Search

Cats were trained to walk and trot on a motor-driven treadmill such that mean kinematic timings were highly uniform. Evidence was sought that variations in electromyographic activity in individual muscles was due to separate sources of control. EMGs were recorded on magnetic tape from a knee extensor, vastus lateralis (VL), and a hip flexor, iliopsoas (IP). At the same time, the cat's movements were recorded on 16 mm cine film at 100 frames per sec. In accordance with previous reports, VL showed one long main burst during the stance (down) portion of the step cycle. However, there were two onset times. A late swing (foot up) component began a few msec before touchdown in every stride in every cat. In contrast, in some cats an earlier burst, that was not completely continuous with the main burst, began 50-100 msec before touchdown and was present in most but not all individual strides. In a few animals there was also an occasional burst in mid-swing. The stance burst itself was further subdivided into multiple peaks that presumably were at least partly reflexive responses to pressure from the belt. The flexor, IP, also showed multiple peaks in its long main burst and other activity whose presence varied from cat to cat. It was concluded that the independence of control for many EMG components during locomotion requires a behavioral analysis of reflexes and conditioned responses to determine the origin of each kind of activity.

Trifluoperazine (TFP) shows cytotoxic activity against human acute lymphatic leukemia (ALL) in vitro. This activity is inhibited by increasing serum concentration and by albumin. Despite its in vitro activity, the drug is inactive in vivo. To determine if increased phenothiazine hydrophilicity could protect against albumin inhibition of antileukemic activity, we compared ALL cytotoxic median effective dose concentrations of a series of hydroxylated phenothiazines in 5% fetal bovine serum (FBS) and in 5% FBS supplemented with albumin. Albumin inhibits the activity of all drugs. A representative derivative 7,8-dihydroxychlorpromazine, although active in vitro, is inactive against L1210 and P388 murine leukemias in vivo.

The diagnosis of fistula of the nose results from the history and inspection of the patient. The radiologist main function is to rule out other diagnoses and to obtain information about location and extension of the fistula-system. This can be obtained by contrast-filling of the fistula-system in a non-infectious interval over thin-catheters or canulas. The Water's view shows whether the fistula reaches of the nasal-septum nor the cribriform-plate. Other diagnoses which have to be excluded are meningoencephalocoeles, mukocoeles and neoplastic diseases. These can be ruled out by tomography of the visceralcranium and the base of the skull.

A simple, inexpensive foot switch was fabricated to record the duration of surface contact for part or all of the foot during human locomotion. The device incorporated electrically conductive metallic foil in a thin foam insole. Advantages over a more conventional thick-soled sandal were documented for the same subjects by examining kinematic values (read from movie film) and electrical signal data (produced by the switch). A person's characteristic manner of placing and lifting the foot while wearing conventional shoes could in some instances distort readings of stance duration by many tens of msec, but the new switch assembly eliminated ambiguities of measurement and interpretation.

Natural anti-DNP antibodies were isolated by affinity chromatography from individual sera of three Cyprinid fish species (carp, goldfish and tench) and their electrofocusing (IEF) spectra were analysed in reducing conditions. In addition, immune anti-penicillin and anti-BSA antibodies were isolated from individual and pooled tench sera, and studied by IEF techniques on reduced samples. Diversity rates appeared to be rather low in the three fish species, and striking similarities arose between individuals of a same species. These results can be interpreted by the existence of particular selective pressures operating in poikilothermic species as it was already suggested by Du Pasquier. No enhancement of antibody heterogeneity could be detected in the tetraploid (carp and goldfish) species. This result is also in accordance with the selection of a restricted germ-line determined antibody repertoire in lower vertebrates.

In 1985 Harvard Medical School initiated an experimental curriculum that incorporated many of the recommendations of the report on the General Professional Education of the Physician (GPEP). Key features are problem-based small group tutorials that emphasize active learning, with increased independent study time and a decreased number of lectures. Tutors serve as guides to their students and are not necessarily experts in the discipline of the cases studied. Learning skills are taught, including information acquisition and criticism and computer literacy. Knowledge is integrated from the beginning by interdisciplinary basic science courses, by earlier introduction of the clinical sciences, and by juxtaposition of the scientific and humanistic aspects of medicine. Preventive medicine, health maintenance, and ambulatory care are given more attention. The students are organized into societies that provide vertical integration and promote cooperation among students and closer contact with faculty. Pathology has proved to be a popular and key bridge in the new curriculum. The success of the early efforts at Harvard and several pioneering medical schools should encourage others to move toward more problem-solving, student-centered, integrative medical education.

