Sucrose for analgesia in newborn infants undergoing painful procedures

BACKGROUND

Management of pain for neonates is less than optimal. The administration of sucrose with and without non-nutritive sucking (pacifiers) has been the most frequently studied non-pharmacological intervention for relief of procedural pain in neonates.

OBJECTIVES

To determine the efficacy, effect of dose, and safety of sucrose for relieving procedural pain as assessed by physiologic and/or behavioural indicators.

SEARCH STRATEGY

Standard methods as per the Neonatal Collaborative Review Group. A MEDLINE search was carried out for relevant randomized controlled trials (RCTs) published from January 1966 - November 1, 1997; EMBASE from 1993-1997; Reference Update search on November 11, 1997 and search of the Cochrane Library Issue 4 on November 11, 1997. Key words and (MeSH) terms included, infant/newborn, pain, analgesia and sucrose. Personal files, bibliographies, the most recent relevant neonatal and pain journals and conference proceedings were searched manually. Unpublished studies were not included. Language restrictions were not imposed.

SELECTION CRITERIA

RCTs in which term and/or preterm neonates undergoing heel lance, venepuncture or intramuscular injection (immunization) received sucrose or water/placebo or no intervention.

DATA COLLECTION AND ANALYSIS

Trial quality was assessed according to the methods of the Neonatal Collaborative Review Group. Quality measures included; blinding of randomization, blinding of intervention, completeness of follow up and blinding of outcome measurement. Data were abstracted and independently checked for accuracy by the two investigators. The inconsistency in outcome measures and differences in the statistical reporting of results made meta-analysis impossible. We were not able to identify two studies in which the same physiologic and/or behavioral outcomes following a noxious stimulus (heel-lance, venepuncture, intramuscular injection) were measured and reported in an identical fashion using means and standard deviations (or standard errors). The results are therefore reported for each accepted study separately.

MAIN RESULTS

Fifteen studies were identified for possible inclusion in this systematic review. Five studies were excluded; three RCTs were excluded as in these trials the number of infants randomized to treatment vs. placebo groups were not reported; one study was not an RCT, and in one RCT the neonates did not undergo a painful procedure. Ten RCTs were included in this review. Sucrose in a wide range of dosages was generally found to decrease univariate physiologic (heart rate) and behavioural (the mean percent time crying, total cry duration, duration of first cry, and facial action) pain indicators and multivariate [Premature Infant Pain Profile (PIPP)] pain outcomes in neonates undergoing heelstick or venepuncture. An optimal dose of sucrose to reduce pain associated with procedures in preterm and term neonates could not be identified through this systematic review.

REVIEWER'S CONCLUSIONS

Sucrose reduces physiologic and/or behavioral indicators of stress/pain in neonates following procedural pain stimuli (heel lance, venepuncture, immunization). There was inconsistency in the dose of sucrose that was effective and an optimal dose to be used in preterm and/or term infants could not be identified. Considerations for future research are to describe the painful procedure and intervention in detail, to use appropriate sample size to show a statistically significant reduction in pain, to use a multidimensional conceptualization of pain, to select outcome measures that are reliable and valid pain indicators and to account for the variation in the infant's response and context in which the pain is experienced. The use of repeated administrations of sucrose in neonates needs to be investigated. Use of sucrose in neonates that are very low birth weight, unstable and/or ventilated also needs to be addressed. (ABSTRACT TRUNCATED)

Relationship of decrease in fecundity with advancing age to structural changes in mouse endometrium

The aim of this study was to determine whether a relationship exists between decrease in fecundity and structural changes in the antimesometrial endometrium of the mouse. Fecundity was calculated as the number of animals showing a placental sign/number of copulated animals x 100 (%). Structural changes in the endometrium were examined by electron microscopy. A negative correlation between age and fecundity was found. Fecundity was 50% at 7 mo of age. At this age, amorphous material appeared in the region between the basement membrane deep to the luminal epithelium and the subepithelial cells. This material was sometimes attached to the basement membrane. It increased in amount with advancing age, as fecundity decreased. The structure of the uterine luminal epithelial cells did not alter with age. The results indicated that decrease in fecundity with advancing age is correlated with the appearance of amorphous material beneath the basal lamina of the endometrial epithelium. It is suggested that this could impair communication between the luminal epithelium and the endometrial stroma, which plays an important role in implantation.

