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H C Su

Publications and source records attributed to H C Su.

At least 37 records · Page 2Linked to original sources
PubMed1993

Application of silver acetate autometallography and gold-silver staining methods for in situ DNA hybridization.

In situ hybridization using biotinylated DNA probes has become an important tool in histopathology. It is well known that the sensitivity of the methods used to demonstrate viral DNA in formalin-fixed and paraffin-embedded specimen depends strongly on the detection system used. In the present study, an optimized in situ DNA hybridization protocol was combined with four different approaches of gold-silver staining methods. For silver enhancement, the recently described method of silver acetate autometallography, a technique allowing highly efficient development without the necessity of dark room illumination has been used. The most efficient detection method found in our experiments was the use of gold-adsorbed anti-biotin antibodies with subsequent silver enhancement. This staining procedure can be completed in 5 hours including hybridization and is a highly sensitive alternative to peroxidase and alkaline phosphatase detection systems.

Cytomegalovirus↗
PubMed1992

Catecholamines modulate epidermal growth factor-induced prostaglandin E2 production in amnion-like (WISH) cells by means of a cyclic adenosine monophosphate-dependent pathway.

OBJECTIVE: The purpose of this study was to test the hypothesis that catecholamines can modulate epidermal growth factor-induced prostaglandin E2 production in amnion-derived cells via a cyclic adenosine monophosphate-dependent pathway. STUDY DESIGN: Human amnion-derived WISH cells were used as the model system to study the regulation of prostaglandin E2 production. The concentrations of prostaglandin E2 and cyclic adenosine monophosphate were measured by radioimmunoassay. Statistical significance was determined with the Student t test. RESULTS: Preexposure of WISH cells to either epinephrine, norepinephrine, or dopamine inhibited epidermal growth factor-induced prostaglandin E2 production. In addition, propranolol blocked both the increase in cyclic adenosine monophosphate accumulation and the inhibition of prostaglandin E2 production caused by epinephrine. CONCLUSIONS: These results indicate that epidermal growth factor-induced prostaglandin E2 production can be attenuated by preexposure of amnion cells to catecholamines and that the inhibitory effect of catecholamines on epidermal growth factor response may be mediated via a beta-adrenergic receptor--coupled adenylate cyclase.

1-Methyl-3-isobutylxanthine↗
PubMed1992

[Pancreastatin].

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Amino Acid Sequence↗
PubMed1991

A role for transforming growth factor-beta 1 in regulating natural killer cell and T lymphocyte proliferative responses during acute infection with lymphocytic choriomeningitis virus.

The role of transforming growth factor beta 1 (TGF-beta 1) in regulating NK and T cell proliferation during acute viral infections was investigated. After infection of mice with lymphocytic choriomeningitis virus, NK cell proliferation peaks on day 3 and subsides by days 5 to 7 postinfection, whereas T cell proliferation peaks on day 7 and declines by days 9 to 14 postinfection. As TGF-beta 1 has been shown to inhibit lymphocyte proliferation in culture, the production and function of TGF-beta 1 during infection was evaluated in this model. Northern blot analysis demonstrated that the accumulation of TGF-beta 1 transcripts remained relatively constant in total splenic leukocytes during infection. The Mv 1 Lu mink lung cell bioassay was modified and used to evaluate the production of biologically active TGF-beta 1 during infection. Media conditioned with splenic leukocytes isolated from infected mice contained factors that inhibited DNA synthesis by the Mv 1 Lu cells. Low levels of inhibition were observed with conditioned media prepared on day 3 postinfection and high levels of inhibition were observed with conditioned media prepared on days 5 through 14 postinfection. Neutralization with antibodies specific for TGF-beta 1 demonstrated that TGF-beta 1 contributed to the inhibitory activity. As TGF-beta 1 was produced at times coinciding with the decline in NK cell proliferation, the TGF-beta 1 sensitivity of in vivo-elicited NK cells was evaluated. In vitro and in vivo studies demonstrated that NK cell proliferation was extremely sensitive to inhibition by TGF-beta 1. In culture, TGF-beta 1 had an ID50 of 8 pg/ml for inhibiting DNA synthesis by blast NK cells. In vivo, administration of a total of 0.18 micrograms of TGF-beta 1 resulted in a 93% inhibition of NK cell-mediated lytic units per spleen on day 3 postinfection. The inhibition was a result of a block in NK cell proliferation, as administration of TGF-beta 1 profoundly suppressed the appearance of blast size NK cells and the incorporation of [3H] thymidine by NK cell-enriched, blast lymphocyte populations on day 3 postinfection. In contrast to NK cell proliferation, T cell proliferation was not inhibited by up to 100-fold higher concentrations of the factor in vitro or in vivo. Taken together, these data demonstrate that TGF-beta 1 is an important regulator of NK cell proliferation in vivo. Furthermore, the results indicate that differential sensitivity to TGF-beta 1 may contribute to the coordination of NK and T cell responses during viral infections.

