Reflex connexions of motoneurones of muscles involved in head movement in the cat.

1. The reflex connexions from muscle afferents and ventral root fibres to the motoneurones of the muscles biventer-cervicis, complexus, sternocleidomastoid, trapezius and splenius, the principal muscles involved in head movement in the cat, were studied with the technique of intracellular recording. 2. Electrical stimulation of homonymous muscle afferents of biventer-cervicis and complexus, sternocleidomastoid and trapezius, at strengths below 1.6 times threshold of the dorsal root afferent volley, produced monosynaptic e.p.s.p.s in the corresponding motoneurones. Recruitment of higher threshold muscle afferents produced additional p.s.p.s with longer central delays. 3. Stimulation of low-threshold muscle afferents did not produce any p.s.p.s in the motoneurones of the ipsilateral antagonist. Stimulation of higher threshold afferents evoked i.p.s.p.s with central delays longer than 1.6 msec, or mixed e.p.s.p.-i.p.s.p.s in the ipsilateral antagonist. 4. Mixed e.p.s.p.-i.p.s.p.s or i.p.s.p.s with central delays longer than 1.5 msec were evoked in trapezius motoneurones upon stimulation of high threshold afferents from biventer-cervicis and complexus, while stimulation of low-threshold biventercervicis and complexus afferents evoked no p.s.p.s in trapezius motoneurones. 5. Stimulation of contralateral low-threshold biventer-cervicis and complexus afferents evoked a sequence of i.p.s.p. disinhibition in sternocleidomastoid motoneurones, and vice versa, with central delays longer than 1.7 msec. 6. Stimulation of the deafferented biventer-cervicis, complexus, splenius, sternocleidomastoid and trapezius muscle nerves frequently activated interneurones in the ventral horn at monosynaptic central delays. Activation of homoynmous ventral root fibres rarely evoked p.s.p.s in biventer-cervicis, complexius, splenius or sternocleidomastoid motoneurones, while it produced disynaptic i.p.s.p.s in 80% of trapezius motoneurones. 7. It is concluded that Ia reciprocal inhibition and recurrent inhibition, two reflex circuits which are so prominent in limb segments of the spinal cord, do not play a major role in the generation of head movement. Rather, head movement may be primarily controlled from supraspinal centres.


An estimation of intracranial blood flow in the new-born infant.

1. A non-invasive method for the estimation of the intracranial blood flow of the new-born infant is described, and results obtained with it are presented. 2. The technique is a novel application of the principle of blood flow measurement by venous occlusion plethysmography. It is possible to apply a plethysmographic technique to the neonatal cranium because the presence of open sutures between the component bones permits small, but readily measurable, changes in intracranial volume to occur. 3. Skull volume changes are calculated from changes in the occipito-frontal circumference of the cranium as recorded and measured with a mercury-in-Silastic strain gauge. 4. The jugular veins in the baby's neck are occluded by finger pressure and there follows an increase in skull volume, which is rapid at first, but which decreases exponentially as venous drainage diverts to non-occluded channels such as the vertebral venous plexus. At the instant of jugular occlusion the rate of skull volume increase is representative of the rate of flow in the jugular vessels prior to occlusion, and so provides an index of the relative magnitude of the intracranial blood flow. The method thus allows changes in intracranial blood flow to be followed. When occlusion is released cranial volume decreases, initially rapidly, but slowing exponentially as resting volume is regained. 5. A theoretical model of the events occurring during the inflow and outflow phases has been developed, and a formula derived which allows an estimation to be made of the flow of blood through uncompressed channels. The measured value of jugular blood flow can then be augmented to an estimate of total intracranial flow. 6. The mean cerebral blood flow of sixteen normal babies was estimated to be 40 ml. 100 g-1.min-1 (S.D. = +/- 11.63).


Inhibitory mechanisms influencing complex cell orientation selectivity and their modification at high resting discharge levels.

1. These experiments have investigated the contribution made by GABA-mediated inhibitory processes to the orientation tuning of complex cells in the cat's striate cortex. The GABA antagonist bicuculline has been ionophoretically applied to individual complex cells and the modifications produced in their orientation tuning documented. 2. In terms of the type of change produced in orientation tuning by the application of bicuculline, it seems that there are two categories of complex cells. 3. In one of these categories the orientation selectivity was eliminated during bicuculline application. The excitatory input to these cells would therefore appear to be non-orientation specific. Their orientation selectivity is presumably generated by a GABA-mediated inhibitory input. 4. In the other category of complex cells, although the orientation selectivity was decreased during bicuculline application, the cells retained a preference for a range of orientations that was generally centred around the original optimal orientation. It is suggested that for these cells the inhibitory input enhances the orientation tuning of an excitatory input that is already broadly orientation tuned. 5. Comparison of normal orientation tuning curves with those observed during the application of bicuculline provides a basis for estimating the orientation tuning of the GABA-mediated inhibitory input. In all cases, it is clear that at normal resting discharge levels, orientations either side of the optimal, and not those centred on the optimal, generate the most powerful inhibitory input. 6. These results would seem to be best explained by inhibitory interconnexions between cortical columns sensitive to different orientations. This type of lateral interaction between columns may serve to enhance the contrast in the orientation domain for the cortical representation of a specific stimulus orientation. 7. Increasing the resting discharge level of a complex cell, without blocking the action of GABA appeared to increase the gain of the inhibitory mechanisms acting on the cell. The normal excitatory responses to optimal or near optimal orientations were greatly reduced, or replaced by inhibitory responses, and non-optimal orientations produced only inhibitory responses. These inhibitory effects were blocked on the context of other observations in the literature. It is tentatively suggested that the interneurones providing the inhibitory drive to complex cells receive an input from recurrent collaterals of the recipient complex cells. Their other inputs would derive from neighbouring colums and from the afferent input to the parent column. The inputs from neighbouring columns would mediate the lateral inhibitory interactions in the orientation domain, and the recurrent collateral feed-back the decreased responsiveness at high resting discharge levels.


The effects of calcium on outward membrane currents in the cardiac Purkinje fibre.

1. Properties of outward membrane currents in Purkinje fibres from sheep's hearts have been studied with particular reference to the effects of external Ca. 2. Altering Cao is found to shift the potential-dependence of channel neutralize negative charges at the external face of the membrane, but the different magnitudes of the effects of low Cao on the pace-maker and plateau currents suggest that the affinities of Ca-binding sites adjacent to each channel type are widely different. 3. Raising Cao causes a positive shift in the pace-maker current reversal potential, EK2, which may reflect a small elevation in the K concentration (Kc) in the restricted cleft space immediately outside the membrane. Other possible causes of the shift in EK2 are also discussed. 4. Raising Cao has effects on the plateau and pace-maker current rectifier relations, and on the time-independent membrane current, which resemble those of a small increase in extracellular K concentration. 5. Possible mechanisms for an increase in Kc in elevated Cao are discussed. Positive shifts in EK2 can be observed even when the membrane current becomes more inward, so it seems unlikely that the increase in Kc results from an activation of K channels by Ca ions. It is possible that increases in Ca partially inhibit the Na:K exchange pump. 6. The maximum transient outward current elicited by strong depolarizing steps is not affected by moderate reductions in Cao. 7. Reducing Nao depresses the pace-maker current rectifier relation with little shift in the activation curve. 8. We conclude that some of the effects of Cao on outward currents are due to shifts in the potential-dependence of channel activation, while others result from a small increase in Kc. No evidence for a direct effect of Ca on K channels has been found in the present study.


Initiation and spread of action potentials in granule cells maintained in vitro in slices of guinea-pig hippocampus.

1. Laminar field potentials due to the synchronous activation of granule cells were studied in slices of guinea-pig hippocampus maintained in vitro. 2. Extracellular recordings confirmed that stimulation of afferent laminae in the molecular layer caused excitatory synaptic current to enter the granule cell dendrites. If large enough this current initiated action potentials at, or near to, the somata 100--200 micrometers away. 3. After a population spike had been initiated via excitatory synapses or via antidromic invasion, the lcoation of inward membrane current (sink) appeared to move from the cell body layer into the dendrites at a velocity of 0.08-0.12 m/sec, for a distance of up to 250 micrometers. 4. The sink movement into the dendrites was blocked by tetrodotoxin and not by agents that blocked synaptic activation. Together with other observations these results led to the conclusion that granule cell dendrites were invaded by action potentials from the cell body region. There was no evidence of dendritic action potentials from the cell body region. There was no evidence of dendritic action potentials preceding the cell body spike initiated by synaptic inputs. Possible functions of this dendritic invasion are discussed.


The effect of ouabain on amino acid and orthophosphate influxes in squid giant axons.

1. Some effects of ouabain on the uptake of 14C-labelled amino acids and 32P-labelled orthophosphate into squid axons have been investigated. 2. Ouabain in artificial sea water reduced the uptake of glycine, L-alanine, L-arginine, L-aspartate and L-glutamate. After a period of 3 hr in ouabain the inhibition of glycine and L-glutamate uptake was appreciable. 3. After 3 hr in ouabain the axoplasmic Na concentration had increased by only about 14% and the K concentration had fallen by only about 9%. It therefore seems unlikely that changes in the Na and K gradients across the membrane due to ouabain are the reason for the inhibition of amino acid uptake. This was confirmed when the axons were made to conduct impulses at 200/sec for 40 min. There was no subsequent inhibition of glycine and L-glutamate uptake, even though the axoplasmic Na increased by about 42% and the K decreased by about 37%. 4. A detailed investigation of the time course of the inhibition of amino acid uptake by ouabain in which intracellular scintillator techniques were used, showed that there was no inhibition for 30--100 min, and then it occurred fairly quickly. This course of events was not affected by the protein synthesis inhibitor cycloheximide. It is unlikely that the inhibition of orthophosphate uptake is subject to a similar delay since this had reached a maximum after 40 min. 5. It is concluded that the inhibitory effects of ouabain on amino acid uptake in squid axons are not due to effects on the Na and K gradients brought about by inhibition of the Na-K pump. The delay in the inhibiton may reflect the operation of an intracellular regulatory mechanis, which is initiated when ouabain inhibits the pump but which takes time to operate. If the formation of an inhibitory second messenger molecule is involved this is unlikely to be a protein.


Responses of neurones in nucleus interpositus of the cerebellum to cutaneous nerve volleys in the awake cat.

