%. The risk of cancer was higher (14.2%) in males than in females (4.3%). The highest incidence of cancer was found in children under the age of 10 (40%). Radioactive iodine scintiscanning was of limited help in differentiating benign from malignant nodules. Early surgery is advised for all patients with single thyroid nodules and all thyroid nodules in children should be excised.


Thyroid carcinoma. Correlation between clinical and pathological findings.

Our survey of 146 cases of thyroid carcinoma showed the following points: (a) in 20% of the cases the gland was diffusely enlarged without nodules; (b) in 35% of 34 cases, thyroid carcinoma was located in areas other than the "cold" zones; (c) multiple foci of carcinoma were found in 67% of cases with total or subtotal thyroidectomy and in 33% of cases with partial thyroidectomy; (d) anaplastic carcinomas (13% of cases) occurred in patients of all ages, 29% of them in patients younger than 30 years.


Etiology of venous disorders.

We have investigated the role played by the bulk and transit time of food in the bowel and the squatting position characteristically adopted by Africans and Asians for defecation in the causation of venous disorders. Refinement of carbohydrates leads to low residue diets and consequent prolonged transit time through the intestines. This, together with abandonment of squatting, as the use of water closets increased, has contributed to the increase in incidence of venous disorders among Westerners.


Lumbar stenosis.

We have analyzed the clinical features, radiologic, myelographic and operative findings in 11 cases of lumbar stenosis. Adequate decompressive laminectomy is necessary in these cases to relieve the symptoms.


Surgical treatment of 150 cases of squamous cell carcinoma of the mouth.

A series of 150 commando operations performed for squamous cell carcinoma of the mouth has been presented. This series is analyzed according to a staging which differs from the TNM standard classification of the Joint Committee. Our criteria of staging are based on local invasion by the primary lesion more than on the size of the lesion alone. The five-year survival for the 50 patients with lesions in the anterior part of the mouth was 62%; for the middle mouth group, 48%; and for the posterior mouth group, 24%.


Ultrastructural description of a "cylinder organelle" in the outer plexiform layer of human retinas.

A cylinder-like organelle ("cylinder organelle") present in the outer plexiform layer of the retina and apparently confined to the horizontal cell processess is described. This structure was studied in detail in three normal human retinas from eyes enucleated for ciliary body melanomas. The cylinder organelle, when cut longitudinally, showed an electron-lucent area bound by two bands of electron-dense filaments. In transverse section, the cylinder organelle revealed a circular profile of electron-dense crisscrossing filaments about an electron-lucent matrix. Since this structure was only found in the rod spherule synaptic complex, it is hypothesized that it may be involved in transmitting impulses.


Crossing axons in the third nerve nucleus.

The research presented in this paper studied the pathway taken by the crossed fibers of the third nerve nucleus in an animal whose nucleus has been well mapped and found to correlate well with higher mammals and man. Autoradiography using tritiated amino acid labeled the cell bodies an axons of the left side of the oculomotor nucleus of the cat. Axons so labeled could be seen emerging from the ventral portion of the left nucleus through the median longitudinal fasciculus (mlf) to join the left oculomotor nerve. Labeled axons were also seen to emerge from the medial border of the caudal left nucleus, cross the midline, and pass through the right nucleus and the right mlf to join the right oculomotor nerve. These latter axons must be the crossed axons of the superior rectus and levator palpebrae subnuclei. Since the path of these crossed axons is through the caudal portion of the nucleus of the opposite side, the destruction of one lateral half of the oculomotor nucleus would result in a bilateral palsy of the crossed subnuclei. Bilateral palsy of the superior rectus and bilateral assymetrical palsy of the levator palpebrae muscles would result.


The effects of acetazolamide on the human electroretinogram.

The effects of acetazolamied on the cerebral circulation and metabolism was previously shown to be due to a raised PCO2 in brain tissue. The effects of the drug on the human electroretinogram (ERG) are investigated in fifteen human volunteer subjects. A significant increase in the b-wave was found. A similitude with the mechanism of acetazolamide administration in brain and retinal tissue seems to be a possible explanation.


Crystals in corneal epithelial lesions of tyrosine-fed rats.

Tyrosine-fed rats develop corneal disease which mimics that found in the human metabolic disorder, tyrosinosis. By electron and polarizing microscopy needle-shaped birefringent crystals are demonstrable in early corneal epithelial lesions of tyronsine-fed rats. The crystals appear as negative images by electron microscopy, their content apparently extracted by fixation and/or embedding fluids. Crystals may be arranged in sheaves or bundles and pass from one cell to another disrupting the continuity of membranes of both cells and nuclei. They are present in desquamating epithelial cells along corneal ulcers. Polarizing microscopy of whole mounts of diseased tissue shows that the crystals are limited to epithelial lesion areas. We hypothesize that the crystals are tyrosine and that crystal growth in cells initiates lesion and subsequent ulcer formation.


Experimental tonography on enucleated human eyes. II. The loss of intraocular fluid caused by tonography.

In clinical work, the loss of intraocular fluid caused by tonography (dV) is usually calculated according to the formula of Grant and Friedenwald. The validity of this formula has been tested by comparing the dV calculated from known factors in the formula with the dV measured directly on enucleated eyes. Our results show a good correlation between the two methods, especially when the rigidity coefficient at the beginning of tonography is used in the calculations. It is concluded from our experiments here and in our previous paper that the theoretical foundation of tonography in principle is valid.


Analysis of ascorbate concentration in the aqueous humor by high-pressure liquid chromatography.

A high-pressure liquid chromatography instrument has been used to establish a method for the analyses of ascorbate concentration in aqueous humor. The method detects only the reduced form of ascorbate. The values obtained by this method are very similar to those of the colorimetric method. The ascorbate value in a group of random samples obtained from human glaucoma eyes varied between 3.5 to 31 mg. per cent, independent to blood ascorbate concentration.


Electrolyte and acid-base status of aqueous humor in perinatal and adult goats.

These experiments were undertaken to determine electrolyte concentration and acid-base status of aqueous humor and arterial plasma H2O in perinatal and adult goats. The distribution of potassium, sodium, chloride, magnesium, and calcium between aqueous humor and plasma H2O in fetal, neonatal, and adult goats changed independently with age and could not be explained by passive Gibbs-Donnan equilibria. Anterior chamber aqueous humor has a reduced pH, PO2, HCO3-, and an elevated PCO2 compared to arterial blood in the neonate and adult.


Aqueous and serum lysozyme values in experimental uveitis in rabbits.

The purpose of this study was to determine what happens to normal aqueous lysozyme levels during experimentally induced uveitis. Horse-serum-induced uveitis increased the average rabbit aqueous lysozyme value (0.9 mug per milliliter) to 13.8 mug per milliliter, but did not elevate the average serum lysozyme value (4.0 mug per milliliter). These findings suggest that ocular inflammation alone is not sufficient to elevate the serum lysozyme level.


New concept of the anatomy of the anal sphincter mechanism and the physiology of defecation. II. Anatomy of the levator ani muscle with special reference to puborectalis.

A study of the surgical anatomy of the levator ani muscles, with special stress on the puborectalis, was performed on 22 cadaveric specimens. The study comprised dissection and microscopic examination. The levator ani was found to consist of two portions only: pubococcygeus and iliococcygeus, the puborectalis being a part of the external anal sphincter. Both levatores decussate at the anococcygeal raphe, which represents a "decussation line" and not a site of insertion for the muscle fibers. A "digastric" pattern of the levator is demonstrated, which is responsible for the harmonic nature of the function of the muscle bundles on each side of the pelvis. The levator hiatus was found to be formed of the medial borders of the pubococcygeus, , and not the puborectalis. A "hiatal ligament" was identified, stretched between the edges of the levator hiatus and the intrahiatal viscera. The role of the pubococcygeus in anal fixation is discussed, and a new concept that the puborectalis does not belong to the levator ani but constitutes na integral portion of the external and sphincter. The puborectalis and the deep external anal sphincter were found to be fused together and identical from the morphologic, histologic, and functional points of view as well as with respect to innervation. Both form a single U-shaped loop which is given the name "top loop."


Neurourologic evaluation after resection of the sacrum.

Five patients with bilateral, and four patients with unilateral, well defined sacral nerve lesions after sacral resection for tumor were examined with a clinical evaluation, cystometry, and cystoscopy including a test of vesical and urethal sensibility with different stimuli. In patients with bilateral division of the sacral nerves below the S 2 level, no active detrusor contractions were registered, indicating that the second sacral segment alone cannot subserve the micturition reflex. In patients with unilateral division of sacral nerves 1 to 5 or 2 to 5, a normal micturition reflex was registered. There was a complete loss of bladder mucosal pain when sacral nerves 3 to 5 had been cut bilaterally, while the sensibility was normal when sacral nerves 4 to 5 had been cut bilaterally. In patients with unilateral division of all sacral nerves below L 5 or S 1, mucosal pain tested by means of electrcoagulation of the bladder and pin-pricking of the urethra could not be felt on the denervated side. Stretching of the detrusor wall with a ureteral catheter, however, could be felt on the denervated side, indicating that this sensation was not mediated in sacral nerves but probably in the hypogastric nerves. Thermesthesia of the mucosa was demonstrated on the intact side of the bladder but not on the denervated side when the patients with unilateral sacral nerve lesions were tested with jet streams of cold or hot saline against the bladder wall.


Role of the kidney in development of cystitis and other toxic effects of cyclophosphamide.