Acute Disease↗
PubMed1991

Treatment of bilateral intrahepatic stones with high duct strictures through selective central hepatic resection.

Bilateral intrahepatic duct stones with strictures, more common in the Orient than elsewhere, are difficult to access surgically. The results of surgical procedures have not been generally successful and are attended by a high postoperative complication and recurrence rate. We report the treatment of 30 patients with intrahepatic calculi and high duct strictures by means of selective central hepatic resection without dissection of the major vessels at the hilum. Central hepatic resection provided satisfactory access to the primary and secondary confluences of the intrahepatic ducts, allowed removal of residual stones and ascariasis, and permitted correction of multiple strictures. Twenty-nine patients so treated were followed for a mean of 32 months after operation. No patients developed recurrent fever, biliary colic, or jaundice after the operation. The technique is therefore recommended as an effective alternative to extensive hepatic lobectomy in the treatment of the intrahepatic calculi with multiple strictures.

Adult↗
PubMed1990

Evidence of a role for protein kinase C in epidermal growth factor-induced prostaglandin E2 synthesis in amnion cells.

Human amnion cells synthesize and release prostaglandin E2 in response to epidermal growth factor. The protein kinase C activator, phorbol 12-myristate, 13-acetate also stimulates amnion cell prostaglandin E2 synthesis. We used a human amnion cell line (WISH) to conduct in vitro experiments to investigate a potential role of protein kinase C in the signal transduction pathway leading to epidermal growth factor-induced prostaglandin E2 production. Pretreatment of cultured amnion cells with a low, nonstimulating dose of phorbol 12-myristate, 13-acetate potentiated the action of epidermal growth factor in causing prostaglandin E2 production as measured by radioimmunoassay. The protein kinase C-selective inhibitor staurosporine inhibited epidermal growth factor-induced prostaglandin E2 production, further suggesting a role for protein kinase C in epidermal growth factor action. Experiments were conducted in which amnion cells were rendered protein kinase C-deficient by chronic exposure to phorbol ester, which has been shown to down-regulate the enzyme. In these cells, epidermal growth factor caused prostaglandin E2 synthesis at levels comparable to native (non-protein kinase C-deficient) cells. We conclude that protein kinase C plays a more modulatory than direct role in the epidermal growth factor signal transduction cascade that leads to prostaglandin E2 production by amnion cells. We propose a bifurcating transduction scheme in which, under conditions of protein kinase C inactivation, epidermal growth factor alone causes prostaglandin E2 synthesis. When protein kinase C is activated by as yet unknown endogenous substances, the epidermal growth factor responsiveness of the amnion cells is greatly enhanced. This pathway could have important implications in a feed-forward mechanism regulating the level of prostaglandin E2 production during the onset of labor.

Alkaloids↗
PubMed1990

Histamine augments colonic secretion in guinea pig distal colon.

We tested the hypothesis that the role of histamine in the control of intestinal secretion is mediated by prostaglandins (PGs). The effects of histamine on ion transport were examined in muscle-stripped sheets of mucosa/submucosa set up in flux chambers. Histamine evoked a transient concentration-dependent increase in short-circuit current (Isc) that was reduced by the Cl- transport inhibitor bumetanide. Histamine also caused the release of PGE2. The Isc response to histamine was reduced by indomethacin and piroxicam, which block PG formation, but not by nordihydroguaiaretic acid, which prevents production of lipoxygenase products. 2-Methylhistamine, but not dimaprit, evoked a concentration-dependent increase in Isc. The Isc response to histamine was reduced by the H1-blocker pyrilamine, but not by the H2-antagonist cimetidine. In addition to its direct effect, histamine augmented the responses of endogenously released neurotransmitters with and without indomethacin and hexamethonium. Tetrodotoxin (TTX) reduced the Isc response to 10(-3) M histamine. In the presence of TTX, exogenous histamine amplified the responses to PGs, vasoactive intestinal polypeptide, 2-chloroadenosine, bethanechol, and carbachol. These results suggest that histamine acts at H1-receptors on cells within the gut to mediate intestinal Cl- secretion in part by releasing PGs and by augmenting the actions of endogenously released neurotransmitters. Our results indicate that histamine has a role in the regulation of colonic transport function.

