Biomedical subjects

H H Lin

Publications and source records attributed to H H Lin.

At least 73 records · Page 4Linked to original sources

PubMed1998

Gap junction Cx26 gene modulation by phorbol esters in benign and malignant human mammary cells.

Connexin (Cx) 26, a major gap junction protein expressed in mammary epithelial cells, has been considered to be a tumor suppressor gene candidate. This study investigated the molecular mechanism of transcriptional up-regulation of Cx26 by phorbol ester (TPA) in human immortalized MCF-10 mammary epithelial cells and MDA-MB-231 mammary cancer cells. Such up-regulation was mediated through the protein kinase C pathway and could be blocked by the PKC inhibitor, calphostin C. Based on the results of the nuclear run-on assay, there was a TPA-induced increase in the rate of transcriptional initiation. We identified a TPA-induced DNase I hypersensitivity (DH) region approximately 1 kb 5' upstream of the ATG translation starting site. Sequence analysis revealed that this DH region was located in intron 1 and contained two TRE-like TGAT/ATCA elements, two 5'TTCA3' motifs and a 5'AGGAAG3' PEA3 motif. Both TRE-like elements were capable of binding AP1. TPA inducibility of this DH region was seen by the CAT reporter assay and appeared to be direction-dependent suggesting a functional cooperation between PEA3/TTCA and TRE.

Base Sequence↗

PubMed1998

Abnormal urodynamic findings after radical hysterectomy or pelvic irradiation for cervical cancer.

OBJECTIVE: To assess urodynamic study results in patients with cervical cancer who had received radical hysterectomy or pelvic irradiation or radical hysterectomy with pelvic irradiation. METHODS: Forty-two patients with stage IB cervical cancer after radical hysterectomy (group A), 11 patients at stage IB or IIA after pelvic irradiation (group B), 15 patients at stage IB or IIA after both radical hysterectomy and pelvic irradiation (group C) and 17 patients at stage IB before treatment (group D) as control were recruited for urodynamic examination. The evaluations for each case included a 20-min pad test, uroflowmetry, both filling and voiding cystometry, and stress urethral pressure profile. ANOVA method with Bonferroni test and Pearson chi2-test were utilized for statistical analysis. RESULTS: The mean ages in sequential groups A, B, C and D were 52.9 +/- 10.2, 62.5 +/- 13.5, 49.8 +/- 11.7 and 49.4 +/- 12.5 years (P = 0.02), respectively. The occurring frequency of either detrusor instability or low bladder compliance was 57%, 45%, 80% and 24%, respectively. Each group revealed decreased bladder capacity as 268.4 +/- 102.8, 164.1 +/- 62.9, 233.5 +/- 73.9 and 293.0 +/- 47.2 ml (P < 0.0001). However, the frequency of abdominal strain voiding was 100% in groups A, B and C as compared to 0% in group D (P < 0.01), and the frequency of abnormal residual urine (> 50 ml) was 41%, 27%, 40% and 24%. Although each case showed a poor pressure transmission ratio (< 100%), the frequency of positive pad test in each group was 81%, 46%, 100% and 18% (P < 0.001). The functional urethral length decreased in each group and was 2.6 +/- 0.8, 2.3 +/- 0.8, 2.5 +/- 0.8 and 2.9 +/- 0.6 cm, but there were no significant differences in maximal urethral pressure or urethral closure pressure among the four groups. CONCLUSIONS: Our data show that abnormal urodynamic findings pre-exist in patients with cervical cancer before treatment especially in bladder storing function, and that these findings may worsen, or that new abnormal findings may happen after radical hysterectomy or pelvic irradiation, or both.

Combined Modality Therapy↗

PubMed1998

Hepatitis B surface antigenemia at birth: a long-term follow-up study.

