The autoradiographic localization of calcitonin gene-related peptide and substance P receptors in human fallopian tube

The binding of [125I] human alpha calcitonin gene-related peptide (hCGRP) and [125I]Bolton-Hunter-labelled substance P (BH-SP) to human fallopian tube tissue sections was characterized and the respective binding sites were localized by light-microscopic autoradiography. The hCGRP binding sites were associated with the muscularis, lamina propria and vascular smooth muscle, the latter being the most intensely labelled. BH-SP binding sites were associated only with blood vessels. This labelling was intense, and appeared to be restricted to the vascular endothelium. These results suggest that calcitonin gene-related peptide and substance P may act together to regulate local blood flow and plasma extravasation.

The effect of the circadian rhythm of vagal activity on bronchomotor tone in asthma

1. The effect of the diurnal activity of the parasympathetic nervous system on bronchomotor tone and heart rate was studied in seven asthmatics with nocturnal asthma using both intravenous atropine and nebulised ipratropium at 04.00 h and 16.00 h. 2. A diurnal variation in vagal activity was demonstrated with higher vagal activity occurring at night. 3. There was a strong correlation between the initial response of both airway calibre and heart rate to vagal block both at 04.00 h and 16.00 h. However the duration of bronchodilation after vagal block was greater than with the heart rate suggesting differing sensitivities of pulmonary and cardiac muscarinic receptors to anticholinergic antagonists. 4. The bronchodilation seen after ipratropium was less than that after atropine suggesting that the intravenous route is preferable to study the physiological effect of vagal block in vivo.

Radiographic features and prognosis in bronchioloalveolar carcinoma; a local experience

The prognosis of 20 patients with histologically proven bronchioloalveolar carcinoma was assessed in the light of their radiographic features and symptoms at presentation. Radiographically, half the patients were classified as having focal disease of which 60% were focal consolidation. Other focal presentations were, a mass lesion in three cases and a single 3 cm nodule in one case. Those with diffuse disease presented with either coarse widespread nodules or diffuse alveolar opacification with or without a focal area of consolidation. All patients were symptomatic at presentation but the severity of the symptoms bore no relation to the radiological findings. Seven cases with focal disease underwent thoracotomy, five of which had evidence of hilar and mediastinal lymph node involvement. They included a case presenting with a nodule, two with a mass and four with focal consolidation. The survival following surgery was generally better with those with a mass or nodule but one case with focal consolidation remains alive 10.5 years following surgery compared with the longest survivor of 4.5 years with a mass. Both these relatively long-term survivors had no histological evidence of hilar or mediastinal lymph node involvement compared with the other surgical cases. The median survival in cases without surgery was one month. The prognosis was better in patients with focal disease where surgery was performed and we feel that a local area of consolidation should be treated as focal disease and surgical resection considered for these patients.

An electronic apparatus for early detection of changes in red cell content of blood during anaesthesia. A preliminary report

An electronic apparatus was developed for anaesthetists to use to detect changes in red cell concentration during surgery. The mechanism is based on the relationship between the red cell content and the electrical conductivity of blood. In a pilot study of 170 blood samples, a correlation coefficient of 0.9806 was obtained between haematocrit and the instrument readings. To evaluate the instrument's performance in practice, and factors that might influence its readings, a series of 10 cases of aortic surgery were investigated. It is concluded that, although changes in electrolyte concentration, pH and temperature do affect the instrument's readings, these are insignificant compared with those of red cell content, and that the device can be used to indicate a drop in red cell concentration.

The presence of beta-adrenoceptors in rat endometrium is dependent on circulating oestrogen

It has been proposed that the change in sensitivity of the uterus to catecholamines during the oestrous cycle may result from changes in beta-adrenoceptor density in the myometrium. In the present work we applied the technique of light-microscopic autoradiography using the radioligand [125I]iodocyanopindolol to study the density and distribution of beta-adrenoceptors in the rat uterus during the normal oestrous cycle, following ovariectomy, and after ovariectomy with oestradiol replacement. We found that beta-adrenoceptor density in the endometrium, but not the myometrium, varied during the oestrous cycle, being highest during pro-oestrous. The endometrium of the ovariectomized rats was devoid of any beta-adrenoceptors, whilst that of the oestradiol-treated rats was very intensely labelled. Following ovariectomy there was an increase in beta-adrenoceptor density in the myometrium, but this was not observed in the animals given oestradiol replacement. It appears that both the presence and density of beta-adrenoceptors in rat endometrium is dependent on circulating oestrogens.

