A parallel architecture for discrete relaxation algorithm

Discrete relaxation techniques have proven useful in solving a wide range of problems in digital signal and digital image processing, artificial intelligence, operations research, and machine vision. Much work has been devoted to finding efficient hardware architectures. This paper shows that a conventional hardware design for a Discrete Relaxation Algorithm (DRA) suffers from O(n2m3) time complexity and O(n2m2) space complexity. By reformulating DRA into a parallel computational tree and using a multiple tree-root pipelining scheme, time complexity is reduced to O(nm), while the space complexity is reduced by a factor of 2. For certain relaxation processing, the space complexity can even be decreased to O(nm). Furthermore, a technique for dynamic configuring an architectural wavefront is used which leads to an O(n) time highly concurrent DRA3 architecture.

Pharmacokinetics of norethisterone in humans

The pharmacokinetics of a dose of 1mg norethisterone administered with 50 micrograms ethynyloestradiol was studied in 83 subjects. The dose was rapidly absorbed and there were wide variations in the serum NET concentrations at any particular time after dosing; the concentrations at 24 h varied from 100 to 1700 pg/ml. There was a significant negative correlation between the serum NET concentration and the time after dosing in all women. There were large inter-subject variations in the pharmacokinetic parameters, the elimination half-life and bioavailability showing 3- and 5- fold variability, respectively. Mean values for the parameters were t1/2, 7.6 h; bioavailability, 53.6 ng/ml/h; C max, 4.63 ng/ml; clearance, 22.6 l/h; and Vd 2361. There were a number of statistically significant correlations between the pharmacokinetic parameters and analysis of the correlations suggested that clearance was an important determinant of the bioavailability and of C max whereas the elimination half-life was the determinant of the NET concentration at 24 h. The pharmacokinetics of NET are compared with those of ethynyloestradiol. The wide variation in pharmacokinetics is likely to be important in determining inter-subject variations in efficacy and, particularly, side-effects of oral contraceptives especially now that low-dose formulations are widely used.

Occurrence, distribution and origin of peptide-containing nerves of guinea-pig and rat male genitalia and the effects of denervation on sperm characteristics

A systematic immunohistochemical and radio-immunological survey of the occurrence, distribution and origin of the peptidergic nerve supply in guinea-pig and rat male genitalia is presented. Neuropeptide Y (NPY), vasoactive intestinal polypeptide (VIP), peptide histidine isoleucine (PHI), substance P and CGRP were detected in the genital organs of both species. The densities and distribution patterns of the peptidergic nerves were compared with those of the adrenergic nerves, as revealed by antibodies raised against dopamine-beta-hydroxylase (D beta H) and tyrosine hydroxylase (TH), and the general neuronal component, as revealed by antibodies raised against neurofilament proteins (NF). Bilateral transection of the hypogastric nerves, in the guinea-pig, resulted in a decrease of substance P-containing nerves in the vas deferens and of NPY-, PHI- and VIP-containing nerves in the seminal vesicle. Unilateral disconnection of the pelvic nerves caused a decrease of VIP, PHI, substance P and CGRP nerve supply in the ipsilateral vas deferens and cauda epididymidis in the guinea-pig. A marked reduction of noradrenergic and NPY-containing nerves was observed in the vas deferens and sexual accessory glands of rats, chemically sympathectomised by chronic injection of low doses of guanethidine. Conversely, increase of substance P and CGRP immunoreactivities were observed, particularly in the vas deferens. After guanethidine, the cauda epididymidis and vas deferens were distended with spermatozoa, suggesting paralysis of the ducts. Spermatozoa had a decreased percentage of attached cytoplasmic droplets, indicating prolonged retention in the ducts.

The regional distribution of NPY-, PHM-, and VIP-containing nerves in the human female genital tract

The regional distributions of neuropeptide Y (NPY), peptide histidine-methionine (PHM), and vasoactive intestinal polypeptide (VIP) immunoreactivities in the human female genital tract have been estimated by specific radioimmunoassays, and their molecular forms determined by chromatography. The localisation and distribution of these three peptides was carried out by immunocytochemistry. The vagina and cervix contain high concentrations of NPY- and VIP-immunoreactive nerves, mainly localised around the vascular and nonvascular smooth muscle. VIP-containing nerves were, in addition, seen beneath the cervical and, in particular, the vaginal epithelium. A comparatively high level of immunoreactive NPY is found in the fallopian tube, mainly around the circular muscle coat. There is evidence that VIP is a neurotransmitter in the female genital tract, and these results suggest a similar role for NPY and PHM.