OBJECTIVE: To investigate the prevalence and outcome of hepatitis B surface antigenemia in newborns of hepatitis B e antigen (HBeAg)-positive hepatitis B surface antigen (HBsAg) carrier mothers under the current immunoprophylaxis program. STUDY DESIGN: From 1984 to 1993, 665 high-risk newborns born to HBeAg-positive HBsAg carrier mothers were prospectively recruited. The newborns were tested for HBsAg soon after birth, before hepatitis B immune globulin administration. All newborns received hepatitis B immune globulin within 24 hours after birth plus subsequent hepatitis B vaccination. Those who were seropositive for HBsAg at birth were regularly followed up for their hepatitis B virus (HBV) markers, liver function profiles, and alpha-fetoprotein levels from 1984 to 1996. RESULTS: Sixteen (2.4%) of the 665 subjects were found to be seropositive for HBsAg at birth, and all remained HBsAg-positive at 6 months of age. Twelve of the 16 received long-term follow-up care, and all were confirmed to have chronic HBV infection. Of the 12, 2 had HBeAg seroconversion, and 1 had alanine aminotransferase flares without HBeAg seroconversion. Delayed appearance of hepatitis B core antibody (anti-HBc) occurred in 2 without alanine aminotransferase elevation. CONCLUSIONS: Current immunoprophylaxis strategy does not protect newborns with surface antigenemia, apparently acquired in utero, from becoming HBV carriers. Immunologic attempts to eliminate HBV may occur in carrier children infected in utero, despite their profound immune tolerance to HBV.

Alanine Transaminase↗

PubMed1998

Antibodies to E2 protein of hepatitis G virus in children: different responses according to age at infection.

OBJECTIVES: To study viral persistence and antibody responses after hepatitis G virus (HGV) infection in children of various ages. STUDY DESIGN: We performed an enzyme immunoassay for antibodies to E2 protein (anti-E2) of HGV and reverse-transcription polymerase chain reaction assay for HGV RNA on serum samples. RESULTS: Of 28 infants born to HGV RNA-positive mothers, 17 were found to be positive for HGV RNA. None were positive for anti-E2. All 17 infected infants continued to have viremia except 1 who converted to HGV RNA-negative status at 24 months. Six infants had mild elevations of alanine aminotransferase levels (5 HGV-positive and 1 HGV-negative). An additional 14 HGV-infected children (aged 6 months to 14 years) with posttransfusion HGV infection were tested for anti-E2 3 months and 12 months after blood transfusion. None of the HGV RNA-positive serum samples were positive for anti-E2; however, 4 of the 8 children with resolving HGV infection were positive for anti-E2 1 year later. CONCLUSIONS: Mother-to-infant transmission of HGV resulted in a high viral persistence rate and lack of immune responses to HGV. In contrast, anti-E2 appeared in children who recovered from posttransfusion HGV infection. Mode of transmission and age at infection may be important factors in determining persistent HGV infection and defective immune response to HGV.

Adenovirus E2 Proteins↗

PubMed1998

GABA- and glycine-mediated inhibitory postsynaptic potentials in neonatal rat rostral ventrolateral medulla neurons in vitro.

Whole-cell patch recordings were made from rostral ventrolateral medulla neurons of two in vitro preparations: (i) brainstem spinal cords of two- to five-day-old rats, and (ii) coronal brainstem slices of eight- to 12-day-old rats, and the inhibitory synaptic activities in these neurons have been studied. In brainstem spinal cord preparations, Lucifer Yellow was diffused into the recording neurons at the end of experiments. Medullary neurons were characterized as: (i) spinally projecting by the appearance of an antidromic spike following electrical stimulation of the spinal tract between T2 and T3 segments, and (ii) adrenergic by the detection of phenylethanolamine-N-methyltransferase immunoreactivity in Lucifer Yellow-filled neurons. Of the 13 spinally projecting and phenylethanolamine-N-methyltransferase-positive medullary neurons, focal stimulation elicited in the presence of glutamate receptor antagonists an inhibitory postsynaptic potential in nine neurons. Inhibitory synaptic potentials were reversibly eliminated by the GABA(A) receptor antagonist bicuculline (10-20 microM) in six of nine neurons, by the glycine receptor antagonist strychnine (0.1-1 microM) in two and by a combination of bicuculline and strychnine in one neuron. In brainstem slice preparations, focal stimulation elicited three types of synaptic potential: (i) an excitatory postsynaptic potential, (ii) an inhibitory postsynaptic potential and (iii) a biphasic synaptic potential consisting of an excitatory synaptic potential followed by an inhibitory synaptic potential. Inhibitory synaptic potentials had a reversal potential between -70 and -80 mV, reversed their polarity in a low (6.7 mM) Cl- Krebs' solution, and suppressed or blocked by either bicuculline or strychnine or both. Elimination of inhibitory synaptic potentials unmasked in some cells an excitatory synaptic potential or enhanced the excitatory synaptic potential component in medullary neurons with a biphasic response, indicating a marked convergence of excitatory and inhibitory inputs onto a single neuron. A population of medullary neurons appeared to be pacemaker neurons whereby they discharged spontaneously. When discharges were suppressed by membrane hyperpolarization, focal stimulation elicited inhibitory synaptic potentials in 8/23 neurons tested. Our results suggest that inhibitory synaptic potentials in medullary neurons are mediated by either GABA and/or glycine which open primarily Cl- channels. The prevalence of inhibitory synaptic potentials in medullary neurons indicates an essential role of inhibitory transmission in controlling the input and output ratio of these neurons.

