Effect of chronic morphine administration on measured levels and chromatographic characterization of six neuropeptides in guinea-pig ileum

Guinea-pigs were chronically treated with morphine by subcutaneous implantation of a compounded morphine pellet. After 7 days, the animals were sacrificed, and the small intestine was removed and extracted for the assay of 6 neuropeptides (substance P, vasoactive intestinal peptide, galanin, dynorphin A (1-8), dynorphin A (1-17) and alpha-neo-endorphin). The neuropeptide content of the extracts was measured by radioimmunoassay, and the extracts were subjected to analysis by reversed-phase high pressure liquid chromatography. The measured level of each neuropeptide was not significantly different from that in a control group of animals, and the chromatographic elution pattern obtained for each peptide was also similar in control and morphine-treated animals. Furthermore, the major peak of immunoreactivity for each peptide occurred with approximately the same retention time as synthetic standards having the porcine sequence for that peptide. It is concluded that chronic morphine treatment does not alter the tissue concentration or molecular form of at least 5 of the 6 neuropeptides studied. In the case of a alpha-neo-endorphin, a peak of immunoreactivity was discovered that did not correspond to the synthetic peptide. The amount of immunoreactive material present in this peak varied with oxidation and so its contribution to the assay results could not be calculated.

Evidence that neuropeptide Y released from noradrenergic axons causes prolonged contraction of the guinea-pig uterine artery

The participation of neuropeptide Y (NPY) in transmission from sympathetic vasoconstrictor neurons was investigated in the guinea-pig uterine artery, where NPY has been demonstrated immunohistochemically in noradrenergic axons. Exogenous NPY produced long-lasting contractions of isolated arterial segments at low resting tone. Low concentrations of NPY (10(-8)-3 X 10(-7) mol.l-1) were more potent than equimolar concentrations of noradrenaline (NA). NPY produced concentration-dependent desensitization to further application of NPY, but did not affect the magnitude of NA contractions. Trypsin (1.4-2 micrograms.ml-1) reduced NPY-induced contractions by 80-100%, but did not alter NA-induced contractions. Transmural electrical stimulation of arterial segments, after surgical removal of vasodilator axons, produced biphasic contractions which were abolished by guanethidine. Prazosin abolished the fast phase of the neurogenic contraction, leaving a slow contraction with a time course similar to that produced by a low concentration of NPY. The slow contraction was more pronounced at higher frequencies of stimulation (15-20 Hz) than at lower frequencies, and was selectively reduced after desensitization produced by NPY (10(-5) mol.l-1), or after exposure to trypsin. These results suggest that sympathetic vasoconstriction of the guinea-pig uterine artery is produced by release of both NA and NPY from noradrenergic axons.

Inhibition of bacterial colonization by antimicrobial agents incorporated into dental resins

The antimicrobial activity of several chemical agents was determined by incorporating these agents into dentine adhesive resin and following the colonization of Streptococcus mutans on the surfaces of the resin and culture vessel, as well as in the surrounding medium, by optical density measurements. It was found that sodium fluoride and dodecylamine, an organic amine, exhibited excellent antimicrobial properties. These chemicals not only inhibited bacterial growth completely but also seemed to reduce the adhesion of the bacteria to the resin surface. A silver compound, protargin, was mildly effective in inhibiting growth of S. mutans. Copper oxide and chelating acids such as vanillic acid, syringic acid, and ethylenediamine-n, n' diacetic acid (EDDA) were not effective as antimicrobial agents against S. mutans.

Antibody reactivity with HBLV (HHV-6) in U.S. populations

500 sera representing healthy blood donors and a random representation of the U.S. population collected 10 years ago were screened by ELISA for antibody reactivity with purified, disrupted HBLV virions. In each group, the ELISA results were normally distributed with no evidence of bimodality. All sera were subsequently retested after preincubation of each with well-characterized preparations of disrupted HSB-2 cells or HBLV-infected HSB-2 cells. Sera showing significant levels of HBLV-specific neutralization (50% or more) were found in Minneapolis, Kansas City, and in a random population survey (81, 88 and 97% of donors, respectively). Mean ELISA test values were the same for all groups and for males and females within the same group. Sera from these normal donors reacted preferentially with viral antigens of 120 and 58 kDa by Western blot. In a hospital-based prevalence study, frequent IgM and IgG seroconversions were apparent among infants less than 1 year old, and mean ELISA test values reached the adult level before school age. Antigen preparations used in blocking experiments showed no competitive cross-reactivity with antisera against EBV, CMV, HSV, VZV, HIV, or adenovirus type 2 at levels which reduced antibody binding to HBLV by more than 90%. Antibody cross-reactivities towards HBLV and other human herpesviruses were assessed by cross-correlation of viral antibody titers against all of the viruses and by cross-absorptions of antisera against the other viruses with HBLV. In these experiments no antibody cross-reactivity between HBLV and other human herpesviruses were detected. The significance of these findings with respect to health/disease status is presently unknown. Further seroepidemiologic studies of quantitative levels of HBLV antibody reactivity to measure the age of primary infection and progressive changes in healthy and selected disease populations are needed to determine the risk of disease associated with HBLV infection.