Effect of 6-hydroxydopamine on neuropeptides in the rat female genitourinary tract

The occurrence and distribution of neuropeptide Y has been determined in the rat female genitourinary tract by radioimmunoassay and chromatographic analysis. Within the bladder, higher concentrations of neuropeptide Y were found in the trigone (48.8 +/- 5.2 pmol/g) than in the dome (36.0 +/- 2.1 pmol/g). In the genital tract, highest concentrations were identified in the vagina (41.4 +/- 2.1 pmol/g). Treatment of rats with 6-hydroxydopamine resulted in significant depletion of neuropeptide Y concentrations in both parts of the bladder, together with vagina, uterine horn and fallopian tube. No change was observed in the cervix, uterine body and ovary. Concentrations of vasoactive intestinal polypeptide were unaffected by treatment with 6-hydroxydopamine except in the area of the cervix where concentrations rose from 64.1 +/- 5.7 pmol/g to 133.6 +/- 15.1 pmol/g (p less than 0.05). There was a generalised, but statistically insignificant rise in substance P concentrations.

Calcitonin gene-related peptide (CGRP) in the female rat urogenital tract

CGRP-immunoreactivity was found throughout the female rat urogenital tract by specific radioimmunoassay, and shown to be present in nerve fibres by immunocytochemistry. The highest concentrations of CGRP-like immunoreactivity were found in the urinary tract, with lower levels in regions of the genitalia. Chromatographic analysis of bladder and vaginal extracts on Sephadex G-50 columns and HPLC revealed at least three CGRP-immunoreactive peaks. The major peak emerged in the same position as synthetic rat CGRP. CGRP nerve fibres were associated mainly with blood vessels, non-vascular smooth muscle, squamous epithelium and uterine and cervical glands, and were particularly abundant in the ureter and bladder. CGRP-immunoreactivity was depleted by neonatal treatment with capsaicin and after surgical section of pelvic and/or hypogastric nerves. Immunocytochemistry demonstrated that depletion occurred predominantly in the mucosal layer of the urogenital tract. These findings indicate a sensory function for most of the CGRP-immunoreactive nerves in the rat urogenital tract.

Cytochemical relationships in the paracervical ganglion (Frankenhäuser) of rat studied by immunocytochemistry

Vasoactive intestinal polypeptide (VIP), neuropeptide Y (NPY) and calcitonin gene-related peptide (CGRP) immunoreactivities have been demonstrated in the paracervical ganglion of the rat using immunocytochemistry. Dopamine beta-hydroxylase (D beta H) and neurofilament protein triplet immunoreactivities have also been demonstrated in this region. The VIP, NPY, D beta H and neurofilament immunoreactivities were located in ganglion cells and nerve fibres, while CGRP immunoreactivity was localized only in nerve fibres. Many cells immunoreactive with D beta H antiserum were also immunoreactive with NPY antiserum. A small number of cells immunoreactive with VIP antiserum were also immunoreactive with NPY antiserum. CGRP-immunoreactive nerve fibres were distributed in certain regions of the ganglion only.

Peptide histidine methionine (PHM) and the human male genitalia

Peptide histidine methionine-like immunoreactivity (PHM-IR) has been demonstrated to be present in the human penis both by radioimmunoassay and immunohistochemistry with particularly high levels in the corpus cavernosum and vas deferens. In the cavernosa, PHM-IR has been localised entirely, in nerves around arteries. High performance liquid chromatography indicated that this PHM-IR co-eluted with synthetic PHM but not porcine PHI. The presence of PHM-IR in the penis suggests that this neuropeptide may play a functional role in penile function.

Bombesin-like immunoreactivity in female rat genito-urinary tract

The quantitative distribution and localization of bombesin-like immunoreactivity (BLI), by antiserum which cross-reacted fully with gastrin-releasing peptide (GRP), was determined by radioimmunoassay and immunocytochemistry in various regions of female rat urogenital tract. The highest concentration of BLI was found in the vagina, with lower but significant concentrations in the uterus and bladder. Bombesin-like immunoreactive nerve fibres were localized by immunocytochemistry in the smooth muscle layer, around blood vessels and in the submucosa of the vagina and bladder. BLI was separable into two immunoreactive peaks on both gel permeation chromatography and reverse phase HPLC. The major peak emerged exactly in the position of neuromedin C (C-terminal decapeptide of GRP) in both chromatographic systems, while the remaining immunoreactivity emerged close to the position of porcine GRP on gel permeation chromatography, but was easily distinguishable from this on HPLC. This suggests a significant species difference between rat and porcine GRP. Amphibian bombesin and mammalian neuromedin C have previously been shown to have potent biological actions in the rat urogenital tract. The presence of mammalian bombesin-like peptides in nerve fibres of the urogenital tract suggests that they may have a regulatory role in these organs.