Animals↗

PubMed1998

Post- and presynaptic GABA(B) receptor activation in neonatal rat rostral ventrolateral medulla neurons in vitro.

Whole-cell patch recordings were made from immature (six- to 12-day-old) rat rostral ventrolateral medulla neurons in brainstem slices. GABA or the specific GABA(B) receptor agonist (-)baclofen (10-50 microM) by superfusion or by pressure ejection induced an outward current or a hyperpolarization, which persisted in a tetrodotoxin (0.3 microM)-containing Krebs' solution in nearly every cell tested. The GABA(B) receptor antagonists 2-hydroxy saclofen (50-200 microM) and CGP 35348 (50-200 microM) dose-dependently suppressed baclofen-currents. Baclofen-currents were suppressed by barium (1 mM) but not by tetraethylammonium (20 mM), low Ca2+ (0.24 mM) solution or in a solution containing the Ca2+ chelator BAPTA-AM (10 microM). The outward current had an estimated reversal potential of -98, -77 and -52 mV in 3.1, 7 and 15 mM [K+]o. Pre-incubation of slices with pertussis toxin (500 microg/ml for 5-7 h) or intracellular dialysis with GDP-beta-S (500 microM) markedly reduced baclofen-currents. Baclofen in low concentrations (1-3 microM) that caused slight or no change of holding currents and of inward or outward currents induced by exogenously applied glutamate or glycine/GABA, decreased excitatory and inhibitory postsynaptic currents by an average of 86.5 +/- 4.3% and 78.4 +/- 2.7%. The GABA(B) antagonist CGP 35348 (100 microM) increased the excitatory postsynaptic currents by an average of 64%, without causing a significant change in holding currents in 10/18 cells tested. Our results indicate the presence of post- and presynaptic GABA(B) receptors in the rostral ventrolateral medulla neurons. Activation of postsynaptic GABA(B) receptors induces an outward K+ current which is barium-sensitive, Ca2+-independent and may be coupled to a pertussis-sensitive G-protein. Activation of presynaptic GABA(B) receptors attenuates excitatory or inhibitory synaptic transmission. More importantly, the observation that CGP 35348 enhanced excitatory synaptic currents implies a removal of tonic activation of presynaptic GABA(B) receptors by endogenously released GABA (disinhibition), supporting the hypothesis that these receptors may have a physiological role in regulating the input and output ratio in a subset of rostral ventrolateral medulla neurons in vivo.

Animals↗

PubMed1998

Prenatal diagnosis of otocephaly using two-dimensional and three-dimensional ultrasonography.

We report a case of the prenatal diagnosis of a very rare anomaly, namely isolated otocephaly, using two-dimensional and three-dimensional ultrasound at 24 weeks of gestation. Two-dimensional ultrasound revealed polyhydramnios, absence of a stomach shadow, hypotelorism and a proboscis-like mass. Three-dimensional ultrasound gave a precise demonstration of the striking craniofacial features of otocephaly including agnathia, synotia, microstomia and protuberance of the nose-mouth fusion. The use of three-dimensional ultrasound provided a whole view of the very rare lethal malformation in utero and contributed significantly to prenatal diagnosis.

Abortion, Legal↗

PubMed1998

Mother-to-infant transmission of GB virus C/hepatitis G virus: the role of high-titered maternal viremia and mode of delivery.