Purification, molecular cloning, and genomic organization of human brain long-chain acyl-CoA hydrolase

An acyl-CoA hydrolase, referred to as hBACH, was purified from human brain cytosol. The enzyme had a molecular mass of 100 kDa and 43-kDa subunits, and was highly active with long-chain acyl-CoAs, e.g. a maximal velocity of 295 micromol/min/mg and K(m) of 6.4 microM for palmitoyl-CoA. Acyl-CoAs with carbon chain lengths of C(8-18) were also good substrates. In human brain cytosol, 85% of palmitoyl-CoA hydrolase activity was titrated by an anti-BACH antibody, which accounted for over 75% of the enzyme activity found in the brain tissue. The cDNA isolated for hBACH, when expressed in Escherichia coli, directed the expression of palmitoyl-CoA hydrolase activity and a 44-kDa protein immunoreactive to the anti-BACH antibody, which in turn neutralized the hydrolase activity. The hBACH cDNA encoded a 338-amino acid sequence which was 95% identical to that of a rat homolog. The hBACH gene spanned about 130 kb and comprised 9 exons, and was mapped to 1p36.2 on the cytogenetic ideogram. These findings indicate that the long-chain acyl-CoA hydrolase present in the brain is well conserved between man and the rat, suggesting a conserved role for this enzyme in the mammalian brain, and enabling genetic studies on the functional analysis of acyl-CoA hydrolase.

Involvement of serotonin in zimelidine-induced hyperglycemia in mice

Effects of a selective serotonin reuptake inhibitor, zimelidine, on plasma glucose was studied in mice. Zimelidine dose-dependently induced hyperglycemia, although it did not change insulin levels. To determine the involvement of the serotonergic system in zimelidine-induced hyperglycemia, effects of the 5-HT depleter p-chlorophenylalanine(pCPA) were examined. pCPA significantly reduced zimelidine-induced hyperglycemia. This suggests that zimelidine-induced hyperglycemia is mediated by the serotonergic system through its 5-HT reuptake inhibition.

Late acquired words in childhood are lost earlier in primary progressive aphasia

The psycholinguistic nature of the dissolution of the mental lexicon in a primary progressive aphasic patient was investigated in light of the general regression hypothesis that language dissolution is the inverse of language acquisition. Four years after onset of the symptoms, the patient scored 60% correct on a picture naming test, exhibiting some effects of lexical and sublexical age-of-acquisition, but 7 years after onset, he scored only 15% correct. While even a weak form of the regression hypothesis is not fully supported, age-of-acquisition effects seem to be preserved throughout the course of the lexical dissolution. Some implications are briefly discussed for future research.

GABA(B) receptor-mediated presynaptic inhibition of glutamatergic and GABAergic transmission in the basolateral amygdala

The information processing at central synapses is mediated not only by homosynaptic transmission with direct synaptic connections but also by heterosynaptic interactions between distinct synaptic inputs. Using rat brain slices and whole-cell recordings this study aimed to examine the roles of GABA(B) receptors in synaptic interactions in the basolateral amygdala (BLA), a critical brain structure related to fear and anxiety. Stimulation in the BLA produced non-NMDA type glutamate receptor antagonist-sensitive excitatory postsynaptic currents (EPSCs) and bicuculline-sensitive inhibitory postsynaptic currents (IPSCs) in the BLA neurons. The GABA(B) receptor agonist baclofen markedly inhibited both EPSCs and IPSCs in a concentration-dependent manner, and the baclofen-induced inhibition was selectively abolished by the GABA(B) receptor antagonist CGP55845A. The paired-pulse ratio of EPSC and IPSC amplitude was increased by baclofen. The effect of baclofen was mimicked by lowering the external Ca2+ concentration but not by glutamate- and GABA(A)-receptor antagonists. The frequency but not the mean amplitude of miniature EPSCs and IPSCs was decreased by baclofen. The findings suggest that activation of GABA(B) receptors by baclofen reduces the strength of excitatory and inhibitory transmission in the BLA by a presynaptic mechanism. Repetitive conditioning stimulation applied to GABAergic synaptic inputs exerted an inhibitory action on glutamatergic excitatory transmission, and the stimulation-induced inhibition was abolished by CGP55845A. Furthermore, the paired-pulse ratio of EPSCs was increased during the stimulation-induced inhibition. The results in this study provide evidence that synaptic activation of GABA(B) heteroreceptors elicits presynaptic inhibition of glutamatergic excitatory transmission in the BLA.