1. A method is described which permitted stable extracellular recordings to be made from 115 neurones in nucleus interpositus of the cerebellum in unanaesthetized free-to-move cats. At least 95% of the neurones were cerebellar efferent cells since they were antidromically invaded following electrical stimulation of the brachium conjunctivum in the region of the contralateral red nucleus. 2. In cats in a state of quiet wakefulness the majority of interpositus neurones were tonically active at rates ranging from 12 to 77 impulses/sec (over-all mean 34/sec). The remaining neurones were silent or discharged only a few impulses throughout observation periods of a few minutes. 3. Cutaneous afferent volleys elicited by single shocks to the superficial radial nerves in the forearm at intensities too weak to evoke a flexion reflex or behavioural arousal produced changes in firing frequency in 62% of eighty-one cells tested. Response patterns varied widely but in 86% of the responding cells the earliest change was a short latency (6--20 ms) increase in discharge probability which from post-stimulus time histograms was found usually to average around one impulse per stimulus. In only four cells (8%) the earliest response was a depression of the tonic firing. However, in many cells the initial acceleration was followed by a reduction in firing frequency which lasted between 10 and 85 ms. 4. In 56% of the responding cells a longer latency (25--80 ms) acceleration was present. Such accelerations varied widely in duration (from 55 to 550 ms) but most commonly lasted 100--200 ms. These responses were usually the most prominent feature in the response pattern: in the majority of neurones between two and five impulses were added per stimulus. 5. Considering the whole time course of the responses, the net effect of nerve volleys was to produce an increase in nuclear cell output. 6. These neurones which were influenced by nerve stimulation also discharged in response to taps to the forepaws. 7. The responses to nerve stimulation are compared with those encountered in previous studies using cats anaesthetized with chloralose or barbiturates and with the responses of Purkinje (P) cells and it is suggested that the longer latency excitatory responses result in large part from a reduction in the tonic inhibitory action exerted on the interpositus neurones by Purkinje cells. 8. The possibility is discussed that interpositus responses to cutaneous input from the limbs might contribute (via the rubrospinal system) to the regulation of spinal flexor mechanisms during locomotion and/or contact placing reactions.


Activity patterns of cerebellar cortical neurones and climbing fibre afferents in the awake cat.

1. Glass-insulated tungsten micro-electrodes were used to record from single neurones in the intermediate zone of the cerebellar cortex of cats in a state of quiet wakefulness. 2. Two hundred and seventy Purkinje (P) cells were recorded extracellularly, 95% of which displayed an irregular tonic discharge at rates between 19 and 95/s (over-all mean 44/s), including complex spikes (c.s.) which occurred at 1.0--2.5/s )over-all mean 1.5/s). The remaining cells discharged c.s. at the usual rate but only one or two simple spikes (s.s.) per minute. C.s. of spike plus wavelet and of multi-spiked type were present in approximately equal numbers of cells. 3. Presumed climbing fibre-e.p.s.p.s were recorded from fifty-six P cells and occurred both singly and in groups of two to six e.p.s.p.s at an intra-group frequency of about 500/s. The cells giving rise to the c.f.s therefore discharge propagated impulses both singly and in short bursts as previously reported for anesthetized animals. A single e.p.s.p. can give rise to more than one spike in the multi-spiked type of c.s., and probably to a complete c.s. event. 4. Following spontaneous c.s. the interval to the next s.s. varied from 8 to 600 ms. There was an inverse correlation between duration of the post-c.s. interval and the rate at which s.s. were discharged in the preceding 100 ms. The duration exceeded the mean s.s. interval provided s.s. rate was less than 40--50/s, and the post-c.s. interval would then constitute a real interruption of s.s. discharge. 5. When the superficial radial (s.r.) nerves were stimulated with single shocks too weak to produce a behavioural response changes in discharge pattern were detected in eighty-eight of 151 P cells tested. The initial responses were almost always excitatory and consisted in seventy-two cells of a c.s., in eleven of a c.s. preceded by a brief increase in s.s. and in two cases of a s.s. discharge alone. The spino-olivo-cerebellar paths responsible for the c.s. showed transmission characteristics similar to those reported for animals anaesthetized with barbiturates. 6. C.s. were readily evoked by tapping or squeezing the forepaws. 7. Excitatory responses to nerve stimulation were usually followed by a depression of the tonic s.s. discharge. Its duration ranged widely in different cells (from 10 to 500 ms) and it would coincide with equally variable periods of facilitation previously seen in neurones of nucleus interpositus. It is therefore likely that such facilitations of the cerebellar nuclear cells result at least in part from reductions in the tonic inhibitory input from the P cells. 8. Thirty-six units were classes as 'probable cortical interneurones'. They discharged more regularly, at rates between 9 and 28/s. Twenty such units (56%) responded to s.r. stimulation with a brief excitation not usually followed by any pronounced depression.


The central control of the lumbar sympathetic pathway to the large intestine of the cat.

1. The origin of the lumbar sympathetic inhibitory outflow to the large intestine was studied by recording simultaneously changes in colonic motility and efferent firing in the lumbar colonic nerves (l.c.n.) following lesions at various levels of the neuraxis. 2. Multiunit recordings from the l.c.n. usually consisted of irregular grouped discharges which were unrelated to spontaneous colonic contractions or to respiratory or cardiac cycles. The firing was depressed by the administration of ganglionic blocking agents or by decentralization of the inferior mesenteric ganglion, indicating that it was post-ganglionic and primarily central in origin. 3. In the majority of experiments colonic motility and l.c.n. firing were not altered by transection of the cervical (C2-C3) or thoracic (T10-T13) spinal cord. However, in these acute spinal animals destruction of the lumbar ventral roots or the lumbar spinal cord markedly enhanced colonic motility and depressed l.c.n. firing. These findings indicate supraspinal mechanisms are not essential for the generation of the lumbar inhibitory outflow to the colon. 4. Transection of the l.c.n. enhanced colonic motility in animals with an intact neuraxis, in acute spinal animals and in animals where the thoracolumbar sympathetic outflow was blocked. It is concluded that peripheral ganglionic as well as spinal pathways can sustain an inhibitory input to the colon. 5. L.c.n. firing was enchanced by stretching or pinching the proximal colon or small intestine or by electrical stimulation of intestinal afferent fibres (Adelta and C fibres) in the l.c.m. and mesenteric branches of the splanchnic nerves. The reflexes occurred via spinal pathways and were blocked by transection of the lumbar dorsal roots. Spontaneous firing in the l.c.n. was also generated by isolated segments of the lumbar spinal cord; however, this firing occurred independently of traditional reflex pathways since it was uanffected by transection of the lumbar dorsal roots. It is concluded that the spontaneous firing must be generated via ventral root afferent pathways or via endogenous oscillator circuits in the lumbar spinal cord.


The kinetics of iron uptake in vitro by human duodenal mucosa: studies in normal subjects.

1. A method for determining initial rates of unidirectional radio-Fe uptake from a ferric chelate of nitrilotriacetic acid by human duodenal biopsy specimens in vitro has been devised. [57Co]cyanocobalamin was used as an extracellular fluid marker, and was shown to give results in close agreement with other markers. 2. Uptake was linear for up to 20 min and exhibited saturation kinetics over the concentration range 18--450 mumole/1. 3. In the presence of 2:4 dinitrophenol and fluoride, uptake was reduced by approxi-50%, indicating dependence on metabolic energy. 4. Uptake of Fe was markedly diminished at reduced incubation temperatures, demonstrating a high activation energy for the uptake process. 5. Many of the criteria for the demonstration that the initial uptake of Fe depends on an active transport mechanism have been fulfilled. 6. The apparent distribution volume of 14C-labelled nitrilotriacetate chelate did not exceed the extracellular fluid space, suggesting that Fe is transferred to specific receptors on the enterocyte. The findings are discussed in relation to the possibility that uptake may be a rate-controlling step for the regulation of net intestinal absorption of Fe in man.


The effect of temperature on the asymmetrical charge movement in squid giant axons.

1. Asymmetrical displacement currents ('gating currents') have been recorded in intracellularly perfused squid giant axons by averaging the currents associated with depolarizing and hyperpolarizing voltage pulses. The effect of temperature on 'gating currents' was studied and compared with the effect of temperature on Na currents. 2. Increasing the temperature in seven steps from 0 to 15 degrees C increased the area under the on- and off-response (Qon, Qoff). The average Q10 values for Qon and Qoff (measured with depolarizing pulses to 0 to 20 mV) were 1.41 and 1.62, respectively. 3. The on- and the off-response were described mathematically by the sum of two exponentials. The first component of the on-response, Qon 1, represented 80% or more of the total charge movement associated with 2.5 msec pulses; the Q10 of Qon 1 was similar to that of total Qon. The first component of the off-response, Qoff 1, represented 50--70% of total Qoff; its Q10 was smaller than that of total Qoff. 4. The temperature dependence of the rate constants (tauon 1)-1 and (tauoff 1)-1 was stronger at temperatures below 6--8 degrees C (Q10 = 3.1--6.4) than at higher temperatures (Q10 = 2.0--3.3). In an Arrhenius plot two lines of different slope were required to fit the data. 5. The effect of increasing the temperature on the Q vs. V curve can be described as an increase of Qmax or, alternatively, as a shift of the curve to more negative potentials. 6. Increasing the temperature from 0 to 15 degrees C increased the peak of the Na current (recorded in sea water with a fifth of the normal Na concentration), increased the rate constants taum-1 and tauh-1 and shifted the m3infinity and hinfinity curves to more positive potentials. 7. The Q10 of the rate constant taum-1 varied between 2.04 and 2.61 and was independent of temperature. In an Arrhenius plot the values for taum-1 could be fitted by a single line. 8. The results support the view that 'gating current' does not simply reflect changes of the Na activation variable m. The increase of Qon, Qoff with increasing temperature may be attributed to an increase in membrane fluidity. The possibility that those charges which become mobile at higher temperatures may not be related to gating is considered.


An investigation into the validity of subatmospheric pressure recordings from synovial fluid and their dependence on joint angle.

1. Synovial fluid hydrostatic pressures were measured in normal knee (stifle) joints of anaesthetized rabbits using perforated cannulae. Pressures were subatmospheric in seventy out of seventy-two joints, with a mean value of -4.6 cm H2O (range 0 to -12 cm H2O) at joint angles of 120--150 degrees. 2. Similar values were obtained by a wick-in-needle technique (mean -4.0 cm H2O), which along with several other tests indicated that the subatmospheric values were not artifactual. 3. A slow rise in pressure of 1--2 cm H2O per hour in the motionless joint was attributed to a net filtration of fluid into the joint space. 4. Pressure increased as a curvilinear function of joint angle when the joint was flexed passively, the slope of the relationship depending on synovial fluid volume. Pressure also increased on active flexion of the joint, or on passively increasing the tension of soft peri-articular tissues. 5. Positive (above atmospheric) pressures in acutely flexed joints declined with time. Pressures declined less rapidly when synovial fluid was replaced by nonabsorbable paraffin oil. It was concluded that joint fluid can be absorbed by the synovium during acute flexion. 6. Processes which might generate subatmospheric pressures are discussed. The hypothesis is advanced that the flexion-dependent 'trans-synovial pump', possibly in series with a lymphatic pump, may account for the maintenance of a small synovial fluid volume and subatmospheric pressure in the face of a net filtration of fluid from synovial capillaries into the joint space.