Stability of immunocytochemical reactivity of neuronal substances following delayed fixation

The rates of deterioration of immunocytochemical staining for 4 peptide and 2 neuronal antigens were studied on human, guinea pig and rat colon and urinary bladder. It was found that if the fixation started within 10 h after surgery or death, little change was seen in the pattern and intensity of the immunostains. When fixation was further delayed, the immunostaining gradually deteriorated in quality and decreased in quantity until, when fixation was delayed for 60-72 h, most of the original immunostaining was absent. The deterioration rates of the neuronal antigens in the urinary bladder were slower than in the colon and all antigens were preserved for longer at 4 degrees C than at 20 degrees C. The deterioration curves produced from the present findings provide a standard for comparison with the immunostaining results obtained on tissues where fixation is delayed.

Somatostatin in the human heart and comparison with guinea pig and rat heart

Somatostatin has been shown to have negative inotropic and chronotopic effects and to restore sinus rhythm in some cases of cardiac arrhythmia. Using acid extracts, regions of human heart were examined by radioimmunoassay to determine their somatostatin content. Mean (SD) concentrations of 4.1 (0.8) pmol/g and 2.9 (0.8) pmol/g were found in atrioventricular node and right atria respectively and were significantly higher than in other heart regions. Using fresh heart tissue from guinea pigs, somatostatin was localised to cardiac nerves by immunocytochemistry. Nerves containing somatostatin were most abundant in the atria, where the concentrations measured by radioimmunoassay were 7.6 (1.0) and 2.6 (0.4) pmol/g for right and left atria respectively. Somatostatin contained in cardiac nerves may have a physiological role in the cardiac conduction system.

Neuropeptide Y in the human male genital tract

Neuropeptide Y (NPY) was found in high concentrations in the male genital tract. NPY levels were highest in the seminal vesicles, prostate, corpus cavernosum and vas deferens, where large numbers of immunoreactive nerve fibres were detected. Considerable quantities were also found in the epididymis and spongiosum. Lower concentrations were found in the glans penis, testis and foreskin. The presence of a large number of nerves containing NPY suggest that this active neuropeptide may play a role in control of genital function.

Antibodies to neurofilament protein and other brain proteins reveal the innervation of peripheral organs

Monoclonal and polyclonal antibodies to neurofilament proteins, neuron-specific enolase, glial fibrillary acidic protein and S-100 have been used to demonstrate nerves, ganglion cells and the supportive glial system of the innervation of various organs. The female genitalia, the urinary tract, the respiratory system, the pancreas, the heart and the skin of several mammalian species, including rat, mouse, guinea pig, cat, pig, monkey and man were fixed in para-benzoquinone and portions of each organ were snap frozen. Serial or free-floating thick cryostat sections were stained using indirect immunofluorescence and peroxidase anti-peroxidase immunocytochemistry. In addition, the newly described and highly sensitive immunogold-silver staining technique was used on Bouin's-fixed and wax-embedded tissues. Antibodies to neurofilament proteins seemed to react with neuronal structures in all the species studied. Alternately stained serial sections showed a similar distribution of neurofilament proteins and neuron-specific enolase-containing nerves. Neuron-specific enolase staining had a diffuse appearance and was found to be highly variable, indicating that the neuron-specific enolase content might be related to the physiological state of the nerves and ganglion cells, whereas antibodies to neurofilament protein gave a consistently intense and very clear picture of the ganglion cells and nerve fibres. Antibodies to S-100 stained supportive elements of the peripheral nervous system in all tissues examined, whereas antibodies to glial fibrillary acidic protein were more selective.

Increase of S-100 immunoreactivity in the urinary bladder from patients with multiple sclerosis, an indication of peripheral neuronal lesion

The Schwann cells in urinary bladder biopsies from multiple sclerosis patients and controls were examined by immunocytochemistry with an antiserum to S-100. S-100 immunoreactivity was found to be markedly increased in these tissues as compared with the controls, indicating a Schwann cell hyperplasia in the urinary bladder in multiple sclerosis. This finding suggests that local neuronal damage exists in the urinary bladder of patients with multiple sclerosis. Therefore, the concept of multiple sclerosis as a disease wholly of the central nervous system should be reexamined.

