Effect of anemia on oxygen transport in hemorrhagic shock. Effect of anemia on tolerance of hemorrhagic shock in rats was studied to examine opposing effects of altered oxygen capacity and viscosity on oxygen delivery at reduced blood flow. Hematocrit was first reduced by exchange transfusion. Hypotension (BP = 30 Torr) was induced and maintained at this level by controlled hemorrhage; it was terminated when reinfusion of shed blood became necessary to sustain this blood pressure. The period of compensation (time at 30 Torr until reinfusion) in control rats (Hct = 42.5 +/- 2.7%) was 59.23 min; in anemic rats (Hct = 23.3 +/- 2.2%) it was 53 +/- 15 min (SD, P = 0.086). Bleeding rate during shock, mortality, VO2, acid-base balance, and mortality were not influenced by anemia, except for slightly higher lactate in late shock in anemia. The lack of influence of anemia (cf. other perturbations of oxygen transport) was apparently due to a 59-88% increase in cardiac ouput during shock in anemia, which maintained VO2.


Effects of common dead space on inert gas exchange in mathematical models of the lung. Theoretical gas exchange is compared in lung models having two different types of dead space. In one, the dead space of a lung unit is "personal" and contains gas equivalent in composition to its own alveolar gas; in the other, the dead space is "common" and contains mixed gas from all gas-exchanging units. Formal algebraic analysis of tracer inert gas exchange in two-compartment models shows that values of compartmental ventilation and perfusion can be found that establish one and only one personal dead-space model equivalent for every common dead-space model. When the total dead space and distribution of blood flow and ventilation in the two models are the same, common dead space will always result in improved inert gas elimination. Under these conditions, the amount of improvement is usually greatest when the partition coefficient of the inert gas is between 0.1 and 1.0 and when there is greatest disparity in the ventilation-perfusion ratios (VA/Q). In the inert gas elimination technique that analyzes all dead space as personal, the presence of common dead space consistently causes the recovered VA/Q distributions to be narrower than the actual distributions, but the resultant error is small.


Method for estimating absolute lung volumes at constant inflation pressure. A method has been devised for measuring functional residual capacity in the intact killed animal or absolute lung volumes in any excised lung preparation without changing the inflation pressure. This is achieved by titrating the absolute pressure of a chamber in which the preparation is compressed until a known volume of air has entered the lungs. This technique was used to estimate the volumes of five intact rabbit lungs and five rigid containers of known dimensions by means of Boyle's law. Results were found to agree to within +/- 1% with values determined by alternative methods. In the discussion the advantage of determining absolute lung volumes at almost any stage in a study of lung mechanics without the determination itself changing inflation pressure and, hence, lung volume is emphasized.


Alterations of mechanical properties and morphology in excised rabbit lungs rinsed with a detergent. To assess the influence of alterations of lung surfactant on the geometry of peripheral air spaces, the morphology of detergent-rinsed rabbit lungs was studied. In comparison to normal excised rabbit lungs, fixed in the same manner by vascular perfusion at different points on the deflation pressure-volume curve, the most important differences are as follows. 1) With decreasing lung volume there is a progressive collapse of alveoli; at low lung volume (40% of total lung capacity (TLC) (most alveoli are collapsed, and the air is contained in overextended ducts. 2) Accordingly, the alveolar surface area-to-volume ratio is considerably smaller in particular at medium and low lung volumes. 3) There is only a slight change of mean air-space curvature between 80 and 40% TLC. Hence, the results indicate that in detergent-rinsed lungs volume changes are brought about predominantly by recruitment and derecruitment of alveoli. It appears that both a normal surfactant and the mechanical interdependence within the fibrous continuum are required to maintain a normal respiratory surface area within the lung volume range of normal breathing.


Influence of exercise hyperthermia on exercise breathing pattern. Passive elevation of the body core temperature (Tc) induces rapid, shallow breathing in resting man. We wondered if exercise-induced Tc elevation would also lead to decreased tidal volume (VT) and increased breathing frequency (f) during exercise. To investigate this question, 10 subjects each performed 47 min of cycle ergometer exercise at 50--60% of the maximal aerobic capacity, with the work rate adjusted to maintain ventilation (VE) constant. This long ride raised mean Tc (rectal) 0.8 degrees C. Before and immediately after the long ride, ranges of VE and VT were obtained from short 6-min rides that progressed from unloaded pedaling to the anaerobic threshold. At the constant VE of the long ride, f rose and VT fell as Tc rose (P less than 0.05). The fall in VT was associated with a fall in inspiratory time (TI); drive (VT/TI) and timing (TI/Ttot)components of VE were unchanged. These effects were consistent over the entire range of VE obtained from the short 6-min rides. Passive heating in warm water to produce equal Tc elevation in the same subjects yielded similar exercise breathing-pattern changes. These findings suggest that increased Tc mediates the VT fall during prolonged exercise, possibly through stimulation of the central respiratory pacemaker.


Time dependence of maximum flow as an index of nonuniform emptying. Nonhomogeneous lungs are predicted to exhibit time dependence of maximal expiratory flow (Vmax): faster regions would contribute more flow early in the expiration, whatever the initial volume, resulting in different Vmax at a given total lung volume, depending on how long flow limitation has been operating. To test this concept a new technique was developed that permits accurate superimposition of Vmax data over small volume intervals. When quick-release interrupted partial curves with similar volume history but different volume of initiation were compared over their late common-volume segments, the volume-history effects could be differentiated from time dependence of the Vmax. Such time dependence was found in 7 of 7 bronchitics, 3 of 5 smokers, and 0 of 14 nonsmokers tested. We conclude that the emptying during the forced expirations is not uniform even in mild disease states and the time dependence of Vmax is a sensitive test of lung inhomogeneity.


Liquid ventilation: cardiovascular adjustments with secondary hyperlactatemia and acidosis. Cardiovascular adjustments during liquid ventilation were investigated in seven cats. Cardiac output (CO) and regional blood flow were measured with radioactive microspheres during both spontaneous air breathing (control) and ventilation with fluorocarbon liquid, FC-80. CO was found to decrease 48% (P less than 0.05) during liquid breathing as compared to control. This decrease largely reflected a reduced stroke volume. Despite the decreased CO, mean arterial pressure remained unchanged, indicating a 48% increase (P less than 0.002) in total peripheral resistance (TPR). Secondary to the reduced CO and increased TPR, extensive redistribution of blood flow occurred during liquid ventilation. The arterial lactate concentration and lactate-to-pyruvate ratio (L/P) were significantly increased (P less than 0.02). Furthermore, the increase in L/P correlated with the decrease in CO (r = 0.70; P less than 0.01). In turn, the significant decrease in pH during liquid breathing was found to correlate with the increase in L/P (r = 0.85; P less than 0.001). These data clearly demonstrate signficant alterations in cardiovascular dynamics during liquid ventilation with secondary hyperlactatemia and acidosis.


Protein metabolism in lung. II. Influence of amino acids and glucose on protein degradation. We used the isolated perfused lung to study protein degradation. Proteins were labeled in vivo during 10 min (fast) or 5 h (slow). The absence of exogenous amino acids lowered the rate of proteolysis of fast but not of slowly turning over proteins. Addition of normal rat plasma levels of amino acids, after 45 min of perfusion without amino acids, returned the rate of proteolysis to control levels. The absence of exogenous glucose increased the rate of degration of rapidly turning over proteins but decreased the degradation rate of slowly turning over proteins. These changes took place in the absence of any measurable effect of amino acids or glucose on the amount of lung water, the rate of perfusate flow, the lung concentration of ATP or the intracellular concentration of free phenylalanine. We conclude that these substrates influence proteolysis in our system and that the degradation of rapidly and slowly turning over proteins are regulated independently in the isolated perfused lung.


Role of cerebellum on ventilatory change due to muscle-receptor stimulation in the dog. The role of the cerebellum in reflex increase of ventilation due to muscle-receptor stimulation was studied in dogs anesthetized with pentobarbital sodium. Stimulilike pressure application or stretch of gastrocnemius muscle produced increase in ventilation. Ablation or cooling of the anterior lobe of cerebellum significantly reduced this ventilatory response to application of the same degree of pressure or stretch of the gastrocnemius muscle. Ablation or cooling of the posterior lobe of the cerebellum did not have any effect on ventilation due to muscle-receptor stimulation. It was concluded that the anterior lobe of the cerebellum is in some way concerned with the ventilatory change produced by muscle-receptor activation.


Role of peripheral tissue receptors in stimulation of ventilation by 2,4-dinitrophenol. Previous workers have demonstrated that hindlimb receptors can mediate some portion of the increase in VE elicited by 2,4-dinitrophenol (DNP). Liang and Hood have recently demonstrated that these hindlimb receptors communicate with the respiratory center via afferent pathways of the lumbar spinal cord. Accordingly, to determine the quantitative contribution of these hindlimb receptors to increases in VE elicited by DNP (4 mg/kg), we compared two groups of animals with respect to ventilatory, metabolic, and thermal responses elicited by this drug. Group I animals underwent complete transection of the spinal cord at the first lumbar level, whereas the spinal cord in Group II animals remained intact. Our results indicate that Group I and Group II animals did not differ with respect to increases in VE, VO2, and rectal temperature elicited by DNP. These results suggest that hindlimb receptors do not play an obligatory role in mediating increases in VE elicited by DNP. Therefore, these observations raise the possibility that multiple afferent pathways may exist for stimulation of VE by DNP.


Arterial-expired PCO2 differences in the dog during acute hypercapnia. A recent report (J. Appl. Physiol. 38: 382-388, 1975) suggests that negative blood-gas CO2 partial pressure (PCO2) differences exist in the dog during hypercapnia, as mean expired PCO2 exceeded arterial PCO2 by more than 10 Torr when the CO2 fraction in inspired gas (FICO2) was 0.1. We have reinvestigated this problem in anesthetized dogs breathing spontaneously room air or hypercapnic mixtures (FICO2 = 0.05 or 0.10). During steady state, arterial blood samples were analyzed with electrodes, care being taken to keep the electrode temperature within +/- 0.2 degrees C at the actual aortic temperature of the animal. Respired gas was measured at the tracheostomy by a sensitive low-noise respiratory mass spectrometer. During room air breathing, the arterial-end-expired PCO2 difference, P(a-E')CO2, averaged +5 Torr and decreased to +0.9 Torr and to +0.1 Torr with FICO2 = 0.05 and 0.1, respectively. Hypoxia (FIO2 = 0.10) had no apparent effect on the P(a-E')CO2 difference. We ascribe the decrease in P(a-E')CO2 with hypercapnia to the diminishing effects of alveolar dead space, whereby end expired PCO2 approached arterial PCO2. We then conclude that in blood-gas equilibration lungs, PCO2 in end-capillary blood comes close to alveolar PCO2, and that the negative blood-gas PCO2 differences reported earlier are probably caused by deficiencies in the techniques used.


