Ruptured Klebsiella pneumoniae liver abscess after high-dose cyclophosphamide for severe aplastic anemia

A 19-year-old woman with severe aplastic anemia who had previously failed antithymocyte globulin/cyclosporine A received high-dose cyclophosphamide without bone marrow rescue. On day +14, she complained of right upper quadrant abdominal pain and fever. A CT scan of the abdomen showed multiple liver abscesses with rupture and Klebsiella pneumoniae was isolated from blood. In spite of aggressive antibiotic therapy, she rapidly deteriorated and died of overwhelming sepsis. To our knowledge, our patient is the first case of fatal ruptured liver abscess after high-dose cyclophosphamide in a patient with severe aplastic anemia.

Inhibitory effect of Artemisia asiatica alkaloids on acetylcholinesterase activity from rat PC12 cells

We screened 42 Korean traditional tea plants to determine the inhibitory effect of acetylcholinesterase and attenuation of toxicity induced by amyloid-beta peptide, which were related to the treatment of Alzheimer's disease (AD). The methanolic extract from Artemisia asiatica among tested 42 tea plants, showed the highest inhibitory effect (48%) on acetylcholinesterase in vitro. The methanolic extract was further separated with n-hexane, chloroform, and ethyl acetate of water, in order. The chloroform solubles, which were high in inhibitory effect of acetylcholinesterase, were repeatedly subjected to open column chromatography on silica gel. From the highest inhibitory fraction (78%) on acetylcholinesterase, the single compound was obtained by the Sep-Pak Cartridge (C18: reverse phase column). This compound was found to react positively on Dragendorff's reagent (potassium bismuth iodide), which typically reacted with the alkaloid. This compound was purified by HPLC (mu-bondapack C18 reverse phase column: 3.9 x 150 mm). The IC50 (the concentration of 50% enzyme inhibition) value of this compound was 23 micrograms/ml and the inhibitory pattern on acetylcholinesterase was mixed with competitive/non-competitive type. We examined the effects of this compound on toxicity induced by A beta (25-35) in rat pheochromocytoma PC12 cells. Pretreatment of the PC12 cells for 2 h with an alkaloid of Artemisia asiatica (1200 microg/ml) reduced the toxicity induced by A beta. This study demonstrated that an alkaloid of Artemisia asiatica, which was metabolized to small molecule in digestive tract and then could pass through the blood-brain barrier, appeared to be an acetylcholinesterase inhibitor with a blocker of neurotoxicity induced by A beta in human brain causing Alzheimer's disease.

Vibrio vulnificus has the transmembrane transcription activator ToxRS stimulating the expression of the hemolysin gene vvhA

In an attempt to dissect the virulence regulatory mechanism in Vibrio vulnificus, we tried to identify the V. cholerae transmembrane virulence regulator toxRS (toxRS(Vc)) homologs in V. vulnificus. By comparing the sequences of toxRS of V. cholerae and V. parahaemolyticus (toxRS(Vp)), we designed a degenerate primer set targeting well-conserved sequences. Using the PCR product as an authentic probe for Southern blot hybridization, a 1.6-kb BglII-HindIII fragment and a 1.2-kb HindIII fragment containing two complete open reading frames and one partial open reading frame attributable to toxR(Vv), toxS(Vv), and htpG(Vv) were cloned. ToxR(Vv) shared 55.0 and 63.0% sequence homology with ToxR(Vc) and ToxR(Vp), respectively. ToxS(Vv) was 71.5 and 65.7% homologous to ToxS(Vc) and ToxS(Vp), respectively. The amino acid sequences of ToxRS(Vv) showed transmembrane and activity domains similar to those observed in ToxRS(Vc) and ToxRS(Vp). Western blot analysis proved the expression of ToxR(Vv) in V. vulnificus. ToxRS(Vv) enhanced, in an Escherichia coli background, the expression of the V. vulnificus hemolysin gene (vvhA) fivefold. ToxRS(Vv) also activated the ToxR(Vc)-regulated ctx promoter incorporated into an E. coli chromosome. A toxR(Vv) null mutation decreased hemolysin production. The defect in hemolysin production could be complemented by a plasmid harboring the wild-type gene. The toxR(Vv) mutation also showed a reversed outer membrane protein expression profile in comparison to the isogenic wild-type strain. These results demonstrate that ToxR(Vv) may regulate the virulence expression of V. vulnificus.