Bioavailability of low-dose vs high-dose 6-mercaptopurine

The bioavailability of oral 6-mercaptopurine (6MP) at standard doses is very low, largely as a result of extensive first-pass metabolism by xanthine oxidase. Fewer than one third of patients achieve 6MP plasma concentrations known to be cytocidal in vitro (greater than 1 mumol/L). Studies in vitro have suggested that first-pass metabolism can be saturated at higher doses of 6MP. To determine whether saturation occurs in vivo at clinically used doses and whether bioavailability can be enhanced by increasing the dose, the bioavailability of different doses of 6MP was studied first in rhesus monkeys and then in children with acute lymphoblastic leukemia in remission. In monkeys a higher dose of 6MP resulted in enhanced bioavailability, whereas in patients the mean relative bioavailability at the higher dose was significantly less. However, all patients achieved cytocidal (greater than 1 to 10 mumol/L) plasma concentrations at the higher dose without manifesting significant clinical toxicity. Therefore cytocidal levels of 6MP can be achieved in patients with oral 6MP without the risk of unexpectedly high levels caused by saturation of first-pass metabolism.

Management of intraocular pressure during cardiopulmonary bypass

Intraocular pressure was measured in two groups of patients undergoing cardiopulmonary bypass surgery. A control group received mannitol at the start of bypass in accordance with standard practice; pressure was found to rise by 6.4 mmHg. In a second group of patients mannitol was administered 30 min prior to bypass; pressure elevation of 2.4 mmHg was found. These findings are discussed in relation to other clinical observations during bypass and to ocular morbidity complicating bypass surgery.

Epidemiological assessment of the health and nutrition of Ethiopian refugees in emergency camps in Sudan, 1985

The findings from epidemiological data that were collected from emergency camps for Ethiopian refugees during a mass influx of refugees into Eastern Sudan in 1985 are presented. An overall mortality of 8.9 per 10,000 a day was recorded during February 1985, and in children under 5 years of age the rate was 22 per 10,000 a day. The estimated prevalence of malnutrition (calculated as less than 80% of the reference weight for height) ranged from 32% to 52% among children of preschool age. The principal causes of morbidity and mortality were measles, diarrhoea and dysentery, respiratory infections, and malaria. The findings suggest that malnutrition and disease increased in these refugees after they arrived in the camps. Epidemiological assessment is essential to help to maintain the health and nutrition of refugees in emergency camps.

Pathway-specific connections between peptide-containing preganglionic and postganglionic neurons in the vagus nerve of the toad (Bufo marinus)

We have examined immunohistochemically the distribution of postganglionic nerve cell bodies and their preganglionic inputs in the vagus nerve of the toad, Bufo marinus. Nerve cell bodies containing immunoreactivity (IR) to somatostatin (SOM) were found at the origin of the oesophago-gastric ramus; these neurons projected to the lung. Cell bodies with SOM-IR also occurred in the intracardiac branches of the vagus, but were absent from the distal segments of the pulmonary and oesophageal rami of the vagus. Cell bodies with IR to vasoactive intestinal peptide (VIP) also occurred at the origin of the oesophago-gastric ramus, but most of these neurons projected to the oesophagus. Most neurons in the distal pulmonary and oesophageal rami were VIP-IR. Some nerve cell bodies in the vagosympathetic trunk and in the intracardiac rami contained both SOM-IR and VIP-IR. Vagal preganglionic nerve fibres with IR both to a somatostatin-like peptide and to substance P were associated exclusively with those postganglionic VIP-IR neurons that projected to the oesophagus. These results provide evidence for highly specific connections between immunohistochemically defined populations of preganglionic and postganglionic neurons in the vagus nerve.