To study mother-to-infant transmission of GB virus C/hepatitis G virus (GBV-C/HGV), blood samples of infants born to carrier mothers were collected beginning 3 months after birth and were tested for GBV-C/HGV RNA until 1 year of age. Of 2046 mothers, 2.1% were positive for GBV-C/HGV RNA, and 25 of their infants were followed for a median of 12 months. Thirteen infants (52%) were viremic, and infection became persistent in all. Maternal GBV-C/HGV RNA levels of this group were >10(7) copies/mL. Nucleotide sequence comparison in 5 viremic mother-infant pairs revealed a homology of 93%-98.2%, and none delivered by elective cesarean section. In comparison, of the 12 uninfected infants' mothers, 10 had lower GBV-C/HGV RNA levels (mean, 5 x 10(4) copies/mL), and the remaining 2 high-titered mothers had elective cesarean section. Thus, high-titered maternal viremia and mode of delivery are closely associated with the mother-to-infant transmission of GBV-C/HGV to infants, and the infection usually becomes persistent.

Carrier State↗

PubMed1998

Primary liver abscess due to Klebsiella pneumoniae in Taiwan.

Pyogenic liver abscess is an uncommon complication of intra-abdominal or biliary tract infection and is usually a polymicrobial infection associated with high mortality and high rates of relapse. However, over the past 15 years, we have observed a new clinical syndrome in Taiwan: liver abscesses caused by a single microorganism, Klebsiella pneumoniae. We reviewed 182 cases of pyogenic liver abscess during the period September 1990 to June 1996; 160 of these cases were caused by K. pneumoniae alone, and 22 were polymicrobial. When patients with K. pneumoniae liver abscess were compared with those who had polymicrobial liver abscess, we found higher incidences of diabetes or glucose intolerance (75% vs. 4.5%) and metastatic infections (11.9% vs. 0) and lower rates of intra-abdominal abnormalities (0.6% vs. 95.5%), mortality (11.3% vs. 41%), and relapse (4.4% vs. 41%) in the former group. Liver abscess caused by K. pneumoniae is a new clinical syndrome that has emerged as an important infectious complication in diabetic patients in Taiwan.

Female↗

PubMed1998

Extremely high prevalence of nasopharyngeal carriage of penicillin-resistant Streptococcus pneumoniae among children in Kaohsiung, Taiwan.

Resistance (intermediate and high) to penicillin among Streptococcus pneumoniae strains is an emerging problem worldwide. From 1995 to 1997, isolates of S. pneumoniae not susceptible to penicillin were seen with increasing frequency from blood, cerebrospinal fluid, pleural fluid, and middle ear fluid from pediatric patients at the Veterans General Hospital-Kaohsiung. To determine the prevalence of carriage of these penicillin-nonsusceptible S. pneumoniae isolates, we obtained nasopharyngeal swab specimens from 2,905 children (ages, 2 months to 7 years) attending day-care centers or kindergartens or seen in our outpatient clinic. S. pneumoniae was isolated from 611 children, and 584 strains were available for analysis. The oxacillin disc test was used as a screening test to evaluate penicillin susceptibility. The MICs of 11 antibiotics (penicillin, cefaclor, cefuroxime, ceftriaxone, cefotaxime, imipenem, chloramphenicol, clarithromycin, rifampin, vancomycin, and teicoplanin) were determined by the E-test. Only 169 (29%) of the strains were susceptible to penicillin; 175 (30%) strains were intermediately resistant and 240 (41%) were highly resistant. The isolates also demonstrated high rates of resistance to other beta-lactams (46% were resistant to cefaclor, 45% were resistant to cefuroxime, 45% were resistant to ceftriaxone, 31% were resistant to cefotaxime, and 46% were resistant to imipenem). The rate of resistance to macrolide antimicrobial agents was strikingly high; 95% of the isolates were not susceptible to clarithromycin. However, 97% were susceptible to rifampin and 100% were susceptible to the two glycopeptides (vancomycin and teicoplanin). While reports of penicillin-resistant S. pneumoniae increased worldwide through the 1980s, the high prevalence (71%) of resistance reported here is astonishing. Surveillance of nasopharyngeal swab specimen cultures may provide useful information on the prevalence of nonsusceptible strains causing invasive disease. Such information could be used to guide therapy of pneumococcal infections.

Ambulatory Care Facilities↗

PubMed1998

Collagen gel overlay induces apoptosis of polarized cells in cultures: disoriented cell death.

