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At least 1,225 records · Page 68Linked to original sources
PubMed1990

Effects of pinacidil upon penile erectile tissue, in vitro and in vivo.

The effect of pinacidil, a new antihypertensive vasodilator, was studied in vitro upon human and porcine Corpus cavernosum and in vivo upon simian Corpus cavernosum. In vitro, pinacidil incubation (10(-5)-10(-3) M) was found to induce a concentration-dependent inhibition of the tissue response to norepinephrine (NE) and high potassium (K+). Likewise a concentration-related relaxation of the tissue, precontracted with either NE or K+, was seen using pinacidil 10(-5)-10(-3) M. Depending on the concentration applied, spontaneous activity as well as tone and amplitude of the contractions were reduced until total relaxation of the tissue was obtained with a pinacidil incubation of 10(-3) M. In vivo, 5 mg pinacidil in 0.3 ml solution was injected intracavernosally in 17 monkeys. Sixteen monkeys developed tumescence and 10, rigidity of the penis as well. Only one of 5 showed a decrease in the systemic blood pressure. Pinacidil might be of clinical interest as an agent facilitating erection when given intravernosally.

Animals↗
PubMed1978

Is sulphated blood-group substance in pancreas a factor in cystic fibrosis?

The present study showed that the pancreas of two monkey species contained sulphated blood-group substance. Such strongly anionic molecules are known to bind calcium, and their solutions form gels in the presence of cations. It is suggested that such a mechanism may be involved in cystic fibrosis.

Animals↗
PubMed1979

Experimental acute salpingitis in grivet monkeys provoked by Chlamydia trachomatis.

Chlamydia trachomatis is a common cause of sexually transmitted diseases. Recently it has been shown that chlamydiae are also responsible for complications to such lower genital tract infections. In this study, isolates of C. trachomatis from the fallopian tubes of patients with acute salpingitis were inoculated direct into the fallopian tubes of two, and through the cervical canal into the uterine cavity of one grivet monkey. The experimental infections resulted in a self-limited acute salpingitis in the three animals. C. trachomatis was recovered from the monkeys 2 and 3 weeks post inoculation. As found at laparotomy, the infected tubes were swollen and reddened, and there was watery exudate in the abdominal ostia. Microscopically, cellular infiltrates--mainly lymphocytes--were seen in the mucosa, muscularis and subserosa of the tubes. Serologically, a primary antibody response with an IgM to IgG conversion was found. Salpingitis did not occur in a control monkey inoculated in the tubes with a medium lacking Chlamydia. The histological changes in the fallopian tubes of the infected monkeys were reminiscent of those described as being characteristic of "gonococcal" salpingitis in man. The fulfilment of Koch's postulates in the animal model used adds to the earlier evidence that C. trachomatis is capable of causing acute salpingitis in humans.

Acute Disease↗
PubMed1975

Cerebral units activated by tactile stimuli via a ventral spinal pathway in monkeys.

Extracellular microelectrode recordings were made in the forelimb and/or hindlimb areas of the cerebral post-central gyri of 7 monkeys before and/or after acute dorsal hemisections of the cervical or low thoracic spinal cord. The animals were anaesthetized with either pentobarbitone sodium or chloralose. Among the units which were encountered after the lesions were 114 which could be influenced from the periphery. 38 units discharged to light tactile stimulation of small receptive fields and had a topographical organization like that observed in the intact animal. The remaining 76 units could be activated by peripheral electrical stimulation and/or by tapping, squeezing or light pinching. No units were found which specifically were activated by noxious stimuli. The two groups of cortical units responded with latencies only slightly longer than those obtained in the intact preparation. In the light of previous findings these electrophysiological data suggest that, unlike carnivora, primates may possess the ventral spinal somatosensory pathway traditionally postulated on the basis of neurological material.

Animals↗
PubMed1975

Radioactively labelled microspheres in regional cerebral blood flow determinations. A study on monkeys with 15 and 35 mum spheres.