Thermogenic control during exercise in a cold environment. To determine whether the voluntary contractions of exercise interfere with involuntary shivering contractions, four male subjects were each exposed to a 10 degrees C environment for 60 min of rest followed by either another rest period or 30 min of cycleergometer exercise. On different days exercise was performed at zero load, light load, and moderate load. Each experiment was performed twice, resulting in a minimum of eight experiments for each subject. Esophageal temperature (Tes), eight skin temperatures (Tsk), oxygen uptake (VO2), and the integrated electrical activity from a neck muscle (EMG) were continuously monitored. Pedaling flushed cold blood into the body core, causing Tes to fall. The rate and absolute magnitude of the decrease in Tes was proportional to the intensity of exercise. Thermoregulatory VO2 (attributable to shivering) and EMG were inversely related both to Tsk during rest, prior to any changes in Tes, and to Tes during exercise, when Tsk was constant, once shivering thresholds were surpassed. The slope of the thermoregulatory VO2-to-Tes relation was significantly suppressed by increasing exercise intensity. The slope of the EMG-to-Tes relation was similarly suppressed; since the neck muscles are not involved in the additional acitivity of exercise, we concluded that the graded inhibition of shivering during exercise was of central origin rather than from the rhythmic contractions required to sustain exercise.


Arterial PCO2 response to intravenous CO2 in awake dogs unencumbered by external breathing apparatus. The steady-state arterial CO2 tension (PaCO2) was examined during control and intravenous CO2 loading in awake dogs unencumbered by any breathing apparatus. The dogs inhaled air while undergoing intravenous CO2 loading, and we estimated the gain, delta VA/delta PACO2. CO2 was introduced into the systemic venous blood via a membrane gas exchanger in a femoral arteriovenous shunt circuit, and the extracorporeal blood flow was maintained constant at 0.5 l/min. A total of 11 experiments were performed in 3 dogs comprising 93 control observations and 83 CO2 loading observations. Intravenous CO2 produced a significant increase in the steady state PaCO2, a finding consistent with our previous study in tracheostomized awake dogs. We conclude that intravenous CO2 produces hypercapnia in the awake dog with an intact airway unencumbered by external respiratory apparatus.


Naloxone enhances respiratory output in cats. To investigate the physiological role of opiate receptors and opiatelike neurotransmitters, which are present in brain-stem respiratory centers, we administered naloxone to 10 cats by intravenous injection. These animals were vagotomized, paralyzed, and servo-ventilated to maintain constant end-tidal CO2; in addition, their carotid sinus nerves were sectioned bilaterally. Respiratory output was assessed by integration of phrenic nerve activity. Control saline infusions had no effect on respiratory output. However, administration of naloxone (0.4 mg/kg) caused phrenic minute output to increase significantly in each of five anesthetized cerebrate cats (control 7,272 +/- 1,615 U/min; 30 min postnaloxone 12,920 +/- 3,857 U/min; P less than 0.05) and five unanesthetized decerebrate cats (control 10,368 +/- 1,222 U/min; naloxone 14,648 +/- 3,225 U/min; P less than 0.05). In addition to the effect on phrenic minute output, naloxone infusion resulted in an increase of the inspiratory rate of rise of phrenic nerve activity in each cat. There was no change in the ratio of inspiratory duration to total respiratory period (TI/Ttot). Because naloxone is a specific opiate antagonist, we suggest that endogenous opiatelike neurotransmitters (endorphins) may modulate central inspiratory drive.


Incorporating the gas analyzer response time in gas exchange computations. A simple method for including the gas analyzer response time in the breath-by-breath computation of gas exchange rates is described. The method uses a difference equation form of a model for the gas analyzer in the computation of oxygen uptake and carbon dioxide production and avoids a numerical differentiation required to correct the gas fraction wave forms. The effect of not accounting for analyzer response time is shown to be a 20% underestimation in gas exchange rate. The present method accurately measures gas exchange rate, is relatively insensitive to measurement errors in the analyzer time constant, and does not significantly increase the computation time.


Topical anesthesia of tracheal receptors. Two types of sensory receptors were individually identified in dogs on the exposed mucosa of the extrathoracic trachea: slowly adapting stretch receptors (SAR) and rapidly adapting receptors (RAR). Increasing concentrations of lidocaine (L), bupivacaine (B), and tetracaine (T) solutions were topically applied on the mucosa over the sensory fields of the receptors, while their neural activity in response to an appropriate stimulus was recorded. Action potentials from SARS were blocked by the anesthetic at a much higher concentration and with larger exposure times than potentials evoked from RARs (mean values: L = 51.1 mM for 7.4 min and 1.48 mM for 1.03 min, respectively; B = 9.4 mM for 9.4 min and 0.13 mM for 0.23 min; and T = 4.9 mM for 9.8 min and 0.06 mM for 2 min). The minimal blocking concentration of the topical anesthetics varied widely (L = 20 times, B = 5, and T = 5) among SARs and less (L = 3.2, B = 2, and T = 4) among RARs. These results could be explained by a different location in the mucosa of the two types of receptors and suggest the feasibility of a differential blockade by topical anesthetics.


Antigen-induced bronchospasm in conscious sheep. In 10 conscious ewes with cutaneous sensitivity to Ascaris suum, measurements of pulmonary resistance (RL), static lung compliance (Cst), functional residual capacity (FRC), and arterial blood gas composition along with arterial plasma histamine concentration (H) were obtained before and after inhalation challenge with A. suum extract. Five animals showed no changes in respiratory mechanics after A. suum challenge; in these H did not change. The remaining five animals responded to A. suum challenge with bronchospasm reflected by the following maximum changes in mean values that were significant 15 and 30 min after beginning of challenge, respectively: RL  248% , FRC 126%, specific pulmonary conductance 33%, and arterial PO2 63% of base line. These parameters returned towards base line by 120 min. No changes occurred in Cst, arterial PCO2, and pH. Five minutes after beginning of A. suum challenge, mean H was increased to 423% of base line with a return to base line 10 min later. In the same 5 animals, no changes were observed in pulmonary function or H after inhalation of ragweed extract (control). These results suggest that antigen-induced bronchospasm in sensitized conscious sheep represents an anaphylactic airway response and shares distinct physiological features with human bronchial asthma including pulmonary hyperinflation.


Maturation of hypoxic ventilatory response of the newborn lamb. The ventilatory response to acute hypoxia was studied in unanesthetized newborn lambs before and after carotid body denervation. Animals studied immediately following operative delivery were compared with a second group who were studied in the 2nd wk of postnatal life. Response time was defined as the interval between the decrease in oxygen saturation in the aortic arch and an increase in tidal volume or ventilatory rate. Animals in the older group demonstrated a significantly shorter response time than those studied immediately following delivery (1.8 s vs. 5.7 s). A ventilatory response was also elicited in carotid body-denervated animals in both study groups. Mean response time following denervation was 29.5 s for the younger and 12.5 s for the older animals. The data suggest that the development of a rapid, carotid body-mediated hypoxic ventilatory response occurs gradually during the first days of postnatal life, and that the central hypoxic response of the fetus (J. Appl. Physiol.: Respirat. Environ. Exercise Physiol. 42:630-635, 1977) persists into postnatal life.


Inflection points of lung pressure-volume curves using a three-balloon-catheter system. We measured the pressure-volume curves (PV curves) of the lung simultaneously at three levels in the esophagus below the tracheal bifurcation using the three-short-balloon-catheter system in 11 normal seated men and compared the inflection points (IP's) of three PV curves with the closing volume (CV) on the single-breath nitrogen washout curve. The mean pressure gradient from the top of the uppermost balloon to the top of the lowermost balloon (10 cm apart) was 0.58 +/- 0.06 cmH2O/cm at 60% total lung capacity (TLC). The IP was dependent on depth within the esophagus; i.e., the lung volume at IP (VIP) of the uppermost balloon was the smallest and the transpulmonary pressure (Ptp) at IP (PIP) of that balloon was the largest of the three IP's. VIP's were significantly larger than CV's and the mean absolute difference between the VIP of the uppermost balloon and the closing capacity (CC) was 0.9 liter. These results suggest that IP may not exactly reflect airway closure.


Deposition of particles in model airways. The deposition of monodisperse aerosols in models of single lung airway bifurcations was studied. The particles, generated by spinning disk, were in the size range of 4.2--8.8 microns (density 1.3 X 10(3) kg . m-3). The model bifurcations were symmetrical, of physiological size, and based on established morphological data. The effects on percentage deposition (P) of flow rate (expressed as Reynolds' number. Re), particle diameter (d), tube diameter (D), and bifurcation angle (2 theta) were studied and a generalized expression for deposition based on these variables was obtained, viz., P = 11.04 X 10(5) Re (d/D)2.5sin3 theta. The applicability of this equation is discussed.


Difference between end-tidal and arterial PCO2 in exercise. The relation between end-tidal carbon dioxide tension (PETCO2) measured by infrared analysis and arterial carbon dioxide tension (PaCO2) during exercise was systematically examined in five healthy adults at two power outputs (25 and 50% VO2max) and at three frequencies of breathing (15, 30, and 45 breaths/min). PETCO2-PaCO2 varied between -2.5 and +9.1 Torr, was inversely related to the frequency of breathing (r = 0.475), and directly related to tidal volume (VT; r = 0.791) and CO2 output (r = 0.627). An equation was obtained by multiple regression analysis, to predict PaCO2 from PETCO2: PaCO2 = 5.5 +0.90 PETCO2 -0.0021 VT (r = 0.915). The equation was applied to measurements of PETCO2 obtained in two previous studies in 10 subjects in which PaCO2 had been measured, and was found to predict PaCO2 to within 1.04 Torr (+/- SD) for PaCO2 between 25 and 58 Torr (n = 56; r = 0.962). The effect of the response characteristics of the CO2 analyzer on the measurement of PETCO2 was also systematically examined by comparison with a fast-responding respiratory mass spectrometer.