In this study, we attempted to investigate the response of polarized cells to inappropriate interaction with the extracellular matrix. Cell lines of epithelial [Madin-Darby canine kidney (MDCK) and LLC-PK1], endothelial [bovine aortic endothelial cells (BAEC)], and mesenchymal (ESK-4 and NIH/3T3) origins were employed. With collagen gel overlay, MDCK cells underwent membrane remodeling and gradually developed lumen formation within 24 h. Apoptosis could also be observed following cell remodeling. The ratio of apoptosis was enhanced from 12.1 +/- 2.4% within 24 h to 58.4 +/- 9.8% at day 3, and finally the monolayer was disintegrated. Collagen gel overlay-induced apoptosis was not a result of physical stress, since agarose gel overlay did not induce any morphological alterations. All epithelial and endothelial cells examined developed apoptosis in response to collagen overlay. In contrast, collagen overlay did not affect growth of fibroblasts at all, although their growth under agarose gel was slightly hindered due to physical stress. Collagen overlay-induced apoptosis seems to be a unique phenomenon for polarized cells and thus is defined as "disoriented cell death." Furthermore, anti-alpha2-integrin antibody could abolish collagen overlay-induced morphological changes and apoptosis in MDCK cells, indicating that signals through alpha2-integrin on the apical membrane are required for disoriented cell death. Finally, Bcl-2 overexpression prolonged survival of MDCK cells in response to collagen overlay, but these cells eventually developed apoptosis due to downregulation of Bcl-2 protein. These findings indicate that inappropriate cell-matrix interaction results in apoptosis, which may account for cell death mechanisms during developmental processes or under pathological conditions.

3T3 Cells↗

PubMed1998

[Septicemic melioidosis in Southern Taiwan: a case report].

The patient was a 56 year-old man, a resident of Hen-Tsueng Township in Ping-Tung County. He worked as a ranger at Ken-Ting Farm in southern Taiwan, and had been to Thailand for sight-seeing 5 years ago. He came to our outpatient department about one month prior to hospitalization for intermittent fever of one week duration. At that time, complete blood count was within normal limits and a chest roentgenogram was unremarkable. He was given erythromycin without showing any clinical improvement. Two days prior to admission, he noted pain in the left hip. The next day, severe dyspnea developed suddenly and chest x-ray film revealed bilateral nodular lesions. Physical examination on hospitalization revealed an acutely ill and jaundiced male with a temperature of 37.4 degrees C, blood pressure: 110/47 mmHg, pulse rate: 137/min, and respiratory rate: 26/min. There were rales in both lungs, but no lymphadenopathy or organ enlargement. Laboratory study showed WBC: 1,470/mm(3), platelet count: 47,000/mm(3), blood sugar: 226 mg/dL, mildly elevated transaminases and bilirubin, and BUN: 69 mg/dL, Cr: 4.3 mg/dL. Arterial blood gas analysis indicated an acute metabolic acidosis with PaO2 of 32 mmHg. Despite the initial impression of melioidosis and administration of ceftazidime plus gentamicin, his condition rapidly deteriorated and expired 18 hours after admission. Two sets of blood cultures grew Burkholderia pseudomallei. Melioidosis has been called a great imitator of diseases and culture results are frequently misinterpreted. The mortality is high even with suggested therapy with ceftazidime, cotrimoxazole, amoxicillin-clavulanate, chloramphenicol, and/or tetracycline. There has been a total of 10 cases reported in southern Taiwan and 2 of them were clearly indigenous. Melioidosis should be included in the reportable diseases, and its prevalence in Taiwan also should be investigated.

Bacteremia↗

PubMed1998

Preoperative concurrent chemotherapy and radiotherapy in rectal cancer patients.

The management of rectal cancer has changed significantly in recent years. The key end-point is no longer survival but rather preservation of sphincter function with improved quality of life. Preoperative radiation can not only render a low-lying rectal tumor amenable to sphincter-preserving surgery but has also been reported to give better local control and lower toxicity than postoperative radiotherapy. From October 1991 through July 1996, 46 patients with local advanced or low-lying rectal cancer were treated with preoperative high-dose radiotherapy and concurrent chemotherapy. All patients underwent pelvic radiotherapy with 5,000 to 5,400 cGy in 25 to 27 fractions. Chemotherapy was given concomitantly and consisted of two courses of 5-fluorouracil (5-FU) at 1,000 mg/m2 for 4 days in week 1 and week 5 plus mitomycin C 10 mg/m2 single bolus on day 1 of week 1. In 30 patients, postoperative adjuvant chemotherapy with 5-FU and levamisole weekly was also given, for a total of 12 months. The most common acute toxicity was grade 1 to 2 diarrhea and tenesmus during radiation or soon afterward. Only five of the 46 patients experienced symptomatic grade 3 acute toxicity. Forty-two patients underwent subsequent surgery 6 to 8 weeks after concurrent chemoradiotherapy. Pathologic examination disclosed complete tumor regression in eight patients and microscopic residual disease in 13 patients after preoperative chemoradiation. Of the 42 patients who completed the intended treatments, only one had local recurrence. The sphincter was preserved in 21 of the 26 patients in whom the tumor was located within 5 cm above the anal verge. Twelve of the 16 evaluable patients had good to excellent sphincter function. The 2-year overall survival rate was 93% and the disease-free survival was 81%. Our findings indicate that preoperative concurrent chemoradiotherapy not only allows low-lying rectal tumors to be resected while preserving sphincter function but also results in good local control and acceptable toxicity.