Cyclosporin A abrogates pleiotropic drug resistance in certain experimental tumors. Its impact on drug-sensitive tumors has not been investigated. Our studies show that in drug-sensitive Ehrlich ascites carcinoma and hepatoma 129 cyclosporin A enhances daunorubicin inhibition of DNA synthesis in vitro and prolongs survival of host mice in vivo. Of particular interest is that cyclosporin A converts ineffective daunorubicin regimens into those which result in prolongation of host mice survival. Other agents known to reverse pleiotropic drug resistance are reported to exert their effects by increasing intracellular drug accumulation. In contrast, our studies of drug transport in drug-sensitive Ehrlich ascites carcinoma and hepatoma 129 show that cyclosporin A causes minimal enhancement of [3H]daunorubicin uptake without inhibition of [3H]daunorubicin efflux in both the presence and absence of interrupted active daunorubicin efflux. This suggests that the mechanism of action of daunorubicin enhancement by cyclosporin A in drug-sensitive tumors is not simply the result of increased intracellular daunorubicin accumulation. In vivo dosages of cyclosporin A in the current study are comparable to those which can be used with reasonable safety in humans. We conclude that cyclosporin A may be useful in the potentiation of anthracycline antibiotic therapy directed against drug-sensitive as well as drug-resistant tumors.

In order to obtain accuracy in the detection of the pre-invasive and early invasive laryngeal cancer microscopy and cytology can be jointly used. The cytologic picture of the early invasive laryngeal cancer is described including its precursors.

Human locomotion, as a behavioral system, is well suited for investigating the interplay of learning with innate biological mechanisms. The present work assembled, from previous findings, a test battery of operant conditioning to modify strong ongoing electromyographic (EMG) activity of the left tibialis anterior (TA), an ankle flexor muscle. An EMG segment 100-400 msec long had to occur within 700 msec, and (in different training regimens) with filtered amplitude both above and below different thresholds--all in response to a colored light that flashed at a designated time in the step cycle. Reinforcement was a high or low tone that indicated success or failure, respectively. All four subjects met training criteria (90% success rate) at a moderate amplitude, just as had been true previously for a relatively inactive knee extensor. Subject-specific limitations were found in operant control at higher and lower amplitudes. New learning was not disruptive, although ipsilateral swing duration increased, nor was it phase-dependent on any portion of the step cycle.

High spontaneous anti-trinitrophenyl (TNP) activities were found in three Cyprinid fish species: Carp (Cyprinus carpio), Goldfish (Carassius auratus) and Tench (Tinca tinca). The molecules involved, isolated by affinity chromatography on dinitrophenyl-lysine Sepharose (DNP-lysine-Sepharose), had the main characteristics of a high molecular weight immunoglobulin (IgM-like). Affinity measurements were performed on natural anti-DNP/TNP antibodies isolated from nine individual tench sera, using the inhibition of DNP-T4 bacteriophage inactivation technique. The antibodies analysed were more specific for TNP than for DNP. No activity was found against paranitrophenyl hapten. Affinities were all very low, even for TNP. In the three species, natural anti-DNP/TNP antibodies constitute as much as 11 to 16% of the total immunoglobulin concentration. This high level of nitrophenyl-binding serum immunoglobulins either suggests the existence of a particular regulatory mechanism in fish or reflects a generally low antibody diversity in these species.