2-Chloroadenosine↗
PubMed1988

Rapid decreases in phosphatidylinositol in isolated luteal plasma membranes after stimulation by luteinizing hormone.

Phospholipid concentrations were determined in plasma membrane preparations from porcine corpora lutea after incubation for 15 to 120 s without or with 0.5 microgram/ml luteinizing hormone (LH) or 2 microM dibutyryl cyclic adenosine 3',5'-monophosphate (dbcAMP). Treatment with LH caused a dramatic loss of 9 nmol in plasma membrane phosphatidylinositol (PI)/mg protein after 15 s of incubation, but no significant changes in other measurable phospholipids. Also, phospholipid concentrations were unchanged in untreated and dbcAMP-treated plasma membranes. The nature of the LH-induced decrease in PI was studied by incubating plasma membrane preparations for 15 s with [gamma 32P] adenosine 3',5'-triphosphate (ATP). 32P was incorporated only into three phospholipids: phosphatidic acid, phosphatidylinositol 4'-phosphate (PIP), and phosphatidylinositol 4',5'-bisphosphate (PIP2). Although LH generated small but significant increases in labeling of PIP and PIP2, less than 0.5 nmol of total phospholipids/mg protein were radiolabeled in 15 s. Phosphatidylinositol kinase activity, the enzyme that converts PI into PIP, was not affected by LH or dbcAMP treatment. However, incubation of luteal plasma membranes for 15 s with LH resulted in an increase of approximately 2 nmol 1,2-diacylglycerol/mg protein more than that observed in untreated or dbcAMP-treated plasma membranes. In summary, these experiments suggest that LH may stimulate hydrolysis of PI (and possibly PIP and PIP2) in isolated luteal plasma membranes.

Animals↗
PubMed1987

Combined axonal transport tracing and immunocytochemistry for mapping pathways of peptide-containing nerves in the peripheral nervous system.

The various combinations of axonal transport tracing and immunocytochemistry used for mapping pathways of peptide-containing nerves, and in particular those of the peripheral nervous system, are reviewed. The advantages and disadvantages of these methods are discussed. The applications and results presented illustrate the future potential value of this approach.

Animals↗
PubMed1987

Dual intrinsic and extrinsic origins of CGRP- and NPY-immunoreactive nerves of rat gut and pancreas.

The origins of nerves containing calcitonin gene-related peptide (CGRP), neuropeptide Y (NPY), and substance P were investigated in the rat stomach, pancreas, and colon, using immunocytochemistry combined with retrograde tracing and surgical and chemical denervation procedures. Compared with nerves containing vasoactive intestinal polypeptide (VIP) and galanin, which have primarily local origins in mammalian gut, CGRP-, NPY-, and substance P-immunoreactive nerves revealed dual extrinsic and intrinsic origins. Immunocytochemistry combined with retrograde tracing showed that the extrinsic CGRP- and substance P-immunoreactive nerves in the stomach and pancreas originate from bilateral dorsal root ganglia mainly at levels T8-T11, while those of the colon are derived from bilateral ganglia at S1 and, to a lesser extent, L1 and L6. Chemical denervations showed that neurons in these ganglia form a sensory input to the gut, and that those containing CGRP form the largest proportion. The results of combined retrograde tracing and immunocytochemistry indicated that extrinsic NPY-immunoreactive nerves originate from postganglionic sympathetic neurons lying in the coeliac and inferior mesenteric ganglia. These nerves were located mainly around blood vessels in gut and pancreas, showed sensitivity to 6-hydroxydopamine, and thus are likely to be noradrenergic. The present study provides a detailed mapping of the origins of some of the major peptide-containing nerves of the rat gastroenteropancreatic tract, thus providing further information on the anatomy of the enteric innervation.