Neuropeptide Y-like immunoreactivity is absent from most perivascular noradrenergic axons in a marsupial, the brush-tailed possum

Noradrenergic perivascular axons were demonstrated in all systemic arteries and veins of a marsupial, the brush-tailed possum (Trichosurus vulpecula), by a catecholamine fluorescence procedure and with antisera directed against the catecholamine-synthesizing enzymes tyrosine hydroxylase (TH) and dopamine-beta-hydroxylase (D beta H). Perivascular axons with neuropeptide Y-like immunoreactivity (NPY-LI) were not found in most systemic arteries and veins using antisera which recognize NPY and other members of the pancreatic polypeptide family in diverse vertebrate species. The exceptions were the renal, coeliac, main mesenteric and iliac arteries, where up to 50% of axons with TH-LI or D beta H-LI also showed NPY-LI with two of the 4 antisera used. No noradrenergic nerve cell bodies in thoracic sympathetic ganglia had NPY-LI, whilst 3% of noradrenergic nerve cell bodies in lumbar sympathetic chain ganglia had weak NPY-LI. This marsupial is the first vertebrate species found to date in which the majority of perivascular noradrenergic axons do not contain NPY-LI. If these axons contain an as yet unidentified neuropeptide, it is unlikely to be closely related to NPY.

The significance of longitudinal excursion in peripheral nerves

It has been shown that nerves do, in fact, have a longitudinal excursion. This excursion is accentuated during adjacent joint motion. It is important for the surgeon treating nerve injuries, compression lesions, and adherent nerves to realize that the restoration of the longitudinal excursion of the peripheral nerves must be accomplished in order to effectively treat the inciting lesion.

Partial depletion of neuropeptide Y from noradrenergic perivascular and cardiac axons by 6-hydroxydopamine and reserpine

The effects of 6-hydroxydopamine (6-OHDA) and reserpine on the storage of neuropeptide Y (NPY) in noradrenergic cardiovascular nerves were examined with both immunohistochemistry and radioimmunoassay (RIA). Immunohistochemical double-labelling techniques demonstrated that NPY was located only in noradrenergic axons in the guinea-pig carotid artery, mitral valve, thoracic inferior vena cava, thoracic aorta, superior mesenteric artery and small saphenous vein. Treatment with 6-OHDA in vivo eliminated noradrenergic, NPY-containing axon terminals from all tissues, but preterminal axons were still prominent in the superior mesenteric artery. The greatest depletion of NPY detected by RIA after 6-OHDA treatment was found in tissues with a predominance of terminal noradrenergic axons, such as the small saphenous vein, whereas NPY accumulating in preterminal axons masked the loss of NPY from terminal axons in the superior mesenteric artery. After treatment with doses of reserpine that led to a rapid depletion of noradrenaline (NA) from perivascular nerves, NPY was still detected histochemically at all times although levels sometimes appeared to be reduced. RIA demonstrated that the partial depletion of NPY after reserpine consisted of a rapid phase seen in the vena cava and saphenous vein after the highest doses, and a slower phase of NPY depletion from all tissues after all doses of reserpine. The greatest depletion of NPY from terminal axons by reserpine (in small saphenous vein) was 85-90%. These results demonstrate that some NPY can be stored in noradrenergic perivascular axons in the absence of noradrenaline, but that partial depletion of NPY from axon terminals results when NA stores are depleted by reserpine. The variation in extent of NPY depletion between tissues after drug treatments can be explained by variation in the ratio of preterminal to terminal axons.

Co-localization of neuropeptide Y, vasoactive intestinal polypeptide and dynorphin in non-noradrenergic axons of the guinea pig uterine artery

Two major populations of perivascular axons containing immunoreactivity to neuropeptide Y (NPY) have been revealed in the main uterine artery of the guinea pig by immunohistochemical procedures which allow the simultaneous visualization of two antigens. One population contained immunoreactivity to dopamine-beta-hydroxylase (D beta H) and was presumably noradrenergic. The other main population of axons with NPY-like immunoreactivity (NPY-LI) did not have D beta H-like immunoreactivity (D beta H-LI) and was presumably non-noradrenergic. These non-noradrenergic axons also contained immunoreactivity to vasoactive intestinal polypeptide (VIP) and dynorphin (DYN). Indeed, nearly all axons with VIP-LI also contained NPY-LI and DYN-like immunoreactivity (DYN-LI). NPY constricted the uterine artery perfused in vitro, whilst VIP dilated uterine arteries preconstricted with noradrenaline or NPY. Thus, we have evidence for the coexistence of a vasoconstrictor peptide and a vasodilator peptide in the same non-noradrenergic perivascular axons, which also contain an opioid peptide, dynorphin.