The influence of hydrostatic pressure on trans-synovial fluid movement and on capsular expansion in the rabbit knee.

1. The flow of Ringer solution or paraffin oil from an infusion reservoir into the cavity of the knee (stifle) joint was measured in anesthetized rabbits, as intraarticular pressure was progressively elevated from its intrinsic slightly subatmospheric value to +25 cm H2O. 2. Paraffin oil did not penetrate the tissues lining the joint cavity, yet a continuous flow of oil occurred into the joint at pressures over +2 cm H2O. It was concluded that the joint investment behaved as a visco-elastic tissue. 3. Trans-synovial flow of Ringer solution was calculated by correcting the observed inflow for visco-elastic expansion of the joint capsule. At intra-articular pressures +2 to +9 cm H2O, trans-synovial flow increased at an average rate of 0.49 microliter min-1.cm H2O-1. The hydraulic conductivity of the synovium was therefore similar to that of subcutaneous connective tissue. At around +9 cm H2O, the 'breaking pressure', the slope of the pressure-flow relationship increased by almost sixfold to 2.81 microliter min-1.cm H2O-1. 4. Changes in joint visco-elasticity, synovial surface area, blood pressure, colloid osmotic pressure of plasma and of joint fluid, and inflammation were excluded as explanations of the marked increase in rate of fluid absorption, which is tentatively attributed to increases in synovial hydraulic conductivity. Some physiological and clinical implications of the data are discussed.


Charge movement and membrane capacity in frog muscle.

1. The transient current required to impose a step charge of potential has a complex time course especially in the region of internal potential between -50 and -40 mV. 2. Examination of non-linear transient current in this voltage range suggests two components of charge movement: (a) an initial more-or-less exponential movement, and (b) a slower component with a complex time course. 3. Measurements of membrane capacity support such a division and confirm the steeper voltage dependence of the slower charge movement. 4. Permanent depolarization to 40 mV appears to immobilize the slowly moving charge. Depolarization to -20 mV immobilizes both charge movements, and uncovers the presence of a third charge which seems to correspond to Charge 2 (cf. Adrian & Almers, 1976b; Adrian, Chandler & Rakowski, 1976).


Sugar transfer from the lumen of the rat small intestine to the vascular bed.

1. A modification of the vascular perfusion technique was used to investigate sugar transfer from the lumen of the rat small intestine to the vascular perfusion technique was used to investigate sugar transfer from the lumen of the rat small intestine to the vascular bed. 2. With this method the transfer of both D-[3H]galactose and L-[14C]glucose were followed in the same experiments. The results indicate that when equimolar concentrations of the two sugars are perfused through the lumen there is a preferential transfer of galactose from the mucosal epithelium to the vascular bed as well as from lumen to the epithelial layer. 3. At high rates of galactose transfer from the lumen to the vascular bed, accumulation of the sugar within the mucosal epithelium is minimal unless the vascular flow is stopped. 4. Phlorizin inhibits galactose transfer from the lumen to the vascular bed, but the inhibition of sugar transfer appears to be restricted to the luminal face of the epithelial cells since the selectivity of the basolateral exit process is unaffected. 5. Replacement of Na+ by K+ in the luminal perfusate reduces the rate of galactose transfer by a factor of 40, but does not completely abolish the preferential transfer of galactose. The presence of luminal Na+ also stimulates the exit of galactose from the mucosal epithelium to the vascular bed. 6. The presence of D-glucose in the vascular perfusate produces a two- to threefold increase in the rate of sugar transfer from the lumen to the vascular bed. This effect is not observed with vascular galactose or luminal glucose.


[Electrical pacing in the gastroduodenal junction area of conscious dogs (author's transl)].

To determine whether the electric activities of the stomach and duodenum are related, the gastroduodenal junction area of the stomach of dogs was paced through implanted bipolar silver electrodes. It was found that the pacing rate of the basic electrical rhythm (BER) in the antrum of the stomach could be increased to a maximum of 8.9 cycles/min, without affecting the BER frequency in the duodenum. Conversely when the pacing rate of the BER in the duodenum was increased to a maximum of 24 cycles/min, the BER frequency in the antrum remained unaffected. These results show that the BER in the stomach and duodenum are independent, and imply that the BER cycles in the stomach and duodenum are due to the presence of two independent pace-maker areas.


Effects of true and inverted feedback on integrated occipital alpha.

Ambient illumination had no effect on baseline levels of alpha of 20 female university students who had their eyes closed, and significant increases from these levels were obtained through true but not inverted feedback procedures. These results indicate that alpha enhancement can be obtained in a manner that is not explicable in terms of disinhibition processes.


Standard intelligence tests are valid instruments for measuring the intellectual potential of urban children: comments on pitfalls in the measurement of intelligence.

Hardy, Welcher, Mellitis, and Kagan altered standard WISC administrative and scoring procedures and, from the resulting higher subtest scores, concluded that IQs based on standardized tests are inappropriate measures for inner-city children. Careful examination of their study reveals many methodological inadequacies and problematic interpretations. Three of these are as follows: (a) failure to use any external criterion to evaluate the validity of their testing-of-limits procedures; (b) the possibility of examiner and investigator bias; and (c) lack of any comparison group that might demonstrate that poor children would be helped more than others by the probes recommended. Their report creates misleading doubts about existing intelligence tests and does a disservice to inner-city children who need the benefits of the judicious use of diagnostic procedures, which include standardized intelligence tests. Consequently, their assertion concerning the inappropriateness of standardized test results for inner-city children is not only premature and misleading, but it is unwarranted as well.


Learned helplessness: performance as a function of task significance.

In a study based on the contention that response decrement may be interpreted in terms of learned helplessness only if Ss are aware that their poor performance is due to factors beyond their control (N = 60 male and female high school students), awareness was manipulated by varying "task significance" within the learned helplessness paradigm. Evidence was provided for the hypothesis that Test Task performance would vary inversely with task significance: i.e., the degree to which Ss perceived their competence to be reflected in low scores on the (unsolvable) Training Task. Compared to the Control group, Experimentals (a) solved significantly fewer Test Task anagrams of moderate difficulty, and (b) showed markedly decreased confidence and increased anxiety about their performance, which they attributed to uncontrollable personal characteristics. These findings supported the assertion that learned helplessness has been inadequately substantiated as the explanation of the results of several previous studies.


Physiology and disease of the respiratory system in pregnancy. A review.

This review has attempted to describe the changes in respiratory physiology which occur during pregnancy and to use this knowledge to aid in the understanding of respiratory disease. Three forms of respiratory failure have been described and representative examples of each discussed.


Estimating vaginal blood loss.

In order to estimate amounts of vaginal bleeding, obstetrician-gynecologists have traditionally asked women the number of napkins, pads or tampons they use. This method of estimation rests on the assumptions that the volume of blood absorbed by various sanitary products is (1) known and (2) equivalent. To test these underlying assumptions the blood absorption capacity of 15 commercially available sanitary products was measured. Mean absorptions ranged from 1.32 to 94.86 ml for different products; a one-way analysis of variance showed that these mean absorptions were not equal (p less than .001). Moreover, products within a single package revealed substantial variations in absorbency. Thus, asking women the number of sanitary products they use is unlikely to yield clinically useful information; such questions should probably be deleted from the gynecologic history.


A rare obstetric contraindication to the use of vaginal prostaglandins for fetal demise.

A rare obstetric contraindication to the use of vaginal prostaglandins for fetal demise is presented in the form of a case report. After two failed pitocin inductions for a third-trimester fetal demise, a patient was referred to the University of Washington for definitive management. She was delivered of an advanced intraligamentous pregnancy at laparotomy. Preoperative diagnosis can avert a futile attempt at evacuation of the dead fetus, but preoperative diagnosis of intraligamentous pregnancy is rare. When the cervix is found in the extreme anterior position high in the vagina behind the symphysis and the fetal head is below it, the diagnosis of extrauterine pregnancy should always be considered.


Late effects of induced abortion. Hypothesis or knowledge?

Recent local, state and federal regulations intending to provide "informed consent" for women considering termination of pregnancy have misrepresented the current state of knowledge about certain long-term complications: the alleged risks are presented to the patient as if they were scientific facts rather than still-unproven hypotheses. While it is possible that some late sequelae are associated with previously induced abortions, there is no agreement in the scientific literature on the magnitude of the risks, if any. Moreover, few studies adequately define the particular method of induced abortion whose effects they are investigating. The current data do not support firm conclusions about induced abortion either causing or not causing any of the alleged long-term complications.


Congenital, complete heart block in the infant of a woman with collagen vascular disease. A case report.

Persistent fetal bradycardia may have multiple etiologies. The following represents a case of persistent fetal bradycardia due to congenital heart block in the infant of a woman with suspected collagen vascular disease. A review of the literature and a discussion of the association of maternal collagen vascular disease and congenital heart block is presented. The prognosis of infants with congenital heart block is reviewed and the possible association with growth retardation discussed.


Cervical dysplasia in a large, predominantly black practice as diagnosed by colposcopy in patients with normal and class II Papanicolaou smears.

Six hundred eighty-four patients were colposcoped over a one-and-one-half-year period. These patients ranged in age from 18 to 42 years. Parity ranged from zero to five. Cytology ranged from normal (class I) to class II Papanicolaou smears. Eighty-five patients were found to have cervical dysplasia, giving an overall picture of 12.4%. Of these 85, 8 had carcinoma in situ, 1 had microinvasive disease, and 1 had frankly invasive disease. The aim of this study was to show the frequency of dysplasia in a high-risk black population that would have been missed if cytology alone were the diagnostic tool.


Contraceptive use-effectiveness and the American adolescent.

Contraceptive use-effectiveness is significantly shaped by the contraceptors' ages, for pregnancy rates are found to be a function of age. Teenagers are more failure prone than older contracepting women, regardless of method. This higher teenage failure rate can indicate clearly the use-effectiveness of various contraceptive methods. Consequently, both user and method (whether modern or traditional) determine outcome levels of contraceptive use-effectiveness.


The effects of prenatal diethylstilbestrol (DES) exposure on the genitalia of pubertal Macaca mulatta. I. Female offspring.