Reflex bronchoconstriction induced by capsaicin in the dog. To determine whether receptors stimulated by the injection of capsaicin into the pulmonary circulation cause reflex changes in airway size, six dogs were anesthetized with chloralose, paralyzed with succinylcholine, and mechanically ventilated (2 cm H2O PEEP). Intrapulmonary airways were outlined with tantalum dust, and diameters were determined by taking serial roentgenograms at end expiration. Capsaicin (20 micrograms/kg) injected into the right ventricle significantly decreased airway diameter (20%), heart rate, aortic pressure, and pulmonary artery pressure. In contrast, capsaicin injected into the left ventricle did not alter airway diameter or aortic pressure, although heart rate and pulmonary artery pressure decreased but to a lesser extent than after right ventricular injection. After vagotomy, capsaicin had no effect on airway diameter or heart rate but aortic pressure and pulmonary artery pressure increased slightly. Results suggest that pulmonary receptors sensitive to capsaicin and accessible via the pulmonary circulation produce reflex bronchoconstriction. One possible function of this vagal reflex is to assist fluid movement from microvasculature to peribronchial space by reducing peribronchial pressure.


Regional blood flow during simulated diving in the conscious Weddell seal. Changes in regional blood flow during simulated normobaric diving were studied in the conscious Antarctic Weddell seal (Leptonychotes weddelli) by injecting 25-microns radioactive microspheres into the left ventricle. Injections were performed before and 8--12 min after submersion of the head in iced seawater. Diving was associated with a fall in cardiac output from a mean control value of 39.8 +/- 10.2 to 5.6 +/- 3.4 l/min (mean +/- SD) and in heart rate from 52 +/- 15 to 15 +/- 4 beats/min. Blood flow to the splanchnic and peripheral vascular bed was reduced by more than 90%, cerebral blood flow was unchanged, right and left ventricular blood flow decreased by 85%, and adrenal blood flow decreased by 39%. The pulmonary fraction of the injected microsphere dose increased from 7.9 to 29.9% during diving. This may signify a large increase of peripheral arteriovenous shunting during the dive and/or increased bronchial artery blood flow. It is concluded that blood flow during diving is directed to organs and tissues according to their metabolic requirements.


Early change in skeletal muscle protein synthesis after limb immobilization of rats. The atrophy of skeletal muscle accruing from disuse, or limb immobilization, is caused by a decreased rate of protein synthesis and an increased rate of protein degradation. Currently, little information is available regarding the initial time of the decline in the rate of protein synthesis in skeletal muscle. The purpose of the present study was to determine, as precisely as possible, the time at which the protein synthesis rate first begins to decline in skeletal muscle, utilizing immobilized limbs of rats for a model. A constant-infusion technique employing [14C]tyrosine was used to estimate protein synthesis rates. During the first 6 h of immobilization, a significant decline of 37% in the fractional rate of protein synthesis from the control level of 5.7%/day was observed. These results suggest that very early changes are occurring in molecular events that regulate protein synthesis in disused or immobilized skeletal muscle.


Effect of training and heat acclimation on exercise responses of sedentary females. In an attempt to explain why females experience greater strain than males during exercise in the heat, we studied the responses of nine females to moderate exercise (40% VO2 max) on a cycle ergometer in a cool (16--20 degrees C, 30% rh) and a hot (45 degrees C, 30% rh) environment. Venous blood was sampled during rest, at the 40th min of exercise, and 25 min after exercise. Test runs were then performed during a 4-wk training program (phase 2) and during heat acclimation (phase 3). Except for K+, changes in plasma constituents during exercise were not altered by training or acclimation. A greater mean decrease in plasma volume occurred during exercise in a hot (11.9%) than in a cool (3.9%) environment. Plasma osmolality and protein concentration increased due to the loss of plasma water. The most striking response to training was a significant expansion of resting plasma volume (9.7%) and total protein content (11.6%). During acclimation, sweat rates increased and mean skin temperatures significantly decreased. Hemodilution reported in heat-acclimated men was not seen. The factor primarily responsible for improved cardiovascular fitness in these women during acclimation may have been the maintenance of a larger central blood volume.


Alveolar volume-surface area relation in air- and saline-filled lungs fixed by vascular perfusion. The influence of volume changes and interfacial forces on the geometry of peripheral air spaces was studied in excised rabbit lungs inflated with either air or saline and fixed by vascular perfusion at four points of the deflation limb of the pressure-volume curve corresponding to 100, 80, 60, and 40% of the total lung capacity (TLC). In air-filled lungs pleating and folding of alveolar septa were observed, especially in alveolar corners. However, the alveolar surfaces were smooth, except at low lung volumes where some surface crumpling occurred. In saline-filled lungs pleats were absent; the alveolar surface was irregular at all inflation levels due to undulating walls and bulging capillaries. Morphometry indicated that at all alveolar volumes (VA) the surface areas (SA) were larger in saline- than air-filled lungs. No simple mathematical function was found to characterize the relation between SA and VA over the entire volume range studied. Within the range of normal breaths (80 to 40% TLC) the best fit for n in the function SA = k.VnA was 0.58 for saline-filled lungs (r = 0.93) and 0.33 for air-filled lungs (r = 0.68), suggesting different and complex deflation patterns.


Castration for treatment of perianal gland neoplasms in the dog. Neoplasms of the perianal gland are common in the dog, particularly the male. Adenomas of the gland develop about 4.5 times more often than do carcinomas of the gland. The adenoma is hormone dependent; thus, castration without excision of the tumor has been successful in promoting regression without recurrence. Microscopic examination of the testes from dogs with perianal gland neoplasms has revealed 1 in 10 with tubular atrophy and 1 in 3 with testicular neoplasia. Interstitial cell tumors have been seen more often than other cell types of testis tumors.


Treatment of metastatic granulosa cell tumor in a dog. A 10-year-old female dog with endocrine abnormalities and abdominal distention was found to have a functional ovarian tumor. Exploratory laparotomy and histologic examination of excised specimens led to a diagnosis of granulosa cell tumor with widespread metastasis. The prognosis appeared grave because tumor tissue remained on the liver and parietal peritoneum. An immunotherapeutic regimen was instituted and was continued for 4 months. The dog appeared to be free of disease on periodic examinations and continued to do well 2 years after diagnosis and surgery.


Myopathy associated with  hyperadrenocorticism in the dog. Naturally occurring or iatrogenic hyperadrenocorticism was associated with myopathy in six dogs. One dog had muscle weakness and muscle atrophy but normal electromyographic findings. Five dogs had muscle stiffness, proximal appendicular muscle enlargement, and myotonic discharges on electromyography. Histologic, electron microscopic, and histochemical findings in the musculature of dogs that were examined were characteristic of noninflammatory degenerative myopathy. Clinical signs of the myopathy improved to varying degrees in five dogs that were treated for the hyperadrenocorticism.


Neurologic complications of IgA multiple myeloma associated with cryoglobulinemia in a dog. A diagnosis of vertebral multiple myeloma, based on radiographic evidence of osteolytic lesions and the finding of monoclonal paraprotein and large numbers of plasma cells in bone marrow biopsies, was made in a mature Doberman Pinscher. The abnormal serum paraprotein was a cryoglobulin of the immunoglobulin A class. Neurologic signs associated with the tumor included pain, progressive pelvic limb paresis, and paraplegia that developed during a 6-week period.


Factor IX deficiency in an Alaskan Malamute. Factor IX deficiency, consistent with hemophilia B, was detected in a 6-month old male Alaskan Malamute with a 2-week history of persistent oozing from an oral wound. Laboratory studies disclosed an intrinsic coagulation defect. Hemophilia A was initially suspected. Further evaluation demonstrated normal factor VIII activity and factor VIII-related antigen, but factor IX activity was only 1.3% of normal.


Polioencephalomalacia in goats.

Polioencephalomalacia in goats. Of six goats with polioencephalomalacia, three responded to thiamin therapy, whereas three died 2 to 7 days after onset of signs. The goats were 2 months to 2 1/2 years old. They were affected during the winter or early spring, and concentrate feeding was a prominent part of the history. Transketolase activity values were obtained from two affected goats and from nine controls. The affected goats had lower transketolase activity than any of the controls.


Estimation of economic loss associated with anaplasmosis in California beef cattle. On the basis of questionnaire surveys and personal interviews with veterinarians, ranchers, and livestock farm advisors, the seriousness of anaplasmosis in California was determined. In 1976, the economic loss due to anaplasmosis in the study sample of beef cattle was $2,203,150. When inferences were made from the sample population to include the whole population of beef cattle, this loss was estimated to be $5,244,319. These values were in contrast to a farm advisors' estimate of $11 million loss due to anaplasmosis, which was included in a total estimated loss of $300 million due to all livestock diseases of economic importance in California. It appeared that anaplasmosis, although having a substantial economic impact in California, is not as economically devastating as it was once thought to be. It was concluded that private programs currently in use (vaccination and treatment) are sufficient to control anaplasmosis.


A review of third phalanx fractures in the horse: sixty-five cases. Sixty-five cases of third phalanx (P3) fracture were retrieved from 20,638 case records at Michigan State University's Veterinary Clinical Center between Feb 1, 1964 and July 1, 1977. The fractures were classified by anatomic location, using a numbering system. Data from case records indicated the most common P3 fracture involved the articular surface of the coffin joint (53 of 65 cases; 81.5%). The greatest occurrence of P3 fracture was in Standardbreds (31 of 65 cases). Thirty-three of the 65 fractures were in geldings of all breeds; 57 of the cases were distributed among racing horses of four breeds; and the mean ages at time of fracture for these groups were 4.9 to 5.3 years. The most common cause of P3 fracture was racing injury. Of 57 P3 fractures of the forelimb, 51 (89.5%) involved the lateral aspect of the left limb or medial aspect of the right limb--the part of each foot supporting most of the horse's weight in turns, while racing counterclockwise. Methods and response of treatment were evaluated by questionnaires obtained from 31 of the 65 owners. This questionnaire solicited information from owners and trainers as to: (1) cause, (2) treatment, (3) outcome, and (4) the use of the horse. Results were tabulated for: (1) questionnaire information obtained, (2) a classification system for P3 fractures, based on the anatomic location of the fracture, and (3) distribution of fractures between limbs and position (medial vs lateral) within limbs.