Norepinephrine-dependent and independent mechanisms of persistent effects of amphetamine in rat cerebellum

Previous studies of the effects of chronic low-dose amphetamine (2 mg/kg per day X 21 days) on the spontaneous discharge rate of cerebellar Purkinje neurons have shown persistent depressant effects for up to 50 days after cessation of drug administration. The depression of spontaneous discharge observed was only partially reversible by various pharmacological agents which disrupt noradrenergic neurotransmission in cerebellum. In the present study, several additional approaches were used to investigate further this persistent effect. Rats were treated, either before or after chronic treatment with amphetamine, with intracisternal 6-hydroxydopamine at doses which destroy most noradrenergic fibers in cerebellum. In either case Purkinje neurons were still significantly slowed after cessation of amphetamine treatment, although the depression was not as great as previously observed. In another experiment, cerebellar cortical levels of 3-methoxy, 4-hydroxy phenyl glycol (MHPG) were measured after cessation of amphetamine administration, to determine if there was biochemical evidence for increased noradrenergic neurotransmission. At ten days, MHPG levels were elevated by 36%, and they returned to control values by 30 days. The evidence obtained in these studies suggests that chronic amphetamine treatment causes a persistent increase in noradrenergic neurotransmission, but non-noradrenergic mechanisms may also be important mechanisms in the long-lasting depression of activity of cerebellar Purkinje neurons.

Residues and metabolites of selected persistent halogenated hydrocarbons in blood specimens from a general population survey

The National Center for Health Statistics collaborated with the National Human Monitoring Program of the U.S. Environmental Protection Agency (EPA) in a four-year study to assess the exposure of the general population to selected pesticides through analysis of blood serum and urine specimens. Specimens were collected on a national probability half-sample of persons 12-74 years of age from 64 locations across the United States comprising the sample areas in the Second National Health and Examination Survey (NHANES II) and analyzed for selected organochlorine, carbamate, chlorophenoxy and organophosphorus pesticides. Medical, nutritional and pesticide usage data are also available for each sample person. Results of the blood serum analyses indicate that the general population is being exposed to some of these types of pesticides. For selected pesticide residues, the percent quantifiable positives and median serum levels by age group are presented for three regions of the United States. Since 1970, EPA has conducted a national probability sampling of human adipose tissue. Specimens obtained on a survey design representative of the general population were analyzed for selected organochlorine pesticides and toxic chemicals. Findings from the 1979 survey also indicate exposure of the general population to some of these chemicals.

Rating verbal communication impairment in schizophrenia and affective disorders

Audio recordings of interviews with 42 psychiatric patients (10 schizophrenic, 11 manic, 11 schizoaffective, and 10 depressive patients) and 10 hospitalized orthopedic patients were rated for the presence of verbal communication impairment using the system developed by Andreasen. The definitions of some categories required additional qualifying statements before agreement could be reached on their meaning and applicability in specific circumstances. Nevertheless, the results indicate that the scales can be used reliably by carefully trained, nonprofessional raters. Significant differences were found between diagnostic groups with regard to the frequency and severity of some categories of communication impairment, but the general pattern of results supports previous suggestions that these problems are not pathognomonic of schizophrenia. Based on our experience, we suggest a few changes that might be helpful to other investigators, both in the procedures used for obtaining samples of speech and the definitions of subcategories of verbal communication impairment.

Measurement and chromatographic characterization of vasoactive intestinal peptide from guinea-pig enteric nerves

The material exhibiting immunoreactivity for vasoactive intestinal peptide in guinea-pig enteric nerves has been characterized by high-performance liquid chromatography in three modes: reversed-phase, cation-exchange and gel permeation. In each case a major portion of the material contained in acetic acid extracts of guinea-pig gut showed the same chromatographic properties as the synthetic porcine peptide of defined amino acid sequence. It is therefore concluded that this immunoreactive material is authentic vasoactive intestinal peptide. The study illustrates a number of the problems encountered in attempting to characterize, and measure reliably, peptides in tissue extracts.