Nosocomial cluster of Candida lipolytica fungemia in pediatric patients

Candida lipolytica has rarely been reported as a human pathogen. An apparent outbreak of Candida lipolytica fungemia (n = 5 cases) occurred in a pediatric ward over a 9-week period. The five patients infected were hospitalized in three adjacent rooms and cared for by the same healthcare workers. The index patient had central venous catheter-related fungemia, whereas the second patient, who was in the adjacent single room, had transient fungemia. Three additional cases of fungemia occurred in patients with hematological disorders who shared the same room; all three patients had central venous catheters and had been receiving oral fluconazole prophylaxis (50 mg/day for more than 3 weeks) at the time of infection. In vitro susceptibility testing of the strains showed that the MIC of fluconazole for all the isolates was 32 microg/ml. Random amplified polymorphic DNA analysis provided evidence of the clonal origin of the isolates, but the source of the outbreak was not identified. All four patients with persistent fungemia were successfully treated via catheter removal or empiric amphotericin B treatment. This outbreak shows the potential for the nosocomial epidemic transmission of Candida lipolytica.

Cloning of a sesquiterpene cyclase and its functional expression by domain swapping strategy

Sesquiterpene cyclase, the first committed step enzyme from the general isoprenoid building block farnesyl pyrophosphate (FPP) for the synthesis of phytoalexin capsidiol, was isolated from the UV-C treated leaves of Capsicum annuum. This sesquiterpene cyclase, termed as CASC2 showing 77% amino acid identity with the previously cloned sesquiterpene cyclase CASC1, was composed of 560 amino acids with a calculated molecular mass of 64,907. The mRNA expression pattern of CASC2 was very similar to that of CASC1 during the time course of UV-C irradiated leaves of pepper on RNA blot analysis by using each specific probe. The heterologous expression in Escherichia coli using the CASC2 full length failed; however the chimeric construct of CASC2 in which the amino terminal 164 amino acid substituted by the equivalent portion of either CASC1 or tobacco sesquiterpene cyclase was capable of expressing the functional sesquiterpene cyclase activities. The radio-labeled enzymatic products catalyzed by the partially purified chimeric CASC2 were comigrated with authentic radio-labeled sesquiterpene on thin layer chromatography.

Distribution of heat shock protein 108 mRNA in the chicken central nervous system

The constitutive expression of heat shock protein 108 (HSP108) mRNA is mapped in a normal chicken central nervous system using in situ hybridization technique. HSP108 mRNAs were found to be mainly localized in the small neuroglial cells of various regions of the brain, although some neuronal cells also showed positive signals. This tendency is observed to be more marked in the cerebellum; HSP108 signals were not found in the Purkinje cells, but in Bergmann glial cells and oligodendrocytes. Although neuronal cells in the deep cerebellar nuclei and the molecular layer showed occasional HSP108 signals, the expression pattern of HSP108 mRNA is different from homologous HSP90 that is mostly expressed in neurons, but rather similar to that of TfBP immunoreactivity, a new member of the HSP108 family. The constitutive neuroglial localization of HSP108 could suggest that HSP108 may play an important role in the normal metabolism of neuroglial cells in the chicken brain.

Osseous metaplasia with functioning bone marrow in hydroxyapatite orbital implants

BACKGROUND

Bone formation within the hydroxyapatite implant has been reported in explanted spheres in humans. Bone-specific differentiation was observed to occur earlier in the pores of spherical hydroxyapatite implants enhanced with osteogenin within the rabbit socket. We observed previously unreported bone marrow formation in a coralline hydroxyapatite implant placed into the rabbit orbit after evisceration.