Cystitis caused by excretion of cyclophosphamide (CY) metabolites in the urine was prevented by nephrectomy. There was a concomitant increase of CY lesions in brain, eye, and spleen due to the avoidance of urinary losses. Anuria caused by extra- or intrarenal obstruction, or by prerenal deviation of water, also prevented cystis; these procedures enhanced other CY lesions more than nephrectomy did. The data are interpreted to indicate significant production of active CY metabolites by the kidneys, a production which is eliminated by nephrectomy but not by other procedures.


Experimental lymphangiography. Experience with direct medium injection into the parenchyma of the rat testis and prostate.

Direct injection of a new hyperemulsified radiopaque medium into the parenchyma of the testes produced rapid and excellent visualization of testicular lymphatic vessels and nodes. The technique is much simpler than previous methods. No ill effects on reproduction were demonstrated. Prostatic injections demonstrated the parenchyma well but no nodes or vessels were demonstrated.


Comparison of polypropylene and polyglycolic acid suture in experimental vasovasostomy.

A preliminary study upon seven dogs comparing vasovasostomy using polypropylene suture to vasovasostomy using polyglycolic acid suture was carried out. Five of the seven vasa anastomosed with polyglycolic acid sutures were patent wherease none of the seven vasa anastomosed with polypropylene sutures were patent. There appeared to be less vasal inflammatory reaction where vasovasostomy had been accomplished with polyglycolic acid. This study indicates that further investigation comparing these and other suture materials in vasovasostomy is justified. It also suggests that improved results in vasovasostomy might be obtained by the use of polyglycolic acid suture.


Asymptomatic bacteriuria, bacteremia, and other infections due to NSU corynebacteria.

By means of the new medium, nonspecific urethritis (NSU) chocolate agar, NSU corymebacteria were isolated from patients with asymptomatic bacteriuria, bacteremia, cervicitis, conjuctivitis, and pericarditis, and also with bone marrow, wound, and cul-de-sac infections. The NSU corynebacteria were considered the etiologic agents. On the basis of biochemical reactions, antibiotic sensitivity, and complement fixation tests some isolates were the same microorganisms. Both patients with conjunctivitis were infected with the same NSU corynebacteria. A second isolate was cultured from patients with osteomyelitis and cervicitis, while a third was recovered from an infected leg wound and from a patient with pericarditis. Seven of the isolates, when injected into rabbits hypersensitive to four NSU corynebacteria isolated from the inflamed epididymis of patients with epididymitis, elicited delayed hypersensitivity reactions, which indicated that they also were related antigenically. It is suggested that nonspecific urethritis and eididymitis may represent an infection with NSU corynebacteria, or may be an extension of bacteriuria due to these microorganisms, with a delayed hypersensitivity reaction as a possible additional complication. Colony counts on NSU chocolate agar of the bacteria in urines from male and female patients were higher than those obtained on conventional agar media. NSU chocolate agar is superior to other agar media for the isolation of pathogenic and saprophytic bacteria not only from the urogenital tract but also from other foci of infection. It is easily prepared from commercial blood agar plates and its use should be considered when a selective medium is not required.


Urecholine test for denervated bladder-.

In the dog the denervation supersensitivity response of the detrusor appears within 7 to 21 days after bilateral pelvic nerve transection. Unilateral denervation cannot be detected by the standard Urecholine test.


Side-to-side right renal artery-vena caval fistula. A new model for experimental hypertension.

A model for the investigation of blood pressure changes resulting from a renal arteriovenous (A-V) fistula is presented. After base line blood pressures were established in five adult mongrel dogs by carotid loop puncture, an A-V fistula was constructed between the right renal artery and vena cava. Weekly blood pressure determination showed a rise in systolic and diastolic pressure over control values. Split renal vein renins and split function studies were obtained at 3 months postfistula. Right nephrectomy at 6 months postfistula resulted in return of blood pressure readings to control values. Although no consistent pattern in the split renal vein renins and split function studies was seen, the data suggest that renin production may be responsible for the rise in systolic and diastolic blood pressure.


Relationship between renal blood flow and ureteral pressure during 18 hours of total unilateral uretheral occlusion. Implications for changing sites of increased renal resistance.

Continuous monitoring of ipsilateral renal blood flow and ureteral pressure during 18 hr of complete unilateral ureteral occlusion in five awake dogs defined the onset of preglomerular vasoconstriction, characteristic of chronic ureteral occlusion. There was a triphasic relationship between ipsilateral renal blood flow and ureteral pressure during the 18 hr of acute ureteral occlusion: (i) 0 to 1 1/2 hr, renal blood flow and ureteral pressure rose; (ii) 1 1/2 to 5 hr, renal blood flow fell while ureteral pressure continued rising; (iii) 5 to 18 hr, renal blood flow and ureteral pressure fell together. These relationships suggest different pathophysiologic mechanisms changing renal vascular resistance during the first 18 hr of complete ureteral occlusion, with increased preglomerular resistance occurring after 5 hr and being dominant in chronic ureteral occlusion.


Dengue carrier culture and antigen production in human lymphoblastoid lines.

Replication of dengue type 2 (D2) viruses was studied in four lymphoblastoid cell lines; Raji, HR1, EB3 and RPMI 6410. The HR1 cell line failed to support D2 growth while the other cell lines showed varying susceptibility. Both D2 strain 16681 and strain New Guinea C (NGC) passaged in LLC-MK2 cells replicated readily in Raji cells, while a high mouse-brain-passaged NGC strain did not. A soluble complement-fixing (SCF) antigen from D2-infected Raji cells showed lines of identity with a D2SCF antigen prepared from infected suckling mouse brains. Electron microscopic studies of a D2 Raji carrier culture showed that virions were located in a membrane-vesicle complex in the cytoplasm of the cells. Precursors of viral particles were more frequently observed in the parts of the vesicle which had rough endoplasmic reticular membranes. Mature virus particles were observed often at the boundary of the other part of the vesicle, which consisted of smooth endoplasmic reticulum. Occasionally, a large crystalloid structure consisting of incomplete viral particles was seen in degenerative cells. Dengue carrier cultures in human lymphoblastoid lines may provide a convenient in vitro system for study of aspects of dengue virus-leukocyte interactions.


Dane particles, DNA polymerase, and e-antigen in two different categories of hepatitis B antigen carriers.

Two different categories of hepatitis B antigen carriers have been investigated. One comprises patients treated with dialysis and known to be highly infectious. The other consists of blood donors found in routine screenings. Serum specimens have been studied with regard to Dane particles. Dane-core-associated DNA polymerase activity, and e-antigen. The two groups differed markedly in the aspects studied. The five healthy blood donors had no, or very few, detectable Dane particles and no detectable DNA polymerase activity; four of the five healthy donors had antibodies against e-antigen. The one xickk donor and all six dialysis patients had many Dane particles and polymerase activity; five of the sick dialysis patients had  e-antigen. Thus, these results further underline the difference between the two groups, and e-antigen and DNA polymerase activity could represent possible useful parameters for judging infectivity.


Acute neonatal isovaleric acidemia. A report of two cases.

Two fatal cases of the fulminant type of isovaleric acidemia are described. Attention is drawn to the existence of two forms of the disease, the severe "Newman" type, occurring in the first week of life and the milder "Tanaka" type, with a later onset. The importance of ruling out isovaleric acidemia in any newborn infant with acidosis is emphasized.


Cytogenetic evaluation of 500 Jerusalem newborn infants.

Cytogenetic investigations were carried out on cord blood lymphocytes of 500 normal healthy newborns. This population was divided into seven geoethnic groups according to the birthplace of the four grandparents of the infant. No numerical chromosomal aberrations were observed, but 10% of the individuals manifested cytogenetic variants. Six inherited structural abnormalities (four inversions and two deletions) were observed, while the remainder were classified as "minor variants." The chromosomal variants were randomly distributed among the population, and no particular variant was characteristic of a given subgroup.


The lymphoid bone marrow. An experimental model.

An experimental model is proposed whereby rat bone marrow is converted to a lymphoid-like tissue. A single i.p. injection of hydroxyurea (250 mg/kg body weight) destroys replicating marrow cells in DNA synthesis. Bone marrow erythroblasts constitute the vast majority of cells in cycle under the steady-state of hematopoiesis. Six hours following a single injection of hydroxyurea, selective damage of erythroblasts is noted. The depleted erythroid compartment appears to be replenished by cells of a lymphoid configuration. At 24 hr after injection the erythroid compartment is restored to normal activity. It is suggested that 6 hr after administration of hydroxyurea, lymphoid cells of rat bone marrow may be a source of stem cells for the depleted erythroid compartment.


Methohexital as an activator in epileptic patients with normal electroencephalograms.

The activation by a short-acting barbiturate, methohexital, of spike and wave discharges in epileptic patients with normal EEG tracings was evaluated. Seventy-five patients and 20 healthy control subjects were studied. Non-specific changes--desynchronization, fast sharp activity and diffuse slowing--appeared in all the tracings. Only eleven patients had positive activation after methohexital administration. The results were not encouraging and indicate that methohexital is not reliable as a diagnostic tool in problematic cases of verified or suspected epilepsy with normal EEG tracings.


Problems in the evaluation of training health personnel.

The place of evaluation in the several phases of training programs is presented as an on-going education process. The framework specifies the sources and methods of data collection on: (1) the improvement in trainee performance; (2) the relevance of the program to the community; (3) the involvement of appropriate groups in planning; (4) the planning process itself; (5) the utilization and diffusion of evaluative feedback; and (6) the consequences of the training activity for the sponsoring organization and consumer.