The distribution of beta-adrenoceptors in human cervix

The distribution of beta-adrenoceptors in sections of human cervix taken at the proliferative phase of the menstrual cycle was studied using light-microscopic autoradiography. The radioligand [125I]iodocyanopindolol (125ICYP) was used to identify specific binding sites. Moderate density of labelling by 125ICYP was seen over smooth muscle and blood vessels. The most intense labelling, however, was seen over glands and surface columnar epithelium. The association of beta-adrenoceptors with glands and surface columnar epithelium suggests a possible adrenergic regulation of secretory function in the cervix.

Treatment of anismus in intractable constipation with botulinum A toxin

In seven patients with anismus the striated sphincter muscle complex was selectively weakened by local injection of Clostridium botulinum type A toxin. Symptom scores improved significantly and correlated with a significant reduction in the maximum voluntary and canal squeeze pressure and a significant increase in the anorectal angle on straining. Botulinum A toxin seems to be promising treatment for some patients with anismus.

A comparison of the distribution of substance P and calcitonin gene-related peptide receptors in the rat bladder

Binding of [125I]Bolton-Hunter labelled substance P (BH-SP) and [125I]human alpha-calcitonin gene-related peptide (h alpha CGRP) to rat bladder tissue sections was characterized and the respective binding sites localized by light-microscopic autoradiography. BH-SP binding sites were localized to epithelium, blood vessels and smooth muscle while hCGRP binding sites were present only over the epithelium. These results suggest that the range of biological actions of substance P and calcitonin gene-related peptide, which may be co-released from the same afferent terminals, might be determined by the different distributions of their respective receptors.

Mechanism of the reaction catalyzed by dihydrofolate reductase from Escherichia coli: pH and deuterium isotope effects with NADPH as the variable substrate

The variations with pH of the kinetic parameters and primary deuterium isotope effects for the reaction of NADPH with dihydrofolate reductase from Escherichia coli have been determined. The aims of the investigations were to elucidate the chemical mechanism of the reaction and to obtain information about the location of the rate-limiting steps. The V and V/KNADPH profiles indicate that a single ionizing group at the active center of the enzyme must be protonated for catalysis, whereas the Ki profiles show that the binding of NADPH to the free enzyme and of ATP-ribose to the enzyme-dihydrofolate complex is pH independent. From the results of deuterium isotope effects on V/KNADPH, it is concluded that NADPH behaves as a sticky substrate. It is this stickiness that raises artificially the intrinsic pK value of 6.4 for the Asp-27 residue of the enzyme-dihydrofolate complex [Howell, E. E., Villafranca, J. E., Warren, M. S., Oatley, S. J., & Kraut, J. (1986) Science (Washington, D.C.) 231, 1123] to an observed value of 8.9. Thus, the binary enzyme complex is largely protonated at neutral pH. The elevation of the intrinsic pK value of 6.4 for the ternary enzyme-NADPH-dihydrofolate complex to 8.5 is not due to the kinetic effects of substrates. Rather, it is the consequence of the lower, pH-independent rate of product release and the faster pH-dependent catalytic step. At neutral pH, the proportion of enzyme present as a protonated ternary enzyme-substrate complex is sufficient to keep catalysis faster than product release.(ABSTRACT TRUNCATED AT 250 WORDS)

Dihydrofolate reductase from Escherichia coli: the kinetic mechanism with NADPH and reduced acetylpyridine adenine dinucleotide phosphate as substrates