Adenocarcinoma↗

PubMed1997

Upstream genomic sequence of the human connexin26 gene.

Human connexin 26 (Cx26) has been considered to be a candidate suppressor gene in mammary epithelial cells. To gain insight into the transcriptional regulation of this gene, we have cloned and sequenced the 5' portion of the gene, which extends 4.8 kb upstream from the ATG translation start site. The 3' end of the non-coding exon 1 (160 bp) is located at 3149 bp upstream from the 5' end of exon 2. Comparison between the human Cx26 gene and the mouse gene reveals a highly conserved promoter region with 81% homology. In addition to six GC boxes and two GT boxes, a TTAAAA box is located at -24 to -19 bp upstream of the transcription start point. Analogous to the mouse beta-casein gene, the promoter region of the human Cx26 gene also contains a YY1-like binding site and a consensus mammary gland factor binding site.

Animals↗

PubMed1997

Oncogenic raf-1 induces the expression of non-histone chromosomal architectural protein HMGI-C via a p44/p42 mitogen-activated protein kinase-dependent pathway in salivary epithelial cells.

The enzyme activity of mitogen-activated protein kinase (MAP kinase) increases in response to agents acting on a variety of cell surface receptors, including receptors linked to heterotrimeric G proteins. In this report, we demonstrated that Raf-1 protein kinase activity in the mouse parotid glands was induced by chronic isoproterenol administration in whole animals. To investigate the molecular nature underlying cellular responses to Raf-1 activation, we have stably transfected rat salivary epithelial Pa-4 cells with human Raf-1-estrogen receptor fusion gene (DeltaRaf-1:ER) and used mRNA differential display in search of messages induced by DeltaRaf-1:ER activation. Through this approach, the gene encoding non-histone chromosomal protein HMGI-C was identified as one of the target genes activated by oncogenic Raf-1 kinase. Activation of Raf-1 kinase resulted in a delayed and sustained increase of HMGI-C expression in the Pa-4 cells. The induction of HMGI-C mRNA level is sensitive to both the protein synthesis inhibitor cycloheximide and transcription inhibitor actinomycin D. The role of the extracellular signal-related kinase (ERK) signaling pathway in the HMGI-C induction was highlighted by the result that the MAP kinase kinase (MEK) inhibitor, PD 98059, blocked DeltaRaf-1:ER- and 12-O-tetradecanoylphorbol-13-acetate-stimulated HMGI-C induction. Altogether, these findings support the notion that the Raf/MEK/ERK signaling module, at least in part, regulates transcriptional activation of the chromosomal architectural protein HMGI-C.

Amino Acid Sequence↗

PubMed1997

Secretoneurin-like immunoreactivity in rat sympathetic, enteric and sensory ganglia.