Twenty-four hours after the intravitreal injection of [3H]palmitate and [14C]docosahexaenoate in dogs, the rod outer segment phospholipids are highly labeled. Palmitate is found predominantly in phosphatidylcholine (PC), with lesser amounts in phosphatidylethanolamine (PE) and very little in either phosphatidylserine (PS) or phosphatidylinositol (PI). Docosahexaenoate most heavily labeled PE followed by PC, with lesser amounts in PS and very little in PI. Two-hour incubations of 3 mm trephine buttons removed from dog retinas produced very similar patterns of labeling with palmitate and docosahexaenoate. In vitro incubation of retina buttons with [3H]arachidonate produced heavy labeling of PI, with much less in PC and very little in either PS or PE. [3H]Glycerol labeled in PC, PI and PE in descending order but PS almost not at all. [3H]Serine labeled PS predominantly, but small amounts were found in PC, PE and PI. The trephine retina buttons can be utilized for multiple-precursor incubations and studies of differential metabolism in retinal regions, particularly when studying scarce tissue from mutant animals or humans with inherited retinal degenerations.

The imaginary audience of 328 early and late adolescents was studied from the viewpoint of providing educators and clinicians with insight into its attributes--those which both facilitate and hinder youths' development. Early adolescents (about 14 or 15 years of age) displayed a greater awareness of an imaginary audience which probably contributed to their observed, elevated group dependence. Unexpectedly, the shyness of adolescents highly sensitive to an imaginary audience increased with age, possibly because they are unwilling to provide themselves with the social experiences necessary for decentering. Likewise, those highly sensitive to an imaginary audience projected low self-concepts and thus imply that their audience is relatively critical; thus, they probably validate a self-fulfilling prophecy, oblivious to a possible contradictory external reality. The anticipated fact that females appeared to be less socially bold and more group dependent than males might account, in part, for females' greater responsiveness to an imaginary audience. It is suggested that educators and clinicians encourage youth to validate social hypotheses in order to promote the dissolution of the imaginary audience, especially of those who are shy and display self-deprecatory tendencies.

When a single-muscle learned behavior was superimposed upon natural human treadmill locomotion, in previous work, it operated as a self-contained behavioral unit. The new behavior altered some features, however, of ongoing stepping patterns. These findings prompted broader consideration of how individual muscle actions combine to form large, patterned ensembles. Accordingly, the present experiment constructed a larger, double-muscle learned behavior to see if it would compete with natural treadmill locomotion or combine with it harmoniously. A demanding requirement was made for in-phase bilateral EMG and contraction by rectus femoris (RF), in opposition to its natural out-of-phase interlimb pattern. EMG bursts were controlled, through computer-assisted operant conditioning, by a flash shortly after left heel strike. The new, double ensemble was conditioned rapidly, within 1-6 days, for all four adults. Harmonious stepping continued, for the most part, with little alteration in step cycle timings. Leg positioning was modified appreciably, however, pointing to complex neural mechanisms. The evidence argued that operant conditioning can construct fine-grained behaviors and also participate powerfully across the full range of single- and interlimb coordination.

Interactions between specific operant conditioning and ongoing treadmill walking have been characterized in several previous investigations of mechanisms that coordinate locomotion. The present study examined a higher walking velocity in which contractile forces and, by inference, reflex behavior, might be more powerful. Two subjects walked on a motor-driven treadmill at 0.90 m/sec. As in past work, at 0.45 m/sec, a conditioning regimen constructed a test operant in the following way. With training, a green light that flashed approximately 200 msec after heel strike on every third step produced, after operant reinforcement, a 100-500 msec electromyographic burst in the rectus femoris (RF) muscle before the end of a 500 msec performance duration. Reinforcement consisted of a tone that sounded after each response and indicated success or failure. Burst durations were shorter than had been typical at a lower treadmill speed, a characteristic that could favor rapid matching of contractile patterns to more rapidly changing conditions. No evidence was gained of interference from stretch reflexes or any other ongoing inborn behavior. The resulting rapid walk was as well coordinated as that seen at lower velocity, to argue for increased emphasis on the role of learning in normal locomotion and to improve pathological walking.