The impact of training on consumer participation in the delivery of health services.

A retrospective evaluation of training provided to six hospital consumer advisory groups is described. The training program was designed to provide information and decision-making skills to consumers of services and community representatives serving on voluntary hospital advisory boards. The evaluation, initiated after the end of the training program, demonstrates different effects of training depending on the stage of development of the consumer board. All but one of the six boards studied showed positive changes in the number and type of activities following training.


A perspective on non-traditional academic programs in the health sciences.

In the 1970s, non-traditional academic programs began to gain impetus, aided by studies and recommendations by such groups as the Carnegie Commission on Higher Education and the Commission on Non-Traditional study. Schools of public health have taken the lead in implementing non-traditional, off-campus programs which are relevant to personnel in health service agencies. Reported in this monograph are three programs representing alternative approaches to off-campus public health programs. As our data base increases and new programs are reported, we may see rapid growth in non-traditional programs, resulting in significant changes in academic programs preparing public health practitioners.


Alkali burns of the rabbit cornea. I. A histochemical study of beta-glucuronidase, beta-galactosidase and N-acetyl-beta-D-glucosaminidase.

In alkali burned rabbit corneas activities of beta-glucuronidase, N-acetyl-beta-D-glucosaminidase and acid beta-galactosidase were studied histochemically in various time intervals after the traumatization. The technic with semipermeable membranes was employed. Within four days after the injury enzyme activities in the traumatized area were almost lacking. The corresponding activities in the unaffected part of the cornea were within the norm. On the 7th day enzyme activities were on an increase (but still subnormal) in the traumatized area. This area was surrounded by a zone of keratocytes with high levels of enzyme activities. This was particularly remarkable in keratocytes subjacent to the epithelium. The activation of all enzymes studied was present in the basal layer of the epithelium and in the endothelium as well. On the 14th day enzyme activities in the traumatized area were nearly restored and on the 32nd day they could not be distinguished from the normal cornea. Beta-galactosidase displayed a relatively maximal increase in the activity of all enzymes investigated.


Microfluorometric measurement at low temperature.

A cooling chamber for microfluorometric measurement is described, which allows to cool under a microscope a biological sample till 77 K and to measure it with an objective of a numerical aperture 0.6. From first experiments with BAO (5)-stained Tradescantia pollen it can be concluded, that experiments in this range of temperature open new aspects regarding the interpretation of microfluorometric phenomena.


A fluorescent water soluable carbodiimide-2-hydroxy-3-naphthoic acid hydrozide reaction for the demonstration of carboxyl groups in proteins and mucosubstances.

The carbodiimide-2-hydroxy-3-haphthoic acid hydrazide reaction as developed by Geyer (1964) was used without subsequent diazonium coupling as a fluorescent method for the demonstration of carboxyl groups in both proteins and mucosubstances. The topological distribution of the fluorophore was similar to that reported by Geyer. Quantitative microfluorometric studies on cartilage sections revealed differences in detail between emissions in cartilage matrix mucoprotein as compared to the dense connective tissue associated with the perichondrium which consists principally of protein. It would also appear that the primary fluorescent emission of unstained preparations at 450 mm should be useful in microfluorometric determinations of proteins.


Cytochemistry of the differentiating flight muscles of the desert locust Schistocerca gregaria.

Cytochemical changes in the metathoracic dorsal longitudinal flight muscle of the female desert locust, Schistocerca gregaria, during its differentiation from the last day of the fourth larval instar, through the fifth larval instar up to the eighth day after the imaginal moult were examined with respect to: (1) DNA content, (2) transcriptional activity, (3) degree of chromatin condensation, (4) RNA content, (5) protein content and (6) cross-secetional fibre area. Microspectrophotometric analysis of Feulgen-stained nuclei shows that polyploidization is not a phenomenon associated with the differentiation of these muscles. The nuclei remain diploid throughout the developmental period. By "staining" with 3H-Actinomycin D, followed by autoradiography, the changes in transcriptional activity coincedent with flight muscle development were examined. At the beginning of the developmental period the transcriptional activity is relatively high and remains so up until about the middle of the fifth instar after which time it declines fairly steadily. These changes in transcriptional activity are accompanied by changes in the degree of chromatin condensation. Generally, the periods of high transcriptional activity exhibit less condensation of the chromatin. The originally high transcriptional activity is accompanied by a steady over-all increase in total RNA content during the developmental period; and in turn a large increase in total protein content. The cross-sectional area of the muscle fibres increases significantly during the growth and differentiation of the flight muscles.


[Must therapy be continued at all costs (author's transl)].

In acknowledging the remarkable progress of medicine, the possible consequential harmful effects should not be overlooked. Judgement should be based on the total welfare of the patient and not on the ease with which technical procedures can be executed. The prolongation of life per se by any means is not the only principal of conduct, especially when it results in extension of the patient's misery. In some situations it may be necessary to renounce any form of treatment from the beginning or to abandon any already in progress. This apparent harshness however does not imply that the terminally ill must be abandoned in his suffering.


[Successful decompression of the facial nerve in facial spasm (author's transl)].

A case of successful surgical treatment of facial spasm by seventh nerve decompression is reported in a female patient who failed to improve by usual methods of treatment. Prior to surgery, tomography of the facial canal was obtained, and revealed an osseous spine involving the posterior wall of the canal. During surgery, this spine was uncovered and removed with pneumatized retrofacial air cells. The patient's spasm disappeared completely following surgery. The present case indicates that the possibility of osseous spines impinging on the facial nerve should be considered in all cases of facial spasm.


[Acute obstructive laryngitis in children (author's transl)].

Three types of acute obstructive laryngitis in children are distinguished: 1. Acute supraglottic laryngitis (Epiglottitis acuta): The usual causative organism is Hemophilus influenzae, type B. Characteristic findings include a swollen red epiglottis. Treatment is based on Ampicillin, Solucortef (hydrocortisone-sodium succinate) i.m., air humidification, intravenous infusions and airway protection (tracheotomy or intubation). From 1958-1967, 68 children were treated, of whom boys were twice as commonly affected as girls. In about 80% of cases, tracheotomy was still found necessary. 2. Acute subglottic laryngitis: Mucosal swelling in the subglottic space causes a clinical picture which initially is common to several groups of deseases. In allergic subglottic edema, a pale "pillow-shaped" swelling occurs which responds favorably to antiallergenics and cortisone. In contrast, infectious swelling is partially caused by the infiltration of inflammatory cells. Parainfluenzae virus was isolated in 60% of these cases at our hospital. During the period studied, 2,741 cases were treated, of whom boys were 3.3 times more frequently affected than girls. The use of Solu-cortef i.m. has decreased the tracheotomy rate from 12% to 0. 3. Acute laryngotracheobronchitis: In this disease process, the initial infection is attributed to a virus, with the infected mucosa secondarily invaded by bacteria. The clinical course is prolonged when compared to subglottic laryngitis, and the general condition seriously affected. Both expiratory and inspiratory stridors occur. Tracheotomy is usually required, with viscous crusts removed by bronchoscopy. Respirator treatment is also often required. Fourteen children have been treated, of whom two have died.


[25 years experience with glottis widening surgery in our clinic (author's transl)].

Between 1949 and 1974, 137 patients with bilateral vocal cord paralyses were operated upon in our Department. In 127 cases King's method of extralaryngeal lateral fixation of the vocal cord or a modification thereof was executed on one or both sides. The modification consisted of securing the lateral-fixating suture around the superior thyroid cornu. This produces an additional displacement of the vocal cord in the vertical plane which provides good respiratory function in spite of only moderate lateral displacement of the cord. In seven cases endolaryngeal arytaenoidectomies and submucus hemicordectomies using Kleinsassers' technique were performed. In three cases endo- and extralaryngeal methods were combined. 120 (87.6%) of all patients could be decannulated. After unilateral extralaryngeal lateral cord fixation, 77.2% of patients could be decannulated within three weeks following operation. Operative results were analysed according to respiratory and vocal function two years postoperatively. After unilateral lateral cord fixation, breathing was good or sufficient in 73.6% of cases and insufficient in 26.4% of cases. The voice was normal or dysphonic in 86% of cases while aphonic in 14% of cases. Among the causes of bilateral vocal cord paralysis, primary strumectomies and operations for recurrent goiter were predominant (95%). All patients were tracheotomized before or after the operation. Two years postoperatively, incidental tracheal stenosis was noted in 73% of all patients. This was insignificant to moderate in 63.5% of cases and severe in 9.5% of the cases.


[Deafness due to hyperinsulinism (author's transl)].

A case is reported of progressive bilateral sensorineural deafness and recurrent unilateral facial paralysis in a patient suffering from hypoglycaemia due to pancreatic Islet cell hyperplasia. Subtotal pancreatectomy was followed by resolution of hyperinsulinism and improvement of the hearing.


[Uncommon findings during surgery of the internal auditory canal (author's transl)].

The following cases are demonstrated:postoperative deafness probably caused by abnormal blood supply to the cochlea, clinical findings of an acoustic neuroma without tumor, atrophy of cochlear and vestibular nerves, bone-like tissue growth in the labyrinthine trauma, hearing improvement after removal of an arachnoid cyst from the internal auditory canal.


[The pathogenesis of functional dysphonias (author's transl)].

The definition, aetiology and symptomatology of functional disorders of the voice are discussed. A classification for these phoniatric disturbances based in clinical and practical issues, especially general psychosocial, latent depressive and neurotic, is recommended.