Nineteen pregnant female rhesus monkeys (Macaca mulatta) received 1 mg/day diethylstilbestrol (DES) over three time periods during gestation: day 21 to delivery (group I), day 100 to delivery (group II) and day 130 to delivery (group III). Seven females and five males of a total of 20 offspring are presently alive at 5 1/2 years of age; one female died at 5 years of age. No deaths have been shown to be treatment related. In female offspring, menstruation began at about 2 1/2 years of age, was irregular for approximately one and one-half to two years and then became regular. Vaginal ridging and/or cervical hooding have been observed in seven of the eight DES-exposed females, and three had histologically demonstrable vaginal adenosis. None of the anomalies was related to a specific treatment period, for they appeared in all treatment groups, nor did they occur in the age-matched controls. Furthermore, none of the animals, either treated or control, showed any evidence of adenocarcinoma. Therefore, exposure of Macaca mulatta females to DES in utero appears to be teratogenic, but thus far no carcinogenicity has been observed. Reports in humans indicate that adenocarcinoma is an additional manifestation of prenatal exposure to DES; also, treatment effects appear to be more commonly observed in individuals exposed during the early stages of gestation. From this viewpoint, the rhesus monkey is a potentially valuable model for the study of vaginocervical anomalies and adenosis, but it is premature to consider it a suitable model for the study of adenocarcinoma.


The comparative efficacy and safety of intraamniotic prostaglandin F2 alpha and hypertonic saline for second-trimester abortion. A review and critique.

Intraamniotic instillation of prostaglandin F2 alpha (PGF2 alpha) is considered by many to be safer than instillation of hypertonic saline for second-trimester abortion. To evaluate the validity of this hypothesis, we reviewed 15 comparisons of these two abortifacients published in the English literature since 1973. These reports suggest that while PGF2 alpha induces abortion faster than saline, PGF2 alpha is associated with higher rates of unpleasant gastrointestinal side effects, incomplete abortion, hemorrhage and surgical reevacuation. In addition, the rate of live-born fetuses after PGF2 alpha-induced abortion may be 5 to 40 times that of saline. The existing literature does not substantiate the claim that PGF2 alpha is superior to saline as an abortifacient.


Use of enzymatically isolated chondrocytes for short term metabolic studies.

Chondrocytes isolated from calf articular cartilage by pretreatment with various enzymes prior to collagenase digestion were examined to determine the effect of enzymatic exposure on cell viability and to establish optimal conditions whereby freshly isolated cells could be used for short term metabolic studies. Pre-collagenase exposure to proteolytic enzymes for short intervals has no effect on cell viability. Trypsin pre-treatment appeared to increase the efficiency of cell isolation. Proteoglycan and RNA synthetic activity was influenced by the conditions of incubation (i.e., cell suspension vs. cell pellet: with or without a 24 hour "rest" period; and differential pre-collagenase enzyme exposure). The data suggest that the experimental conditions of incubation and the enzymes used in isolation of the cells, materially alter the freshly isolated chondrocyte's "pattern" of metabolic activity in short term culture studies.


Normal erythrocyte sedimentation rate with hyperfibrinogenemia in 6-sulfanilamidoindazole arthritis.

The erythrocyte sedimentation rate (ESR) is the most frequently employed laboratory indicator of inflammatory activity. The plasma fibrinogen concentration is usually increased in inflammatory disorders and is thought to contribute to the ESR elevation, 6-sulfanilamidoindazole induced arthritis in rats produces very high plasma fibrinogen concentrations and increased blood viscosity but no change in ESR.


Further studies on the specific infectious agent isolated in rheumatoid arthritis.

The active agent in crude or extracted materials from patients with acute rheumatoid arthritis (RA), when injected into embryonated eggs, produced an increased percentage of characteristic "crooked toe" defects in the bioassay. Experimental RA chick materials also produced these defects. A protein-free ribonucleic acid extract from RA synovia and joint fluids of patients with acute or subacute classical RA produced the same experimental RA lesions as did the crude materials, but non-RA materials and controls did not. The injected RA material produced the "crooked toe" disease in chicks in direct proportion to the clinically diagnosed severity of the RA in the patient, and inversely with dilution.


Hydroxyapatite crystal-induced inflammation and prostaglandin E1.

Hyroxyapatite (HOAp), tribasic calcium phosphate, crystals induced typical signs of inflammation when injected into the footpad of the rat. Rats deficient in essential fatty acids (EFA) and thereby deficient in prostaglandins (PG) demonstrated less swelling than did normal controls. Similar reduced inflammatory swelling resulted from the use of HOAp crystals heated to 200 degrees C. The reduced inflammogenic effect of the heated crystal and the reduced response of the EFA-deficient rat were comparable and were corrected by adding PGE1. This PGE1 influence was of short duration in both test systems. A new theory of crystal induced inflammation is presented based on experiments using PGE1 with monosodium urate, calcium pyrophosphate and HOAp crystals. It is suggested that this inflammation is a membrane phenomenon related to synthesis or release of PG from cellular membranes stimulated by an electrostatic force from the crystals.


Gastrointestinal involvement in rheumatoid arthritis: a biopsy study.

Gastric, colonic and rectal biopsies were obtained from patients with rheumatoid arthritis. The histologic study demonstrated a greater incidence of pathological findings compared to normal subjects or in patients with gastrointestinal diseases. The histologic changes were characterized by partial or complete loss of superficial epithelium and glanmphocytes, plasma cells, granulocytes, and the presence of vasculitic lesions. These histologic findings suggest that a chronic rheumatoid inflammatory process may affect the gastrointestinal system, in keeping with the concept that rheumatoid arthritis is a systemic disease.


Manubrio-sternal joint subluxation in rheumatoid arthritis.

A patient is described in whom subluxation and erosions were present in the manubrio-sternal joint. The literature relating to the manubrio-sternal joint in rheumatoid arthritis is reviewed.


Classification of drugs by discriminant analysis using fragment molecular connectivity values.

An investigation was made into the use of linear and quadratic discriminant analysis, along with K nearest-neighbor analysis, in the classification of a set of 51 compounds which were divided into five therapeutic categories. By superimposing each compound on a pattern structure, as first proposed by Cammarata, eight positions were assigned on the molecule. Each position was coded with the numerical value of a descriptor index. Relative molar refraction, which was the index used by Cammarata, was compared with a number of molecular connective indices. For each of the indices studied, it was found that only four of the eight positions contributed significantly to between-class differences. It was also found that first-order molecular connectivity, calculated as the sum of the contributions of each of the bonds joining a given position, resulted in consistently fewer misclassifications as compared with the other indices. Using first-order molecular connectivity, validation procedures were performed on the original set of compounds, on random samples drawn from this set, and on a set of ten compounds not included in the analysis. The results obtained were highly data dependent, but they, nevertheless, suggest that molecular connectivity indices should prove useful in structural classification procedures.


Computer-assisted structure-activity studies of chemical carcinogens. A heterogeneous data set.

A structure-activity relations study has been performed on a heterogeneous set of organic compounds to develop predictive ability for carcinogenic potential. The compounds employed came from more than 12 structural classes and numbered 130 carcinogens and 79 noncarcinogens. A set of 28 calculated molecular structure descriptors was identified that supported a linear discriminant function able to completely separate 192 compounds into the carcinogenic and noncarcinogenic classes. A predictive ability of 90% for carcinogens and 78% for noncarcinogens was obtained in randomized testing. The results demonstrate that pattern-recognition methods can be used to analyze a diverse set of compounds each represented by calculated molecular structure descriptors for a common biological activity.


IgA deficiency in juvenile chronic polyarthritis.

Immunoglobulins measured sequentially in 582 juvenile chronic polyarthritis patients revealed 12 with persistently absent IgA and 15 consistently below 20 mg/dl. There was an increased presentation with pauciarticular onset but systemic disease was the same as in the whole group. Follow-up showed that 9 of the 12 without IgA developed polyarthritis as have 11 of the 15 with low IgA; in contrast to previous studies, the disease has been severe in at least half of the patients.


Amyloidosis in Reiter's syndrome.

A patient with a 27-year-history of chronic relapsing Reiter's syndrome who developed secondary amyloidosis is described. While there are only 2 reports of this association in the English literature, additional cases are suggested in the light of our present concepts. The patient represents the only case of clinically apparent secondary amyloidosis among 158 patients with HLA B27 associated arthropathies currently followed at our institution. Our patient's amyloidosis was treated for nearly 1 year with colchicine without response.


Quantitative structure-activity relationships in 2,5-bis(1-aziridinyl)-p-benzoquinone derivatives against leukemia L-1210.

Antileukemic activities of more than 30 2,5-bis(1-aziridinyl)-p-benzoquinones (4) were correlated against well-defined physicochemical constants. These compounds were evaluated against lymphoid leukemia L1210 in BDF1 mice. The best equations obtained exhibited a linear dependence on the hydrophobic constant, pi. Characteristic aspects of the equations are that the larger the relative hydrophilicity of the drugs the stronger the antileukemic activity will be and that the more hydrophilic compounds have a greater chemotherapeutic index. Steric and electronic effects were also determined to be important. Based on the correlations, three compounds (11, 15 and 19) were designed, synthesized, and biologically evaluated.


Fine detail radiography of the femoral head in osteoarthritis.

In an effort to define the relationship of articular cartilage to subchondral bond in osteoarthritis, fine detail radiography of over 600 femoral heads were examined. In general, cartilage loss was paralleled by subchondral bone thickening, but this was not a uniform finding. In the inferomedial part of the femoral head, thickening of the subchondral bone plate never occurred. If the cartilage thickening in this area exceeded 2 mm then a new subchondral bone plate was formed.


Alkylating nucleosides 1. Synthesis and cytostatic activity of N-glycosyl(halomethyl)-1,2,3-triazoles. A new type of alkylating agent.

1,3-Dipolar cycloaddition of benzyl azide or peracetylated glucopyranosyl azides to propargyl halides or 1,4-dihalobutynes yielded 1-benzyl- or 1-glycosyl(halomethyl)-1,2,3-triazoles. Alkylating chloromethyl- bromomethyl- and iodomethyl-1,2,3-triazoles were also obtained from the corresponding hydroxymethyl derivatives by treatment with (C6H5)3P/CCl4, (C6H5O)3P/Br2, and (C6H5O)3P/I2, respectively. 1-Benzyl-4-(fluoromethyl)-1,2,3-triazole was obtained from 1-benzyl-4-(bromomethyl)-1,2,3-triazole by treatment with KF and 18-crown-6. Chloromethyl-, bromomethyl-, and iodomethyl-1,2,3-triazole derivatives inhibited the "in vitro" growth of HeLa cells. Some of these compounds increased the life span of mice bearing tumors.


Structural modification study of bis(substituted aminoalkylamino)anthraquinones. An evaluation of the relationship of the [2-[(2-hydroxyethyl)amino]ethyl]amino side chain with antineoplastic activity.