Time course of effect of capsaicin on ultrastructure and histochemistry of substance P-immunoreactive nerves associated with the cardiovascular system of the guinea-pig

Capsaicin, a neurotoxin which depletes substance P from primary afferent nerve fibres, was injected systematically into adult guinea pigs. The effects of capsaicin were studied by immunohistochemistry, electron microscopy and radioimmunoassay at times from 5 min to 1 year. Within 5 min after a single injection of capsaicin (50 mg/kg) substance P immunofluorescence appeared less intense and less homogeneous than normal (i.e. it appeared granular). Large nerve trunks remained evident, but there were fewer fine single nerve fibres. With increasing time there was a progressive decrease in the number of immunoreactive fibres; by 4 h there was a marked reduction in the number of fibres and by 24 h only an occasional fibre was evident. In animals sacrificed 2 or more hours after treatment large brightly fluorescent swellings were seen in many nerves. Depletion of substance P-immunoreactivity persisted for as long as 365 days after treatment. Electron microscopy revealed alterations in capsaicin-sensitive nerve fibres within 5 min after treatment. Many fibres appeared swollen and there was disruption of their internal morphology, e.g. loss of microtubules and filaments and presence of an amorphous flocculent material in the axons. With increasing time after treatment, electron-dense profiles, indicative of degenerating nerve fibres, were commonly seen associated with Schwann cells. These findings demonstrate that the effects of systemic administration of capsaicin to adult guinea pigs occur rapidly in capsaicin-sensitive nerve fibres. The long lasting depletion of substance P-containing fibres is due to their degeneration.

Health education: perspective for PAs

Health Education is a valid part of the PA's armamentarium which should be developed to maintain pace with the continuing role evolution of PAs. The Health Belief Model is useful as a means of understanding how patients are motivated to accept health-promoting behavioral and life-style changes. The PA, according to his or her own unique interests, experience, and ingenuity, must develop plans and methods for implementation of specific interventions, but the five priority actions delineated by the Surgeon General can serve as a basis. These include the areas of smoking cessation, alcohol and drug management, nutritional guidance, and the management of psychosocial stress. The authors provide a table of references in these areas.

Substance P-containing nerves in the human small intestine. Distribution, ultrastructure, and characterization of the immunoreactive peptide

Light and electron microscopic immunocytochemical techniques were used to examine the distribution and ultrastructure of substance P-immunoreactive nerves in human jejunum and distal ileum. The organization of human enteric substance P-containing nerves closely resembled that in other species. Dense arrays of varicose immunofluorescent fibers occurred in myenteric and submucous ganglia (which contained immunoreactive nerve cell bodies) and in the mucosa. There were fibers in both muscle layers, in the muscularis mucosae, and around blood vessels. Fibers in the myenteric plexus contributed to both ascending and descending pathways. Substance P-immunoreactive axon profiles contained small round and large round vesicles and were apposed to nerve cell bodies, and nonimmunoreactive and immunoreactive axon profiles. Synapselike contacts were occasionally observed on nerve cell bodies and processes. The substance P-like material was characterized by high pressure liquid chromatography and radioimmunoassay and found to be indistinguishable from the authentic undecapeptide. These results suggest that enteric nerves containing substance P may play similar roles in humans as in other species.

Neuropeptides contained in peripheral cardiovascular nerves

The neuropeptides, substance P, vasoactive intestinal peptide (VIP), neuropeptide Y and enkephalin have been found in nerves associated with the heart and blood vessels of a range of mammals, including man. There is also evidence for some cardiovascular nerves with gastrin releasing peptide and neurotensin immunoreactivity. Substance P is in sensory nerves with a widespread distribution to the heart and all vascular beds. In general, large arteries have the densest innervation and the density of nerves decreases as arterial size decreases. In adult guinea-pigs, an adequate treatment with capsaicin causes the degeneration of almost all cardiovascular substance P nerves. Using capsaicin as a tool it has been shown that the substance P containing sensory nerves are not essential for baroreceptor reflexes. VIP nerves also have a widespread distribution, being particularly prominent in the cerebral arteries, uterine arteries and arteries of erectile and secretory tissues. Neuropeptide Y is located in the same cardiovascular nerves as noradrenaline. It is depleted from the nerves by reserpine or 6-hydroxydopamine. Enkephalin nerves have been reported with small arteries in only a few vascular beds.