Peptide-immunoreactive nerves in the mammalian female genital tract

Vasoactive intestinal polypeptide, substance P, neuropeptide Y and peptide histidine isoleucine immunoreactivities have been demonstrated in the female genitalia of rat, cat, mouse and guinea-pig using immunocytochemistry and radioimmunoassay. They were localized to nerves. Each type of immunoreactive nerve showed a distinct pattern of distribution, though all were associated to some degree with blood vessels and smooth muscle. Vasoactive intestinal polypeptide-immunoreactive and neuropeptide Y-immunoreactive nerves were the most abundant. Higher concentrations of peptides were detected in the female genitalia of the mouse than those of the other species studied. Vasoactive intestinal polypeptide-immunoreactive nerves were particularly concentrated in the cervix (89.1 +/- 17.2 pmol/g, mean +/- S.E.M.) and the uterus (57.4 +/- 14.8 pmol/g) of the mouse, while neuropeptide Y immunoreactivity was more abundant in the Fallopian tube of the mouse (31.6 +/- 11.8 pmol/g) and the vagina of the rat (38.6 +/- 4.8 pmol/g) than in other regions. Separate populations of ganglion cells in the paracervical ganglia were found to contain vasoactive intestinal polypeptide and neuropeptide Y immunoreactivities. Peptide histidine isoleucine-immunoreactive and vasoactive intestinal polypeptide-immunoreactive nerves were similarly distributed, but the former were much less frequent. Substance P-immunoreactive nerves were seen mainly beneath the epithelium of the vagina and were, in general, more numerous in the guinea-pig than in other species. The significance of these peptide-immunoreactive nerves in the female genital organ remains to be determined.

Demonstration of paracervical ganglion origin for the vasoactive intestinal peptide-containing nerves of the rat uterus using retrograde tracing techniques combined with immunocytochemistry and denervation procedures

The origin of the abundant vasoactive intestinal peptide (VIP)-immunoreactive nerves in the uterus has not been fully determined. In this study, a fluorescent dye, True Blue was injected into the uterus of rat and 6 days later, neuronal cell bodies of the paracervical ganglion were found to be labelled by this dye. Some of these labelled ganglion cells were also found to contain VIP immunoreactivity by immunocytochemistry. When the preganglionic pelvic and/or hypogastric nerves of rats were sectioned, the VIP-immunoreactive nerves in the uteri were not depleted, indicating that these nerves did not originate from the splanchnic ganglion, dorsal root ganglion or the spinal cord. Therefore it is concluded that VIP-immunoreactive nerves in the uterus originate from the paracervical ganglion.

Peptide-containing nerves in human urinary bladder

Nerves containing immunoreactive vasoactive intestinal polypeptide (VIP), substance P and two newly discovered peptides, neuropeptide tyrosine (NPY) and PHI (peptide having N-terminal histidine and C-terminal isoleucine), have been found in the human urinary bladder by immunocytochemistry and radioimmunoassay. Somatostatin immunoreactivity was detected by radioimmunoassay. The VIP-immunoreactive nerves were widely distributed in all regions, but were particularly dense beneath the epithelium and in the muscle layer. Scattered intramural ganglia were found to be reactive to VIP antiserum. Higher concentrations of extractable VIP were detected in the trigone than in the dome. VIP- and PHI-immunoreactive nerves were similarly distributed, the latter being less numerous. NPY-immunoreactive nerves were seen mainly in the muscle layer, particularly in the trigonal area. The distribution patterns of VIP- and NPY-immunoreactive nerves resembled those of the previously reported cholinergic and adrenergic nerves, respectively. Many blood vessels were found to be innervated by both types of immunoreactive nerves. Scattered substance P-immunoreactive fibers were occasionally seen, being present in the submucosa and around the detrusor muscles. The significance of these nerves remains to be elucidated.

Neuropeptide Y in the guinea-pig biliary tract

High concentrations of neuropeptide Y (NPY) have been demonstrated in the gall bladder (16.7 +/- 5.4 pmol/g), cystic duct (25.4 +/- 9.2 pmol/g) and common bile duct (54.7 +/- 11.5 pmol/g) of the guinea-pig using a recently developed radioimmunoassay. Immunoreactive NPY containing nerves were demonstrated in all layers of the biliary tree using immunocytochemistry, being particularly dense in the myenteric and mucosal plexuses.