[The circadian structure of the parotid gland. morphologic and morphometric investigations (author's transl)].

Male Wistar rats were standardized on a "light-dark" cycle. Daily light exposure was maintained from 07.00 to 19.00, while food and water were freely provided to each animal. During one 24-hour period, subgroups of five animals were sacrificed at four-hour intervals. The parotid glands were quickly removed from each animal, after which individual gland volume and weight were determined. Tissue samples were then fixed in glutaraldehyde and osmium and embedded in epon. Other samples were fixed in Carnoy and embedded in paraffin. A stereologic model of the rat parotid gland was constructed by morphometric methods. It could be demonstrated that the volume and weight of the glandular components changed during a 24-hour period. The maximum and minimum for each component were found to vary significantly; in most instances, the maximum occured during the evening at the onset of the eating cycle, whereas the minimum occurred in the morning with the completion of eating. The most dramatic differences were seen within the glandular acinar cells (Fig. 1 and 2). During a normal 24-hour period or physiological secretory cycle, the following volume changes were found: secretory granules, 160%; nuclei, 30%; nucleoli, 80%; golgi-areas, 60%; rough endoplasmic reticulum, 10%. The present study indicates that the parotid gland has a time-dependent structure which reflects the rhythmic activity of the gland in production, storage and extrusion of secretory material.


[Indications for mediatinoscopy (author's transl)].

The problems of routine mediastinoscopy such as the differential diagnosis of unrecognisable specific pathology of the mediastinum or lung, assessment of the operability of malignancy in the thorax prior to surgery, and the execution of minor mediastinal surgery are discussed. It is recommended that mediastinoscopy may also be performed where no radiological abnormality exists, and it is considered necessary that it is performed with biopsy where bronchial carcinoma has already been positively identified. Personal experience shows that previous mediastinoscopy or mediastinal irradiation are not contraindications to this procedure, but an adequate thoracic surgical unit and adequate after-care are essential prerequisites.


[A persistent craniopharyngeal canal combined with a meningoencephalocele (author's transl)].

The anatomical and embryological facets of the persistent craniopharyngeal canal combined with a meningoencephalocele are reviewed, and the case of a 6 year old girl is reported. Postnatal dyspnea and cyanosis improved after perforation of nasopharyngeal cyst, and adenoidectomy was performed at the age of 8 months. The second episode of meningitis led to its radiological assessment and correct diagnosis. Surgical treatment is limited because the location of the pituitary in this child is not known.


[An observation on cricothyroid muscle function (author's transl)].

The cricothyroid muscle is important to the singing voice, in the male in the chest and falsetto registers and in the female in the head register, assisting in production of the highest notes. In speech its contraction only occurs during high pitched speech. It serves as an additional tensor of the vocal cord.


[The local treatment of ozaena with streptomycin and novocaine (author's transl)].

The essence of this treatment is the injection of a mixture of 250 mgm of streptomycin (5 ml) and novocaine 1% (5 ml) on alternate days. The 10 ml mixture was injected into the conchae and submucosally into the septum on either side. Cure generally required a total of 2--3 gm of streptomycin over 15--20 days. Review of 25 cases treated over the past 15 years showed that 44% became symptom free and "good" results occurred in another 40%. In 16% treatment proved ineffective. Rehabilation was manifest by relief of subjective symptoms and disappearance of crusting and foetor. Atrophy remained irreversible.


[Legal responsibilities in patient explanation prior to ethmoid surgery].

The Superior Court of Stuttgart sentenced an E.N.T. surgeon for neglecting to explain the possible consequences and dangers to life of radical maxillary surgery and ethmoidectomy. As a result of this surgery meningitis occurred. The Court decided that the operative risks carried by surgeons is greater outside University or large hospitals. The Court therefore demanded full preoperative explaination only at the smaller hospital. Comparison of statistics from between the Tübingen University E.N.T. Clinic and a non-teaching clinic confirmed that the operative risks with ethmoid surgery is lower with the latter unit, and the the judgement of the Stuttgart Superior Court is based on fallacy. The further views and conclusions of the court are critically reviewed, and aspects of patient clarification are discussed.


[Rhinogenic subdural abscesses in childhood and their successful treatement (author's transl)].

Three cases of rhinogenic subdural abscesses are described, and the characteristic symptoms of the lesions summarized. Each presents a typical temporal sequence which is similar to that of frontal brain abscesses and permits differentiation of each into initial, latent and terminal stages. In collaboration with our neurosurgeon, a treatment was devised which included drilling two or more bore holes over the abscess area and irragating this site with an antibiotic solution. This technique provided favourable conditions for rhinosurgical operation as well as for complete healing.


[Atresia of the ear (author's transl)].

The results of operations for congenital deformities of the external and middle ear throughout a 10-year period, 1962-1972, are presented. 38 ears were operated upon, of which 26 obtained an average hearing gain of 25 dB. In 12 ears no improvement was obtained, and no ear became worse. Among the 15 patients with bilateral deformities 11 obtained a postoperative hearing in one or both ears of 40 dB or better, in average 30 dB.


[The natural progress of atherosclerosis of the lateral vessels of the tongue (author's transl)].

The writer discusses the progress of atherosclerosis of the lateral vessels of the tongue and also demonstrates the clinical and diagnostic value of observing these changes. On the lateral undersurface of the tongue, which is uniformly pink in young persons on account of the delicate and rich vascular network, blue and pointed nodules start to appear in the fourth decade. These nodules are pathological and represent venous dilatations and thromboses. In advancing age more and more vessels obstruct, and the reduction of perfusion causes in all individuals a paleness and advancing atrophy. Examination of this region discloses the state of the vascular system. The number, location and severity of the thromboses has an important relevance in the assessment of vitality and biological aging of the individual.


[Two cases of hepatic complication from halothane anesthesia following pediatric tonsillectomy (author's transl)].

A report of two cases of hepatic complications (one of these with fatal consequence) after pediatric tonsillectomy using halothane anesthesia is given. Although in both cases it could not be proven that the halothane was the cause of the hepatic complication, an exacerbation of occult liver dystfunction by the anesthetic was considered possible.


[Spontaneous remission of objective tinnitus (author's transl)].

The presence of a systolic loud tinnitus over the right mastoid in a 21 year old male was established by auscultation and phonocardiograph recording. Selective angiography of the carotids excluded a vascular abnormality. The tinnitus, which persited for 1 year, disappeared spontaneously over a 4 week period. The cause and the course of this tinnitus are discussed.


[Age-dependent electric response audiometry (ERA)-findings in correlation with speech development (author's transl)].

The occurrence of periods of speech-certainty and speech-uncertainty can be observed in normal as well as in children impaired with hearing, voice and speech defects. This behaviour of voice and speech development has not yet been explained by subjective pure-tone or speech audiometry. 19 normal children were grouped into four age populations according to electroglotto- and phonographic analysis. This collective was then examined by Electric Response Audiometry (ERA) at the frequencies of 0.5 kHz, 1.0 kHz, 2.0 kHz, and 4.0 kHz. Speech-certainty was observed at a mean age of 4.5 years (Group II) and 6.5 years (Group IV), whereas speech-uncertainty was found at a mean age of 2.5 years (Group I) and 5.5 years (Group III). The supraliminal ERA results of contralteral pickup were evaluated in amplitude and in behaviour of latency. Because of the variety of ERA-characteristics, the age-dependent and frequency-specific development of the acoustic system is figured by integration below the characteristics in the supraliminal range. The mathematical result shows two opposite regions as well as the "hearing dynamic" as at the "dynamic of the behaviour of latency": a low-frequency region of 0.5 and 1.0 kHz and a high-frequency region of 2.0 and 4.0 kHz. Evaluation of the electroglottograms following Fourier's analysis shows a typical amplitude spectrum at speech-certainty and at speech-uncertainty.


Surgical management of radial physeal growth disturbance in dogs.

Premature closure of the distal radial physis can result in severe developmental deformities of the involved forelimb. Recognition of the problem early in its course is necessary to minimize valgus deformity and secondary osteoarthritis of the elbow and carpus. By  forcing the radius to elongate, following radial osteotomy and use of a Stader apparatus, these deformities can be minimized.


Blood lead concentrations in three groups of dogs from a suburban Illinois community.

Of 89 clinically normal dogs that were regular patients of a suburban Illinois veterinary hospital, all had blood-lead concentrations (BLC) within the range cited as normal in the literature. In contrast, 22% of 50 dogs from city pound and 15.3% of 98 dogs owned by low-income families of the community had BLC in excess of the normal limits. Additionally, 8% of dogs from the city pound and 4.1% of dogs from low-income families had BLC that are reported to the reliably associated with clinical lead poisoning. Socioeconomic characcteristics of the dog-owning family were more reliably associated with abnormally high BLC than were either history or clinical signs.


Effect of five daily intravenous treatments with oxytetracycline hydrochloride on the carrier status of bovine anaplasmosis.

Intravenous administration of oxytetracycline hydrochloride at the rate of 22 mg/kg daily for 5 days was effective in rendering parasite-free 11 adult cattle that were naturally infected Anaplasma marginale carriers. The treatment did not cause any noticeable distress or side effect. Through 12 posttreatment months, the efficacy of the treatment procedure was evaluated by serologic tests and subinoculation of blood into susceptible splenectomized calves. Results of the rapid card agglutination test were positive for 5 cattle at 2 months after treatment, but negative for all cattle at 4 through 12 months. Complement-fixation titers were variable and transient in posttreatment serologic studies. After subinoculation of blood into splenectomized calves (at 4 and 12 months after chemotherapy), serologic, hematologic, or clinical evidence of infection with A marginale was not seen during a 60-day observation period.