Physiochemical studies on indocyanine green: molar lineic absorbance, pH tolerance, activation energy and rate of decay in various solvents

Physiochemical studies were carried out on the tricarbocyanine dye indocyanine green in biological fluids and organic solvents. The molar lineic absorbance epsilon of the compound was highest in organic solvents (methanol, 1.2-propanediol, dimethylformamide) and bile, but lowest in water and duodenal fluid. Indocyanine green remained stable in methanol and bile (t1/2 greater than 1 year) but was rapidly decomposed to a colourless derivative in duodenal fluid and distilled water (t1/2 3.6 days and 1.4 days, respectively). It was thermostable (120 degrees C) in methanol and 1.2-propanediol but thermolabile in water and dimethylformamide where the activation energy for the decomposition reaction was low. At ambient temperature (20 degrees C) indocyanine green was particularly labile at pH less than 5 and pH greater than 11. The rate of decay of indocyanine green in various solvents indicated that the rate limiting step in the decay process was either a first or zero order reaction.

Phase contrast microscopy of microbial aggregates in the gingival sulcus of Macaca mulatta. Subgingival plaque bacteria in macaca mulatta

The objective of this study was to study the relationship of microbial aggregates in the subgingival crevice to changes in periodontal health in Macaca mulatta. The sample included 68 oral sites from 17 Rhesus monkeys of various ages. The periodontal health of each site was evaluated using Plaque and Gingival Indices and crevice depth measurement. The subgingival plaque samples were examined by phase contrast microscopy and recorded on 16 mm film. A Microbial Index was developed based on a qualitative estimate of the numbers of organisms, morphology of predominant organisms, and the presence or absence of motility. The Microbial Index was demonstrated to be simple in use and highly reproducible. The findings indicate that changes in the Microbial Index are consistent with tissue changes seen in the periodontal status in M. mulatta. From this preliminary study, the oral flora of adult M. mulatta appears to have sufficient similarities to human oral flora to be used as a microbial model for experimental periodontal disease research. Future studies to refine and confirm the validity of the Microbial Index are warranted. It may prove to be a useful tool to monitor the effect of various treatment modalities on the periodontal flora and to determine the presence or absence of active disease.

Plasma homovanillic acid and tardive dyskinesia during neuroleptic maintenance and withdrawal

Plasma levels of homovanillic acid (HVA), a dopamine metabolite, were examined in 19 psychiatric inpatients during maintenance treatment on neuroleptic medications. A significant positive correlation was found between the level of HVA and the severity of tardive dyskinesia (TD) in these patients. Seven patients had their medication discontinued for 12 days. In spite of a fall in neuroleptic levels to negligible values, plasma HVA levels remained essentially stable while scores on the Abnormal Involuntary Movement Scale (AIMS) fell only slightly. The data support the hypothesis that some forms of TD may involve a persistent increase in presynaptic dopaminergic activity.

Partial resolution of tardive dyskinesia with treatment of co-existing thyrotoxicosis

Neuroleptic-induced tardive dyskinesia improved after treatment of thyrotoxicosis. Neuroleptic blood levels indicated that the improvement was not caused by masking of the symptoms by rising drug levels. Dopamine metabolite measurements suggested that the thyrotoxicosis caused an increase in the sensitivity of caudate neurons to dopamine, rather than a change in release of dopamine.

Physiochemical studies of indocyanine green (ICG): absorbance/concentration relationship, pH tolerance and assay precision in various solvents

Indocyanine green (ICG) obeyed the Beer-Lambert law within the concentration range 1.25 micrograms/ml-10.0 micrograms/ml in distilled water, methanol, dimethylformamide (DMF), 1.2-propanediol and aqueous buffers (pH 9.0), but only up to 7.5 micrograms/ml in human bile and 0.5% human albumin, and only to 5.0 micrograms/ml in human duodenal fluid. ICG was rapidly (less than 1 h) decomposed to a colorless derivative at pH less than 5 and greater than 11, but remained relatively stable for 48 h at pH 8-10. ICG is an indicator and a weak acid with a pKa of 3.27. In bile stabilized with 25% methanol, the precision of the method (CV) is 5% and the accuracy is 106-127%.

Baroreceptor reflexes in conscious guinea-pigs are unaffected by depletion of cardiovascular substance P nerves

Adult guinea-pigs were injected with doses of capsaicin increasing from 10 mg/kg to 400 mg/kg over 6-days. The guinea-pigs were supplied with indwelling arterial cannulae 14 days later and the next day cardiovascular function was assessed in the conscious animals. Resting blood pressures and heart rates were recorded and then baroreceptor reflex function was evaluated by recording the changes in heart period which were evoked by blood pressure responses to injections of phenylephrine and glyceryl trinitrate. Substance P was measured by radioimmunoassay and its localization examined by immunohistochemistry. The capsaicin treatment caused a substantial reduction in substance P levels in vascular and cardiac nerves. However, there were no changes in resting heart rate, blood pressure or baroreceptor sensitivity. It is concluded that the widespread substance P nerves associated with the heart and blood vessels are not necessary for baroreceptor reflex function. Their role or roles remain unknown.