METHODS

One eye of each of 10 New Zealand white rabbits weighing between 2 and 3 kg was eviscerated and implanted with hydroxyapatite spheres. The explanted hydroxyapatite spheres 20 weeks after surgery were examined under the microscope.

RESULTS

Histopathologic examination of the excised implants showed the presence of trabeculae of mature bone with fatty marrow and hematopoietic elements. Scattered throughout the fatty tissue were bone marrow elements consisting of precursors of the granulocytic and erythroid series and also megakaryocytes.

CONCLUSION

The osseous metaplasia with functioning bone marrow was incidentally observed in the coralline hydroxyapatite implant without the addition of any osteogenesis-inducing agents.

Molecular cloning and expression analysis of carp (Cyprinus carpio) interleukin-1 beta, high affinity immunoglobulin E Fc receptor gamma subunit and serum amyloid A

Suppression subtractive hybridisation (SSH) is a powerful means to identify genes of cytokines and other genes that express small amount of mRNA. In this study, cDNA of normal fish (carp) head kidney cells (HKC) was subtracted from pooled cDNA of HKC and peritoneal cell (PC) obtained from fish which had been injected with sodium alginate (SA) and scleroglucan (SG) 3-48 h earlier. This subtraction produced 248 clones of cDNA fragments. After sequencing some of the fragments of interest were used as probes, and yielded full-length cDNAs homologous to mammalian interleukin-1 beta (IL-1 beta), the gamma subunit of high affinity Fc receptor for IgE (Fc epsilon RI gamma) and serum amyloid A (SAA); these were cloned and sequenced. Carp IL-1 beta shows 21.8-24.7% amino acid identities to mammalian mature IL-1 beta, and lacks a signal sequence, which is consistent with mammalian IL-1 beta. Carp Fc epsilon RI gamma, which was the first cloned non-mammalian Fc receptor subunit, shows 39.3-40.4% amino acid identities to mammalian Fc epsilon RI gamma, and contains the immunoreceptor tyrosin-based activation motif characteristic of the signal transduction subunit of antigen- and Fc-receptors. Carp SAA is most similar to mammalian acute phase responsive type SAA with 53.0-55.3% amino acid identities. Both SA-elicited and SG-elicited PC expressed higher amounts of IL-1 beta and SAA mRNA compared to saline-injected fish HKC and PC, indicating that these proteins are associated with inflammatory responses, similar to mammalian homologues. Fc epsilon RI gamma was constitutively expressed in leucocytes and not immunopotentiator-responsive, but this indicates that Fc receptor including Fc epsilon RI gamma subunit is likely functional in the carp immune system.

Relative sparing of calretinin containing neurons in the substantia nigra of 6-OHDA treated rat parkinsonian model

A certain calcium binding protein (CaBP) has been known to exert a neuroprotective effect in various neurodegenerative diseases. Using the 6-OHDA induced rat Parkinsonian model, we examined if calretinin (CR), one of CaBP family, could play the similar role in the Parkinson's disease because CR is profusely localized in dopaminergic neurons of the substantia nigra pars compacta (SNPC) of the rat. Employing immunohistochemical analyses, we found that the survival rate of CR neurons was significantly higher than that of tyrosine hydroxylase (TH) neurons in the SNPC of the Parkinsonian rat. Furthermore double-labeled fluorescent microscopy revealed that almost all surviving TH neurons were also positive to CR. Our data suggest that CR-positive neurons are less vulnerable to 6-OHDA and CR in the dopaminergic neurons may have a protective function for survival of these neurons in the experimentally induced Parkinsonian rat.