Benzocaine-induced methemoglobinemia in dogs. Methemoglobinemia developed in three dogs after the owners' use of benzocaine-containing products for topical treatment of the dogs' pruritic skin conditions. The products were intended for use in man. In two of the dogs, clinical signs of shock were observed within a few hours after the application of a skin lotion containing 5% benzocaine. Methemoglobin was assayed in one case and found to be 51% of total hemoglobin. Both dogs recovered after whole blood transfusions were given. The third dog, which had been treated for several weeks with small amounts of an anesthetic aerosol containing 20% benzocaine, was anorectic and lethargic when examined. Methemoglobin content was 30%, and Heinz bodies were observed in 20% of the erythrocytes. The methemoglobin content and proportion of Heinz bodies decreased rapidly after use of the spray was discontinued. The two benzocaine-containing products incriminated in development of the methemoglobinemia did not induce measurable increases in methemoglobin content in clinically normal dogs, when applied to unbroken skin. Small increases in methemoglobin content were measured, however, when these products were given orally to clinically normal dogs. It was concluded that the skin lesions in the three clinically affected dogs enhanced absorption of the drug, resulting in methemoglobin formation.


Cataracts in Chesapeake Bay Retrievers.

Cataracts in Chesapeake Bay Retrievers. Cataracts developed in 13 of 27 related Chesapeake Bay Retrievers. The posterior pole, "Y" sutures, and equatorial cortices of the lens were predominantly affected. In one affected dog, the cataracts had progressed to hypermaturity, permitting restoration of vision. The trait was believed to be dominant, with incomplete penetrance.


Radiographic findings in induced bacterial pyelonephritis in dogs. Unilateral bacterial pyelonephritis was induced in nine dogs. The upper urinary tracts of these and six control dogs were evaluated by excretory urography prior to and 9 to 10 days following experimental manipulations. Two of the dogs with unilateral pyelonephritis and one control dog were evaluated at intervals throughout a 58-day period. At necropsy, all nine inoculated kidneys were infected, one experimental dog had bilateral pyelonephritis, and one control dog had unilateral pyelonephritis. Most of the infected kidneys had abnormal radiographic changes 9 to 10 days after induction of infection. There was no statistically significant radiographic change in size of infected kidneys at 9 to 10 days. Seven of the 11 infected kidneys and 7 of the 9 inoculated kidneys had renal pelvic and ureteral dilatation. Of the nine dogs with unilateral pyelonephritis, six had decreased opacity of contrast medium in the collecting system and of the vascular nephrogram on the infected side. The size of infected kidneys decreased progressively during the 58-day period. In one of the two dogs evaluated throughout the period, the collecting system of the infected kidney remained dilated; in the other, it returned toward normal size.


Surgical repair of fractured capital femoral epiphysis in three foals. Fracture of the capital femoral epiphysis occurred in three foals. One fracture was repaired by means of pinning under radiographic control and the two other fractures were repaired by means of trochanteric osteotomy.


Repair of incisional hernias in the horse. Incisional abdominal hernias in three horses were repaired, using synthetic mesh with a fascial flap overlay. The repair of large ventral abdominal hernias of horses can be accomplished by using synthetic mesh that is sutured across the defect. This material can be placed subperitoneally, retroperitoneal but subfascial, retrofascial and subfascial, or retroperitoneal but subfascial with a fascial overlay. Advantages of using this material are that it can be used for repair of large hernias, it is easy to apply, it is strong and flexible, and it is less likely to be rejected, when compared with other synthetic materials.


Intoxication of dogs with the mycotoxin penitrem A. Mycotoxicosis caused by ingestion of moldy cream cheese was suspected in two dogs with severe muscle tremors and generalized seizures. Penicillium crustosum and its toxin, penitrem A, were isolated from the moldy cream cheese.


Congenital elbow luxation in the dog.

Congenital elbow luxation in the dog. Four cases of bilateral and two cases of unilateral congenital elbow luxation in the dog were reviewed. In all cases, lameness was severe, osseous abnormalities were marked, and the dislocations primarily involved the humeroulnar articulation. Treatment consisted of closed reduction and external support in one dog and surgical reduction and stabilization in four dogs. One dog died before surgery could  be performed. Treatment resulted in return of function to the affected limbs, even though osseous abnormalities and varying degrees of malarticulation persisted. Posttreatment observations, for as long as 4 years, demonstrated the persistence of near normal function of the limbs and minimal elbow deformity.


Effect of atropine on tear formation in anesthetized dogs. Tear production (as determined by the Schirmer I tear test) in five dogs given atropine (0.02 mg/kg) subcutaneously and in five dogs given 0.9% saline solution subcutaneously was compared before and during halothane anesthesia. Fifteen minutes after the atropine injections, mean tear production was 15.0 +/- 2.9 mm/minute, as compared with 23.8 +/- 2.9 mm/minute before treatment rate. There was no change in tearing 15 minutes after injection of the saline solution. Tear production declined in both groups during anesthesia. Ten minutes after anesthetic induction, mean tear formation was 20% of pretreatment value in the atropinized dogs and 54% of the pretreatment value in the dogs given saline solution. At the end of 1 hour of anesthesia, tearing was essentially zero in both groups.


Ocular manifestations of the Chédiak-Higashi syndrome in four species of animals. Ocular examinations were performed on cattle, cats, mink, and mice affected with Chédiak-Higashi syndrome (CHS). Bovine eyes were examined grossly and with an indirect ophthalmoscope, and Schirmer tear tests were performed. Feline eyes were examined grossly as well as with an indirect opthalmoscope and a slit lamp biomicroscope, and Schirmer tear tests were done on them. Postrotatory nystagmus was induced and measured in clinically normal Siamese cats, in clinically normal Persian and domestic short-haired cats, and in cats with CHS. Mink and mouse eyes were examined grossly with focal illumination. The animals with CHS had photophobia, pale irises, and fundic hypopigmentation associated with red fundic light reflections. Cats with CHS also had cataracts. Spontaneous nystagmus was observed in four of nine cats with CHS, and the duration of induced nystagmus was longer in the cats with CHS and in Siamese cats than in clinically normal cats that were not Siamese. Tear secretion appeared to be normal in all species of animals with CHS. The ocular manifestations of CHS in these animals were compared with those reported in man and were found to be similar.


The origin of the neural macrophage: a quantitative ultrastructural study of cell population changes during Wallerian degeneration. The changes that follow a localised crush injury to the rat sural nerve have been used to study endoneurial populations during Wallerian degeneration. The removal of products of degeneration, and in particular myelin debris, is accomplished by globule-laden cells which appear in the endoneurium during the first few days of repair. The origin of these cells has been investigated using a quantitative ultrastructural technique. Serial planimetric measurements of all populations, identifiable in terms of criteria that did not pre-judge their true nature, were made at intervals over a period of 15 days. Cell counts obtained immediately below the site of injury and 1 and 3 cm distally were compared, and graphs of endoneurial population changes constructed from these measurements. Additional descriptive evidence was invoked to assist in establishing the actual identity of the extratubal vacuolated cells which had been classified and measured empirically. Comparing the changes in the number of these cells with that of the intratubal vascuolated cell population, and taking account of the presence of immature macrophages in both proximal and distal situations, lead to the conclusion that the extratubal vacuolated cells are mostly derived from the bloodstream, the rest being of local intratubal origin. There was no evidence to support the notion that Schwann cells transform into macrophages.


The lateral vestibular nucleus of the rat, with a note on its dorsal extension into the cerebellum. The lateral vestibular nucleus of the rat has been studied in Nissl preparations: It is similar, in shape and position, to its counterpart in cats and monkeys. A dorsal extension of the nucleus into the cerebellum has been described for the first time. Two types of neurons, large multipolar and small, have been demonstrated histologically, and their significance correlated with available neurophysiological information.


The ultrastructure of the sweat glands of the ox, sheep and goat during sweating and recovery. The ultrastructure of the sweat glands of cattle, sheep and goats was studied before, during, and after, exposure of the animals to controlled warm environments. In cattle, sweating induced little ultrastructural change in the gland, although fluid-filled spaces appeared between the myo- and secretory epithelial layers. The mechanism appears to be one of fluid transport and exocytosis of secretory vesicles, which in this species seem to be derived from the Golgi apparatus and/or mitochondria. The glands of the sheep and goat also displayed signs of vesicle exocytosis and of fluid transport during sweating. The sweating 'fatigue' in these species was apparently due to failure of the secretory cells, some of which ruptured and were extruded into the lumen. The evidence during subsequent recovery indicates that neighbouring cells spread to make contact, encase remnants of atretic cells between them and the underlying myoepithelium, and engulf them. Sweat in these species appears to be formed (a) by secretion and (b) from cells which can no longer meet the demands of stimulation. The role in sweating of cell replacement, and of undifferentiated cells found between the myo- and secretory epithelia, is discussed.


Evidence for autonomic paraneurons in sympathetic ganglia of a shrew (Tupaia glis). The morphological relationships between blood vessels and the small monoamine-storing cells have been studied in the superior sympathetic ganglia of Tupaia. Substantial clusters of these cells were found to be associated anatomically with vascular loops or glomeruli. Blood from these glomeruli enters the capillary bed that supplies principal ganglionic neurons. Thus the vascular path for catecholamine transportation is rather clearly defined in Tupaia, providing new morphological evidence for the existence of a portal system for conveying catecholamine from clusters of paraneurons to principal ganglionic neurons. On the basis of vesicle criteria, two populations of small, granule-containing cell were distinguished, and both were encountered in the same cluster. On the basis of fluorescence microscopy, the relatively small number (14.3%) of solitary SIF cells may be true interneurons because, although there has been no electron microscopic identification of efferent synapses, their processes are much longer than those of the paraneurons.


Calcaneocuboid joint and stability of the longitudinal arch of the foot at high and low gear push off. The calcaneocuboid joint was studied in ligamentous specimens of ten human feet, and in skeletons of two gorillas (Gorilla gorilla beringei), six chimpanzees (Pan troglodytes), three orangutans (Pongo pygmaeus) and 25 human feet. The movement of the transverse tarsal joint was further studied in a living foot on a walk-way with a glass plate inserted, and with an underlying mirror. In man the joint is shaped as an asymmetrical sector of one end of an hour-glass shaped surface of revolution with its main axis oriented longitudinally in the foot. The calcaneocuboid joint becomes close packed by a pronation of the forefoot in relation to the hind foot because of a congruency between the joint surfaces obtained in this position and because the calcaneus overhangs the cuboid dorsally and stops the movement. At low gear push off the foot is inverted and the calcaneocuboid joint loose packed. The stresses are absorbed across the fibular, postaxial border of the foot. At high high gear push off there is a functional pronation of the forefoot with a stabilization of the transverse tarsal joint and a more effective tightening of the plantar aponeurosis. The foot becomes a rigid lever for propulsion. In contrast to the human condition, the anthropoid calcaneus has an anteromedial extension associated with symmetry of the calcaneocuboid joint. The calcaneus does not overhang the cuboid and there appears to be no close packed position. Correspondingly, the anthropoid foot has a mid-tarsal break at each push off in addition to the metatarsophalangeal break.