Pharmacological inhibition of chenodeoxycholate-induced fluid and mucus secretion and mucosal injury in the rabbit colon

The effects of various pharmacological agents on bile acid-induced fluid secretion, mucus secretion, and mucosal injury were investigated using a perfusion technique in rabbit colon. Atropine markedly reduced and carbachol potentiated the fluid secretion, mucus output, and mucosal damage observed during bile acid perfusion. In contrast, pretreatment of the colonic mucosa with lignocaine and parenteral administration of methysergide and somatostatin produced a modest reduction in the fluid secretory response without apparent effects on mucus output or mucosal damage. These results suggested that cholinergic agonists and antagonists influence the mucosal resistance to bile acid-induced injury possibly through their effects on mucus secretion. Increasing or decreasing mucosal resistance to the detergent effects of bile acids appeared to have marked effects on the magnitude of induced fluid secretion. A minor reduction in overall secretory response to bile acids was also apparent with agents not influencing mucus secretion or mucosal injury.

Somatostatin is contained in and released from cholinergic nerves in the heart of the toad Bufo marinus

The heart of the toad Bufo marinus contained a substance with somatostatin-like immunoreactivity which eluted with somatostatin on reverse phase high pressure liquid chromatography. Immunoreactivity to somatostatin was localised histochemically to nerve fibers in muscle bundles of the sinus venosus, atria and ventricles and to nerve cell bodies in the sinus venosus and inter-atrial septum. Nerve cell bodies were localised both by interference contrast microscopy and immunohistochemistry; all detectable intracardiac neurons were immunoreactive. Synthetic somatostatin inhibited the rate and force of beat of atrial preparations, but did not affect the driven ventricle. Vagal stimulation caused inhibition of all cardiac chambers. After muscarinic blockade with hyoscine, vagal stimulation with 3 Hz or more still caused inhibition of the pacemaker and atrium, but not of the ventricle. The hyoscine-resistant vagal effects were diminished by about 60% after induction of tachyphylaxis to somatostatin. When when the vagus nerves were stimulated intermittently for 1 h at 10 Hz, in the presence or absence of hyoscine, the effect of somatostatin was reduced by about 60%. It is concluded that the cholinergic postganglionic neurons of the cardiac vagus contain somatostatin. When the vagus is stimulated at 3 Hz or more, the neurons release sufficient somatostatin to inhibit the pacemaker and atrial muscle.

Characterization of substance P-like immunoreactivity in peripheral sensory nerves and enteric nerves by high pressure liquid chromatography and radioimmunoassay

Material exhibiting immunoreactivity for substance P in enteric nerves, obtained from the myenteric plexus of the guinea pig small intestine, and in the peripheral ends of sensory nerves of the ureter, atrium and superior mesenteric artery, was characterized by separation by high pressure liquid chromatography, and quantified by radioimmunoassay of fractions collected from the chromatograph. Capsaicin, which depletes substance P-like immunoreactivity from sensory, but not from other substance P-containing nerves, reduced the content of substance P-like immunoreactivity in ureter, atrium and superior mesenteric artery by more than 99.5%, whereas the reduction in immunoreactive material in the myenteric plexus was less than 10%. Separation of extracts of myenteric plexus, ureter and atrium on a reversed-phase column gave major peaks corresponding to authentic substance P and minor peaks that coeluted with oxidized substance P. If the extracts were oxidized with hydrogen peroxide before chromatography, all the immunoreactivity was found in the peak corresponding to oxidized substance P. In the superior mesenteric artery extracts, in addition to the components corresponding to substance P and its oxidized derivative, there was a small intermediate peak that has yet to be identified. Physalaemin, which has been suggested to be present in mammalian nerves, was not detectable in any of the extracts. It is concluded that both enteric nerves and the peripheral processes of sensory nerves which show immunoreactivity for substance P in this species contain the authentic peptide.