Several anthraquinones containing the [2-[(2-hydroxyethyl)amino]ethyl]amino, the [2-(dimethylamino)ethyl]amino, and the 2-(dimethylamino)ethoxy groups were prepared. Preparation of a lucanthone analogue, a 7-chloroquinoline derivative, and derivatives of naphthoquinones containing the [2-[(2-hydroxyethyl)amino]ethyl]amino side chain and related amino-substituted side chains was also conducted. It was found that the antineoplastic activity of anthraquinones containing the [2-[(2-hydroxyethyl)amino]ethyl]amino side chain is superior to those containing the tertiary amino side chain. However, the presence of the [2-[(2-hydroxyethyl)amino]ethyl]amino chain is an important, but not a sufficient, factor for good antineoplastic activity, as indicated by the lack of significant biological activity of other ring systems containing this side chain.


Chronic lower leg ulceration in systemic lupus erythematosus.

Four patients with chronic recurrent deep lower leg ulcerations complicating systemic lupus erythematosus are reported. In each case, highly expressed systemic lupus erythematosus was evident and the ulcers were generally poorly responsive to therapeutic maneuvers and were severely debilitating. This lesion appears to be associated with a poor prognosis.


Synthesis and antitumor and antiviral activities of 1-beta-D-arabinofuranosyl-2-amino-1,4(2H)-iminopyrimidine and its derivatives.

1-beta-D-Arabinofuranosyl-2-amino-1,4(2H)-imino-5-fluoropyrimidine (10), 1-beta-D-arabinofuranosyl-2-amino-1,4(2H)-imino-5-fluoropyrimidine 3'-phosphate (9), and 1-beta-D-arabinofuranosyl-2-amino-1,4(2H)-imino-5-chloropyrimidine (11) have been synthesized from 2,2'-anhydro-1-beta-D-arabinofuranosyl-5-fluorocytosine (5), 2,2'-anhydro-1-beta-D-arabinofuranosyl-5-fluorocytosine 3'-phosphate (4), and 2,2'-anhydro-1-beta-D-arabinofuranosyl-5-chlorocytosine (6), respectively. 2,2'-Anhydro-1-beta-D-arabinofuranosylcytosine 3'-phosphate (7), 1-beta-D-arabinofuranosyl-2-amino-1,4-(2H)-iminopyrimidine (13), 1-beta-D-arabinofuranosyl-2-amino-1,3(2H)-iminopyrimidine 3'-phosphate (12), and compounds 4, 5, and 9 showed significant in vitro activity against a number of DNA viruses. Compounds 7 and 12 were also effective in vivo against type 1 herpes simplex virus. Compounds 7, 12, and 13 were extremely effective in the treatment of mice bearing leukemia L1210.


Synthesis and platelet aggregation inhibitory activity of 6-isobutyl-alpha-methyl-3-pyridineacetic acid.

2-(4'-Isobutylphenyl)propionic acid, ibuprofen, is an antiinflammatory agent which possesses moderate platelet aggregation inhibitory activity. It was therefore of interest to determine what effect the replacement of the phenyl group of ibuprofen by a 3-pyridyl ring would have on platelet aggregation inhibitory activity. As a result, 6-isobutyl-alpha-methyl-o-pyridineacetic acid (7) and its 2-chloro analogue 13 were synthesized. The key step in the synthesis of 7 and 13 involved the oxidative rearrangement of enol ether 11 to the carboxylic ester 12 with thallium trinitrate. The entire sequences of reactions for the synthesis of compounds 7 and 13 are described in detail. Platelet aggregation inhibitory evaluation of 7 and 13 showed 7 to possess activity equivalent to ibuprofen; however, 13 was devoid of platelet aggregation inhibitory activity at an equivalent dose.


Conformational analogy between beta-lactam antibiotics and tetrahedral transition states of a dipeptide.

The three-dimensional structures of various penicillins and cephalosporins are compared to the spatial characteristics of glycylglycine and the tetrahedral adducts formed when a nucleophile attaches to the amide carbonyl carbon of this dipeptide. The dipeptide is taken to model the D-alanyl-D-alanine terminus of the precursors of bacterial cell-wall peptidoglycan cross-links. Least-squares fitting shows that the spatial match between the dipeptide and the antibiotic depends on the thiazolidine or dihydrothiazine ring conformation, as well as the conformation of the dipeptide. In general, the tetrahedral adducts fit somewhat better than the parent dipeptide. A previously unobserved 3-cephem conformer is found by molecular mechanics calculations to be less stable than the usual crystallographically observed conformer.


Synthesis and analgesic activities of some (4-substituted phenyl-1-piperazinyl)alkyl 2-aminobenzoates and 2-aminonicotinates.

A series of (4-substituted phenyl-1-piperazinyl)alkyl 2-aminobenzoates and 2-aminonicotinates has been prepared and screened for analgesic and antiinflammatory properties in mice and rats. The tabulated results reveal several 2-(4-substituted phenyl-1-piperazinyl)ethyl 2-(7- or 8-substituted 4-quinolinylamino)benzoates to be six to nine times more potent analgesics than the reference compounds (glafenine and aminopyrine) and to possess minor antinflammatory activity. Compound 45, 2-[4-[3-(trifluoromethyl)phenyl]-1-piperazinyl]ethyl 2-[[7-(trifluoromethyl)-4-quinolinyl]amino]benzoate (antrafenine), showed marked analgesic activity, long duration of action, and excellent tolerance in pharmacological and toxicological studies, as well as in clinical trials.


Synthetic antagonists of in vivo responses by the rat uterus to oxytocin.

As part of a program in which we are attempting to synthesize in vivo antagonists of oxytocin, the following four analogues were synthesized and tested for antagonistic activities in rat uterus and rat vasopressor assay systems: [-(beta-mercapto-beta,beta-diethylpropionic acid), 4-threonine]oxytocin (1, dEt2TOT), [1-beta-mercapto-beta,beta-cyclopenta-methylenepropionic acid), 4-threonine]oxytocin [2, d(CH2)5TOT], [1-deaminopenicillamine,2-O-methyltyrosine]oxytocin [3, dPTyr(Me)OT], and [1-deaminopenicillamine,2-O-methyltyrosine,4-threonine]oxytocin [4, dPTyr(Me)TOT]. The required protected intermediates were synthesized by a combination of solid-phase peptide synthesis and by individual 8 + 1 couplings in solution. All four analogues antagonize the actions of oxytocin on the rat uterus (a) in the absence of Mg2+, (b) in the presence of 0.5 mM Mg2+, and (c) in situ. They exhibit, respectively, the following pA2 values in each of the assay systems a-c: (1) (a) 7.72 +/- 0.11, (b) 7.36 +/- 0.09, (c) 6.47 +/- 0.11; (2) (a) 7.91 +/- 0.13, (b) 7.81 +/- 0.09, (c) 6.94 +/- 0.11; (3) (a) 7.76 +/- 0.12, (b) 7.80 +/- 0.12, (c) 6.86 +/- 0.12; (4) (a) 7.64 +/- 0.14, (b) 7.79 +/- 0.09, (c) 6.84 +/- 0.10. They have the following antivasopressor pA2 values: (1) 6.30 +/- 0.13; (2) 5.86 +/- 0.03; (3) 7.59 +/- 0.05; (4) 7.32 +/- 0.04. Compounds 2-4 are among the most potent in vivo antagonists of oxytocin reported to date.


Synthesis and chemical carcinogen inhibitory activity of 2-tert-butyl-4-hydroxyanisole.

The title compound 1 was selectively synthesized in its pure isomeric form by means of the hydroxyl-protecting reagent dimethyl-tert-butylchlorosilane. Exclusive silylation occurred at the less hindered hydroxyl group of 3. Dimethyl sulfate methylation of 4 gave 5 in excellent yield. Compound 1 was then obtained by acid hydrolysis of 5. The two BHA isomers, 1 and 2, were tested on their inhibitory effects toward benzo[alpha]pyrene-induced neoplasia in the forestomach of the ICR/Ha mouse. Both isomers, when added to the diet, reduced the number of mice with tumors and the number of tumors per mouse. Isomer 1, which has the less hindered free hydroxyl group, showed higher inhibitory effect in the present experimental model.


Biomolecules bearing the S- or SeAsMe2 function: amino acid and steroid derivatives.

A series of molecules of the type GXAsMe2 have been synthesized in which X is S or Se and G is a moiety such as an amino acid, a di- or tripeptide, or a lipid. The compounds have been characterized by NMR, mass spectroscopy, and elemental analysis. Cysteine was found to react directly with dimethylarsinic acid to yield cystine and S-dimethylarsinocysteine (1). This reaction occurs also with other biomolecules containing thiol groups and raises serious questions concerning the use of cacodylate buffers in the study of enzyme kinetics and in sample preparation for electron microscopy. In the presence of dimethylchloroarsine and diethylamine, homocysteine thiolactone reacts to form both the dipeptide and the S-AsMe2 bond. Results of carcinostatic, bacteriostatic, and fungicidal testing of these compounds are reported. A hypothesis is advanced to explain the observed carcinostatic action of the dimethylarsino group.


Platinum and palladium derivatives for chemotherapy studies.

Analogues of cis-dichlorodiammineplatinum(II) were prepared in which substituted pyridines (A), 1-(4-aminobenzylidene)indene (B), or DL-3,5,3'5'-tetraoxo-1,2-dipiperazinopropane (ICRF-159) was used in place of ammonia, and in some cases platinum(IV) or palladium(II) was used in place of the platinum(II). Both platinum complexes with ICRF-159 were active against leukemia 1210, but none of the others produced significant life extension following a single ip dose of 400 mg/kg. Attempts to prepare complexes of ICRF-159 with Zn(II), Mn(II), and Cr(III) were unsuccessful, but there were indications of complex formation with CuCl2 and with NiCl2.


Synthesis and biologic distribution of mercapto derivatives of palmitic acid.

Mercapto derivatives of palmitic acid are capable of binding 99mTc. Based on the hypothesis that 99mTc-labeled palmitic acid derivatives would behave biologically like palmitic acid and thus could be used as myocardial imaging agents, three mercaptopalmitic acid derivatives have been prepared. The synthesis of 2-mercaptopalmitic acid, 2-mercapto-1,16-hexadecanedioic acid, and 16-mercaptopalmitic acid was accomplished by reaction of the corresponding bromo compound with thiourea. The 35S-labeled compounds and [16-14C]palmitic acid were evaluated in rats with a heat-inflicted myocardial infarction to study the effect of the introduction of the mercapto group. The organ distribution of 2-[35S]mercaptopalmitic acid was most similar to that of [16-14C]palmitic acid.


Synthesis of a proposed thymic factor.

Less than Glu-Ala-Lys-Ser-Gln-Gly-Gly-Ser-Asn, a proposed serum thymic factor, has been synthesized. The protected precursor, less than Glu-Ala-Lys(i-Noc)-ser(Bzl)-Gln-Gly-Gly-Ser(Bzl)-Asn, was prepared by a combination of solid phase and solution methods. The benzyl blocking groups were removed by HF and the i-Noc blocking group was removed by catalytic hydrogenation.