The serotonin precursor 5-hydroxytryptophan elevates serum leptin levels in mice

The effects of a serotonin (5-HT) precursor 5-hydroxytryptophan (5-HTP) on serum leptin levels were investigated in mice. 5-HTP dose dependently increased serum leptin levels in mice. Pretreatment of the peripheral aromatic amino acid decarboxylase inhibitor carbidopa suppressed 5-HTP-induced hyperleptinemia. These results suggest that the secretion of leptin may be modified by serotonergic mechanisms.

Role of tumor necrosis factor receptors TNFR-I (P55) and TNFR-II (P75) in corneal transplantation

BACKGROUND

To determine the role of tumor necrosis factor-alpha (TNF-alpha) receptor (TNFR) function in corneal allograft immunology.

METHODS

Animals with gene-targeted deficiency in TNFR-I (p55-/-), TNFR-II (p75-/-), or combined TNFR-I/TNFR-II deficiency (p55-/-p75-/-) and their wild-type controls were used as recipients of fully-mismatched (BALB/c; n=88) or multiple minor alloantigen-mismatched (BALB.b; n=62) orthotopic corneal transplants to determine the effect of selective deficiency in one or both TNF-alpha receptors on corneal allograft survival. Grafted recipients were followed biomicroscopically for signs of rejection, and survival data were analyzed by the Kaplan-Meier method.

RESULTS

There was no discernible difference in survival of fully-mismatched BALB/c corneal grafts in p55-/- (n=12; P=0.76) or in double-knockout p55-/-p75-/- (n=13; P=0.41) as compared with wild-type C57BL/6.129 hosts. However, the survival of BALB/c allografts was lower in p75-/- (n=10; median survival 20 days) as compared with control C57BL/6 (n=30; median survival 30 days) hosts (P=0.02). In contrast, there was no discernible effect in survival of minor alloantigen-disparate BALB.b corneal grafts in p75-/- (n=13; P=0.95) or in combined p55-/-p75-/-(n=10; P=0.17) hosts as compared with C57BL/6 (n=9) and C57BL/6.129 (n=10) wild-type controls, respectively. However, there was a profound enhancement in the survival of BALB.b allografts in p55-/- recipients (n= 10; median survival 35 days) as compared to wild-type C57BL/6.129 (n=10; median survival 25 days) controls (P<0.01).

CONCLUSIONS

Our data suggest that the two TNF-alpha receptors largely play discrete roles in mediating rejection of murine corneal allografts. TNFR-I (p55) function seems to be integral to the rejection of minor-disparate grafts, and its selective suppression leads to enhancement of allograft survival. In contrast, TNFR-II (p75) function appears to be associated with enhanced survival of major histocompatibility complex-disparate allografts. The combined deletion of TNFR functionality in p55-/-p75-/- confers no net advantage or disadvantage to major histocompatibility complex or minor alloantigen-disparate grafts.

Selective serotonin reuptake inhibitors fluoxetine and fluvoxamine induce hyperglycemia by different mechanisms

The effects of the selective serotonin reuptake inhibitors, fluoxetine and fluvoxamine, on plasma glucose levels were investigated in mice. Both fluoxetine and fluvoxamine elicited significant hyperglycemia, while a selective noradrenaline reuptake inhibitor maprotiline had no effect. Fluoxetine and fluvoxamine did not change serum insulin levels, although they elicited hyperglycemia. Pretreatment with the serotonin (5-hydroxytryptamine, 5-HT) depleter, p-chlorophenylalanine (pCPA), abolished fluvoxamine-induced hyperglycemia, although pCPA did not affect the fluoxetine-induced glycemic effects. These results suggest that the selective serotonin reuptake inhibitors fluoxetine and fluvoxamine induce hyperglycemia by inhibition of insulin release. Moreover, our findings indicate that the glycemic effects of these drugs are differentially associated with serotonergic mechanisms.