Kinetic studies on the reaction catalyzed by dihydrofolate reductase from Escherichia coli have been undertaken with the aim of characterizing further the kinetic mechanism of the reaction. For this purpose, the kinetic properties of substrates were determined by measurement of (a) initial velocities over a wide range of substrate concentrations and (b) the stickiness of substrates in ternary enzyme complexes. Stickiness is defined as the rate at which a substrate reacts to give products relative to the rate at which that substrate dissociates. Stickiness was determined by varying the viscosity of reaction mixtures and the concentration of one substrate in the presence of a saturating concentration of the other substrate. The results indicate that NADPH is sticky in the enzyme-NADPH-dihydrofolate complex, while dihydrofolate is much less sticky in this complex. At higher concentrations, NADPH functions as an activator through the formation of an enzyme-NADPH-tetrahydrofolate from which tetrahydrofolate is released more rapidly than from an enzyme-tetrahydrofolate complex. Higher concentrations of dihydrofolate also cause enzyme activation, and it appears that this effect is due to the ability of dihydrofolate to displace tetrahydrofolate from a binary enzyme complex through the formation of a transitory enzyme-tetrahydrofolate-dihydrofolate complex. As NADPH and dihydrofolate function as activators and as NADPH behaves as a sticky substrate, the kinetic mechanism of the dihydrofolate reductase reaction with the natural substrates is steady-state random. By contrast with NADPH, reduced 3-acetylpyridine adenine dinucleotide phosphate exhibits only slight stickiness and does not function as an activator.(ABSTRACT TRUNCATED AT 250 WORDS)

Parasympathetic nervous system in nocturnal asthma

To investigate the effect of vagal blockade with atropine on nocturnal fall in peak expiratory flow rate 10 patients with asthma who had a diurnal variation in peak expiratory flow rate of greater than 20% were given 30 micrograms/kg of intravenous atropine or a placebo at 4 am and 4 pm. Vagal blockade caused significant bronchodilatation at 4 am and 4 pm (peak expiratory flow rate rose from 260 to 390 l/min at 4 am and 400 to 440 l/min at 4 pm) and significantly increased the pulse rate from 60 to 121 beats/minute at 4 am and from 76 to 122 beats/minute at 4 pm. Nocturnal asthma was almost totally reversed, implying that vagal mechanisms are fundamental in its pathophysiology. Other mechanisms--diurnal changes in plasma adrenaline concentration, the activity of non-adrenergic non-cholinergic nerves, and circadian rhythms of inflammatory mediator activity--may also be implicated.

Reproducibility of walking test results in chronic obstructive airways disease

Thirty six patients with chronic airflow obstruction were studied to examine (1) the reproducibility and order effect of repeated walking tests when performed over consecutive days or consecutive weeks; (2) the correlation between walking distance and spirometric measurements; and (3) the effect of static visual clues on performance. In study 1, where 12 patients performed 12 walks over three consecutive days, five minute walking distance increased by 33% between walks 1 and 12, half of the increase occurring after the first three walks. In study 2, where 24 patients performed 12 walks over four consecutive weeks, five minute walking distance increased by 8.5% between walks 1 and 12. A learning effect was seen over the first nine walks. Static visual clues to performance did not affect the distance walked. Spirometric measurements showed no order effect in either study. Although walking distance correlated significantly with FEV1, forced vital capacity, and peak expiratory flow, these measurements were poor predictors of exercise performance. The learning effects seen on repeated performance of walking tests over short intervals should be considered when an individual's response to treatment is being interpreted. When walking tests are used in clinical trials a placebo group or randomised crossover design is essential.

General practitioner referrals for static miniature chest radiography: indications and diagnostic yield

The chest clinic based miniature radiographic service had been studied prospectively with the view to assessing its efficiency and correlating radiological and clinical findings. We conclude that such a service provides advantages for rapid patient recall and assessment. The fact that it is organized by chest physicians allows a more selected pattern of clinic referral.