Synthesis of hydroxy- and amino-substituted benzohydroxamic acids: inhibition of ribonucleotide reductase and antitumor activity.

Benzohydroxamic acids inhibit mammalian ribonucleotide reductase and exhibit antineoplastic activity in L1210 leukemic mice. Five new hydroxy- and amino-substituted benzohydroxamic acids (3,4- and 3,5-OH, 3,4-NH2, 2,3,4- and, 3,4,5-OH) were prepared and tested along with 12 previously reported benzohydroxamic acids (BHA) for enzyme inhibition and antitumor activity. The most potent enzyme inhibitor in this series was 2,3,4-OH-BHA (ID50 = 3.5 microM), which is 140 times more potent than hydroxyurea, but its toxicity limited the antitumor activity to a 30% increase in life span of L1210 bearing mice at 125 (mg/kg)/day ip for 8 days. The most effective antitumor agent in this series was 3,4-OH-BHA which prolonged the life span of L1210 bearing mice 103% at 600 (mg/kg)/day ip for 8 days.


A structural modification study of procarbazine.

Eight analogues of the antineoplastic compound procarbazine were prepared by varying one portion of the molecule, keeping either the methylhydrazinomethyl or the N-(1-methylethyl)benzamido portion of procarbazine intact. Preliminary screening results indicated that none of the analogues tested in leukemias L1210 and P388 were as active as the original compound.


1-(Dichloroacetyl)-1,2,3,4-tetrahydro-6-quinolinol esters. New potent antiamebic agents.

A series of 1-(dichloroacetyl)-1,2,3,4-tetrahydro-6-quinolinols and certain O-acyl derivatives thereof have been prepared and shown to be potent antiamebic agents in the Entamoeba criceti infected hamster model. Compounds were compared with etichlordifene and diloxamide and one of them, 1-(dichloroacetyl)-6-(2-furoyloxy)-1,2,3,4-tetrahydroquinoline (4), was selected for human trial.


Intramolecular hydrogen bonding and conformational studies of bridged thebaine and oripavine opiate narcotic agonists and antagonists.

A conformational study of a series of oripavine derivatives is reported using the PCILO semiempirical quantum mechanical method. Low-energy conformers of carbinol substituents on C7-C19-R1R2OH are found with and without intramolecular hydrogen bonding to the C6-OCH3 group. The relative energies of these conformers depend on the R1 and R2 groups and the diastereoisomerism of the alcohol. The results are consistent with available NMR and IR studies of intramolecular hydrogen bonding and with crystallographic data. The importance of interaction between specific conformations of C19 carbinols and a lipophilic receptor site is suggested. A hypothesis is formulated to explain observed differences in pharmacological activity between diastereoisomers at C19 in the oripavine series and also to explain how these diastereoisomers alter the established pattern of N-substituent effects on relative agonist/antagonist potency found in other rigid opiates. By contrast, conformational studies of the C19 optical isomers of the C7-C8 etheno form of buprenorphine lead to the prediction of greatly reduced intrinsic potency differences between C19 diastereoisomers for this compound and for buprenorphine itself.


Quantitative structure-activity relationships involving the inhibition of glycolic acid oxidase by derivatives of glycolic and glyoxylic acids.

The enzyme glycolic acid oxidase oxidizes glycolate to glyoxylate and glyoxylate to oxalate. Three series of compounds related to the natural substrates, substituted glycolic, oxyacetic, and glyoxylic acids, have been investigated as inhibitors of this enzyme using the techniques of regression analysis and quantitative structure-activity relationships. The best overall correlation with inhibitory potencies was found with the Hansch hydrophobic parameter pi. The classical electronic parameters sigmap, sigmam, F, and R performed poorly. For the substituted glyoxylic acids, a dummy parameter relating to the presence of a nucleophilic group in close proximity to the alpha-carbonyl of the glyoxylate group was found to be highly significant. The syntheses of six novel glycolic and glyoxylic acids are described.


Quantitative structure-activity relationship of 5-(X-benzyl)-2,4-diaminopyrimidines inhibiting bovine liver dihydrofolate reductase.

The inhibitory effect for a set of 23 5-(X-benzyl)-2,4-diaminopyrimidines acting on bovine liver dihydrofolate reductase (DHFR) had led to the following quantitative structure-activity relationship (QSAR): log 1/C = 0.62pi3 + 0.33epsilon sigma + 4.99, where r = 0.931 and s = 0.146. C in this expression is the molar concentration of inhibitor producing 50% inhibition, pi3 is the hydrophobic parameter for substituents on the 3 position of the phenyl moiety, and epsilon sigma is the the sum of the Hammett sigma constants for the 3, 4, and 5 substituents of the phenyl ring.


Design of species- or isozyme-specific enzyme inhibitors. 1. Effect of thymidine substituents on affinity for the thymidine site of hamster cytoplasmic thymidine kinase.

5-(Ethylamino)- and 5-acetamido-2'-deoxyuridine 5'-triphosphates were synthesized; the extent and concentration dependence of their inhibitory action on the title enzyme resembled that of the feedback inhibitor TTP. This and other findings provide a tentative indication that bulk tolerance near C-5 of the thymine ring may be more extensive at the TTP site than at the thymidine site. Enzyme-inhibitor dissociation constants (Ki values) were determined for thymidine derivatives monosubstituted at various positions. Competitive inhibition with respect to thymidine (indicative of substituent tolerance in the enzyme-thymidine complex) was produced by 3-amylthymidine (Ki = 65 muM), trans-5-bromo-6-ethoxy-5,6-dihydrothymidine diastereoisomers (Ki = 180 and 310 muM), 5'-C-(acetamidomethyl)- and 5-C-(propionamidomethyl)thymidine epimers (Ki range 65--1100 muM), 3'-acetamido- and 3'-(ethylthio)-3'-deoxythymidines (Ki = 2.5 mM and 12 muM, respectively), and certain 5'-(alkylamino)- and 5'-(alkylthio)-5'-deoxythymidines (Ki range 180--1200 muM). Evidence indicates that bulk tolerance at some, if not most, of the above atoms of thymidine is found in the enzyme-thymidine complexes of human and other mammalian thymidine kinases; attachment of suitable substituents to such atoms could, in principle, lead to thymidine site directed isozyme-specific inhibitors of human cytoplasmic thymidine kinase, which is a candidate target in the design of antineoplastic drugs.


S-2,omega-Diaminoalkyl dihydrogen phosphorothioates as antiradiation agents.

To enable further structure-activity comparisons among radioprotective phosphorothioates, S-2,omega-diaminoalkyl dihydrogen phosphorothioates were synthesized from L-2,4-diaminobutyric acid, L-ornithine, L-lysine, and DL-2,7-diaminoheptanoic acid as homologues of S-2,3-diaminopropyl dihydrogen phosphorothioate (4) and as isomeric analogues of S-2-[(omega-aminoalkyl)amino]ethyl dihydrogen phosphorothioates (e.g., 1). The preferred route that evolved from exploratory trials retained optical activity and involved the reduction of methyl 2,omega-bis(benzoylamino)alkanoates with lithium borohydride, debenzoylation-bromodehydroxylation, and reaction of the resulting 1-(bromomethyl)-1,omega-alkanediamine dihydrobromides with trisodium phosphorothioate. The products of an alternative route that involved the reduction of phthaloylated intermediates with sodium borohydride were racemic. Exploratory conversions of N-(omega-alkenyl)phthalimides failed to provide suitable precursors of the target compounds. In terms of a protective index, these homologues were significantly more radioprotective than the parent phosphorothioate 4 when administered intraperitoneally to mice prior to whole-body gamma irradiation. The homologues derived from L-lysine also showed good peroral activity. No apparent difference was observed in the protection afforded by optically active homologues and the corresponding racemates.


Studies on biologically active nucleosides and nucleotides. 5. Synthesis and antitumor activity of some 2,2'-anhydro-1-(3',5'-di-O-acyl-beta-D-arabinofuranosyl)cytosine salts and 2,2'-anhydro-1-(3'-O-acyl-beta-D-arabinofuranoxyl)cytosine 5'-phosphates.

A series of 3',5'-diesters of a 2,2'-anhydro-1-(beta-D-arabinofuranosyl)cytosine salt bearing functional substituents on the ester side chains (4--16) have been synthesized. The synthesis of these diesters involved the reaction between cytidine and the corresponding acid anhydride or acid chloride in the presence of boron trifluoride etherate. Similar reaction of bis(cytidine 5'-)suberate (21) with pivaloyl chloride gave bis[2,2'-anhydro-1-(3'-O-pivaloyl-beta-D-arabinofuranosyl)cytosine 5'-]suberate dihydrochloride (22). The reaction could also be extended to a one-step synthesis of 3'-esters of 2,2'-anhydro-1-(beta-D-arabinofuranosyl)cytosine 5'-phosphate (24) from 5'-cytidylic acid. These compounds have been examined for antitumor activity against L1210 leukemia in BDF1 mice. The diesters with a long-chain carboxylic acid (4c, 7c, 12, and 24d) showed high activity when administered intraperitoneally. The compound 24d exhibited moderate activity when administered orally.


Chemical and biological studies of 1-(2,5-dihydroxy-4-methylphenyl)-2-aminopropane, an analogue of 6-hydroxydopamine.

Autoxidation of the bis(O-demethyl)-p-hydroquinone metabolite of the psychotomimetic amine 1-(2,5-dimethoxy-4-methylphenyl)-2-aminopropane (DOM) at pH 7.4 leads exclusively to a bicyclic imino quinone. This imino quinone is a good alkylating agent, forming covalent adducts via 1,4 addition to thiols. The autoxidation appears to be dependent on trace metal catalysis and is dramatically inhibited by components of the 10000g supernatant fraction of rabbit liver homogenates. Incubation of tritium-labeled hydroquinone with bovine serum albumin under oxidizing conditions leads to significant amounts of nonextractable radioactivity which presumably is dependent on imino quinone alkylation of nucleophilic functionalities present on macromolecules. Incubation of tritium-labeled DOM with rabbit microsomes in the presence of NADPH leads to irreversible binding of the label to macromolecular components of the microsomes. Since this binding is NADPH dependent, it is likely that metabolic conversion of DOM to the hydroquinone is involved. The imino quinone oxidation product is highly lypophilic and is capable of crossing the blood-brain barrier. Intravenous administration of tritium-labeled imino quinone to rats resulted in significant nonextractable radioactivity in brain tissue. These properties of the hydroquinone metabolite parallel those reported for the structurally related sympatholytic compound 6-hydroxydopamine and have led to the hypothesis that the psychotomimetic properties of DOM may be mediated through 6-hydroxydopamine-type interactions of the hydroquinone with important macromolecules in the brain.