Morphological study on pigmented cells in the horse testis

One of the most attractive characteristics of a horse testis is the change of the weight during development. As the testicular weight changes and the number of Leydig cells decreases, pigments appear in interstitial tissues. In the present study, the characteristics of the pigments found in the interstitial tissues were examined histochemically and ultrastructurally. Specific stainings indicated that the pigmented granules showed almost all of the histological and histochemical characteristics of ceroid or ceroid-like pigment. The cells showed positive reaction for acid phosphatase while the pigmented cells contained a lot of lysosomes ultrastructurally. These results suggest that macrophages might phagocytize Leydig cells, and store their digested materials as ceroid-like pigment.

Role of CD4+ T cells in immunobiology of orthotopic corneal transplants in mice

PURPOSE

To determine, with the use of mice genetically deficient in expression of CD4 or CD8 molecules, which T cells are responsible for rejection of orthotopic corneal allografts in mice.

METHODS

Corneas were prepared from major histocompatibility complex (MHC)-only incompatible, minor histocompatibility (H)- only incompatible, and MHC-plus-minor H incompatible donors and grafted orthotopically to eyes of CD4 knockout (KO), CD8KO, and wild-type control mice. Graft survival patterns were assessed clinically and compared. Mice that retained healthy corneal allografts beyond 8 weeks were evaluated for evidence of donor-specific tolerance and anterior-chamber-associated immune deviation (ACAID) using local adoptive transfer reactions and challenge with orthotopic skin allografts.

RESULTS

Corneas grafted to CD8KO mice were rejected with an incidence and tempo indistinguishable from that in wild-type control animals. By contrast, MHC-only, and minor-H-only incompatible corneal grafts survived indefinitely in eyes of CD4KO mice. Approximately 50% of corneal grafts that confronted CD4KO recipients with both MHC and minor H alloantigens experienced delayed rejection, whereas similar grafts in wild-type recipients were rejected acutely. CD4KO mice with long-accepted grafts displayed neither donor-specific ACAID nor allograft tolerance.

CONCLUSIONS

CD8+ T cells play little or no role in acute rejection of orthotopic corneal allografts. Instead, acute rejection is mediated almost exclusively by CD4+ T cells. Moreover, when corneal allografts survive for 8 weeks without acute rejection, CD4+ T cells promote donor-specific ACAID thereby insuring long-term graft acceptance.

Geographical variation of the skull morphology of the common tree shrew (Tupaia glis)

Geographical variation was examined morphologically in the common tree shrew (Tupaia glis) in some Indochinese and Malayan regions. Osteometrical examination and principal component analysis elucidated the morphological differences among various populations. The populations from southern and western Thailand were distinguished morphologically from the other populations. Variation in males from south Thailand and Kuala Lumpur suggests that the Isthmus of Kra may have an influence on the variation of skull morphology. However, the Isthmus of Kra was not completely considered as a factor of geographical separation in this species, because we could not confirm the separation in skull size and shape between the localities at least in females. While, the Kanchanaburi population in western Thailand was significantly smaller than the other population in skull size, and constituted the morphologically separable group in our study.

Prompt recovery of damaged adrenal medullae induced by salinomycin

The morphologic changes in the adrenal medullae of rats treated with an ionophore antibiotic, salinomycin, are described. Male rats of approximately 7 wk of age were treated orally with a single dose of salinomycin at 80 mg/kg body weight. Following this treatment, the adrenal glands were examined, using immunohistochemistry, for neurofilament, laminin, fibronectin, and S-100 protein; the glands were also examined using transmission electron microscopy. One hour after the treatment, a karyopyknosis was observed in the clusters of affected chromaffin cells in which the neurofilament, laminin, and fibronectin were present. The lesions became progressively conspicuous between hours 5 and 10. Ultimately, the outcome was cell lysis. Five hours after salinomycin treatment, unaffected chromaffin cells strongly stained to tyrosine hydroxylase. At 10 hr, new chromaffin cells, which were irregular in shape with electron-dense cytoplasm (dark cell), that were strongly stained for tyrosine hydroxylase appeared at the basement membrane site of the necrotic clusters, and these cells contained very few immature catecholamine granules of less than 80 nm. At 17 hr, the catecholamine granules increased in number and size to about 200 nm. The newly formed chromaffin cells grew within the clusters to fill in the medulla by 24 hr, and cytoplasmic granules progressively increased in number and size. The interstitial tissue was seen to be edematous at 5 hr. New capillaries were found in the adrenal medullae of both control and salinomycin-treated rats. The protruding chromaffin cells (protruding cells), which we previously described in normal rats, were also observed in salinomycin-treated rats, which suggests that holocrine secretion is performed in the adrenal medullae. The results indicated that the rat adrenal medullae have the ability to make a rapid recovery after an insult by salinomycin.