We have studied the influence of verapamil hydrochloride on the in vitro and in vivo effects of daunorubicin in Ehrlich ascites carcinoma. Daunorubicin-sensitive tumor was rendered resistant to daunorubicin by the continuous treatment of sequential generations of tumor-bearing BALB/c mice. The ability of daunorubicin to inhibit [(3)H]uridine and [(3)H]thymidine incorporation and the effect of daunorubicin on the mean survival time of host animals bearing daunorubicin-sensitive and daunorubicin-resistant Ehrlich ascites carcinoma were compared. The addition of verapamil to daunorubicin in vitro reduced the concentration of daunorubicin required to inhibit 50% of DNA and RNA synthesis in the daunorubicin-resistant tumor to that required in the daunorubicin-sensitive tumor, from 6 and 4.4 mug/ml to 1.5 and 1.3 mug/ml, respectively. Verapamil also restored drug sensitivity to daunorubicin-resistant Ehrlich ascites carcinoma in vivo. The 21.7+/-0.7 d mean survival time (MST) of BALB/c mice bearing daunorubicin-resistant tumor treated with daunorubicin alone rose to 44.0+/-0.7 d when the same tumor was treated with verapamil and daunorubicin, P < 0.001. This in vivo effect is specific for daunorubicin-resistant Ehrlich ascites carcinoma, since there is no alteration in MST of BALB/c mice bearing daunorubicin-sensitive or daunorubicin-resistant tumor when they are treated with verapamil alone or when BALB/c mice bearing daunorubicin-sensitive tumor are treated with daunorubicin and verapamil.

A 45-year-old woman with corneal opacification and severe coronary artery disease was noted to have the following plasma lipid levels (mg/dl, +/- SD): total cholesterol 111 +/- 13, triglyceride 62 +/- 6, very low density lipoprotein cholesterol 4 +/- 1, low density lipoprotein cholesterol 106 +/- 14, and high density lipoprotein (HDL) cholesterol 1 +/- 1 (normal, 50 +/- 14). Her two offspring and one brother were found to have HDL cholesterol values (mg/dl) of 23, 20, and 20, respectively. The percentage of cholesterol in the esterified form in the patient's plasma was normal at 70%. Lipoprotein electrophoresis showed no alpha lipoprotein band, and no HDL was detectable when plasma was subjected to analytic ultracentrifugation. Only trace amounts of lipids were noted within the HDL density region following preparative ultracentrifugation. Mean plasma apolipoprotein (apo) A-ll, apo B, and apo C-ll plasma levels were 13.8%, 130.6% and 26.6% of normal, respectively. The ratio of apo B to cholesterol within LDL was elevated. Apo A-l, the major HDL protein constituent, was immunologically undetectable in this patient's plasma. A decreased HDL cholesterol concentration has been associated with premature coronary artery disease. These data indicate that plasma apo A-l absence results in a striking reduction in HDL, is associated with premature coronary artery disease, and represents a new distinct disease entity.

Empirical and theoretical reasons were given to investigate operant conditioning in a new, integrative approach within motor control physiology. Elements of inborn and learned behavior were presented in a framework specifying their stimuli and responses. The operant was redefined as a controlling discriminative stimulus, Sd, together with the response, R, it produces, on the basis of a previous literature of operant and instrumental research. Complex motor and neural activity were reviewed in accordance with partitioning of: responses, controlling stimulation, reinforcement, and functions of movement-produced stimulation. Schematics portrayed reinforcement principles through analysis of a fast pathway from Ia muscle spindle afferents to motor outflow. Methods were suggested to minimize operant units through selective reinforcement and establish them to defined end points of learning within composite, ongoing behavior. It was argued that operant neural mechanisms can be investigated efficiently only by starting with individual operants that are thoroughly characterized.