The origin of microglial cells.

The origin of microglial cells. The rat brain has been studied between 6 hours after birth and 100 days, using histochemical techniques for acid phosphatase and peroxidase, and silver impregnation for microglial cells. The results indicate that microglia come initially from acid phosphatase-positive cells of the meninges. These invade the nervous parenchyma and transform into ramified microglia. At 3 days of age similar cells are present on the outer surface of the large blood vessels, from which site they migrate into the nervous parenchyma. In 100 days old rats the acid phosphatase-positive cells are practically all pericytes. None of the microglial cells or their precursors give a positive reaction for peroxidase.


Metrial gland cells in deciduomata of pseudopregnancy. Light and electron microscope studies were carried out on the metrial gland cells of deciduomata of pseudopregnancy in the rat. At the light microscope level these cells were characterised by a comparatively pale staining cytoplasm with numerous glycoprotein granules. Some also had extensive cytoplasmic deposits of glycogen. In electron micrographs the metrial gland cell cytoplasm as a whole was much less electron-dense than that of fibroblasts and decidual cells, but it contained densely stained pleomorphic granules. There were stacks of rough endoplasmic reticulum, oval or round profiles of fibroblasts and decidual cells, but it contained densely stained pleomorphic granules. There were stacks of rough endoplasmic reticulum, oval or round profiles of mitochondria, and an extensive Golgi network. The metrial gland cells were roughly spherical in appearance, with irregular surface projections. In all these features, and in the sequence of their appearance, first in the decidua basalis, and later in the mesometrial triangle, the granulated metrial gland cells of deciduomata resembled the metrial gland cells of pregnancy. In addition to granulated metrial gland cells, decidual cells and fibroblasts, a number of other cell types were identified. These cells could be placed in a series, with each member of the series minimally different in morphological appearances from its neighbours. It is proposed that the series represents the differentiation of granulated metrial gland cells, in situ, from lymphocyte-like cells. The differentiation from a lymphocyte precursor appears to follow a sequence in deciduomata formation similar to that previously described in pregnancy.


A semithin light microscopic, transmission electron microscopic and scanning electron microscopic study of macrophages in the lateral ventricle of mice from embryonic to adult life. A developmental study of intraventricular macrophages was carried out from 11 days post-conception up to 90 days post-natum, using semithin sections, transmission electron microscopy and scanning electron microscopy. In semithin sections and in the TEM three main morphological types (and some transitional forms) were identified and are described as circular, irregular and flattened, respectively. In the SEM three corresponding types were identified, a relatively smooth spherical type, a highly ruffled type and a fairly smooth flattened type. A fourth, multi-blebbed type, was occasionally seen in late prenatal and early postnatal mice. It seemed most likely that these cells were mitotic. The likely sequence of development is that the spherical or circular type is the most primitive, although capable of phagocytosis; and that this differentiates into the ruffled or irregular variety, which in turn differentiates into the flattened type, which is by far the most common type found after birth.


Morphometric observations on the kidney of the camel, Camelus dromedarius. Morphometric analysis of the kidney of the camel was carried out on gross slices and histological sections using standard morphometric methods. The renal cortex occupied about 50% by volume of the kidney, and the ratio of the thickness of the medulla to that of the cortex was about 4:1. The relative thickness of the medulla was about 7.89. This parameter is an indicator of the lengths of the loops of Henle and vasa recta, and, according to the countercurrent theory, is consequently an indicator of the ability of the kidney to concentrate urine. In each kidney the volume and surface area of the cortical tubules and the number of glomeruli were determined and compared with these parameters in some other mammals. In addition the architectures of the renal pelvis and medulla and their significance in relation to the excretion of hypertonic urine were discussed. It was concluded that the kidney of the camel possesses the anatomical requisites for the production of hypertonic urine.


Changes in the surface fine structure of rat third ventricular ependyma following chronic acetazolamide treatment. Participation of non-choroidal elements, particularly of ventricular ependyma, in CSF production is well recognized. The present investigation is an attempt to elucidate possible surface changes in the ventricular lining following chronic acetazolamide administration in the rat. A progressive time-dependent change was observed in the ependyma of the third ventricle. In the dorsal ciliated zone the appearance of dilatations and surface evaginations on cilial shafts were the predominent features. The ventral non-cilated area was characterized by eruption of blebs and microvilli with apical swellings. The significance of these surface fine structural changes are discussed in the light of available studies. It appears that the ependyma is stimulated into increased activity. However, the precise nature of such a response--whether secretory or absorptive--must remain conjectural until correlative scanning and transmission electron microscopic data become available.


The distribution of nuclei in imprints of feline osteoclasts. Fresh imprints of metaphyseal bone from the femurs of four kittens aged 18 weeks were stained by histochemical methods for succinate, malate, beta-hydroxy butyrate, and glutamate dehydrogenases. In these preparations the unstained nuclei contrasted sharply with the background stained cytoplasm, making possible accurate nucleus counts in intact osteoclasts. The nuclei in 1683 osteoclasts were counted and the data revealed an asymmetric distribution of cells having different numbers of nuclei. The method may be of value in determining the precise significance of osteoclast size in relation to function.


Afferent and efferent myelinated fibres in branches of the avian vagus. The numbers of afferent and efferent myelinated fibres in the branches of the vagus nerve in the domestic fowl were studied. The vago-glossopharyngeal anastomosis contained large fibres (up to 14 micrometer), the majority of which were efferent. The right recurrent nerve contained more fibres than the left one; in the right recurrent nerve about one third of the myelinated fibres were afferent. Almost all the myelinated fibres in the right cranial cardiac nerve were afferent. About half of those in the pulmono-oesophageal nerve and in the thoracic vagus were afferent.


Quantitative studies of the regeneration of rat myelinated nerve fibres: variations in the number and size of regenerating fibres after repeated localized freezings. The number and size of myelinated nerve fibres were determined in the nerve to the medial head of the gastrocnemius muscles of rats whose left sciatic nerve was repeatedly frozen (one to five times at three weekly intervals). The contralateral nerve was used as a control. Results varied according to the number of freezings performed and, for a given number of freezings, according to the period of regeneration. When measurements were completed 1 month after the last of several localized freezings, the number of regenerating myelinated nerve fibres increased regularly up to the third freezing, reaching to about 220% of the control value, but no higher values were recorded after four or five freezings. The nerve fibre distribution was unimodal in all the nerves studied. The mean diameter of all myelinated fibres decreased with the number of freezings from 50% of the control value after the first to 36% after the fifth. When measurements were made 1, 3, 6, 12 and 18 months after the third and final freezing, the number of regenerating myelinated nerve fibres decreased by about 30% between the first and third month and then stabilized at 190% of the control value. Nerve fibre distribution became bimodal from the third month onwards, and the mean diameter of all myelinated fibres increased regularly. However, by the eighteenth month, the size of regenerated myelinated nerve fibres had only reached 70% of the normal contralateral value.


Basic stereological relationships for quantitative microscopical anatomy--a simple systematic approach. There exists in the literature a core of formulations regarded as 'the basic stereological principles' for quantifying cell and tissue morphology. They may be used to obtain information relating component volume, surface area, length and number to a specified containing volume (the so-called component densities in a volume: VV, SV, MV and NV). However, principles may also be formulated for relating these component dimensions to a containing surface (SS, MS and NS), containing length (MM and NM) and a containing number (NN). Methods for estimating these previously neglected stereological relations are presented. Possible biological applications of the principles are also discussed.


Herbicidins F and G, two new nucleoside antibiotics. A mutant of Streptomyces saganonensis No. 4075, obtained with N-methyl-N'-nitro-N-nitrosoguanidine treatment, produced herbicidins F and G without herbicidins A and B. Isolation of the antibiotics was performed by adsorption on resinous adsorbent followed by elution with aqueous MeOH. Herbicidin F was obtained as colorless needles after extraction of the eluate using methylene dichloride. Purification of herbicidin G was completed with silica-gel chromatography to give a crystalline powder. physico-chemical characterization revealed that herbicidins F and G were new nucleoside antibiotics having an adenine moiety in their structures. There was no inhibition activity at 100 micrograms/ml of herbicidins F and G against all of bacteria and yeast tested. Herbicidin F, as well as herbicidin G, are inhibitory activity against some of fungi such as Tricophyton rubrum (MIC; 6.25 micrograms/ml), T. asteroides (6.25 micrograms/ml), T. mentagrophytes (6.25 approximately 12.5 micrograms/ml), Botrytis cinerea (12.5 micrograms/ml), Blastomyces brasiliensis (12.5 approximately 25 micrograms/ml).


Fortimicins C, D and KE, new aminoglycoside antibiotics. From the fermentation broth of Micromonospora olivoasterospora CS-26 that produced fortimicins A and B three new aminoglycoside antibiotics, fortimicins C, D and KE, were isolated. Fortimicins C and D exhibited potent, broad spectrum antibacterial activities against Gram-positive and negative bacteria, while fortimicin KE was only weakly active.


Conglobatin, a novel macrolide dilactone from Streptomyces conglobatus ATCC 31005. Fermentation of deposited cultures of Streptomyces conglobatus, known to produce the polyether antibiotic, ionomycin has resulted in the isolation and characterization of a second metabolite, conglobatin (C28H38N2O6). X-Ray analysis revealed a dimeric macrolide dilactone structure for conglobatin, similar to the structures of the mold metabolites vermiculin and pyrenophorin, from which the absolute configuration of conglobatin has been inferred. The dimer consists of two molecules of 7-hydroxy-8-oxazoyl-2,4,6-trimethyl-2-octenoic acid joined by two ester linkages.


Deltamycins, new macrolide antibiotics. III. Chemical structures. The structures of deltamycins A1,A2,A3 and A4 belonging to the basic macrolide family of antibiotics were determined mainly from their spectral properties. Deltamycin A4 was identified as carbomycin A having an isovaleryl group on the mycarose moiety of the molecule. Deltamycin A1,A2 and A3 possess similarities to the structure of deltamycin A4, but they have acetyl, propionyl and n-butyryl group, respectively, in the place of isovaleryl group of deltamycin A4. These structures were confirmed by chemical synthesis from deltamycin X (4''-O-deacyldeltamycin) and the corresponding acyl chlorides.