15 mum and 35 mum radioactive microspheres, differently labelled, were used simultaneously for rCBF-determinations in monkeys. Flow values calculated from data for 35 mum spheres were 27 +/- 7 g/min per 100 g higher for grey matter and 10 +/- 3 g/min per 100 g lower for white matter than flow values calculated from 15 mum spheres, while both sphere sizes resulted in similar values for the choroid plexus. A large number of 35 mum spheres were trapped in extracerebral pial arterioles. It is concluded that entrpment in relatively large arterioles of the 35 mum spheres explains the differences in flow values, and that this invalidates the use of 35 mum spheres, and larger, in rCBF-determinations.

Animals↗
PubMed1980

Aqueous humour and ultraviolet radiation.

Studies on the ultraviolet ray absorption in the aqueous humour of rabbit, cat, monkey, guinea pig, and rat showed marked species differences. In the rabbit aqueous the ascorbic acid, the proteins, and some amino acids (tyrosine, phenylalanine, cystine, and tryptophane) are together responsible for the total absorption, and a very great part of it refers to the ascorbic acid content. Accordingly, species with significant amounts of ascorbic acid in the aqueous (monkey, rabbit, guinea pig) have a greater absorption capacity towards ultraviolet radiation than species (cat, rat) lacking this substance. This effect of the ascorbic acid may contribute in protecting the lens against the most biotoxic ultraviolet rays. It seems that the ascorbic acid concentration is highest in the aqueous of typical day animals and lowest in species being active in the dark, indicating a correlation between the aqueous' ascorbic acid level and the quantity of incident light on the eye. The possible significance of changed aqueous ultraviolet ray absorption in the pathogenesis of human cataract development is discussed.

Animals↗
PubMed1979

Characteristics of the internal anal sphincter and the rectum of the vervet monkey.

1. The physiology of the internal anal sphincter of the vervet monkey was investigated. 2. Strips of sphincter in vitro contracted to noradrenaline and adrenaline; adrenoceptors were mainly alpha-excitatory. Strips of rectal circular muscle relaxed to noradrenaline and contained both inhibitory alpha- and beta-adrenoceptors. 3. All strips contracted to acetylcholine. After hyoscine or atropine, high doses of acetylcholine relaxed all strips by stimulating intramural inhibitory neurones as relaxations were blocked by tetrodotoxin and hexamethonium. Nicotine and DMPP gave relaxations with similar characteristics. 4. It was concluded that relaxations to acetylcholine, nicotine and DMPP were not adrenergic as relaxations still occurred in strips from sympathetically denervated or reserpinized animals. The block of these relaxations by propranolol and guanethidine was considered to be unrelated to their actions as adrenergic blocking drugs. 5. All strips relaxed to field electrical stimulation (1--5 Hz) through stimulation of intramural inhibitory neurones as tetrodotoxin blocked these relaxations. Adrenergic blocking drugs, prior reserpinization or prior section of the hypogastric nerves did not block these responses. The relaxations were not therefore adrenergic. 6. 5-Hydroxytryptamine relaxed all strips but was not the transmitter in relaxations to acetylcholine, DMPP or nicotine, nor to field electrical stimulation, as desensitization of strips of 5-HT did not alter these responses. 7. The circular smooth muscle of the internal anal sphincter had a dense terminal adrenergic innervation which rapidly decreased orad. 8. In vivo, hypogastric nerve stimulation relaxed the rectum but contracted the sphincter. Sacral nerve root stimulation caused an after-contraction in both rectum and sphincter. In vivo, a close arterial injection of adrenaline or noradrenaline inhibited the spontaneous contraction waves of the rectum, but contracted the sphincter. Both these responses were blocked by phentolamine. 9. It was concluded that the internal anal sphincter is a discrete high pressure zone which was excitatory cholinergic and adrenergic innervations and an inhibitory non-adrenergic innervation.

Adrenergic Fibers↗
PubMed2003

The relationship between acoustic structure and semantic information in Diana monkey alarm vocalization.