Influence of the non-competitive NMDA receptor antagonist MK-801 on 2-deoxy-D-glucose-induced hyperphagia in rats

The effects of the glutamate N-methyl-D-aspartate (NMDA) receptor antagonist (5R,10S)-(+)-5-methyl-10,11-dihydro-5H-dibenzo[a,d]cyclo-hepten-5, 10-imine (MK-801) on 2-deoxy-D-glucose-induced hyperphagia were investigated in rats. MK-801 significantly increased 2-deoxy-D-glucose-elicited eating. The facilitating effects of MK-801 on 2-deoxy-D-glucose-elicited feeding were not affected by coadministration of a nitric oxide (NO) precursor, L-arginine. Because NO synthase inhibitors inhibit 2-deoxy-D-glucose-induced hyperphagia and activation of the NMDA receptor leads to NO formation, our results suggest that blockade of the NMDA receptor increases 2-deoxy-D-glucose-induced hyperphagia, which is unrelated to inhibition of NO, and that NMDA receptors may play a role in satiety.

A neuronal nitric oxide synthase inhibitor 7-nitroindazole reduces the 5-HT1A receptor against 8-OH-DPAT-elicited hyperphagia in rats

The effects of the neuronal nitric oxide (NO) synthase inhibitor 7-nitroindazole on 8-hydroxy-2-di-n-(propylamino)tetralin (8-OH-DPAT)-induced hyperphagia, which is mediated by the 5-HT1A autoreceptor, were investigated in rats. 7-Nitroindazole suppressed 8-OH-DPAT-elicited increases in food intake. The inhibitory effects of 7-nitroindazole on 8-OH-DPAT-induced feeding were prevented by the NO precursor L-arginine. Although 8-OH-DPAT decreases 5-hydroxytryptamine (5-HT) synthesis, 7-nitroindazole did not reverse the 8-OH-DPAT-elicited decrease in 5-HT synthesis. Therefore, these results indicate that NO formed in the brain is involved in 8-OH-DPAT-induced hyperphagia and that the hypophagic effects of 7-nitroindazole are not dependent on 5-HT synthesis.

Endocrinological and biophysical responses to further reduction in oxygenation following sustained hypoxemia in fetal goats

OBJECTIVE

The purpose of this study was to determine fetal endocrinological and biophysical responses to the further reduction in oxygenation following prolonged nonacidemic hypoxemia in fetal goats.

METHODS

Seven further hypoxic experiments were performed after prolonged (24-h) nonacidemic hypoxemia, caused by an infusion of nitrogen into the maternal trachea and by reducing uterine arterial blood flow in four chronically instrumented goat fetuses at 123-131 days' gestation. We measured arginine vasopressin, adrenocorticotropic hormone, cortisol, and catecholamines as endocrinological parameters. Fetal heart rate, fetal blood pressure, and fetal breathing movement were observed as biophysical parameters.

RESULTS

Fetal arterial pO2 was significantly decreased from 27.0 +/- 1.2 mmHg (control) to 18.0 +/- 0.7 mmHg and 11.3 +/- 1.3 mmHg at the end of the prolonged hypoxemia and the further hypoxia, respectively. The further hypoxia induced reductions in fetal heart rate, increases in fetal blood pressure, and a series of gasping. Arginine vasopressin and catecholamines were elevated significantly by the further hypoxia. Although adrenocorticotropic hormone and cortisol were increasingly elevated, they did not reach a significant level.

CONCLUSIONS

Some specific fetal responses-excessive elevations of fetal catecholamines, arginine vasopressin, accompanied with fetal gasping-were observed during further severe hypoxia.