Distribution of secretoneurin-like immunoreactivity (SN-LI) was studied in the rat sympathetic ganglia/adrenal gland, enteric and sensory ganglia by immunohistochemical methods. SN-LI nerve fibers formed basket-like terminals surrounding many of the postganglionic neurons of the superior cervical, stellate, paravertebral chain ganglia, coeliac/superior mesenteric and inferior mesenteric ganglia. Postganglionic neurons of the superior cervical and other sympathetic ganglia exhibited low-to-moderate levels of SN-LI. In all these sympathetic ganglia, clusters of small diameter (< 10 microm) cells, which may correspond to the small intensely fluorescent (SIF) cells, were found to be intensely labeled. Surgical sectioning or ligation of the cervical sympathetic trunk for 7-10 days resulted in a nearly total loss of SN-LI fibers in the superior cervical ganglia, whereas immunoreactivity in the postganglionic neurons and small diameter cells remained essentially unchanged. In the thoracolumbar and sacral segments of the spinal cord, SN-LI nerve fibers were detected in the superficial layers of the dorsal horn as well as in the intermediolateral cell column (ILp). Occasionally, SN-LI somata were noted in the ILp. SN-LI nerve fibers formed a delicate plexus underneath the capsule of the adrenal gland, some of which traversed the adrenal cortex and reached the adrenal medulla. While heavily invested with SN-LI nerve terminals, chromaffin cells seemed to express a low level of SN-LI. In the enteric plexus, varicose SN-LI nerve fibers and terminals formed a pericellular network around many myenteric and submucous ganglion cells; the ganglionic neurons were lightly to moderately labeled. A population of ganglion cells in the dorsal root, nodose and trigeminal ganglia exhibited moderate-to-strong SN-LI. The detection of SN-LI in nerve fibers and somata of various sympathetic ganglia, enteric plexus and adrenal medulla and in somata of the sensory ganglia implies an extensive involvement of this peptide in sympathetic, enteric and sensory signal processing.

Animals↗

PubMed1997

Identification and characterization of a seven transmembrane hormone receptor using differential display.

Targeted mutagenesis analysis has shown that the Cmyb proto-oncogene, which encodes a sequence-specific DNA binding protein, is required for normal murine fetal liver erythropoiesis and myelopoiesis. To identify novel genes involved in hematopoiesis, differential display analysis was conducted using total liver RNA isolated from 14.5-day postcoitus Cmyb wildtype, heterozygous, and homozygous mutant littermates. Using 4 oligo(dT) 3' primers and 5 arbitrary decamers as 5' primers, 22 differentially expressed genes have been identified. Eight putatively novel genes were identified from 12 cDNAs that were sequenced. One gene, initially designated DD7A5-7, is primarily expressed in cells of the myeloid lineage. The full-length DD7A5-7 cDNA is 3239 nucleotides, encoding a putative protein of 931 amino acids. The protein is a member of a family of hormone receptors containing 7 transmembrane segments. The receptor also contains 7 epidermal growth factor-like (Egf-like) motifs at the amino terminal of the predicted protein. The gene is alternatively spliced, resulting in the deletion of one or more copies of the Egf-like motif. DD7A5-7 maps to mouse Chromosome 17 and is the putative homologue of EMR1, a recently described Egf-like module containing mucin-like hormone receptor with 7 transmembrane segments in humans. Our results indicate that the Cmyb mutant fetuses represent a unique resource for identifying genes involved in hematopoiesis.

Alternative Splicing↗

PubMed1997

Excitatory action of pituitary adenylate cyclase activating polypeptide on rat sympathetic preganglionic neurons in vivo and in vitro.

In vivo and in vitro experiments were undertaken to evaluate the effects of pituitary adenylate cyclase activating polypeptide-38 (PACAP-38) on rat sympathetic preganglionic neurons (SPNs). Intrathecal injection of PACAP-38 (0.1-1 nmol) via an implanted cannula to the T2-T3 segments of urethane-anesthetized adult rats caused a dose-dependent increase of mean arterial blood pressure from minutes to over 1 h. The pressor response was not antagonized by prior injection of the PACAP type II receptor antagonist PACAP6-38 (0.5 nmol), but was significantly attenuated by prior intravenous administration of phentolamine (1 mg/kg). As a positive control, intrathecal injection of glutamate (1 micromol) and substance P (SP, 5 nmol) caused a short- and long-lasting pressor response. Vasoactive intestinal polypeptide (VIP, 1 nmol) had no significant pressor effect. In the second series of experiments, whole-cell patch recordings were made from antidromically identified SPNs of immature (12-16-day-old) rat thoracolumbar spinal cord slices. Applied to the spinal cord slices by superfusion, PACAP-38 (10-30 nM) caused intense neuronal discharges with or without a long-lasting membrane depolarization. The depolarization was not prevented by superfusing the slices with tetrodotoxin (0.3 microM) or low Ca2+ (0.25 mM) solution, indicating that PACAP-38 directly depolarized the SPNs. The depolarization was insensitive to the type II PACAP receptor antagonist PACAP6-38. Collectively, these results provide evidence that PACAP-38 exerts a potent and long-lasting excitatory effect on SPNs, leading to an increase of spinal sympathetic outflow and one of the consequences of which is an elevation of blood pressure.

Animals↗