4-N-Aminoacylfortimicins E.

4-N-Aminoacylfortimicins E. The conversion of fortimicin E, a minor metabolite from the Micromonospora olivoasterospora fermentation which also produces fortimicin A and fortimicin B, to four 4-N-aminoacylfortimicins E was accomplished. The new 4-N-aminoacylfortimicins E showed only weak antimicrobial activity against several Gram-negative and Gram-positive microorganisms.


New cephalosporins and 7 alpha-methoxy cephalosporins. Chemistry and biological activities. The synthesis and the in vitro activity of a number of cephalosporins and 7 alpha-methoxy cephalosporins having 7-acyl substituents derived from 1-methyl-4 (or 5)-nitro-1H-imidazolyl-thioacetic acids are described. The microbiological profile is influenced by the position of both the nitro group and the side-chain sulfur atom on the 1-methyl imidazole, and by the nature of the 3-substituent.


Rosamicin, a macrolide with in vitro activity against Ureaplasma urealyticum. A new macrolide antibiotic, rosamicin, was shown to have much greater activity in vitro against ureaplasmas isolated from humans than erythromycin or the tetracyclines tested. A marked ureaplasmacidal effect was also shown.


Metabolic products of microorganisms. 184. On the mode of action of cladosporin. Cladosporin, a fungal isocoumarin derivative, strongly inhibits the uptake and thereby the incorporation of uracil and leucine into cells of Bacillus brevis and the incorporation of uridine but not leucine into cells of the ascitic form of Ehrlich carcinoma (ECA) of mice. Normal uptake was not restored by removal of the antibiotic. In cells of Escherichia coli A 19-15 (met-) the inhibition of methionine uptake is associated with the cessation of growth. In a methionine-prototrophic revertant from this organism, the uptake of methionine is still inhibited; growth, however, is hardly affected by cladosporin. In vitro no effect on the DNA-dependent RNA polymerase from E. coli and on the RNA polymerase II from wheat germ could be detected. The poly(U)-directed poly(Phe) synthesis was also not inhibited by cladosporin. It is concluded that cladosporin inhibits uptake processes which, for the case of essential nutrients, leads to loss of viability.


FI schedules and persistence at gambling in the U.K. betting office. This study reports on the direct observations of customers in two U.K. betting offices gambling on horse and dog races. These observations revealed that bets were more frequently placed in the last minutes just prior to the start (the OFF), and that this was caused by high-frequency gamblers (customers who had eight or more bets in a session) consistently placing their bets in the last two minutes prior to the OFF. Low-frequency gamblers (three or fewer bets/session) avoided this time period placing their bets earlier, or after the OFF, i.e., on a later race. It was argued that the betting behavior of the "gamblers" could not be explained either in terms of "skillful betting" or solely in terms of variable ratio schedules but was more adequately accounted for in terms of an interval schedule. It was further suggested that time-based schedules might be of heuristic value in generally understanding persistence at gambling while losing.


Operant control of pathological tongue thrust in spastic cerebral palsy. Pathological tongue thrust (reverse swallowing) has been associated with neuromuscular disorders and linked to dental malocclusion, articulation problems, difficulty in eating, and excessive drooling. In this study, observable tongue thrust in a 10-year-old retarded male was modified during mealtime using a procedure consisting of differential reinforcement (presentation of food contingent upon tongue in) and punishment (gently pushing the tongue back into the mouth with a spoon). Results of a reversal design showed substantial decreases in tongue thrust and food expulsion, and a large increase in observed chewing. These data compared favorably with data obtained for other retarded persons not judged to be tongue thrusters; in addition, the objective results of the treatment program were substantiated via pre-post evaluations done by occupational and physical therapists. These findings suggest that operant techniques may be an effective means of treating tongue thrust and its associated problems, and that further development and evaluation of behavioral interventions may provide a desirable alternative to more intrusive surgical or mechanical procedures.


Behavioral treatment of caffeinism: reducing excessive coffee drinking. Excessive coffee drinking can have deleterious effects because of the large amounts of caffeine that are ingested. Caffeine is thought to be addicting, and prolonged and excessive use can lead to caffeinism, a condition that has serious behavioral and physiological side effects. The present study developed and evaluated a treatment program to reduce excessive daily coffee drinking to moderate and presumably safer levels. Three habitual coffee drinkers received individualized changing criterion programs that systematically and gradually reduced their daily caffeine intake. The coffee drinkers were required to self-monitor and plot their daily intake of caffeine. They received monetary prizes for not exceeding the treatment phase criteria and forfeited a portion of their pretreatment deposit when they did. Their coffee drinking decreased from almost nine cups per day (over 1100 mg of caffeine) during baseline to less than three cups per day (less than 343 mg) at the end of treatment or a reduction of 69%. The treatment effect was maintained during a 10-month follow-up, averaging a 67% reduction from baseline. The program appears to be a reasonable method of reducing and then maintaining daily caffeine intake at less harmful levels.


The effects of feedback on blood pressure discrimination. Discrimination of blood pressure in the natural environment as a function of feedback was assessed. Seventeen normotensives screened for blood pressure lability were randomly assigned to two groups. These subjects were then asked to estimate their systolic and diastolic blood pressure values two times per day over a 4-week period. Feedback for accuracy of blood pressure discriminations was implemented across the two groups in a multiple baseline fashion, using a feedback withdrawal condition in Group I to assess maintenance effects over time. Results showed improvement in discrimination accuracy for subjects in both groups when feedback was used, and no decrement in performance over a 2-week period after feedback was removed for subjects in Group I. Discrimination of systolic pressures improved at a slightly faster rate than discrimination of diastolic pressures.


The effects of sequential pictorial cues, self-recording, and praise on the job task sequencing of retarded adults. The present study investigated the effects of a self-recording procedure using sequentially organized picture cues on independent task changes of four mentally retarded adults. Independent task changes were identified as the beginning of new tasks without directives or instruction. In addition to investigating treatment effects, the long-term maintenance of the task-change behavior was measured. During self-recording and picture-cue training, the subjects completed an increased proportion of independent task changes, and this behavior was maintained for more than 10 wk following removal of the training procedures. Self-recording using picture cues was shown to be an effective procedure for teaching mentally retarded adults to function more independently in a job setting.


Use of a self-recording and supervision program to change institutional staff behavior. The use of a self-recording and supervision program to increase interactions between direct care staff and profoundly retarded persons in a state residential facility was investigated. Following baseline, staff were provided with instructions regarding what to self-record, criteria for how many interactions to record, and a prepared card on which to make the recordings. Throughout the study, the staff supervisor monitored intermittently staff-client interactions. Observations indicated that when the staff recorded their interactions with clients in a loosely structured dayroom setting, the rate of interactions increased noticeably for each staff person. Behavioral ecology measures indicated that other staff responsibilities, such as maintaining the cleanliness of residents and the physical area, were not affected detrimentally when social interactions increased and actually showed small improvements. Additionally, small decreases in resident self-stimulatory and disruptive/aggressive behaviors occurred when the rate of social interactions from staff persons increased. Follow-up measures indicated that the rate of staff self-recording was variable, but when staff did self-record, the increased rate of staff-client interactions maintained.


Satiation therapy: a procedure for reducing deviant sexual arousal. Two single-case experiments demonstrated the efficacy of satiation therapy with adult males who had long-standing deviant sexual interests. The procedure involves the pairing of prolonged masturbation (1 hour) with the verbalization by the patient of his deviant sexual fantasies and in both cases the designs permitted the attribution of control over aberrant responding to the satiation therapy. The results are discussed in terms of the possible active ingredients of the procedure.


Overjustification effects in token economies. This study tested the relevance to clinical token economies of the overjustification hypothesis that tangible reward interferes with intrinsic interest in target behaviors and causes such behaviors to be less probable following a period of reinforcement than preceding such a period. The study was carried out in an ongoing token economy for chronic psychiatric patients. Alternated over an 8-week period were weeks of token and no-token reward for one of the program's target behaviors, toothbrushing. Two different amounts of token reward were employed in order to examine whether reward magnitude might influence the presence or extent of overjustification effects. Little evidence was found for the presence of overjustification effects in token economies. However, maintenance of toothbrushing was greater in no-token weeks following weeks of low amounts of token reward than in no-token weeks following weeks of higher amounts of reward. The importance of such complex functional relationships is discussed.


Time delay: a technique to increase language use and facilitate generalization in retarded children. Institutional breakfast-serving procedures were manipulated to assess what effect changes in that aspect of the environment would have on requests for food. During baseline, six severely retarded children were required to pick up their food trays and return to their seats. The first manipulation, delaying the giving of the food tray for 15 seconds, served as a cue to evoke meal requests by three of the six children. Two of the remaining three required a model of an appropriate meal request (i.e., "Tray, please.") at the end of the 15-second delay before they began requesting their meals. To evoke meal requests from the sixth child, an intensive training procedure, consisting of massed trials of delay and modeling, was required. Three different probes were administered to assess generalization across the people serving the meals, across mealtimes, and across both people and mealtimes.  Typically, generalized responding in these new situations could be prompted by use of the 15-second delay procedure. Functional aspects of the delay procedure and its potential usefulness for evoking speech and facilitating generalization are discussed.


Instructions, feedback, and reinforcement in reducing activity levels in the classroom. The biomotometer, an electronic device which simultaneously measures motor activity and provides auditory feedback, was used in combination with material reinforcers in an experiment to reduce children's activity level in a classroom setting. Subjects were nine boys and two girls, aged 9--13, from a day hospital program for emotionally disturbed children. After five baseline trials, each child had five contingent reinforcement trials in which he/she received feedback "beeps" from the biomotometer and was given toy or candy rewards after each trial in which activity fell at least 20% below mean baseline level. Then five noncontingent reinforcement trials were run in which children received rewards for wearing the apparatus without the feedback attachment. Results indicated that the intervention "package," including instructions, feedback, and contingent reinforcement, was successful in all five trials for 8 of 11 children. Activity levels increased during the final noncontingent phase.