Brucella infections in Illinois veterinarians.

Serums collected from Illinois veterinarians at 6 state conventions between 1956 and 1972 were tested for Brucella antibodies, with 70 of 394 (17.8%) samples reactive. Interviews with 1,261 veterinarians in 1967 and 1968 yielded 175 (13.9%) with a history of a prior clinical illness diagnosed as brucellosis. When duplicates were eliminated, there was a 17.0% (224/1,315) infection ratio. The prevalence of infection was found to be decreasing, as reflected by decreasing serologic reactor rates and by decreasing numbers of clinical diagnoses during the period. Strain 19 brucella vaccine appeared to be increasing in relative importance as a source of infection for veterinarians. Most of the small animal practitioners with a history of clinical brucellosis had been infected either as students or in an earlier practice type. Onset of clinical illness occurred the year of graduation for 21 (13%) veterinarians, with 62% between 4 years before and 4 years after graduation. Part of the explanation for the decreasing infection rates following graduation might have been the existence of a group of veterinarians at high risk of infection because of personal habits. Early infection, because of their high risk, would have resulted in rapid depletion of susceptible individuals from this group. As a result, in a few years the infection rate of the total veterinary population would no longer be dominated by this high risk group but would more nearly reflect the infection probability for the average veterinarian. There was no significant difference in death rates or cause of death between infected and noninfected veterinarians.


Renal failure associated with pericardial effusion in a dog.

Signs of heart failure due to cardiac tamponade developed in a young dog with previously unrecognized renal disease. The uremic syndrome was considered the likely cause of the effusive pericarditis found at necropsy. In a review of necropsy records from 150 dogs with renal disease, 11 had pericardial lesions.


Aorticopulmonary septal defect in a dog.

A 2-year-old Brittany Spaniel ahd clinical signs of pulmonary diseases and pulmonary hypertension, with cardiac murmur and congestive heart failure. Aorticopulmonary septal defect was detected by means of cardiac catheterization. Attempted surgical correciton was unsuccessful.


Some effects of reinforcement schedules in teaching picture names to retarded children.

The effects of several different schedules of primary reinforcement were compared in a picture-naming task with retarded children. In Experiment I, number of correct responses and learning rate were higher under fixed-ratio schedules than under continuous reinforcement. In Experiment II, number of correct responses and learning rate tended to be greater under in intermediate than under low or high fixed-ratio schedules. In Experiment III, number of correct responses was higher under interlocking schedules, in which the response requirement increased with time following the previous reinforcement, than under comparable fixed-ratio schedules. Learning rates were generally low and, perhaps because of this, not very different under the two types of schedules in this experiment. Accuracy (i.e., proportion of trials on which correct responses occurred) was typically high and insensitive to variations in schedule and schedule parameter throughout each experiment.


Electrical activity of phrenic nerve and diaphragm in utero.

Phrenic nerve activity, diaphragmatic EMG, and tracheal or pleural pressure changes were recorded in a chronic fetal sheep preparation. Three patterns of fetal phrenic nerve activity were observed: 1) a single burst; 2) irregular nonrhythmic bursts; and 3) prolonged rhythmic activity, seen only prior to fetal death. The total recording time was 54.53 h and the total duration of phrenic nerve activity was 65.34 min (2.16%). When an inactive period was defined as the absence of phrenic nerve activity for 60 s or more, active periods occupied 44.7% of the total time. Phrenic nerve activity was present in all fetuses and 97.5% of the time was coupled with diaphragmatic EMG. Both diaphragmatic EMG and intrapulmonary pressure changes occurred in the absence of phrenic nerve activity. In three fetal animals both phrenic nerves were transected. Tracheal pressure changes were seen which were not coupled with corresponding intrauterine pressure changes. Thus, changes in fetal tracheal pressure or diaphragmatic EMG do not necessarily represent the output of the fetal respiratory center. This study suggests that the fetal respiratory center is active in utero, but this activity is minimal and has a different pattern that that present after birth.


Evaluation of a reservoir in the main excretory duct of rat submaxillary gland.

Cannulation of salivary gland main excretory duct at its oral opening is routinely used for collecting fluid, in situ, from the luminally perfused duct, or saliva from the stimulated gland. For perfusion of the main excretory duct, in situ, or for saliva collection, rat submaxillary gland is often the organ of choice, since electrolyte transport occurs at high rates both in the whole gland and in the main excretory duct. Recently, it has been reported that there is a pouchlike dilatation of the main excretory duct at its oral end, and that this dilatation may serve as a fluid reservoir. Because of possible effects of such a reservoir on measurements of electrolyte transport by the whole gland or the main duct segment, the size and form of the reservoir have now been examined. For this, techniques of histology, radiography, and microcatherization were employed. It was found that, while the functional volume of the reservoir exceeds that of the main duct proper, the time needed for displacement of reservoir fluid by perfusate or saliva would probably be only on the order of 1-3 min at higher rates of saliva or perfusate flow. Therefore, if adequate allowance is made for equilibration time, collection of saliva or luminal perfusate by oral cannula seems justified.


Frequency response of the chest: modeling and parameter estimation.

The frequency response of the respiratory system was studied in the range from 3 to 70 Hz in 15 normal subjects by applying sinusoidal pressure variations around the chest and measuring gas flow at the mouth. The observed input-output relationships were systematically compared to those predicted on the basis of linear differential equations of increasing order. From 3 to 20 Hz the behavior of the system was best described by a 3rd-order equation, and from 3 to 50 Hz by a 4th-order one. A mechanistic model of the 4th order, featuring tissue compliance (Ct), resistance (Rt) and inertance (It), alveolar gas compressibility (Cg) and airway resistance (Raw), and inertance (Iaw) was developed. Using that model, the following mean values were found: Ct = 2.08-10(-2)1-hPa-1 (1 hPa congruent to 1 cm of water); Rt = 1.10-hPa-1(-1)-s; It = 0.21-10(-2)hPa-1(-1)-s2; Raw = 1.35-hPa-1(-1)-s; Iaw = 2.55-10(-2)hPa-1(-1)-s2. Additional experiments devised to validate the model were reasonably successful, suggesting that the physical meaning attributed to the coefficients was correct. The validity of the assumptions and the physiological meaning of the coefficients are discussed.


Effect of elastic loading on ventilatory response to hypoxia in conscious man.

Ventilatory responses to isocapnic hypoxia, with and without an inspiratory elastic load (12.1 cmH2O/l), were measured in seven healthy subjects using a rebreathing technique. During each experiment, the end-tidal PCO2 was held constant using a variable-speed pump to draw gas from the rebreathing bag through a CO2 absorbing bypass. Studies with and without the load were performed in a formally randomized order for each subject. Linear regressions for rise in ventilation against fall in SaO2 were calculated. The range of unloaded responses was 0.74-1.38 1/min per 1% fall in SaO2 and loaded responses 0.71-1.56 1/min per 1% fall in SaO2. Elastic loading did not significantly alter the ventilatory response to progressive hypoxia (P greater than 0.2). In all subjects there was, however, a change in breathing pattern during loading, whereby increments in ventilation were attained by smaller tidal volumes and higher frequencies than in the control experiments. These results support the hypothesis previously proposed in our studies of resistive loading during progressive hypoxia, that a similar control pathway appears to be involved in response to the application of loads to breathing, whether ventilation is stimulated by hypoxia or hypercapnia.


Modification of respiratory center output in the unanesthetized fetal sheep "in utero".

Diaphragmatic electromyographic activity, tracheal and amniotic fluid pressures, lung liquid flow, and carotid and jugular venous pressures were measured on eight fetal lambs who survived for periods of 9-43 days postoperatively. The fetal gestational age ranged from 98 to 113 days at operation. Respiratory center output of the fetus as indicated by electromyographic activity was modified by the following stimuli. It was suppressed by anesthesia and fetal hypoxia (Pao2 = 12 mmHg), tonically reduced by lung inflation, and stimulated by cyanide injections (150-600 mug) into the fetal jugular vein. Neuromuscular transmission to the diaphragm was blocked with d-tubocurarine (0.2-0.6 mg). These experiments indicate that central and motor pathways to the diaphragm are sufficiently mature by 101 days in the fetal sheep to permit their output to be modified by chemical and mechanical stimuli.


Body composition and Vo2max of exceptional weight-trained athletes.

The maximal oxygen uptake and body composition of 30 exceptional athletes who have trained extensively with weights was measured. The sample included 3 world record holders, 8 other world class athletes, and 19 national class competitors. The sports represented were shot-putting, discus throwing, body building, power lifting, wrestling, and olympic lifting. Vo2max as determined on a bicycle ergometer by the open-circuit method was 4.6 +/- 0.7 1-min-1 (mean +/- SD) (48.8 +/- 7 ml-kg-1., 56.4 +/- 8.6 ml-(kg LBW)-1). The mean maximal heart rate was 185.3 +/- 11.6 beats-min-1. The subjects attained a work rate of 1,728.2 +/- 223 kpm-min-1 on a continuous progressive bicycle ergometer test and had mean maximal ventilations of 152.5 +/- 27.7 1-min-1 BTPS. Body composition was determined by densitometry. Body weight averaged 96.0 +/- 14.9 kg, with mean percent fat of 13.8 +/- 4.5. The results of this study indicate that exceptional weight-trained athletes are within the normal college-age population range in body fat and of somewhat higher physical working capacity.