Decrease of vasoactive intestinal polypeptide (VIP) in the penises from impotent men

Vasoactive intestinal polypeptide (VIP)-containing nerves were depleted in the penises of 28 impotent men. The extent of the decrease in VIP-containing nerves broadly reflected the severity of erectile dysfunction. VIP-immunoreactive nerves were most depleted in those men with complete erectile impotence, irrespective of the aetiology of the dysfunction, whereas in those men in whom some erectile function persisted, loss of VIP-immunoreactive nerves was more variable and less complete. Conventional histology demonstrated only mild changes (muscle atrophy and occasional thickening of blood vessel walls). VIP levels, measured by radioimmunoassay of tissue extracts, were depleted by more than 80% in penises from impotent diabetics (43.4 +/- 9.9 pmol/g wet weight [mean +/- SEM]), when compared with 6 controls (189.9 +/- 45.9 pmol/g). These findings not only support the contention that VIP may be the principal neurotransmitter involved in penile erection, but also suggest that depletion of this powerful vasodilatory peptide may play a key role in the development of penile impotence.

High concentrations of a novel peptide, neuropeptide Y, in the innervation of mouse and rat heart

A newly discovered bioactive peptide, neuropeptide Y (NPY), has been found in the innervation of the mouse and rat heart by immunocytochemistry, NPY-immuno-reactive nerves were very dense around the nodal tissues. They also surrounded the coronary arteries and arterioles and were found in close association with the cardiac muscle. The distribution of NPY-containing nerves paralleled that of noradrenergic fibers, demonstrated by the use of antibodies to the catecholamine-converting enzymes tyrosine hydroxylase and dopamine beta-hydroxylase. Furthermore, NPY was seen to be present in a proportion of intrinsic neurons mostly found in the atria and in close proximity to the nodal tissue. The concentrations of extractable NPY-immunoreactive material (about 150 pmol/g in whole mouse heart) by far surpasses those of the other peptides so far reported in the cardiac tissue. High performance liquid chromatography demonstrated the NPY immunoreactivity to elute in a single sharp peak, in an identical position to brain NPY.

The origin of VIP-containing nerves in the urinary bladder of rat

The innervation of the urinary bladder is known to include a considerable number of nerves containing vasoactive intestinal polypeptide (VIP). The origin of such nerves in the bladder of rat was investigated in this study using the methods of immunocytochemistry and radioimmunoassay combined with surgical sectioning of the hypogastric and/or pelvic nerves to the bladder. Eight days after pelvic nerve sectioning proximal to the main pelvic ganglion, VIP-immunoreactive nerves and VIP content were markedly increased from the level in the sham-operated rat bladder. Sectioning of hypogastric or both nerve pathways led to a less significant increase. It was therefore postulated that the majority of VIP-immunoreactive nerves originate from ganglia located either close to the bladder or within the bladder wall. It is interesting that in these experiments the VIP content of the bladder nerves is inversely related to the changes in motility that would be expected to result from the nerve sections.

Peptide immunoreactive nerves and cells of the guinea pig gall bladder and biliary pathways

Using the methods of immunocytochemistry and radioimmunoassay, five peptides (vasoactive intestinal polypeptide (VIP), substance P, somatostatin, met-enkephalin, and bombesin) have been found in the gall bladder and the biliary tracts of guinea pig and each of them possesses a characteristic distribution pattern. Networks of nerves containing each peptide were found in the smooth muscle, around blood vessels and, occasionally, in the lamina propria. The distribution of the peptide immunoreactive nerves in the gall bladder and biliary tract is similar to those found in the gut. Vasoactive intestinal polypeptide (11 +/- 1.5 pmol/g in the sphincters, mean +/- SEM) and substance P (21.5 +/- 1.8 pmol/g in the common bile duct) were found to be the most abundant peptides and a few VIP and substance P immunoreactive neurones were localised in the ganglionated plexus. Bombesin immunoreactive nerves were mainly seen in the sphincter of Oddi, where the mean concentration of extractable bombesin was 14.6 +/- 2 pmol/g. Somatostatin immunoreactive mucosal endocrine cells were identified in the epithelium of the common bile duct and the sphincter. The extractable somatostatin in these regions were 76 +/- 19 pmol/g and 162 +/- 30 pmol/g respectively.