Self-control training in the classroom: a review and critique. Self-control training in classroom settings is becoming widespread. Establishing effective self- rather than externally controlled behavior modification programs in schools would enable children to control their own academic and social behavior, while enabling teachers to devote more time to teaching. The following components of self-control are reviewed in the present article: self-recording, self-evaluation, self-determination of contingencies, and self-instruction. Self-control strategies designed for the maintenance of appropriate classroom behavior, and issues associated with self-control training, such as the reliability of self-observation, response maintenance, generalization, and the role of external control, are examined. Finally, suggestions for maximizing the potential effectiveness of self-control training in the classroom (e.g., teaching self-observational procedures, teaching students to provide themselves with instructions and praise), as well as future areas for experimental investigation (e.g., social changes that may be associated with self-control procedures), are presented.


Proteins of small subunits of rat liver ribosomes that interact with poly(U). II. Cross-links between poly(U) and ribosomal proteins in 40 S subunits induced by UV irradiation. (1) When rat liver 40 S ribosomal proteins in 6 M urea were were mixed with poly(U) at an appropriate ratio, a precipitate was formed which was also insoluble in the sample solution for two-dimensional acrylamide gel electrophoresis. Analyses by two-dimensional acrylamide gel electrophoresis showed that S7 and S10 proteins (according to our numbering system) had disappeared selectively from the fraction soluble in 6 M urea. These two proteins were present in the fraction insoluble in 6 M urea, and became soluble in the sample solution after treating it with RNase. The results suggest that S7 and S10 proteins have strong affinities for poly(U). When rat liver 40 S subunits were incubated with poly(U), similar results were obtained. (2) After incubation of 40 S subunits with [3H]poly(U) and then with unlabeled poly(U), UV irradiation cross-linked poly(U) to the protein moiety of the 40 S subunit. When the protein fraction insoluble in the sample solution for two-dimensional electrophoresis was prepared from 40 S subunits cross-linked to poly(U) and then subjected to two-dimensional acrylamide gel electrophoresis after RNase treatment, S7 and S10 proteins were detected on the gel. In addition to the S7 protein spot, a triangular area spreading from the spot to the origin contained radioactivity. The results suggest that poly(U) is cross-linked to S7 protein and oligo(U) fragments bound to S7 protein affect its electrophoretic mobility. (3) Ribosomal proteins were prepared from 40 S subunits cross-linked to carrier-free [3H]poly(U) and analyzed by three-dimensional acrylamide gel electrophoresis (Terao, K. & Ogata, K. (1975) Biochim. Biophys. Acta 402, 214--229) after RNase treatment. It was found that S7, S6, and S15 proteins are cross-linked to poly(U). From the results of the present and preceding experiments it is concluded that S7 is the poly(U)-binding protein. The possibility that other proteins in 40 S ribosomal subunits interact with poly(U) is discussed.


High-speed gel filtration of polypeptides in sodium dodecyl sulfate. The separation of polypeptides treated with SDS was studied using G3000SW packing prepared from silica for high-speed gel filtration. The peaks of ovalbumin, chymotrypsinogen A, cytochrome c, aprotinin, and insulin B chain were completely separated in the presence of 0.1% SDS and 0.05 M sodium phosphate buffer (pH 7.0). A plot of the logarithm of molecular weight of polypeptides versus Kd was linear over a molecular weight range of 3,000 to 50,000 at the above concentrations of SDS and sodium phosphate. The slopes of the plots of log molecular weight versus Kd depend to a significant extent on the concentration of the sodium phosphate buffer (pH 7.0).


Occurrence of hematoside with two moles of N-acetyl-neuraminic acid in a certain breed of Persian cat. The glycolipids of erythrocytes from individual cats were examined. The main glycolipid of cat erythrocytes was generally NeuGc-NeuGc-Gal-Glc-ceramide (NeuGc-GD3), but among 41 cats of 5 breeds and 2 mongrels examined, 2 Persian cats were found to have NeuAc-NeuAc-Gal-Glc-ceramide (NeuAc-GD3). This is the first report of the occurrence of NeuAc-GD3 in cat erythrocyte membranes.


A study of heat of formation of acetyl-alpha-chymotrypsin intermediate by stopped flow calorimetry. The catalytic hydrolysis of p-nitrophenyl acetate by alpha-chymotrypsin was studied by stopped-flow calorimetry and spectrophotometry at pH 8.0 and 25 degrees C. The initial burst and subsequent steady state of the reaction were observed by rapid calorimetry and spectrophotometry. Based on the three-step mechanism established for the enzymatic reaction, E + S in equilibrium ES leads to acetyl-E + P1 (p-nitrophenol) leads to E + P1 + acetic acid, the enthalpy change of formation of the acetyl enzyme from ES complex was estimated to be -29 kJ . mol-1.


Studies on the glycosphingolipids of the starfish, Asterina pectinifera. III. Isolation and structural studies of two novel gangliosides containing internal sialic acid residues. Two gangliosides, provisionally named Gangliosides 1 and 2 in previous studies, were isolated from starfish, Asterina pectinifera by silicic acid, DEAE-Sephadex, and Iatrobeads column chromatography procedures, and preparative thin-layer chromatography, and their structures were established. On the basis of the results of partial acid hydrolysis, methylation and oxidation with chromium trioxide, Gangliosides 1 and 2 were proposed to be Ara p beta(1 leads to 6)Gal p beta(1 leads to 4)8-O-MeNeuGc(2 leads to 3)Gal p beta(1 leads to 4)Glc p beta(1 leads to 1)-ceramide and Ara p beta(1 leads to 6)Gal p beta(1 leads to 4)NeuGc(2 leads to 3)Gal p beta(1 leads to 4)Glc p beta(1 leads to 1)-ceramide, respectively. The ceramide moieties of both gangliosides had similar phytosphingosine and 2-hydroxy fatty acid compositions, and both gangliosides were structurally related to the previously described Ganglioside 3.


Thermodynamic analysis of the nonspecific interaction of sodium dodecyl sulfate with swollen Bio-Gel beads. In frontal gel chromatography on Bio-Gel P-2, sodium dodecyl sulfate (SDS) at the concentrations below its critical micelle concentration (cmc) showed anomalously high partition coefficients (Kav obs) indicative of strong interactions with the swollen gel phase; further, Kav obs was found to increase with concentration and temperature. This preferential partition of SDS in the Bio-Gel phase was analyzed in terms of the transfer free energy of SDS from the mobile phase (0.1 M NaCl) to the swollen Bio-Gel phase. The results showed that the overall transfer process is primarily governed by hydrophobic free energy arising from the anomalous nature of hydrated water in the gel matrix; that is, in highly hydrated water "iceberg" formation is evidently limited and the hydrophobic free energy is accordingly lowered, resulting in the preferential partition of SDS in the swollen Bio-Gel phase. The increase in the negativity of transfer free energy with concentration, though relatively small, indicated a definite tendency for the formation of SDS clusters in the gel phase. Finally, a model illustrating the states of SDS molecules in the gel matrix is presented, which may also be pertinent to SDS-protein and SDS-amylose complexes.


Consecutive analysis of sphingoglycolipids on the basis of sugar and ceramide moieties by high performance liquid chromatography. A quantitative consecutive method was developed for analysis of sphingoglycolipids in biological materials by high performance liquid chromatography (HPLC). Crude lipid extracts were separated into neutral and acidic fractions on a DEAE-Sephadex column. Glycolipid fractions were obtained by acetylation and Florisil column chromatography, and the acetylated glycolipids were N-p-nitrobenzoylated by treatment with p-nitrobenzoyl chloride in pyridine at 60 degrees C for 6 h. Excess reagent and by-products were removed by solvent partition and gel filtration. The glycolipid derivatives were analyzed by their absorption at 254 nm on Zorbax SIL, a silica gel column, with a gradient of 0.5--7% isopropanol in hexane-chloroform (2 : 1, v/v) at a flow rate of 0.5 ml/min. The detector response was linear with up to 60 nmol of injected glycolipids. The practical lower limit of detection was about 50 pmol. The derivatives were separated on the basis of their sugar chains. Effluents corresponding to each peak were collected and analyzed further on the basis of their lipid portion on mu-Bondapak C18, a reversed phase column. This combined procedure was applied to the analysis of erythrocyte glycolipids. Samples containing as little as 20 micrograms of glycolipids could be analyzed by this method.


Divalent cation binding properties of slow skeletal muscle troponin in comparison with those of cardiac and fast skeletal muscle troponins. 1. New methods of preparing troponins from slow skeletal and cardiac muscle of the chicken have been developed. The electrophoretic mobilities of slow skeletal muscle troponin subunits were different from those of the corresponding fast skeletal muscle subunits. 2. A new method for determining the amount of divalent cations bound to troponin was developed. The principle of the method is to immobilize troponin by conjugating it with Sepharose 4B resin, thus making it readily sedimentable. 3. The numbers of Sr and Ca ions bound to slow muscle troponin at concentrations sufficient to produce maximum contraction were 1.73 and 1.36 mol per mol, respectively, being nearly equal to those of cardiac troponin but half of those of fast muscle troponin. 4. The concentrations of Sr and Ca ions giving half-maximal ion binding to slow muscle troponin (K50%) were 5.5 X 10(-6) M and 4.6 X 10(-7) M, respectively. 5. K50% for Sr of cardiac troponin was significantly higher than that of slow muscle troponin. Although K50% for Sr of cardiac troponin was the same as that of fast muscle troponin, cardiac troponin bound more Sr ions than fast muscle troponin at lower Sr ion concentrations. The mechanism underlying the high sensitivity of cardiac muscle contraction to Sr ions is discussed in comparison with that of slow muscle.


A simple method for measuring phosphatidylcholine as its hydrophobic complex with tetrathiocyanatocobaltate. A sensitive colorimetric method for quantitative determination of phosphatidylcholine is described. The procedure is very simple, not involving lipid extraction or acid digestion, and can be used for direct estimation of phosphatidylcholine in blood plasma. The method depends on the formation of a stable hydrophobic complex of phosphatidylcholine with tetrathiocyanatocobaltate. Similar complexes are formed by other species of diacylglycerophosphoryl esters, but the absorbance coefficients of these complexes are only 10 to 20% of that of the phosphatidylcholine complex. Phospholipids without unsaturated fatty acids, such as dipalmitoyl phosphatidylcholine, do not form hydrophobic complexes. Lysophosphatidylcholine and sphingolipids also do not form similar complexes.


Trituration and creep.