p53 codon 72 polymorphism and risk of cervical carcinoma in Korean women

A common polymorphism of the wild type p53 is known at codon 72 of exon 4, with 2 alleles encoding either arginine (CGC, p53Arg) or proline (CCC, p53Pro). A recent study suggested that this polymorphism affects the susceptibility of p53 protein to human papillomavirus E6 oncoprotein mediated degradation and that individuals homozygous for p53Arg are seven times more susceptible to HPV-associated carcinogenesis of the cervix than heterozygotes. To examine whether the p53Arg genotype could be a risk factor for HPV-associated cervical carcinomas in the Korean population, we analyzed the p53 codon 72 polymorphism status of HPV-positive invasive cervical carcinomas from 52 Korean women and 103 healthy control samples. The proportion of individuals homozygous for p53Arg, homozygous for p53Pro, and heterozygous for the two alleles were 40%, 19%, and 41% in normal healthy controls; 42%, 17%, and 40% in women with HPV-positive invasive cervical carcinoma. There were no significant differences in the distribution of p53 genotypes between controls and cervical carcinomas. This finding indicates that the p53Arg genotype is not associated with an increased susceptibility to cervical carcinoma in Korean women.

Immunocytochemical study on the distribution of nitrotyrosine in the brain of the transgenic mice expressing a human Cu/Zn SOD mutation

In the previous study, we reported increased NOS expression in the astrocytes in the spinal cord of the transgenic mice that are used as ALS animal model. In the present study, we performed immunocytochemical studies to investigate the changes of nitrotyrosine-immunoreactivity in the brains of the transgenic mice, and demonstrated in vivo evidence of peroxynitrite-mediated oxidative damage in the pathogenesis of ALS. In the spinal cord of the transgenic mice, immunocytochemistry showed intensely stained nitrotyrosine-IR glial cells with the appearance of astrocytes, but no nitrotyrosine-IR glial cells were observed in the spinal cord of the control mice. In the transgenic mice, nitrotyrosine-IR neurons were observed in the hypoglossal nucleus, lateral reticular nucleus, medullary reticular formation and cerebellar nuclei. Interestingly, nitrotyrosine-IR neurons were observed in the hippocampal formation and septal area of the transgenic mice. In the hippocampus, nitrotyrosine-IR neurons in the CA1 region showed intense staining, and the immunoreactivity was localized mainly in the pyramidal cell layer. Recent studies have shown that antioxidants and selective neuronal NOS inhibitor increase survival in the SOD1 transgenic mouse model of FALS. It is possible that therapy with these agents may slow the neurodegenerative process in human ALS, perhaps through reduction of nitrotyrosine formation.

Micellar electrokinetic chromatography for the analysis of D-amygdalin and its epimer in apricot kernel

We have developed a simple, rapid and reproducible method for the determination of D-amygdalin and its epimer by using micellar electrokinetic chromatography (MEKC). Separation of D-amygdalin was performed in a 20 mM sodium borate buffer (pH 8.5) containing 300 mM sodium dodecyl sulfate using a bare fused-silica capillary. The eluates were monitored by the absorbance at 210 nm. The applied electric field was 278 V/cm, and the time needed for the separation of D-amygdalin did not exceed 6 min. The calibration curve for D-amygdalin showed excellent linearity in the concentration range of 5-500 microg/ml. The migration time and the corrected peak area show relative standard deviations (n=6) of 0.86% and 1.48%, respectively. The limit of detection (S/N=3) for D-amygdalin was 2 microg/ml. Under acidic and neutral conditions, amygdalin exists only as the D-form; however, under basic conditions, it shows both the D- and L-forms with a concentration ratio of 1:1.3 (D-amygdalin/L-amygdalin). Results of HPLC, UV-Vis spectrophotometry, and mass spectrometry reconfirmed the identification of D-amygdalin and its epimer. The number of theoretical plates of D-amygdalin is about 100,000 in MEKC, which is significantly higher than approximately 8,000 of HPLC. This method has been successfully applied to the determination of amygdalin epimers in various apricot kernel extracts and pharmaceutical products.

Localization of bcl-2 mRNA in the rabbit central nervous system

In this study, we demonstrated bcl-2 expression in the rabbit brain using in situ hybridization and compared the results with the studies done on the other animals. Although the bcl-2 expressions of the rabbit were generally similar to those of the other animals, some differences were also found; the cells in molecular and Purkinje cell layers of the cerebellum, which were bcl-2 negative in the others, showed intense bcl-2 positive signals, while the ependymal cells, arachnoid villi and granular layer, which were positive in the other animals, were not well stained with bcl-2 riboprobes in the rabbit brain. Our findings clearly showed the similarities and differences of rabbit bcl-2 mRNA as compared with the other species for the first time, and provided the basis of further study on the properties of bcl-2 in this species.