Rat retinas were intravitreally labeled with [3H]palmitic acid, [3H]arachidonic acid or [3H]glycerol to study the turnover of the component parts of the major phospholipids in rod outer segments at times ranging from 2 hr to 12 days post injection. Rod outer-segment and retinal debris fractions were extracted and the major phospholipids separated by two-dimensional thin-layer chromatography. In darkness, [3H]glycerol rapidly labeled phosphatidylinositol in both rod outer-segment and retinal debris fractions. The label in phosphatidylinositol subsequently decreased dramatically, demonstrating a rapid turnover of phosphatidylinositol with a half-life of less than 1 day. Phosphatidylcholine and phosphatidylethanolamine were maximally labeled by glycerol in the retinal debris at the 2-hr time-point and were maximally labeled in rod outer segments between 1 and 5 days post injection, with somewhat longer residence times in the rod outer segments. Phosphatidylserine showed a lag in initial labeling in both rod outer-segment and retinal debris fractions indicating that this phospholipid is not a major precursor of phosphatidylcholine and phosphatidylethanolamine in rat retinas. [3H]Palmitate and [3H]arachidonate labels were rapidly incorporated into outer-segment phospholipids by 1-2 hr post injection. Eighty per cent of the palmitate label was initially associated with phosphatidylcholine at 2 hr. The total amount of palmitate label in rod outer-segment phosphatidylcholine did not change for 12 days post injection. Outer-segment phosphatidylethanolamine steadily increased in palmitate label throughout the 12-day period, suggesting that phosphatidylethanolamine may be utilized for recapture of palmitate released from breakdown of palmitate esters of rhodopsin or vitamin A or from phospholipids. Arachidonate primarily labeled phosphatidylinositol and phosphatidylcholine of both rod outer segments and retinal debris. The arachidonate label did not decrease dramatically during the first day in phosphatidylinositol as did the glycerol label, indicating that arachidonic acid is reutilized by the retina. Turnover of the individual phospholipids, as measured by a decrease in glycerol labeling of the phospholipid backbone, is more rapid than the loss of palmitate label, indicating that there is extensive reutilization of palmitate in both phosphatidylcholine and phosphatidylethanolamine of the rod outer segment. The data indicate that palmitate derived from many sources could be used by the photoreceptor to acylate rhodopsin.(ABSTRACT TRUNCATED AT 400 WORDS)

An operant conditioning history can produce highly uniform kinematic performances by cats on a motor-driven treadmill, but in the present work there was additional stimulus control such that the animals moved smoothly backward or forward on the belt, "startled," or reached for a food tray at the front of the chamber. The resulting responses were filmed and EMG records were taken from VL (vastus lateralis, a knee extensor) or IP (iliopsoas, a hip flexor) or both muscles. Both ipsilateral and bilateral responses were observed, and sometimes the change was restricted to just one portion of the VL or IP activity, showing precise moment-to-moment control. Forelimb reaching caused an early VL burst prior to touchdown, which may help understanding of extensor bursts that "anticipate" the contact of a limb. In other cases, an absence of control of hindlimb events was the major finding. No evidence was gained for vestibular or neck reflexes, since there was no response to large isolated head or neck excursions. Also, an animal might complete a full hindlimb step without any VL activity. It was concluded that acquired stimulus control could bring about marked separations of functional subdivisions of the step cycle.

It is possible that a genetic defect observed in the prcd poodle involves the abnormality of an enzyme which functions in phospholipid or lipoprotein metabolism. In our studies thus far, we have been unable to detect any defect in retinal phospholipid biosynthesis, but we have noted a decrease in plasma levels of 22:6w3 which may be a result of an enzyme defect in liver biosynthesis of 22:6w3 from its dietary precursor, linolenic acid, or some defect in the blood lipoprotein transport of this essential fatty acid. If 22:6w3 is essential to the normal elaboration and functioning of the photoreceptor outer segment, it is possible that decreased access to this fatty acid due to lower blood levels of 22:6w3 could cause photoreceptor abnormalities. Further studies are needed to confirm the possible defect in delta-4 desaturase activity and possible dietary modification of the course of this prcd retinal degeneration.

Increasing experimental concern with locomotion and its neural control prompted the construction of a motor-driven treadmill for cats. The apparatus was designed for kinematic analysis of gait from 16 mm movie film, but it will also permit a variety of other records to be taken. A box, or base, houses two large drums and the belt drive. Space is provided on top of the base for a closed locomotion compartment that is transparent on the filming side. There is also sufficient space on top of the base for support apparatus, operator controls, and animal exits. Cats may be trained to work for food reward alone, as delivered from the front by the operator. Alternatively, they can be trained to stay near the front of the treadmill belt in order to avoid an aversive jet of air or electric shock, either of which can be delivered at the rear of the test chamber. The operator can maintain forward belt velocity at fixed levels between 0.5 and 6 m/sec, or he can vary velocity continuously. Displays of a tachometer and a special timing device are large enough to be clearly visible on the film. These various features in combination provide a controlled and varsatile stepping environment, in which the cat can move without physical restraints.