Some factors affecting tissue Po2 in the carotid body.

In the carotid body (CB) of the anesthetized cat tissue Po2 (Pto2) measured with a micro O2 electrode averaged about 65 mmHg at normal arterial pressure (mean = 96 mmHg). Pto2 correlated significantly with the hematocrit of the arterial blood but not with % saturation. When arterial pressure was reduced (mean = 58 mmHg) by bleeding Pto2 fell significantly. Phentolamine injection (1 mg/kg iv) at the reduced pressure caused Pto2 to rise significantly. At normal arterial pressure blowing moistened O2 over the CB did not affect Pto2 if the electrode tip was about 90 mum into the CB. At a reduced pressure (and blood flow) the sensitive depth increased to about 301 mum, and to about 600 mum when flow was stopped. We concluded that a) the increased chemoceptor discharge usually seen with hemorrhage is due to reduced Pto2; b) the reduction in Pto2 is probably due to reduced blood flow which is, in turn, caused partly, at least, by sympathetic nervous system activity; c) O2 content, rather than Po2, may determine chemoreceptor discharge rate; and d) there are no barriers in the CB which are impermeable to O2.


Relationship between respiratory nerve and muscle activity and muscle force output.

To demonstrate the most satisfactory way of using electrical activities of respiratory nerves and muscles, activities of phrenic nerve and external intercostal muscle (ICM) and the airway pressure changes generated by respiratory muscle contraction were recorded in anesthetized cats during complete airway occlusion. Electrical activities were rectified, integrated and processed in terms of peak and average inspiratory rates per 0.1 s and of total activity per breath. Peak rate of phrenic nerve activity exhibited a high linear correlation (r = 0.974) with peak inspiratory pressure. Average phrenic rate showed a similar high correlation (r = 0.973). Peak rate of external ICM was linearly related to peak pressure but the correlation was less good (r = 0.915). Total phrenic activity per breath was too dependent upon inspiratory duration to be a satisfactory correlate (r = 0.674). In this experiment occlusion pressure was an index of muscle force generation and respiratory control system output. It is concluded that peak or average rates of phrenic activity provide an electrical index of output changes. On theoretical grounds, peak rate is probably better.


Salicylate hypothermia in rats exposed to hyperbaric air and helium.

Rectal temperatures of salicylate-treated and untreated rats were observed in 21-23 degrees C air at 1, 3, 6, and 8 ATA, in 21-23 degrees C helium at 1 and 6 ATA, and in 1 ATA thermal neutral air (28 degrees C). Significant dose-related temperature decreases occurred in 21-23 degrees C 1 ATA air with 180 and 300 mg/kg of salicylate; 60 mg/kg had no effect. However, in thermal neutral air, 300 mg/kg significantly elevated temperatures. Hyperbaric air and helium had temperature-lowering effects which were correlated with thermal properties of these environments, and in them the hypothermic effects of salicylate were similar to those in 1 ATA air, the total temperature decreases being the sum of the salicylate hypothermia and that caused by the hyperbaric air or helium. These additive temperature effects are unlike previously reported results in which the temperature lowering effects of 5 degrees C cold exposure and salicylate together were greater than the sum of the two individual effects.


Orthostatism and heat acclimation.

Three groups of subjects (6 subj in each group) underwent the following precedures: group A was given a 20-min head-up tilt at 21 degrees C followed by 4 h of exercise at 33.9 degrees C DB, 32.2 degrees C WB, and a repetition of tilting after exercise in heat; group B underwent the same procedure at 21 degrees C; group C was tilted at 21 degrees C, rested in heat for 4 h and was retilted in heat. The above procedures were repeated for 8 days, and on the last day groups B and C underwent the same treatment as group A. Group A showed the usual decreases in heart rate and rectal temperature and an increase in sweat rate on acclimation. This corresponded to marked improvements in heat-orthostatism. While five subjects in group A fainted during post-exposure tilting on the first exposure, none fainted on the last day. Resting in heat (group C) did not cause any acclimation to work in heat. This corresponded to poor heat-orthostatism after the work-heat procedure when five subjects fainted. Mild training at 21 degrees C (group B) resulted in minor improvements to work in heat as evident by some improvements in heart rate responses after the 1st and 2nd h of exposure. This corresponded to better heat-orthostatism and fewer men fainting than in group C. The results indicated that heat-orthostatism improves on acclimation to the same extent as exercise heart rate and rectal temperature.


Residual levels and biochemical changes after ventilation with perfluorinated liquid.

Twenty-three beagle dogs were ventilated with perfluorinated liquid, perfluoro-1-isopropoxy-hexane (Caroxin-F) for 1 h and were reconverted to gaseous breathing. Hematologic and biochemical changes were studied in five dogs for 1 yr and the remaining animals were followed for evidence of retained Caroxin-F for up to 3 yr. We found that the dogs could be ventilated with liquid Caroxin-F and returned to spontaneous breathing of gaseous oxygen with normal blood gas exchange within 24-72 h. Serum alkaline phosphatase, serum cholesterol, and white blood cell count increased with liquid ventilation but returned to normal in less than 1 wk. Trace amounts of Caroxin-F were detected by chromatography in all tissues studied for the entire 3-yr period. The highest levels of Caroxin-F were found in the lungs and associated lymph nodes. No histologic evidence of the presence of Caroxin-F was seen except for local accumulations of vacuolated macrophages in the lungs and associated lymph nodes. We conclude that Caroxin-F can be breathed without residual deleterious effects, even though trace amounts remained for at least 3 yr.


Relative contributions of rib cage and abdomen to breathing in normal subjects.

By use of the method of Konno and Mead and the respiratory magnetometer, the partition of respired gas volumes into rib cage and diaphragm-abdomen components was accomplished in 81 normal subjects including 32 young and middle-aged men, 29 young and middle-aged women, and 20 elderly men. Studied were isovolume maneuvers and the relaxation configuration over the inspiratory capacity range, quiet tidal breathing, increased amplitudes of slow breathing, rapid inspirations and expirations, and both quiet and forceful phonation. No major differences were noted between men and women or between the young and the elderly during any respiratory acts. During quiet breathing most normal subjects are abdominal breathers when supine and thoracic breathers when upright. Rapid respiratory maneuvers were accomplished mostly through rib cage displacement suggesting that rib cage muscles are capable of more rapid action than diaphragm and abdominal muscles. Data from deep breathing and rapid maneuvers supported the view that abdominal and rib cage muscles often act to optimize the mechanical (length-tension) advantage of the diaphragm.


Using body size to understand the structural design of animals: quadrupedal locomotion.

Many parameters of gait and performance, including stride frequency, stride length, maximum speed, and rate of O2 uptake are experimentally found to be power-law functions of body weight in running quadrupeds. All of these parameters are reasonably easy to measure except maximum speed, where the question arises whether one means top sprinting speed or top speed for sustained running. Moreover, differences in training and motivation make comparisons of top speed difficult. The problem is circumvented by comparing animals running at the transition between trotting and galloping, a physiologically similar speed. Theoretical models are proposed which preserve either geometric similarity, elastic similarity, or static stress similarity between animals of large and small body weights. The model postulating elastic similarity provides the best correlation with published data on body and bone proportions, body surface area, resting metabolic rate, and basal heart and lung frequencies. It also makes the most successful prediction of stride frequency, stride length, limb excursion angles, and the metabolic power required for running at the trot-gallop transition in quadrupeds ranging in size from mice to horses.


Man's physiologic response to long-term work during thermal and pollutant stress.

Metabolic, temperature, and cardiorespiratory responses of 19 healthy males, age range 18-30 yr for one group and 40-55 yr for another, were studied during 210 minutes submaximal work at 35% Vo2 max. The subjects were exposed to four different pollutant gas mixtures at two different temperatures, 25 degrees C and 35 degrees C (relative humidity 30%). The four gas mixtures were filtered air (FA), 50 ppm carbon monoxide in filtered air (CO), 0.24 ppm peroxyacetyl nitrate in filtered air (PAN), and a combination of all three mixtures (PANCO). In the CO exposure, the heart rate was significantly greater than that observed during FA conditions (P less than 0.05). Metabolic and thermoregulatory responses to long-term work were not different in the various pollutant environments. Significant decreases in stroke volume and increases in heart rate were observed during the course of the 25 degrees C exposures with no alteration in cardiac output. Heart rates were higher during 35 degrees C exposures while cardiac output remained at the same level with a consequent further reduction in stroke output.


Predicting the carboxyhemoglobin levels resulting from carbon monoxide exposures.

Data from a series of human exposures to carbon monoxide (CO) were analyzed to determine the fit to the theoretical Coburn-Forster-Kane (CFK) equation which describes CO absorption and excretion. The equation was found to predict carboxyhemoglobin (HbCO) saturations for both men and women at exercise rates ranging from sedentary to 300 kpm/min when they were exposed to steady CO concentrations of 50, 100, and 200 ppm for 0.33-5.25 h. Methods for determining values of each of the variables in the CFK equation were collected and a rational, efficient procedure for solving the equation by trial and error was outlined. The CFK equation was then used to prepare a graph, relating HbCO saturation to exposure duration and concentration, and also to describe the effect of several variables on the rate of CO uptake and equilibrium HbCO levels, important considerations in the determination of permissible public, occupational, and experimental exposure to CO.


Insulative power of body fat on deep muscle temperatures and isometric endurance.