Prospective study of the effects of postanal repair in neurogenic faecal incontinence

The most important factor associated with a good result in the surgical treatment of neurogenic faecal incontinence by postanal repair is considered to be restoration of the obtuse anorectal angle. Sixteen patients (14F:2M; median age 59 years) with neurogenic faecal incontinence confirmed by a raised fibre density in the external anal sphincter underwent postanal repair. Pre- and postoperative manometric assessment was performed in 16 and radiological assessment in 12. Normal ranges for these parameters were established in age and sex matched control subjects. Continence was improved in 14 (88 per cent) patients, 6 (38 per cent) of whom regained normal continence, at a minimum of 15 months follow-up. A successful outcome was associated with no significant change in basal (pre-operative 35 (10-85) cmH2O, postoperative 44 (12-105) cmH2O; n.s.) or voluntary (pre-operative 43 (5-150) cmH2O, postoperative 32 (12-180) cmH2O; n.s.) components of anal canal pressure. There was a small but significant increase in sphincter length (pre-operative 2 (0-3) cm, postoperative 2.5 (0-3.5) cm; P less than 0.01). There was no significant change in the anorectal angle at rest (pre-operative 96 (90-110) degrees, postoperative 107 (79-118) degrees; n.s.) in the patients in whom continence was restored and five of these patients had resting anorectal angles within the normal range (75-94 degrees). Thus postanal repair need not be restricted to patients with widening of the anorectal angle since its beneficial effects do not appear to be related to reduction of this angle.

An excitatory influence of dorsolateral pontine structures on urinary bladder motility in the rat

The effects of electrical stimulation of dorsolateral pontine structures on urinary bladder motility have been compared with those of microinjection of an excitatory amino acid, DL-homocysteic acid (DLH), which is believed to activate neuronal cell bodies but not axons. Increases in the intravesical pressure (IVP), indicative of urinary bladder contractions, were observed following low intensity (less than 50 microA) electrical stimulation in the brachium conjunctivum (BC) and the surrounding parabrachial nucleus (PBN). In contrast, increases in IVP evoked by DLH were observed only after its injection into a localised area just dorsal to the BC, in the region of the lateral parabrachial nucleus. These results suggest that cell bodies of neurones with an excitatory influence on the urinary bladder are located in restricted regions of the PBN, dorsal to the BC.

Pressure and prolapse--the cause of solitary rectal ulceration

The cause of solitary rectal ulceration has been investigated using a method that radiologically visualises rectal voiding whilst simultaneously measuring intrarectal pressure and external anal sphincter electromyographic activity. Control subjects and patients with the solitary rectal ulcer syndrome, both with and without mucosal ulceration, have been studied. A high incidence of rectal prolapse (94%) was present in the patients who voided. Overactivity of the anal sphincter during evacuation contributed to the fact that patients with mucosal ulceration required higher intrarectal pressures to void than the controls and the patients without mucosal ulceration. The results indicate that a combination of rectal prolapse and a high voiding pressure may act to cause the mucosal ulceration in this syndrome by exposing the rectal wall to a high transmural pressure gradient.

The effects of beta-adrenoceptor blockade on breathing during progressive exercise in normal man

1 We have studied the effects of single oral doses of 80 mg propranolol and 100 mg atenolol on breathing during progressive exercise in nine healthy men in a double-blind, placebo-controlled experiment. As judged by their effects on exercise heart rate significant levels of beta-adrenoceptor blockade were achieved. 2 At the two lower levels of work rate (50 watts and 100 watts) minute ventilation on atenolol was lower than on placebo while at the highest level of work (200 watts) minute ventilation was higher on atenolol than on placebo. The regression of VE atenolol on VE placebo was 1.28 which is significantly different from unity (P less than 0.001). The results with propranolol were more scattered and failed to reach the 5% level of significance. 3 Effects on the pattern of breathing are small but when minute ventilation is matched with placebo, atenolol results in larger tidal volumes and prolonged inspiratory and expiratory time. 4 These observations are discussed in relation to other work in the literature.