SEPs were elicited by stimulation of the dorsal penile nerve (DPN) or posterior tibial nerve (PTN) under 3 conditions of stimulation: random and constant interstimulus intervals, and subject-initiated stimulation. Within these conditions, the effects of repeated stimulation were also examined. The latency of the N90 peak decreased with repeated stimulation. N90 amplitude decreased with increased foreknowledge as well as with repeated stimulation. Factors extracted by principal components analysis revealed similar effects. A difference between DPN and PTN stimulation was seen in a factor associated with the N90 peak, wherein the condition involving subject self-initiation of the stimulus reflected a significantly greater decrease in SEP amplitude when the DPN was stimulated. Morphological commonalities were observed in the SEPs elicited by DPN and PTN for a given subject.

Plasma membranes were isolated from the ameba Acanthamoeba castellanii by low-speed velocity centrifugation followed by equilibrium centrifugation in a sucrose gradient. The isolated membranes had a high ratio of sterol to phospholipid (0.98 moles/mole) and of phospholipid to protein (0.43 mg/mg). The plasma membranes had very low concentrations of DNA, RNA, lipid inositol, and glycerides. Glycolipids and glycoproteins were enriched in the plasma membranes relative to their concentrations in the whole cell. The plasma membranes were also judged to be of high purity by the absence, or very low level, of enzymatic activities considered to be indicative of other cell membranes, and by electron microscope examination. Alkaline phosphatase and 5'-nucleotidase activities were enriched in the plasma membranes 13-fold relative to the whole homogenate and had higher specific activities in the plasma membranes than in any other cell fractions. A Mg(++) adenosine triphosphatase (ATPase) was enriched sixfold in the plasma membranes relative to the whole homogenate. The phospholipids of the plasma membranes contained more phosphatidylethanolamine and phosphatidylserine and less phosphatidylcholine than did the phospholipids of the whole cells. There were differences in the fatty acid compositions of corresponding phospholipids in the plasma membranes and whole cells but no difference in the ratios of total saturated to unsaturated fatty acids. The membranes of phagosomes isolated from amebae that had ingested polystyrene latex had essentially the same phospholipid, sterol, and enzymatic composition as plasma membranes.

A method is described for the rapid and efficient isolation of phagocytic vesicles from large scale cultures of Acanthamoeba castellanii (Neff) that have been incubated with polystyrene latex beads. Cells were allowed to phagocytose latex beads for 30 min and then were homogenized, and the phagocytic vesicles were isolated by one centrifugation through several layers of sucrose. Identity and purity of the phagocytic vesicles were determined by electron microscopy, chemical analyses, and assays of acid phosphatase, alpha- and beta-glucosidase, and reduced nicotinamide adenine dinucleotide dehydrogenase. When phagocytosis was allowed to occur for longer periods the phagocytic vesicles appeared to fuse with each other and perhaps with digestive vacuoles. The resultant vesicles which contained many beads were heavier than those which consisted of only one bead or a few beads with a closely applied membrane. Ultrasonication ruptured the isolated vesicles, and the membranes could then be isolated in 30-50% yield based on phospholipid analysis. These membranes were essentially free of acid hydrolases and, presumably, other soluble proteins, as was also indicated by their low ratio of protein to phospholipid. The membranes have been prepared both as closed vesicles and as open sheets.

Selective ultrastructural staining of acid mucosubstances in sites containing histochemically identifiable sulfo- and sialomucins has been obtained in fixed cryostat sections with both ferric chloride and colloidal iron solutions. The rectosigmoid region of mouse colon was fixed in glutaraldehyde, formalin, or phosphate-buffered osmium tetroxide, and 40 micro cryostat sections of this material were treated with 0.1 to 0.4% ferric chloride or with a solution of dialyzed ferric chloride, ammonia, and glycerin. Specific staining depended upon the pH of the iron-containing solutions, and the optimal value was found to be approximately 2.0. Specific localization of acid mucosubstances has been noted in intracellular sites, including globules within colonic goblet cells and "deep crypt" mucous cells, small vesicles of the superficial nongoblet epithelial cells, and Golgi lamellae within each of these cell types. Extracellular material, presumed to be acid mucosubstance, was found on the surface of the epithelial microvilli and on the lumenal surface of capillary endothelium. Similar material formed a reticular network surrounding stromal cells, collagen bundles, and various colonic connective tissue elements.