Effectiveness of nantradol in blocking narcotic withdrawal signs through nonnarcotic mechanisms

Male rats were made narcotic dependent through continuous intravenous infusion of morphine. During withdrawal, nantradol, clonidine, and morphine were found to block withdrawal signs in a dose-dependent manner. Almost complete alleviation of withdrawal occurred with nantradol or clonidine at 0.16 mg/kg and with morphine at 40 mg/kg. The effectiveness of morphine, but not of nantradol or clonidine, was reversed by naloxone. Likewise, in naive rats given castor oil, naloxone did not block the antidiarrheal effect of nantradol or clonidine. In order to compare possible subjective effects of nantradol with other antiwithdrawal drugs, naive rats were trained to discriminate either morphine, cyclazocine, or clonidine from vehicle by selecting different levers for reinforcement. Nantradol failed to produce any generalization to morphine, cycloazocine, or clonidine, suggesting that this drug does not produce central subjective effects like those of the training drugs. In additional testing in behavioral experiments, nantradol failed to produce any sign of anxiogenic activity.

Serologic response in blastomycosis: diagnostic value of double immunodiffusion assay

Double immunodiffusion (DID) is a useful, inexpensive antibody screening test that is more specific than complement fixation for blastomycosis. Seven of 10 patients with proved blastomycosis had positive results on DID assays for antibody to the A antigen of Blastomyces dermatitidis. Sputum cytologic examination and skin or other tissue biopsies may be diagnostic if the organism is demonstrated. Culture remains the sina qua non of diagnosis, and a negative DID test result for A precipitin does not rule out this infection. Follow-up serologic studies of patients in remission and in relapse should be undertaken to determine the evolution of the immune response to the A antigen.

Cyanidation products of organoboranes derived from linalyl acetate

The seven-membered cyclic borane obtained from the reaction of linalyl acetate and thexylborane loses 2,3-dimethylbut-2-ene, and the resulting dialkylborane gives an alcohol on treatment with sodium cyanide, followed by trifluoroacetic anhydride and oxidation. The structure is confirmed by synthesis. The generality of this reaction was investigated but, of the dialkylboranes examined, only 9-borabicyclononane participated in the cyanidation procedure. A simple synthesis of menthone is presented.

Dose-related effects of chenodeoxycholic acid in the rabbit colon

The effects of bile acid (BA) concentration on fluid secretion, mucus secretion, and mucosal damage were investigated during dose-response studies in the rabbit colon with 1, 2.5, and 5 mM sodium chenodeoxycholate (NaCDC). 1 mM NaCDC resulted in mucus secretion followed by mucosal damage but no change in fluid transport was observed. At 2.5 mM concentration, mucus secretion and mucosal damage were evident within 1 hr of perfusion whereas fluid secretion developed in the second hour only. At 5 mM concentrations, all changes occurred simultaneously. The magnitude of changes increased with the concentration of BA perfused. These results are consistent with the hypothesis that mucus secretion with loss of its cytoprotective effect precedes, and thus may permit, the detergent effects of the di-alpha-hydroxy bile acid on the mucosa, resulting in mucosal damage. Both these effects precede changes in fluid and electrolyte transport.

Imaging Photopolarimeter on Pioneer Saturn

An imaging photopolarimeter aboard Pioneer 11, including a 2.5-centimeter telescope, was used for 2 weeks continuously in August and September 1979 for imaging, photometry, and polarimetry observations of Saturn, its rings, and Titan. A new ring of optical depth < 2 x 10(-3) was discovered at 2.33 Saturn radii and is provisionally named the F ring; it is separated from the A ring by the provisionally named Pioneer division. A division between the B and C rings, a gap near the center of the Cassini division, and detail in the A, B, and C rings have been seen; the nomenclature of divisions and gaps is redefined. The width of the Encke gap is 876 +/- 35 kilometers. The intensity profile and colors are given for the light transmitted by the rings. A mean particle size less, similar 15 meters is indicated; this estimate is model-dependent. The D ring was not seen in any viewing geometry and its existence is doubtful. A satellite, 1979 S 1, was found at 2.53 +/- 0.01 Saturn radii; the same object was observed approximately 16 hours later by other experiments on Pioneer 11. The equatorial radius of Saturn is 60,000 +/- 500 kilometers, and the ratio of the polar to the equatorial radius is 0.912 +/- 0.006. A sample of polarimetric data is compared with models of the vertical structure of Saturn's atmosphere. The variation of the polarization from the center of the disk to the limb in blue light at 88 degrees phase indicates that the density of cloud particles decreases as a function of altitude with a scale height about one-fourth that of the gas. The pressure level at which an optical depth of 1 is reached in the clouds depends on the single-scattering polarizing properties of the clouds; a value similar to that found for the Jovian clouds yields an optical depth of 1 at about 750 millibars.