Four male subjects were examined to assess the relationship of body fat content to deep muscle temperature and the endurance of a fatiguing isometric handgrip contraction at a tension set at 40% MVC. Muscle temperature was altered by the immersion of the forearm in water at temperatures varying from 7.5 to 40 degrees C. In all subjects, there was a water bath temperature above and below which isometric endurance decreased markedly; the difference among individuals was solely accounted for by the individual's body fat content. Thus, subjects with higher body fat content required lower bath temperatures to cool the forearm musculature to its optimum temperature, which we found to always be approximately 27 degrees C measured 2 cm perpendicularly to the skin in the belly of the brachioradialis muscle. Further, in one subject, we found that a reduction in this subject's body fat content resulted in a corresponding increase in the water bath temperature necessary to cool his muscles to their optimum isometric performance. The data demonstrate the striking insulative power of the thin layer of fat around the forearm in man in protecting shell tissues from cold exposure.


Untrained females: effects of submaximal exercise and heat on body fluids.

Five untrained females having no history of heat exposure worked in a cool (16-20 degrees C db, 28% rh) environment on day 1 and a warm environment on day 2 (45 degrees C db, 28% rh). Exercise level (bicycle ergometer) was 30% of individual Vo2 max values and work time on both days was 45 min. Venous blood samples were obtained at rest, after 40 min of exercise and 25 min after exercise ceased. Analysis of blood samples indicated an 8.3% increase in Hct during exercise on day 1 and a plasma volume reduction of 12.8% though total circulating protein increased 11.5%. Except for K+ all parameters approximated control values within 25 min postexercise. On day 2, exercise in heat caused a 12% increase in Hct and a plasma volume reduction of 17.7%. Mean total protein did not significantly change from resting values. These data indicated that for a given % Vo2 max, untrained females suffer considerably greater reductions in plasma volumes than do exercised males. Similar to males, dilatation of the cutaneous vascular bed in unacclimatized females resulted in loss of protein from the vascular volume.


Effect of altitude exposure on platelets.

Since decompression from depth is known to produce a fall in platelet count, the effect of altitude decompression and high-altitude exposure on platelets was investigated. Sixteen subjects decompressed without hypoxia to 20,000 ft simulated altitude for two hours showed a significant (P less than 0.01) drop in circulating platelet count of approximately 10% for three days following decompression. Four of five subjects similarly exposed had a shortened autologous platelet survival compared to that prior to exposure. Subjects exposed to 9,800 ft and then 17,600 ft in a mountain environment showed a significant mean decrease in platelet count on day 2 of 7% and 25% respectively, which had returned to control by day 5. Nonhypoxic and hypoxic decompressed rabbits which received homologous chromium-51-labeled platelets had an increase in lung radioactivity compared with sea-level controls. It is postulated that altitude decompression produces platelet reductions similar to these seen after decompression from depth, and that platelets sequester in the pulmonary vascular bed.


D2 18O (deuterium oxide) method for CO2 output in small mammals and economic feasibility in man.

A test of the validity of the isotopic steady state relationships of the doubly labeled water (H2O) method has been carried out with D2 18O in small mammals (three chipmunks and one mouse). CO2 outputs calculated just from 1) the rate of water intake and 2) the ratios of the isotopic concentrations in the body water to the intake water agreed satisfactorily with observed values. Moreover, reconstructed energy and material balances agreed reasonably with similar balances reconstructed for an immediately succeeding period on the same animals studied by the previously validated decay procedure. We conclude from an error analysis that by expressing the isotopic specific activities as abundances in excess of the body water of a subject on a given regimen, the decay procedure is economically feasible in the human with available accuracy of isotopic analyses and the present cost of H2 18O. The method therefore appears to be a useful tool ready for application to the field of human energy metabolism.


Dynamic stiffness profiles in the left ventricle.

Diastolic pressure-volume (P-V) curves were calculated on a beat-to-beat basis in the open-chest, pentobarbital-anesthetized dog, using the technique of direct transmitral flow measurement previously described. P-V curves were constructed and the slope (dP/dV) was plotted vs. pressure and time. dP/dV was used as an index of stiffness in each heart and its instantaneous changes with time were followed throughout the diastolic period. The end-diastolic P-V relation based on points from successive cycles during volume loading was found to be exponential. In contrast, the instantaneous P-V relation during any one diastolic period was not exponential. That is, the dynamic dP/dV vs. pressure plot was nonlinear. In the normal heart, stiffness was characterized in early diastole by a negative dP/dV as the ventricle continued to relax, and then frequently decreased prior to a second stiffness rise with atrial augmentation. These findings can be explained by a model containing an element whose deformation is rate dependent, i.e., a parallel viscous element. Stiffness profiles in mitral stenosis where dynamic effects are minimized substantiate this conclusion.


DC temperature-regulating device for anesthetized experimental animals.

A temperature-regulating device for anesthetized experimental animals is presented. The rectal temperature of the animal is measured with a thermistor and this variable controls via nonlinear amplification the power fed to the heating pad on which the animal is placed. Rectal temperature variations of not more than +/- 0.1 degrees C are reached after 30 min of operation.


Surgical techniques for long-term studies of thoracic duct circulation in the rat.

Two techniques for cannulation of the thoracic duct in the rat, thoracic duct shunt and thoracic duct side fistula, are described. They give access, for repetitive sampling, to a normal thoracic duct circulation and are suited for study of the circulation under physiologic conditions. The thoracic duct shunt creates, with tubing, a shunt between the caudad and cephalad ends to the cisterna chyli. The exteriorized midportion of the shunt allows observation of the lymph. In the thoracic duct side fistula, the short arm of a T tube is placed within the cisterna and sampling is done via the long arm of the tube. Ten shunts functioned for 8-26 days and 10 side fistulas functioned for 8-30 days. Average lymph flow was 0.044 ml/min (shunts) and 0.042 ml/min (side fistulas). Average thoracic duct lymphocyte output was 1,729,000 cells/min (shunts) and 2,310,000 cells/min (side fistulas). Average blood lymphocyte count was 11,700 cells/mm3 (shunts) and 12,600 cells/mm3 (side fistulas). All parameters remained stable during the period of study. Advantages of those techniques over the Bollman end fistula are presented.


Quantitation of pharyngeal motor function in normal human subjects.

A need exists for accurate pressure recording of pharyngeal motor events. Results of this study indicate that accurate quantitation of pharyngeal motor activity is not possible using a water-filled catheter system, even when high infusion rates are used. An intraluminal strain gauge system, however, achieves high-fidelity recording. Quantitation of pharyngeal peristalsis using the intraluminal strain gauge system reveals peristaltic pressure amplitudes higher than those hitherto recorded. In normal subjects, peristaltic amplitude averages about 200 mmHg in the hypopharynx, complexes in one subject being as high as 600 mmHg. A zone of relatively low pressure exists in the oropharynx. Mean pharyngeal wave duration decreases progressively in an aboral direction, from 1.0 to 0.3 s, and peristaltic wave speeds range between 9 and 25 cm/s. Accurate quantitation of pharyngeal peristaltic variables provides the necessary basis for characterization and assessment of pharyngeal motor disorders.


Pyrolysis-gas chromatographic analysis of black paints.

Samples of 79 black paints from 27 manufacturers in the United States were examined to determine the extent to which paints can be distinguished by pyrolysis-gas chromatography. Evaluation by a Carbowax column showed some differences among paints from different manufacturers and among batches of paints from the same manufacturer. However, it was not possible to conclude that paints with identical chromatograms had a common origin.


Direct plating method for enumeration of Staphylococcus aureus: collaborative study.

Considerable evidence has been published regarding the adverse effect of sodium chloride on physiologically impaired cells of Staphylococcus aureus, such as are to be expected in processed foods. A direct plating method for enumeration of S. aureus eliminating the use of sodium chloride was devised and subjected to collaborative study by 16 analysts. Results obtained by the direct plating method were compared to those obtained by the AOAC official first action method (46.036--46.040). Participating analysts examined duplicate samples at population levels of 91, 34, and 20 S. aureus/g. Coefficients of variation among analysts were considerably lower for the direct plating method (31, 81, and 48%, respectively) than for method 46.040 (59, 156, and 150%, respectively) at all 3 population levels. High coefficients of variation for the direct plating method at 2 of the 3 levels were due principally to low populations of S. aureus. The direct plating method has been adopted as official first action for general purpose use and use of method 46.036--46.040 has been restricted to raw food ingredients and nonprocessed foods.


Thermal susceptibility of Salmonella in the Moroccan food snail, Helix aspersa.

Thirty samples of 10-15 Helix aspersa food snails were examined for Salmonella by a surface rinsing method and by analysis of whole snails rinsed with 70% ethanol. Thirteen samples were positive by the rinsing method and 6 were positive by whole snail analysis, with this difference being significant (P less than 0.01). Although Salmonella contamination in H. aspersa appeared to be predominantly surface, the pathogen was also found within the snail meat. The ability of surface and subsurface Salmonella organisms to survive in cooked snails was determined in 90 samples. Thermocouple readings indicated that an internal temperature of at least 200 degrees F (93 degrees C) was reached within the snail meat during cooking by a typical recipe. This temperature was sufficient to kill both surface and subsurface Salmonella in 29 samples positive for the pathogen prior to heating. A variety of serotypes representing several somatic groups was isolated.


Spectrophotometric assay of salsolidine hydrochloride.

The proposed method is based on the reaction of salsolidine HCl with carbon disulfide and ammoniacal copper sulfate. The resulting salsolidine-copper-dithiocarbamate complex is extracted with benzene and measured spectrophotometrically at 448 nm. The method is applicable for the detection of 40-500 mug salsolidine/5 ml.