Immunohistochemical survey of the gut endocrine cells in the common tree shrew (Tupaia belangeri)

Regional distribution and relative frequency of endocrine cells in the gastrointestinal tract of the common tree shrew (Tupaia belangeri) were studied immunohistochemically. Ten types of immunoreactive endocrine cells were localized in the gastric mucosa, i.e., chromogranin-, serotonin-, gastrin-, somatostatin-, bovine pancreatic polypeptide (BPP)-, enteroglucagon-, pancreatic glucagon-, peptide tyrosine tyrosine (PYY)-, motilin-, and substance P (SP)-immunoreactive (IR) cells. In the intestine, 13 types of immunoreactive cells were observed, i.e., chromogranin-, serotonin-, somatostatin-, gastrin-, BPP-, enteroglucagon-, PYY-, secretin-, cholecystokinin (CCK)-, gastric inhibitory peptide (GIP)-, motilin-, neurotensin-, and SP-IR cells. The regional distribution and relative frequency of the cell types varied along the gastrointestinal tract. Basically, the types, distribution, and relative frequency of the gut endocrine cells were similar to those reported in other mammalian species. However, some characteristic findings were noted in the present study: (1) the considerably large number of gastrin-IR cells in the pyloric region; (2) numerous serotonin-IR cells in the stomach; (3) appreciable number of BPP-IR cells in the transitional region of the stomach; and (4) wide distribution of PYY- and motilin-IR cells in the gut.

Alterations in cardiac sarcoplasmic reticulum Ca2+ regulatory proteins in the atrial tissue of patients with chronic atrial fibrillation

OBJECTIVES

Our purpose was to determine whether atrial fibrillation (AF) patients have alterations in sarcoplasmic reticulum (SR) Ca2+ regulatory proteins in the atrial myocardium.

BACKGROUND

Clinically, AF is the most frequently encountered arrhythmia. Recent studies indicate that an inability to maintain intracellular Ca2+ homeostasis with a consequent increase in membrane-triggered activity could be the primary initiating factor in some circumstances, and that cytosolic Ca2+ abnormalities are an important mediator of sustained AF.

METHODS

We measured the maximum number of [3H]ryanodine binding sites (Bmax) and the expression levels of ryanodine receptor (RyR) mRNA and calcium-adenosine triphosphatase (Ca2+-ATPase) mRNA in atrial myocardial tissue from 13 patients with AF due to mitral valvular disease (MVD) and 9 patients with normal sinus rhythm (NSR).

RESULTS

In AF patients, 1) Bmax was significantly lower in each atrium (0.21+/-0.03 pmol/mg [right], 0.16+/-0.04 pmol/mg [left]) than in the right atrium (0.26+/-0.08 pmol/mg) of NSR patients; 2) Bmax was significantly lower in the left atrium than in the right atrium; 3) Bmax in the left atrium was significantly lower at higher levels of pulmonary capillary wedge pressure; 4) the expression level of RyR mRNA was significantly lower in both the left (1.24 x 10(-2)+/-1.28 x 10(-2)) and right (1.70 x 10(-2)+/-1.78 x 10(-2)) atrium than in the right atrium of NSR patients (6.11 x 10(-2)+/-2.79 x 10(-2)); and 5) the expression level of Ca2+-ATPase mRNA was significantly lower in both the left (5.67 x 10(-2)+/-4.01 x 10(-2)) and right (7.71 x 10(-2)+/-3.56 x 10(-2)) atrium than in the right atrium (12.60 x 10(-2)+/-3.92 x 10(-2)) of NSR patients.

CONCLUSIONS

These results provide the first direct evidence of abnormalities in the Ca2+ regulatory proteins of the atrial myocardium in chronic AF patients. Conceivably, such abnormalities may be involved in the initiation and/or perpetuation of AF.

Functional morphology of the locomotor system in the northern smooth-tailed tree shrew (Dendrogale murina)

The locomotor system of the northern smooth-tailed tree shrew (Dendrogale murina), one of the arboreal species of Scandentia, was examined by means of macroscopic anatomy. In this study, we describe the muscular system in the shoulder, forearm, hip and crural regions. The M. deltoideus and the acromion of the scapula were well-developed. The characteristic postscapular fossa was distinguishable in the scapula. The M. teres major and M. triceps brachii possessed large bundles and were attached to the postscapular fossa. In the hindlimb region, the M. biceps femoris was inserted into large area of distal hindlimb. The M. tenuissimus was discernible beneath the M. biceps femoris. We suggest that these findings may contribute to our understanding of arboreal locomotion in this species, and that this may typically represent the arboreal adaptational pattern of the muscular system in the Scandentia.