Trituration and creep. Creep values of amalgam have been thought to be typical and nearly equal to their order of magnitude, depending on composition and particle shape. Recently it has been shown that trituration time may cause changes in creep magnitudes. The type of mixer and its frequency have contributed additional variabilities. These variations could not be related consistently to changes in creep values. Increases in condensation pressure did contribute to more predictable and constant values found with different mixing times.


Removal of gamma-II phase in amalgam.

Removal of gamma-II phase in amalgam. To examine the quantitative change in the gamma 2 phase, specimens of three conventional, four dispersed-phase and two ternary amalgams were prepared. A higher energy amalgamator caused more gamma 2 phase to be formed in conventional amalgam and less in the dispersed-phase material. With storage at 37 degrees C this gamma 2 phase decreased quantitatively in dispersed-phase amalgams over one week but not in conventional amalgams. The selective etch system of gamma 2 did not disclose this phase in the ternary amalgams.


A method for the measurement of dimensional change of dental amalgam. A dimensional change occurs during the setting of a dental amalgam. A measurement circuit, which makes it possible to register these changes, is introduced. To this purpose strain gages were used. The registration instrument is tested by comparing different dental amalgam products.


Blood-surface interactions: Fourier transform infrared studies of protein surface adsorption from flowing blood plasma and serum. The adsorption of blood proteins onto various surfaces in contact with flowing blood plasma or serum has been investigated using Fourier Transform infrared spectroscopy (FT-IR) coupled with attenuated total reflection (ATR). Comparison of adsorption from a static versus a flowing blood plasma system indicated that a greater amount of protein was adsorbed when the static system was employed, but desorption was observed with the static system and not in the flowing system. When plasma and serum were compared in terms of amount and type of protein adsorbed, little difference was noted in either kinetics of adsorption or stability of the adosrbed layers. Variations in the ratios of infrared adsorption bands (from either plasma or serum) indicate that changes occur during the adsorption process in the protein layers. A comparison of poly(vinyl chloride) to germanium as the protein adsorbing surface in the static system showed differences in terms of the composition of the adsorbed layers.


A resonance frequency technique to determine elastic modulus of hydroxyapatite. A resonance frequency technique was applied to determine the elastic modulus of hydroxyapatite. A Free-Free Vibration Transducer was designed to determine elastic modulus in a longitudinal direction. A Fixed-Free Vibration Transducer was also designed to study elastic modulus of materials were specimens longer than 3 cm in length were not available. Six lots of hydroxyapatite were prepared utilizing the same process. The elastic modulus of hydroxyapatite varied between 3.94 x 10(10) (dyn/cm2) and 6.30 x 10(10) (dyn/cm2) in a longitudinal direction. For the same six lots, it varied between 1.95 x 10(10) (dyn/cm2) and 3.20 x 10(10) (dyn/cm2) in a cross direction. The elastic modulus values of cortical bone from dog tibias, fibulas, and femurs were also determined.


Contact pressure dependence of wear rates of ultra high molecular weight polyethylene. Wear rates of orthopaedic polyethylene in 37 degrees C water are not very contact stress dependent below 1000 psi (6.9 MPa) but above that level they accelerate substantially. The pressure dependence overall follows an exponential function. Creep in the contact pressure range of 3--17 MPa and above is a much larger factor than wear in indentation effects. For accurate measurement of wear rates by depth measurements it is necessary to permit creep to proceed under static load until it ceases before beginning the wear test.


Evaluation of sunlight stability of polyurethane elastomers for maxillofacial use. II. The effect of selected UV stabilizers on the stability of mechanical properties of a polyurethane material, Calthane ND2300, was evaluated. The addition of UV stabilizers prolonged the service life of the systems studied but did not achieve completely satisfactory results. The tensile strength and modulus of elasticity decreased after extended exposure to UV. The rate of decrease, however, was much less for the specimens with UV stabilizers. The polyurethane system that contains a mixture of a UV stabilizer and an antioxidant is considered to be the best of the groups tested, in terms of the percentage of retention of tensile strength and modulus of elasticity. It was also found that elongation at break was increased when the duration of UV aging was increased. This phenomenon occurred in all the systems, with or without UV stabilizers, and can be understood in terms of the concepts of the fragmentation of macromolecules that resulted from UV aging. The physical appearance in conjunction with mechanical property tests are needed to ensure the successful performance of any UV stabilizer.


Acute fractures and dislocations of the cervical spine. An analysis of three hundred hospitalized patients and review of the literature. Of 300 patients who were hospitalized for acute cervical injuries, 216 lived, fifty-one died within four months of injury, and thirty-three were lost to follow-up. The important findings in a retrospective review were that laminectomy resulted in a high mortality rate and loss of motor function and that steroids did not improve neural recovery in quadriplegics and their use was associated with gastrointestinal hemorrhage. Closed or open reduction followed by posterior fusion for subluxations or dislocations, and anterior decompression and fusion for vertebral compression fractures, offered the best chance for recovery of neural function and restoration of stability. Massive epidural hemorrhage was found only in patients with ankylosing spondylitis.


Reconstructive surgery in the adult for failed scoliosis fusion. Fifty-nine adult patients were examined who had undergone previous spine surgery for scoliosis but in whom pain (78 per cent), loss of correction (68 per cent), or dyspnea (36 per cent) subsequently developed. Twenty-six patients had idiopathic scoliosis, twenty-five had paralytic scoliosis secondary to poliomyelitis, and eight had scoliosis secondary to miscellaneous etiologies. A one-stage reconstructive procedure was performed in sixteen patients and a two-stage procedure, in forty-three patients. The two-stage procedure consisted of exposure of the spine and multiple osteotomies, followed by two weeks of halofemoral traction to obtain correction. The spine fusion was then extended, using Harrington instrumentation to maintain correction. At an average follow-up of 3.3 years there was reduction of pain in 67 per cent of the patients and a solid fusion in all but two. The complication rate was high (71 per cent), the most important complications being pseudarthrosis, wound infection, urinary tract infections, loss of lumbar lordosis, and pressure sores. The mortality rate was 3.4 per cent. No patient became paraplegic at the initial surgical procedure and early recognition and treatment of pseudarthrosis will reduce the number of patients requiring this salvage operation.


Total hip replacement following failed femoral hemiarthroplasty. Total hip-replacement arthroplasty performed for failed femoral hemiarthroplasty achieved results that were as good as those of the same operation done for other conditions. In forty-one patients who underwent such a procedure and who were followed for an average of three years, there was marked improvement in pain rating and range of motion. However, there were more cases of progressive loosening of the prosthesis than occur ordinarily, and three revisions had to be done. Fixation of the femoral component with cement was complicated by the presence of the fibrous membrane and bone deficiency preoperatively.


Ender nailing in fractures of the diaphysis of the femur. Sixteen fractures of the diaphysis of the femur were nailed according to the Ender technique. Fifteen of these were of types for which Küntscher nailing was contraindicated. In five of the injuries a comminuted fracture of the femoral shaft was present, associated with a fracture of the proximal end of the femur. Most of the nailings were done closed. The time of surgery was short and the blood loss, small. All of the fractures healed and no major postoperative problems were noted.


Knee ligament injuries in children.

Knee ligament injuries in children. Nine children who were less than fourteen years old and had open physes and ligament injuries of the knee were studied. Despite an initial thorough physical and roentgenographic evaluation, the full extent of the lesion was determined only at operation in seven of the nine patients. The intercondylar eminence of the tibia was avulsed in five patients, four of whom had associated collateral ligament injuries and a positive anterior drawer sign. Despite surgical repair, all nine patients demonstrated some degree of postoperative ligament instability. This was increased in those patients in whom menisectomy had been performed concomitantly with ligament repair. Although none of the children were symptomatic at the time of writing, development of degenerative arthritis in the future must be considered. Ligament injury must be considered in the differential diagnosis of the child suffering from knee trauma. The association of avulsion of the tibial spine and collateral ligament injury is emphasized.


Bone-mineral content, surface hardness, and mechanical fixation in the human radius. A correlative study. The bone-mineral content of seventeen intact forearms from eleven cadavera was determined by the non-invasive photon-absorptiometric scanning technique (Norland-Cameron Bone-Mineral Analyzer). Each radius was then removed and three surgical screws were implanted. The forces required to push out the screws retrograde were used to represent the security of mechanical fixation and were correlated with bone-surface hardness and bone-mineral content. A high degree of correlation (r = 0.89 or more) was found between bone-mineral content and the force required for extraction. A much lower correlation existed between surface hardness and extraction force (r = 0.30). We concluded that surface hardness does not correlate well with the screw-holding capacity of bone but that bone-mineral content, as determined by a non-invasive means, does so within a 10 per cent error. This study demonstrates a high degree of positive correlation between bone density and the security of screw fixation in the human radius. Measuring bone density using a highly accurate, non-invasive, safe technique has clinical relevance in preoperative assessment of osteopathic patients who are being considered for internal fixation of the radius with plates and screws.


Microvasculature of the cruciate ligaments and its response to injury. An experimental study in dogs. The normal vascular anatomy of the cruciate ligaments was investigated in eight dogs by microangiography, histology, and tissue-clearing (Spalteholz) techniques. The vessels were found to originate predominantly from the soft tissues (infrapatellar fat pad and synovial membrane) of the joint. The vascular response to partial surgical transection of the anteromedial mid-portion of the anterior cruciate ligament was evaluated in twelve dogs. This response, which was vigorous and extensive, appeared to arise from the soft tissues. Resection of the infrapatellar fat pad and synovial membrane at the time of injury tended to decrease this response. Spontaneous healing of the defect had not occurred in either group by eight weeks. The predominant soft-tissue, as opposed to osseous, origin of the blood supply to the cruciate ligaments may be an important consideration in the repair of these structures. The preservation and utilization of the infrapatellar fat pad and synovial envelope may optimize the vascular response and healing of the ligament.


Traumatic winging of the scapula.

Traumatic winging of the scapula. Fourteen patients with traumatic winging of the scapula were reviewed, all of whom had had injuries producing sudden depression of the shoulder girdle from either a direct blow to the top of the shoulder or downward traction on the arm. The diagnosis was commonly missed for a considerable interval. Seven patients recovered spontaneously within six months of injury. Three of the other seven patients were treated by reattachment of the insertion of the sternal portion of the pectoralis major muscle via a fascia lata graft to the lower pole of the scapula. In one of these patients a reoperation was needed, but all three ultimately recovered satisfactory function of the shoulder. Anatomical studies suggested that the injury results from compression of the long thoracic nerve against the second rib and not from entrapment of the nerve by the scalenus medius muscle.