Mammalian vocal production mechanisms are still poorly understood despite their significance for theories of human speech evolution. Particularly, it is still unclear to what degree mammals are capable of actively controlling vocal-tract filtering, a defining feature of human speech production. To address this issue, a detailed acoustic analysis on the alarm vocalization of free-ranging Diana monkeys was conducted. These vocalizations are especially interesting because they convey semantic information about two of the monkeys' natural predators, the leopard and the crowned eagle. Here, vocal tract and sound source parameter in Diana monkey alarm vocalizations are described. It is found that a vocalization-initial formant downward transition distinguishes most reliably between eagle and leopard alarm vocalization. This finding is discussed as an indication of articulation and alternatively as the result of a strong nasalization effect. It is suggested that the formant modulation is the result of active vocal filtering used by the monkeys to encode semantic information, an ability previously thought to be restricted to human speech.

Acoustics↗
PubMed1984

The acoustic features of vervet monkey grunts.

East African vervet monkeys give short (125 ms), harsh-sounding grunts to each other in a variety of social situations: when approaching a dominant or subordinate member of their group, when moving into a new area of their range, or upon seeing another group. Although all these vocalizations sound similar to humans, field playback experiments have shown that the monkeys distinguish at least four different calls. Acoustic analysis reveals that grunts have an aperiodic F0, at roughly 240 Hz. Most grunts exhibit a spectral peak close to this irregular F0. Grunts may also contain a second, rising or falling frequency peak, between 550 and 900 Hz. The location and changes in these two frequency peaks are the cues most likely to be used by vervets when distinguishing different grunt types.

Acoustics↗
PubMed1987

Differences in human and monkey sensitivity to acoustic cues underlying voicing contrasts.

Humans and monkeys were compared in their differential sensitivity to various acoustic cues underlying voicing contrasts specified by voice-onset time (VOT) in utterance-initial stop consonants. A low-uncertainty repeating standard AX procedure and positive-reinforcement operant conditioning techniques were used to measure difference limens (DLs) along a VOT continuum from--70 ms (prevoiced/ba/) to 0 ms (/ba/) to + 70 ms (/pa/). For all contrasts tested, human sensitivity was more acute than that of monkeys. For voicing lag, which spans a phonemic contrast in English, human DLs for a/ba/(standard)-to-/pa/ (target) continuum averaged 8.3 ms compared to 17 ms for monkeys. Human DLs for a/pa/-to-/ba/ continuum averaged 11 ms compared to 25 ms for monkeys. Larger species differences occurred for voicing lead, which is phonemically nondistinctive in English. Human DLs for a /ba/-to-prevoiced/ba/ continuum averaged 8.2 ms and were four times lower than monkeys (35 ms). Monkeys did not reliably discriminate prevoiced /ba/-to-/ba/, whereas humans DLs averaged 18 ms. The effects of eliminating cues in the English VOT contrasts were also examined. Removal of the aspiration noise in /pa/ greatly increased the DLs and reaction times for both humans and monkeys, but straightening out the F1 transition in /ba/ had only minor effects. Results suggest that quantitative differences in sensitivity should be considered when using monkeys to model the psychoacoustic level of human speech perception.

Acoustic Stimulation↗
PubMed1993

Effects of varying signal duration on pure-tone frequency discrimination in humans and monkeys.

This study examined the effects of varying signal duration and pulse repetition rate on pure tone frequency difference limens (FDLs) at 500 Hz and 4 kHz in humans and monkeys. Two experiments examined FDLs as a function of tone duration from 12-400 ms, using stimuli presented either with a constant pulse rate, or with a constant interstimulus interval. In both cases, at 500 Hz, human FDLs increased more than monkey FDLs as duration decreased from 400 to 12 ms. This effect resulted in monkey FDLs that were about 14 times larger than human FDLs at 400 ms, but only about 4 times larger at 12 ms. At 4 kHz, human and monkey FDLs showed more similar rates of increase as duration decreased. A third experiment examined FDLs at 500 Hz for a 100-ms tone as a function of pulse rate (1 per 250-2000 ms). Here, FDLs for humans and monkeys varied in a similar fashion, indicating that both species' sensitivity was similarly affected by manipulating temporal variables relating to memory load, rather than sensory coding. These data provide evidence that, at 500 Hz, humans have a qualitatively different pure tone frequency analyzing mechanism from monkeys, possibly based on better access to phase-locking mechanisms.

Acoustic Stimulation↗