Synthesis and antihypertensive activity of novel 3-hydrazino-5-phenyl-1,2,4-triazines.

In an effort to develop antihypertensive agents with peripheral vasodilator activity, a series of 40 novel 3-hydrazino-5-phenyl-1,2,4-triazines (II) were synthesized and evaluated in the spontaneously hypertensive rat assay (SHR assay). Based on the performance of the structurally related standard, hydralazine (I), 15 triazines were active. Thirteen of these hypotensive triazines possessed LD50 values in the mouse greater than I (LD50 = 100 mg/kg); only one active triazine had an LD50 value greater than 300 mg/kg (11d). Four asymmetric triazines had moderate antihypertensive activity and LD50 values greater than 300 mg/kg (6b, 7c, 8f, and 9g). Based on the relationship between toxicity and antihypertensive activity, three triazines (8f, 9g, and 11d) were chosen for dose-responses studies in the SHR assay. None were as efficacious as I, but all three were less toxic, resulting in similar therapeutic indices relative to I.


Application of quantitative structure-activity relationships in the development of the antiallergic pyranenamines.

QSAR techniques played a major role in development of the antiallergic pyranenamines (I). Graphical analysis of data resulting from an unsuccessful Topliss approach suggested that increased substituent hydrophilicity might enhance potency. The 3-NHAc-4-OH derivative which first resulted was an order of magnitude more potent than any preceding series member, and its deacylated congenar is clinical candidate SK&F 78729 (R1 = -NH2, R2 - OH, R3 = H). Further pursuit of hydrophilicity and other strategies suggested by multiple regression yielded 98 pyranenamines, the most active [R1 = R3 = NHCO(CHOH)2H, R2 = H] being 1000 times more potent than any original series member.


Preparation and purification of L-(+/-)-5-formyl-5,6,7,8-tetrahydrofolic acid.

Reinvestigation of the conversion of folic acid to leucovorin [L-(+/-)-5-CHO-THF] led to improved methods for the synthesis of this drug, which is suitable for clinical use. Also, methods were developed for the chromatographic and nonchromatographic purification of less pure samples of L-(+/-)-5-CHO-THF.


Synthesis and antibacterial activity of 2-oxocephalosporins.

The first reported synthesis of 2-oxocephalosporin derivatives has been achieved via ozonolysis of the corresponding 2-methylenecephalosporins. The new cephalosporin derivatives showed some antibacterial activity against Gram-positive bacteria, but the 2-oxo analogue of cephalothin was much less active than cephalothin itself.


Synthesis of imidazolidinediones and oxazolidinediones from cyclization of propargylureas and propargyl carbamates.

A synthetic procedure for the preparation of imidazolidinediones by the base-catalyzed cyclization of propargylureas is described. This method appears to be the most versatile way of obtaining these compounds containing tertiary groups substituted on ring-nitrogen number 3. One of these derivatives, 3-tert-butyl-5,5-dimethyl-2,4-imidazolidinedione (1a), has shown a moderate level of subcutaneous metrazole seizure threshold activity (scMet indicates potential for control of petit mal epileptic seizures) in control screens on mice, as determined by the National Institute of Neurological and Communicative Disorders and Stroke.


Blood glucose lowering sulfonamides with asymmetric carbon atoms. 3. Related N-substituted carbamoylbenzoic acids.

Both enantiomers of 4-N-[1-(5-Fluoro-2-methoxyphenyl)ethyl]carbamoylmethylbenzoic acid display hypoglycemic activity. The more potent (S) enantiomer is approximately equipotent with the acylaminoethylbenzoic acids of the type HB 699 (Figure 1; Table I). Observations are given that suggest that these benzoic acids act at the same receptor as the hypoglycemic sulfonylureas and sulfonylaminopyrimidines and further that this receptor includes important binding sites.


Genetic heterogeneity in osteogenesis imperfecta.

An epidemiological and genetical study of osteogenesis imperfecta (OI) in Victoria, Australia confirmed that there are at least four distinct syndromes at present called OI. The largest group of patients showed autosomal dominant inheritance of osteoporosis leading to fractures and distinctly blue sclerae. A large proportion of adults had presenile deafness or a family history of presenile conductive hearing loss. A second group, who comprised the majority of newborns with neonatal fractures, all died before or soon after birth. These had characteristic broad, crumpled femora and beaded ribs in skeletal x-rays. Autosomal recessive inheritance was likely for some, if not all, of these cases. A third group, two thirds of whom had fractures at birth, showed severe progressive deformity of limbs and spine. The density of scleral blueness appeared less than that seen in the first group of patients and approximated that seen in normal children and adults. Moreover, the blueness appeared to decrease with age. All patients in this group were sporadic cases. The mode of inheritance was not resolved by the study, but it is likely that the group is heterogeneous with both dominant and recessive genotypes responsible for the syndrome. The fourth group of patients showed dominant inheritance of osteoporosis leading to fractures, with variable deformity of long bones, but normal sclerae.


Cystic fibrosis in Northern Ireland.

In a retrospective study of cystic fibrosis in Northern Ireland for 1961 to 1971, the incidence was 1 in 1857 livebirths, which is comparable to figures from Great Britain and the Republic of Ireland.


Family evaluations in acute intermittent porphyria using red cell uroporphyrinogen I synthetase.

Acute intermittent porphyria (AIP) is a primary disorder of haem biosynthesis that is chemically characterised by raised urinary porphobilinogen (PBG). A defect in the biochemical pathway at the step of PBG conversion to uroporphyrinogen has been shown to be a result of a partial deficiency of the enzyme uroporphyrinogen I synthetase (uro I syn). The ascertainment rate of latent AIP (that is, chemically manifest but clinically asymptomatic) was examined in 185 individuals from 12 AIP kindreds using three parameters: red cell uro I syn, quantitative urinary PBG, and pedigree analysis with respect to uro I syn. Approximately 80% of individuals could be assigned as normal or latent AIP on the basis of the uro I syn assay alone. The remaining 20% could not be assigned because of an intermediate range of activity for the red cell assay in which the diagnosis cannot be certain. When the pedigree was used in the evaluation of the uro I syn data, the number of uncertain individuals, with respect to AIP, decreased to 10%. The enzyme method detected latent AIP in 37.5% of blood relatives, whereas quantitative urinary PBG alone detected only 15.2%. The pattern of inheritance for the uro I syn deficiency is consistent with Mendelian dominant inheritance, and it is likely that it is the basic inherited defect in AIP.


Achondroplasia and hypochondroplasia. Comments on frequency, mutation rate, and radiological features in skull and spine.

An attempt was made to ascertain all the dwarfs in the State of Victoria. The incidence of achondroplasia proved to be approximately 1 in 26,000 live births in the period 1969 to 1975 when ascertainment was nearly complete. This indicates a mutation rate of 1.93 X 10(-5) per generation in this locus. Paternal age was shown to influence mutation. Ascertainment in earlier years of the study was low despite the very great effort made to find all cases. Patients with hypochondroplasia were particularly difficult to find. However, 25 cases were found for study. Overlap between hypochondroplasia and achondroplasia was found in all features except the facial appearance (which was the basis of definition). Achondroplasia was more severe in all regards, but some individuals with hypochondroplasia were very short and some had extreme degrees of spinal canal stenosis. The classical measurements used to describe the skull changes in acondroplasia failed to distinguish this condition from hypochondroplasia. More efficient indices were devised, but visual assessment of the size of the facial region compared to that of the cranial valult proved more reliable than any index. The clinical distinction based upon facial appearance remains the arbitrary basis of definition.


Camptodactyly, cleft palate, and club foot (the Gordon syndrome). A report of a large pedigree.

A second family is described in which camptodactyly, club foot, and cleft palate (the Gordon syndrome) is transmitted in a pattern consistent with autosomal dominant inheritance with reduced penetrance and variable expressivity. Penetrance appears to be more reduced in females than in males, and cleft palate is the least frequently manifested trait.


Two cases with different deletions of the long arm of chromosome 7.

Two mentally and physically retarded girls, one with an interstitial deletion 7 (pter leads to q21::q32 leads to qter), and the other with an interstitial deletion 7 (pter leads to q11::q22 leads to qter), are described. Their clinical features are compared with those of 11 earlier reported cases with a deletion 7q. The Hageman factor, the locus of which is assigned to the distal part of 7q, was in both cases within normal limits. The data available do not justify the delineation of a specific clinical syndrome.


Trisomy 13 and extended survival.

A 9-year-old boy with classical clinical features of trisomy 13 (Patau's syndrome), with confirmation on chromosome analysis of blood and skin, is reported in view of his relative longevity.


Anencephaly with diaphragmatic hernia in sibs.

Two sibs who both had anencephaly and diaphragmatic hernia are reported. The type of diaphragmatic defect seen in anencephaly may differ from the defect seen in other babies. It is important to perform a necropsy in anencephaly.


Symphalangism, short stature, skeletal anomalies, and accessory testis: a new malformation syndrome.

A 17-year-old Jewish Sephardi male is described with symphalangism, short stature, multiple skeletal anomalies, and an accessory testis, which appears to be a new malformation syndrome of possible genetic aetiology.


Gastric adenocarcinoma due to ataxia-telangiectasia (Louis-Bar syndrome).

A 26-year-old male with ataxia-telangiectasia died with a gastric adenocarcinoma. Malignancy is a recognised complication of this condition, the majority of cases being reticuloendothelial. There have been three reports of gastric adenocarcinoma associated with ataxia-telangiectasia; this, however, is the first in British published reports.


Isolation and characterisation of bacteria from abscesses in the subcutis of cats.

Thirty-six closed abcesses in the subcutis of cats were examined. Of 168 bacterial strains isolated, 121(72%) were anaerobes and 47 (28%) were facultative anaerobes. Twenty-six abscesses contained mixtures of facultative anaerobes and anaerobes, six contained anaerobes only and four contained facultative anaerobes only. Bacteriodes was the genus most commonly isolated (28.6% of all isolates) followed by Fusobacterium (19.0%) and Pasteurella (multocida) (13.1%). Peptostreptococcus anaerobius was the most commonly isolated anaerobic species (13.2% of anaerobic isolates and 9.5% of all isolates)and Past, multocida was the most commonly isolated facultative anaerobe (46.8%; 13.1%of all isolates).


Electrostatic interaction between merocyanine 540 and liposomal and mitochondrial membranes.

The fluorescence of merocyanine 540 (MC) in liposomal and mitochondrial suspensions was measured under various conditions. Under a given condition, both the amount of dye bound to the membrane and the zeta potential were determined simultaneously. It was found that the fluorescence intensity was proportional to the amount of bound dye and correlated with the zeta potential of particles. The fluorescence intensity was represented quantiatively in terms of the Langmuir adsorption isotherm, when the electrostatic interaction acting between MC and membrane surface was properly taken into account. It was concluded that the changes in MC fluorescence in the liposomal and mitochondrial suspensions are mainly attributed to the changes in the surface potential of the membranes.