Anorectal function in the solitary rectal ulcer syndrome

The anorectal function of nine patients with solitary rectal ulcer syndrome (SRUS) (5 F: 4 M, median age, 27 (range, 19-41 years) and nine control subjects (5 F: 4 M, median age, 47 (35-66) P less than 0.01) has been investigated by a new technique that radiologically visualizes the anorectum during voiding of a semisolid contrast medium, while simultaneously measuring intrarectal pressure and anal sphincter EMG activity. A degree of rectal prolapse was demonstrated in eight of the SRUS patients; six of these lesions were clinically occult. Abnormal failure of the anal sphincter to relax on voiding was present in seven of the SRUS patients. These abnormalities resulted in the SRUS patients requiring a greater increase in intrarectal pressure (median, 100 cm water) to void than the control subjects (median, 65 cm water, P less than 0.01). This combination of high intrarectal pressure and rectal prolapse during staining seems to be the cause of SRUS.

Electrophysiological evidence for an excitatory projection from ventromedial forebrain structures on to raphe- and reticulo-spinal neurones in the rat

Spinally projecting neurones in nucleus raphe magnus (NRM) and the adjacent reticular formation of the medulla were identified by their antidromic responses to electrical stimulation in the lumbosacral spinal cord. Identified raphe-spinal and reticulo-spinal neurones were then tested for the effects of electrical stimulation at sites in the ventromedial forebrain, including the anterior hypothalamus and preoptic area (AH/POA). The results of these experiments have demonstrated that a considerable proportion of raphe- and reticulo-spinal neurones receive an excitatory input from the AH/POA. It is suggested that activity in this descending pathway might contribute to the inhibitory effects of AH/POA stimulation on the nociceptor-evoked activities of spinal dorsal horn neurones.

Calcitonin gene-related peptide immunoreactivity in afferent neurons supplying the urinary tract: combined retrograde tracing and immunohistochemistry

The innervation of rat and guinea pig urinary tract was examined using immunohistochemistry, radioimmunoassay and True Blue retrograde tracing techniques and was further assessed following both surgical and chemical denervation experiments. Substantial amounts of calcitonin gene-related peptide-like immunoreactivity (range 20-150 pmol/g) were detected in tissue extracts and localised to nerve fibres distributed throughout the urinary tract of both species, these being concentrated in the ureter and base of the bladder. In the guinea pig, the number and distribution pattern of calcitonin gene-related peptide-like immunoreactive nerves appeared to be identical to that of substance P-containing nerves, whereas in the rat the former predominated. Seven days after injection of the fluorescent dye True Blue into tissues of the urinary tract, retrogradely labelled cells were found in the dorsal root ganglia. These cells had a segmental distribution pattern which was specific for each of the injection sites. Thus, after injection of True Blue into the left kidney hilum a single group of labelled cells were found in the ipsilateral T10-L2 dorsal root ganglia. In contrast, injection into the left ureter produced labelled cells in two separate groups of ipsilateral ganglia (T11-L3 and L6-S1). Injection into the wall of the bladder and upper urethra resulted in bilateral labelling, with most labelled cells occurring in L6 and S1 ganglia. Approximately 90% of labelled cells in T10-L3 dorsal root ganglia displayed calcitonin gene-related peptide-like immunoreactivity, but only 60% of retrogradely labelled bladder neurons in L6-S1 ganglia were immunoreactive for this peptide. Adult guinea pigs and neonatal rats injected systemically with capsaicin subsequently exhibited a marked reduction both in the amount of calcitonin gene-related peptide immunostaining and the concentration of immunoreactive material in the urinary tract, dorsal root ganglia and spinal cord. In rats treated neonatally with capsaicin, there was a significant reduction in the number of retrogradely labelled cells and a hypertrophy of the bladder. Sectioning of the pelvic and hypogastric nerves in the rat also resulted in a depletion of calcitonin gene-related peptide-like immunoreactive nerves in the bladder, whereas chemical sympathectomy appeared to have no effect. The results indicate that calcitonin gene-related peptide immunoreactivity occurs in a major proportion of afferent neurons supplying the urinary tract of the rat and guinea pig.(ABSTRACT TRUNCATED AT 400 WORDS)

The role of pelvic floor denervation in the aetiology of idiopathic faecal incontinence