An immunohistochemical survey of catecholamine-synthesizing enzyme-immunoreactive nerves and endocrine cells in the bovine pancreas

The distribution of catecholamine-synthesizing enzyme-immunoreactive nerves and endocrine cells in the pancreas of the calf and cow was studied immunohistochemically using antisera against tyrosine hydroxylase (TH) and dopamine beta-hydroxylase (DBH). TH- and DBH-immunoreactive nerve fibres were abundant both within and around the islet of Langerhans. A few TH- and DBH-immunoreactive nerve fibres were seen around the large islets characteristic of calf pancreas, but the majority of cells in the large islets, and some in islets of Langerhans, showed TH immunoreactivity. In the exocrine pancreas, both TH- and DBH-immunoreactive nerve fibres were distributed randomly among the acini, with the DBH-immunoreactive fibres being more numerous. Abundant TH- and DBH-immunoreactive nerve fibres were seen in close association with blood vessels and in the connective tissue around the interlobular duct. Immunoreactivity for both enzymes was also observed in the nerve cell bodies and fibres of the intrapancreatic ganglia. The findings suggest an important role for catecholamines in the regulation of bovine pancreatic function.

Mice with Th2-biased immune systems accept orthotopic corneal allografts placed in "high risk" eyes

CD4+ T cells of the Th1 type play a central role in acute rejection of solid tissue grafts, including orthotopic corneal allografts. Th1 cells, which mediate delayed hypersensitivity, are the polar opposites of CD4+ Th2 cells, and the latter cells cross-regulate Th1 cells through the unique pattern of cytokines they secrete. As such, Th2 cells may have a useful role to play in preventing rejection of corneal allografts. To test this possibility, the immune systems of adult mice were biased toward Th2 responses by immunization with keyhole limpet hemocyanin plus IFA. When immunized subsequently with either OVA or allogeneic corneal tissue, these mice acquired Ag-specific primed T cells of the Th2 type. More important, allogeneic corneas grafted into neovascularized eyes of Th2-biased mice experienced significantly enhanced survival. To demonstrate that enhanced survival was promoted by donor-specific Th2 cells, lymphoid cells from keyhole limpet hemocyanin-immune mice bearing healthy corneal allografts suppressed orthotopic corneal allograft rejection when adoptively transferred into naive, syngeneic recipients. We conclude that acceptance of corneal allografts in neovascularized mouse eyes can be significantly enhanced by biasing the recipient immune system toward Th2 responses.

Scanning electron microscopic observation of apical sites of open-type paraneurons in the stomach, intestine and urethra

The apical region of open-type paraneurons in tubular organs functions as a receptor site for chemical information in the lumen. Electron microscopic studies have demonstrated a tuft of microvilli on the luminal surface of cells, but failed to visualize it three-dimensionally. The present scanning electron microscope (SEM) observation succeeded in viewing, from the luminal side, open-type paraneurons distributed in epithelia of the stomach, intestine, and urethra. The pyloric antrum of avian species and the duodenum of human fetuses, the latter forming an endocrine cell colony at every villus tip, were chosen for SEM observation in order to eliminate visual obstruction by adjacent epithelial cells with developed microvilli. The luminal surface of gut endocrine cells was consistently covered with a tuft of 80-200 microvilli. Pyloric paraneurons possessed thick and stiff microvilli as compared with those of exocrine cells. The microvilli on intestinal paraneurons were more irregular in length and more loosely grouped than those composing the striated border of enterocytes. Urethral paraneurons containing serotonin were surrounded by three or four polygonal epithelial cells. Their narrow apical surface was provided with 30-100 microvilli which varied in length from cell to cell, and which were conspicuously projected above the luminal surface of the urethra. The microvillous crown of the gut and urethral paraneurons was so prominent and constant a structure on the apical surface as to allow easy identification of open-type paraneurons under the SEM.