Colorimetric and volumetric assays of colchicine in galenicals and in pharmaceutical preparations.

In the method described the amide group in the colchicine molecule is reduced with lithium aluminum hydride to the corresponding secondary amine. The latter is extracted with chloroform and then determined either colorimetrically by the copper dithiocarbamate reaction or volumetrically by dissolving in acid and titrating with sodium hydroxide or perchloric acid. The results were comparable with those obtained by the Egyptian Pharmacopoeia spectrophotometric method.


Determination of amphetamine by Schiff base formation and quantitative gas-liquid chromatography.

A procedure was developed to determine amphetamine salts in solid dosage forms. Amphetamine was extracted from the solid matrix with dilute hydrochloric acid and reacted with cyclohexanone in a strongly basic aqueous methanolic solution. The Schiff base reaction product was extracted with hexane for gas chromatographic determination. Reaction time and optimum conditions were studied. Phenethylamine, similarly treated, was used as an internal standard. Results compared favorably with those obtained by using USP methods.


Detection of twelve mycotoxins in mixed animal feedstuffs, using a novel membrane cleanup procedure.

A multimycotoxin thin layer chromatographic screening method is described which is applicable to most animal feedstuffs. Interference from nonspecific lipid, pigment, and other components of simple and mixed feeds is reduced to a minimum by using a membrane cleanup step. Aflatoxins B1, B2, G1, and G2, citrinin, diacetoxyscirpenol, ochratoxin A, patulin, penitrem A, sterigmatocystin, T-2 toxin, and zearalenone may be reliably detected. The sensitivity of the method is generally low for mixed feeds but even so aflatoxin B1 can be detected at a level of 3 ppb and ochratoxin A at 80 ppb. While the basic method is less sensitive for sterigmatocystin (330 ppb), patulin (600 ppb), zearalenone (1000 ppb), and the trichothecenes (1000-4000 ppb), it may be adapted so as to reduce the above detection limits when the presence of these toxins is suspected. Lower levels may be detected in extracts of simple feeds.


Confirmation of polybrominated biphenyl residues in feeds and dairy products, using an ultraviolet irradiation-gas-liquid chromatographic technique.

An ultraviolet (UV) irradiation-gas-liquid chromatographic (GLC) detection procedure was used to confirm the presence of polybrominated biphenyl (PBB) residues in sample extracts after GLC quantitation. Chromatograms of PBB standard and sample extract solutions showed similar photodecomposition peak patterns dependent on time and intensity of UV irradiation. Confirmation of PBBs in sample extracts by this procedure was possible for any amount detectable by the GLC system employed. Prolonged UV irradiation resulted in complete disappearance of all PBB peaks from the chromatogram, permitting their distinction from background peaks due to extraneous sample material unaffected by UV irradiation.


Determination of polybrominated biphenyl residues in dry animal feeds.

A new procedure is described for the determination of polybrominated biphenyls (PBBs) in dry animal feeds and developmental results are discussed. Finely ground feed is packed into a chromatographic column containing Celite and then eluted with methylene chloride. The concentrated extract is cleaned up by elution with petroleum ether through Florisil before gas-liquid chromatographic quantitation. Chromatograms thus obtained were essentially free of the interfering peaks encountered when using AOAC methods for pesticide residues in dry products. Results of feed analyses by the proposed procedure averaged 30% higher than those obtained by AOAC procedures. Recoveries of PBBs from samples fortified at levels of 0.04 to 0.4 ppm ranged from 90 to 104%, with an average of 98%.


Gas-liquid chromatographic determination of vinyl chloride in vinyl chloride polymers, food-simulating solvents, and other samples.

The determination of vinyl chloride (VC) in polyvinyl chloride (PVC), vegetable oils, food-simulating solvents, mouthwashes, and blood anticoagulant solutions by gas-liquid chromatography is described. PVC polymers are disolved in either tetrahydrofuran or dimethyl acetamide. Vegetable oils are diluted with an equal volume of tetrahydrofuran. The resulting solutions are injected into a gas-liquid chromatograph equipped with a flame ionization detector. Mouthwashes, blood anticoagulant solutions, and 3 food-simulating solvents, 3% acetic acid, 50% ethanol, and heptane, are analyzed by direct injection into a chromatograph. Sensitivities are such that 0.05 ppm VC in solution or 1 ppm VC in PVC can be quantitated.


A screening method for determining nitrofuran drug residues in animal tissues.

A method was developed for measuring low levels of total nitrofurans in animal tissues and milk. The antimicrobial nitrofurans (5 or more products) used in agriculture are extracted from tissue with aqueous acid in the presence of ethyl acetate. After centrifugation and evaporation, the organic residue is washed with hexane and the nitrofurans are hydrolyzed to 5-nitrofuraldehyde in aqueous acid at 70 degrees C. The hydrolysis product is extracted with benzene and measured by gas-liquid chromatography with electron capture detection. Recoveries  of nitrofurazone and furazolidone from fortified poultry and swine tissues at the levels of 0.5 and 0.1 ppm are 75 and 65%, respectively. This procedure can be used to detect the total nitrofuran content of as little as 10 ppb muscle tissues and milk, 100 ppb liver, and 50 ppb fat with no interference from related veterinary nitrodrugs.


A rapid method for the determination of manganese ethylenebisdithiocarbamate and its residues on grains.

A method has been developed, based on the periodate oxidation of the manganese in the coordination product of zinc ion and manganese ethylene bisdithiocarbamate to permanganic acid, to determine DithaneM-45. The relationship between the intensity of color and the concentration of manganese obeys Beer's law up to 100 mug at 540 nm. The method can be easily applied to the determination of the active ingredient in formulations and also for residue analysis. The method is sensitive to 0.6 mug and can be used to determine 6 mug fungicide at the 20 g sample level.


Collaborative study of a spectrophotometric method for determining maleic hydrazide residues in tobacco and vegetables.

A distillation-spectrophotometric method for the determination of maleic hydrazide residues in tobacco and vegetables reported previously was studied collaboratively. Ten laboratories submitted analytical results on 10 samples containing residues resulting either from field treatment or laboratory fortification. The samples were estimated to contain from 0.99 to 16.36 mug maleic hydrazide/0.5 g sample analyzed. The coefficients of variation based on precision standard deviation ranged from 57.7% for the lowest residue content to 32.4% for the highest. The corresponding coefficients of variation based on overall standard deviations were estimated to be at least one-fifth larger. Strong evidence of systematic laboratory differences was found (F-test, significant at 0.1%). Apparent recoveries of 10.0 mug maleic hydrazide added to 0.5 g fluecured tobacco and potato were 97.3 and 89.7%, respectively. Apparent recoveries of 16.0 and 16.5 mug added to 0.5 g green bean were 87.4 and 85.5%, respectively. The precision of the method studied was no better than that of the current official final action method, 29.121--29.127, and its adoption is not recommended.


Comparative study of methods for the extraction of eleven organophosphorus pesticide residues in rice.

Several extraction methods are compared for the simultaneous analysis of organophosphorus pesticides in unpolished rice. Four stationary phases were used for the subsequent gas-liquid chromatographic (GLC) determination of the selected pesticides. Using 3 different GLC columns, 11 pesticides were completely separated and identified. The efficiency of the cleanup and the sensitivity of the analytical method were evaluated by using powdered unpolished rice samples fortified with the pesticides and also wheat and dried bean samples. Average recoveries ranged from 74.7% for disulfoton to 97.4% for malathion in unpolished rice and from 68.1% for disulfoton to 108.3% for malathion in other crops. The method described is applicable to the analysis of selected organophosphorus pesticide residues in unpolished rice, wheat, buckwheat, and dried beans.


Asthma predictors in infantile atopic dermatitis.

In a search for predictive factors in early childhood for later developing childhood asthma, sixty chidren who suffered in the first year of life from atopic dermatitis were examined at ages between 6-11 years. There were 40 boys and 20 girls, of whom 21 were asthmatic boys and 10 asthmatic girls. The non-asthma group was similar to the asthma group in age, sex and socio-economic background and familial-hereditary background. The psychosocial aspects of the study were not reported in this paper. The atopic dermatitis followed a different pattern in the asthmatic group than in the non-asthma group. A continuation of the atopic eczematous condition in infancy beyond two years appeared to be highly predictive for future childhood asthma. Severity of the eczema in infancy does not seem to be a strong predictor in boys and not at all in the small group of girls. Persistent eczema appeared twice as much in the asthmatic boys as in the asthmatic girls. There was no distinct difference between the asthmatic children and the non-asthmatic children in time of onset of the infantile eczema nor in the location of the atopic dermatitis.


Effect of growth conditions on the activation and inactivation of citrate lyase of Rhodopseudomonas gelatinosa.

Cells of Rhodopseudomonas gelatinosa growing with citrate anaerobically in the light contained citrate lyase only in the acetylated, enzymatically active form of this enzyme. After exhaustion of citrate in the culture medium citrate lyase was deacetylated to yield the inactive sulfhydryl (HS) enzyme. Acetylation of HS-citrate lyase required light, anaerobic conditions and the availability of citrate as substrate. The acetylation reaction already in progress stopped immediately when the culture was placed in the dark. Deacetylation of citrate lyase occurred anaerobically in the light when citrate was exhausted and under aerobic conditions in the presence or absence of citrate. In cells of R. gelatinosa fermenting citrate in the dark neither the acetylating enzyme nor the deacetylating enzyme was active.