Conductance noise of monazomycin-doped bilayer membranes.

The conductance noise of the monazomycin pore has been studied by autocorrelation analysis in multi-pore systems. The autocorrelation function could be described by a superposition of two single exponential functions of different time- and voltage-dependence. The slow voltage-dependent correlation time in the range of seconds is assigned to the formation of nonconducting pore precursors. The fast voltage-independent correlation time in the msec range is related to fluctuations in the number of open pores whereby each pore adopts only two conducting states (open and closed). The corresponding correlation amplitude depends on monazomycin concentration and could be related to the single pore conductance. With increasing voltage, a slight increase of the single pore conductance was obtained which is explained on the basis of an electrostatic barrier within the pore. The pore was found to be virtually unselective for different alkali ions (Li, K, Cs).


Distribution of potassium and chloride permeability over the surface and T-tubule membranes of mammalian skeletal muscle.

The distribution of K and Cl permeability, PK and PCl, over the surface and T-tubule membranes of red rat sternomastoid fibers has been determined. Membrane potential, Vm, was recorded with 3-M KCl-filled glass microelectrodes. Changes in Vm with changes in [K]o or [Cl]o were used to estimate PCl/PK in normal and detubulated preparations. The results show that the T-tubule membrane has a high PCl and is therefore different from the T-tubule membrane of amphibian fibers. Analysis of the time course of depolarization when [K]o was raised (in SO4 solutions) showed that PK was distributed over the surface and T-tubule membranes. Two observations suggested that T-tubule PCl was higher than the surface PCl. Firstly, in normal fibers, the depolarization caused by an increase in [K]o was 3.5 times greater in SO4 solutions than in Cl solutions. In marked contrast, the depolarization in glycerol-treated fibers was independent of [Cl]o. Secondly, the rapid change in Vm when [Cl]o was changed was reduced by 80% after glycerol treatment. Both observations suggest that PCl was low in glycerol-treated fibers. PCl/PK was calculated from the Vm data using Goldman, Hodgkin and Katz equations for Na and K or for Na, K, and Cl. In normal fibers PCl/PK = 4.5 and in glycerol-treated fibers PCl/PK = 0.28. Since it is unlikely that glycerol treatment would increase PK, the reduction in the ratio must follow the loss of Cl permeability "channels" in the T-tubule membrane.


On the environment and the rotational motion of amphiphilic flavins in artificial membrane vesicles as studied by fluorescence.

The incorporation of four amphiphilic flavins ("amphiflavins") as fluorescence markers bearing C18-hydrocarbon chains at various positions of the chromophore into artificial membrane vesicles has been investigated. The vesicles utilized were made from three different saturated phospholipids. The stability of the flavin-charged vesicles was found to be good over several days, depending somewhat on the temperature, the pH, and their concentration. A marked increase of the fluorescence quantum yield near the vesicle phase transition (crystalline leads to liquid crystalline) was found which was taken to indicate that the flavin nuclei are imbedded more deeply into the hydrophobic portion of the membranes. This is further supported by a hypsochromic shift of the near flavin UV-peak and the increase of absorbance at 450 nm upon melting. Rotational relaxation times of the various amphiflavins bound to the different vesicles are obtained from measurements of the fluorescence polarizations as a function of temperature. From these data, the microviscosities in the region of the chromophors are calculated. Measurements of the fluorescence polarization as a function of the solvent viscosity and vesicle phase (crystalline-liquid crystalline) indicate that below the phase transition the flavin nucleus is protected from the suspension medium by a lipid-water interphase, which softens above phase transition. The dependence of the flavin orientation and microenvironment on the position of the substitution of the aliphatic chain is reflected in the differences of the fluorescence yields and the shape of the emission spectra.


Pathways for bicarbonate transfer across the serosal membrane of turtle urinary bladder: studies with a disulfonic stilbene.

Bicarbonate is transferred across the serosal (S) membrane of the epithelial cells of the turtle bladder in two directions. Cellular HCO3- generated behind the H+ pump moves this membrane into the serosal solution. This efflux of HCO3- is inhibited by SITS (4-isothiocyano-4'-acetamido-2,2'-disulfonic stilbene). When HCO3- is added to the serosal solution it is transported across the epithelium in exchange for absorbed Cl-. This secretory HCO3- flow traverses the serosal cell membrane in the opposite direction. In this study the effects of serosal addition of 5 x 10(-4) M SITS on HCO3- secretion and Cl- absorption were examined. The rate of H+ secretion was brought to zero by an opposing pH gradient, and 20 mM HCO3- was added to S. HCO3- secretion, measured by pH stat titration, was equivalent to the increase in M leads to S Cl- flux after HCO3- addition. Neither the S leads to M flux of HCO3- nor the M leads to S flux of Cl- were affected by SITS. In the absence of electrochemical gradients, net Cl- absorption was observed only in the presence of HCO3- in the media; under such conditions, unidirectional and net fluxes of Cl- were not altered by serosal or mucosal SITS. H+ secretion, however, measured simultaneously as the short-circuit current in ouabain-treated bladders decreased markedly after serosal SITS. The inhibition of the efflux of HCO3- in series with the H+ pump and the failure of SITS to affect HCO3- secretion and Cl- absorption suggest that the epithelium contains at least two types of transport systems for bicarbonate in the serosal membrane.


Limitations of the Eadie-Hofstee plot to estimate kinetic parameters of intestinal transport in the presence of an unstirred water layer.

In the presence of an intestinal unstirred water layer, the relationship between substrate concentration (C1) and unidirectional flux (Jd) is not described by the equation for a rectangular hyperbole. Accordingly, transformations of the Michaelis-Menten equation may not necessarily be linear and may lead to serious errors in the estimation of the affinity constant (Km) and maximal transport rate (Jdm) of carrier-mediated processes. An equation has previously been derived which described Jd under conditions of varying effective thickness or surface area of the unstirred water layer, the free diffusion coefficient of the probe molecule, and the distribution of transport sites along the villus. These theoretical curves have been analyzed by using the Eadie-Hofstee transformation (Jd vs. Jd/C1) of the Michaelis-Menten equation. Use of this plot leads to serious discrepancies between the true and apparent affinity constants and between true and apparent maximal transport rates. These differences are further magnified by failure to correct for the contribution of passive permeation. The Eadie-Hofstee plot is of use, however, to infer certain qualitative characteristics of active transport processes, such as the variation in affinity constants and overlying resistance of the unstirred water layer at different sites along the villus and to predict the adequacy of the correction for the contribution of passive permeation.


Three-dimensional view of the chromatin in freeze-fractured chicken erythrocyte nuclei.

The freeze-fracture thaw-fix (FfTF) technique described in earlier papers is applied in the present work to more detailed study of the chicken erythrocyte, by transmission replicas and high resolution scanning electron microscopy (3 nm scan beam size). The three-dimensional structure of the chromatin, and possibly the non-histone protein matrix, of fractured nuclei is to a large extent retained in this method of preparation and seen in stereomicrographs. In these micrographs the helical sub-structure of the 25 nm chromatin strands can be seen at about the same resolution as that of previously published micrographs in which extracted chromatin is viewed by negative contrast or after metal shadowing. The useful resolution of the secondary electron micrographs, for a suitably mounted specimen, is shown to be as good as that of transmission micrographs of platinum-carbon replicas of the same material.


A scanning microinterferometer with correction of errors caused by overlapping 'ghost' images.

An experimental setup has been built to correct the errors caused by overlapping 'ghost' images when scanning and integrating measurements are carried out with the Jamin-Libedef interference microscope. First a reference field with the object, producing the 'ghost' image, is scanned and the values of the optical path difference (OPD) of each point in the reference field are stored in a computer. Subsequently, the OPD of the object to be measured is calculated for each point by adding the measuring result to the average OPD of five points, located around the corresponding point in the reference field. The applicability of the setup has been tested by measurements with Sepharose beads, Hela cells and the Zeiss microinterference refractometer. The difference between measurements on the same object with and without overlapping 'ghost' image was about 10%. The reproducibility was tested by repeated measurements on the same cell whereby a standard deviation of 1.1% was found.


Intercellular junctions in FANFT-induced carcinomas of rat urinary bladder in tissue culture: in situ thin-section, freeze-fracture, and scanning electron microscopy studies.

This paper describes a set of simple methods for comparative light and electron microscopy studies on tissue cultured tumour cells derived from both noninvasive and invasive carcinogen-induced rat urinary bladder carcinomas. Cells are grown on Thermanox plastic coverslips and fixed in situ. Each plastic coverslip is then divided with scissors into four parts: the first is processed for light microscopy, the second for thin-section electron microscopy, the third for freeze-fracture electron microscopy, and the fourth for scanning electron microscopy. In some experiments, portions of the culture which have first been examined by light microscopy are subsequently prepared for electron microscopy. In this way, the culture conditions are kept constant and comparison of structural features (i.e. intercellular junctions) by several preparative techniques is possible. Noninvasive and invasive rat bladder tumour cells, characterized by numerous pleomorphic microvilli, have normal zonulae occludentes at the apices of lateral surfaces of tumour cells in all cultures. In some areas of invasive tumour cells, occludens junctions are focally attenuated, consisting of only one or two strands, and occasionally the strands are discontinuous. Gap junctions, type PF-1, as well as numerous demosomes are present in all cell lines. Thus, intercellular junctions in noninvasive and invasive rate bladder epithelial cell lines bear a striking resemblance to those previously described in the comparable solid primary tumours. These culture systems may be useful for studying factors which influence the formation of intercellular junctions during malignant transformation.


The hind limb musculature of the brown kiwi, Apteryx australis mantelli.

The most complete account of the hind leg muscles of the kiwi was published a century ago by Sir Richard Owen, in his seventy-fifth year. This extensively-cited work has several omissions and errors, and while certain of these were corrected by subsequent authors, sufficient uncertainty remains to warrant a reinvestigation. In the present study a detailed description of the hind leg musculature is given, based upon dissections of two frozen specimens. An indication of the possible function of each muscle is given by assessing its size, action, and fiber-arrangement, together with tentative data on the relative abundance of twitch and tonus fibers. The correlation between surface features of bones and muscle attachments is investigated with a view to interpreting palaeontological material. Although the limb and pelvic bones are marked by numerous features which suggest muscle attachments, relatively few can be positively identified with specific muscles. Only 23% of the muscle origins and insertions can be identified, and, with three possible exceptions, no indication of relative size is given by the scars. The possibility of being able to reconstruct the musculature of the kiwi from its skeletal anatomy, much less that of its extinct relatives, is remote.