Animals↗
PubMed1986

CGRP-immunoreactive nerves in the genitalia of the female rat originate from dorsal root ganglia T11-L3 and L6-S1: a combined immunocytochemical and retrograde tracing study.

The origin of the calcitonin gene-related peptide (CGRP)-immunoreactive nerve fibres in the genital organs of the female rat was investigated by immunocytochemistry and retrograde tracing with the fluorescent dye True blue. The tracing results revealed that these tissues receive an afferent nerve supply from two separate groups of dorsal root ganglia: T11-L3 and L6-S1. In T11-L3 ganglia 66-86% of True blue-labelled neurones displayed CGRP immunoreactivity whilst 45-63% of labelled cells in L6-S1 ganglia contained the peptide. The results indicate that CGRP-containing dorsal root ganglion neurones form a major part of the afferent sensory nerve supply to the female rat genitalia.

Animals↗
PubMed1986

Composition and central projections of the pudendal nerve in the rat investigated by combined peptide immunocytochemistry and retrograde fluorescent labelling.

The central distribution of the afferent and efferent projections of pelvic striated muscles, the pudendal and sciatic nerves, were systemically investigated in rats by retrograde tracing techniques combined with immunocytochemistry using antibodies to 9 neuropeptides. True Blue was injected into either the pelvic muscles, pudendal or sciatic nerves. Seven days later the spinal cord and dorsal root ganglia (L3-S2 levels) were processed for immunocytochemistry. Injection of tracer into the pelvic muscles labelled dorsomedial, ventral and dorsolateral motoneuron groups of the L6 segment and a few sensory neurons in the respective dorsal root ganglia. Pudendal nerve injection also labelled the same motoneuron groups, 50% of neurons of the retrodorsolateral column and numerous sensory neurons of the dorsal root ganglion. Concomitant labelling of pudendal and sciatic nerves with different fluorescent tracers revealed a small number of double-labelled cells in the dorsal root ganglia but only single-labelled cells in the retrodorsolateral nucleus. Enkephalin-, somatostatin- and neuropeptide Y-containing fibres were particularly abundant in and around dorsomedial and dorsolateral groups as well as the intermediolateral cell column. We conclude that in the rat (a) the pudendal nerve has motor, sensory and autonomic (parasympathetic) components in contrast to the sciatic which is primarily motor and somatosensory, (b) some afferents from these nerves exhibit pre-spinal convergence and (c) dorsomedial and dorsolateral motoneuron groups are homologous to Onuf's nucleus in man.

Animals↗
PubMed1986

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.

Afferent Pathways↗
PubMed1986

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)

Animals↗
PubMed1985

Distribution of galanin immunoreactivity in the central nervous system and the responses of galanin-containing neuronal pathways to injury.

Radioimmunoassay and immunocytochemistry were used to study the distribution of galanin, a novel 29 amino acid porcine intestinal peptide, in the central nervous system of the rat and pig. The pattern of distribution was similar in the two species, with the highest concentrations of galanin-like immunoreactivity found in the neurohypophysis, hypothalamus and sacral spinal cord. Immunocytochemical studies of these regions localized galanin-like immunoreactivity to cell bodies in the paraventricular and supraoptic nuclei of the hypothalamus, to fibres in the pars nervosa and to numerous cell bodies and fibres in the dorsal horn of the spinal cord. On both gel and high pressure liquid chromatography, galanin-like immunoreactivity in rat and pig nervous tissue eluted as a single peak in a position similar to purified procine intestinal galanin standard. Surgical and pharmacological manipulations in the rat suggest the presence of galanin in afferent fibres. An increase of galanin-like immunoreactivity was observed in the sacral spinal cord of the rat following thoracic spinal cord transection. Thus galanin-like immunoreactivity in the brain is mainly localized in the hypothalamopituitary region. The decrease of galanin-like immunoreactivity in the dorsal horn of the spinal cord, following dorsal rhizotomy and pre-treatment of rats with capsaicin, indicates that many of the fibres, which are of small diameter, may well be derived from spinal sensory neurones.

Animals↗
PubMed1984

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

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

Animals↗