Weakness of the muscles of the pelvic floor and external anal sphincter may in theory be caused by a traction injury to the pelvic nerves incurred as a result of the excessive perineal descent that accompanies straining in the descending perineum syndrome (DPS). To investigate the role of this weakness in the aetiology of idiopathic faecal incontinence (IFI), measurements of perineal position, puborectalis mean fibre density (MFD), anal canal pressures, rectal sensation, capacity, and compliance were made in continent (DPS alone, n = 20) and incontinent (DPS + I, n = 19) patients with DPS, and a group of age and sex matched control subjects (n = 20). Perineal descent on straining was greater in DPS alone than in DPS + I. Puborectalis MFD was raised by similar degree in both DPS groups compared with the control subjects, and external anal sphincter function, assessed as voluntary squeeze pressure, was impaired by similar degree in DPS + I and DPS alone compared with the control subjects. Maximal basal anal canal pressure and rectal compliance were significantly reduced in DPS + I compared with DPS alone and the control subjects. Thus IFI did not result from progression of neurogenic muscle weakness, but occurred when there was also diminished internal anal sphincter tone and reduced rectal compliance.

Mechanism of inhibition of dihydrofolate reductases from bacterial and vertebrate sources by various classes of folate analogues

Different classes of folate analogues have been examined with respect to the mechanism of their inhibition of dihydrofolate reductases from Escherichia coli and chicken liver. In addition, the degree of synergism between the binding of these compounds and NADPH has been investigated. Methotrexate acts as a slow, tight-binding inhibitor of both enzymes whereas trimethoprim is a slow, tight-binding inhibitor of the enzyme from E. coli and a classical inhibitor of the chicken-liver enzyme. Pyrimethamine, 2,4-diamino-6,7-dimethylpteridine, a phenyltriazine, folate and folinate exhibit classical inhibition. The degree of synergism between the binding of NADPH and the inhibitor varied from low for pyrimethamine and folate to very large for the phenyltriazine which binds to the chicken-liver enzyme almost 50 000-times more tightly in the presence of NADPH. The degree of synergism is reflected in the type of inhibition that the folate analogues yield with respect to NADPH. Compounds which exhibit slight synergism give noncompetitive inhibition whereas those with a high degree of synergism yield uncompetitive inhibition. With the exception of folinate, all compounds that act as classical inhibitors give rise to competitive inhibition with respect to dihydrofolate. Folinate exhibits competitive inhibition against NADPH and noncompetitive inhibition against dihydrofolate. These results are consistent with the formation of an enzyme-dihydrofolate-folinate complex. The (6S, alphaS)-diastereoisomer of folinate was bound at least 1000-times more tightly than the (6R, alphaS)-diastereoisomer. Consideration has been given to the possible interactions that occur between residues on the enzyme and groups on the inhibitor that give rise to slow-binding inhibition.

A VIP/PHI-containing pathway links urinary bladder and sacral spinal cord

Nerve fibres containing VIP and the co-produced PHI are found in the dorsal horn and autonomic centres of the sacral spinal cord and in pelvic organs. We have investigated the origin of these nerve fibres and a possible peptide-containing pathway linking pelvic viscera with the spinal cord of the cat and rat using neurochemical and neurosurgical procedures, retrograde tracing and immunocytochemistry. Cell bodies were located in the dorsal root ganglia (after colchicine injection), pelvic ganglia and bladder wall. Capsaicin treatment induced a loss of VIP/PHI from the dorsal horn. Retrograde tracing from the bladder revealed True Blue labelled cells in the dorsal root ganglia (L6, S1), parasympathetic nuclei and pelvic ganglia. Labelled cells were sequentially immunostained for VIP/PHI which were numerous in pelvic ganglia and scattered and weak in dorsal root ganglia. Pelvic nerve section induced a decrease of VIP/PHI immunoreactivity from the spinal cord and no change or a minimal increase in immunoreactive nerve fibers of the bladder. Thus pelvic visceral afferents with cell bodies in the dorsal root ganglia are a significant source of VIP/PHI-containing fibres in the sacral dorsal horn.