Reactive astrocytes express p53 in the spinal cord of transgenic mice expressing a human Cu/Zn SOD mutation

In a previous study, we reported increased NOS expression in the astrocytes in the spinal cord of SOD mutant transgenic mice that are used as ALS animal model. Recently, Messmer and Brune suggested that nitric oxide-induced apoptosis is intimately related with p53-dependent signaling pathway, and de la Monte et al. reported increased p53-immunoreactivity in the spinal cord of ALS patients. In the present study, we performed immunocytochemical studies to investigate the changes of p53-immunoreactivity in the brains of the mutant transgenic mice expressing a human Cu/Zn SOD mutation. Immunocytochemistry showed intensely stained p53-IR glial cells with the appearance of astrocytes in all levels of the spinal cord of the mutant transgenic mice, but no p53-IR glial cells were observed in the spinal cord of the control mice. P53-IR astrocytes were also detected in the brain stem of the mutant transgenic mice. In the medulla, they were observed in the medullary reticular formation, hypoglossal nucleus, vestibular nucleus, dorsal motor nucleus of the vagus and nucleus ambiguus. In the pons, their presences were noted in the pontine reticular formation, and trigeminal and facial nuclei. In the midbrain, astrocytes were detected in the mesencephalic reticular formation, red nucleus and periaqueductal gray matter. In the cerebellum, intensely stained p53-IR astrocytes were detected in the intracerebellar nuclei. In contrast to the mutant transgenic mice, no p53-IR astrocytes were detected in the brain stem and spinal cord of the control mice. Further multidisciplinary investigations involving p53-mediated cellular damage and pathogenesis of ALS are needed to clarify the importance of these results.

Spectrum of opportunistic infections and malignancies in patients with human immunodeficiency virus infection in South Korea

To determine the frequency and types of major opportunistic diseases in patients with HIV infection in South Korea, we reviewed the medical records of 173 HIV-infected patients. The patients were seen from 1985 to 1998 at a referral hospital for AIDS in South Korea. Most patients (85%) were male, and 107 (62%) were infected by heterosexual contacts. CD4+ lymphocyte counts at presentation were <200/microL in 27% of the patients. Tuberculosis was the most frequent opportunistic infection (25% of patients), followed by candidiasis (21%), herpes zoster (20%), Pneumocystis carinii pneumonia (10%), cytomegalovirus disease (9.8%). There were no cases of toxoplasmosis. Kaposi's sarcoma developed in 3 patients (1.7%), and non-Hodgkin's lymphoma, in 2 (1.2%). Eleven patients (6.4%) developed peripheral neuropathy, and 8 (4.6%) had HIV encephalopathy. Tuberculosis was the single most important HIV-related infection in South Korean patients.

Effects of interleukin-10 on chemokine KC gene expression by mouse peritoneal macrophages in response to Candida albicans

Chemokine KC has been considered to be a murine homologue of human GRO/MGSA and was identified as chemoattractant for monocytes and neutrophils. This study examined the expression of KC mRNA in thioglycollate-elicited mouse peritoneal macrophages that were stimulated in vitro with Candida albicans (CA). Also examined were the inhibitory effects of IL-10 on the CA-induced expression of KC gene by Northern blot analysis. CA was found to induce chemokine gene expression in a gene-specific manner, CXC chemokine IP-10 mRNA expression was not detected in CA-stimulated macrophages. Maximum KC mRNA expression was observed approximately 2 hr after adding CA. The inhibitory action of IL-10 to CA-induced KC mRNA expression on mouse peritoneal macrophages was independent on concentration and stimulation time of IL-10 and was observed approximately one hour after adding IL-10 and CA simultaneously. IL-10 produced a decrease in the stability of KC mRNA, and CA-stimulated macrophages with cycloheximide blocked the suppressive effect of IL-10. These results suggest that CA also induces chemokine KC from macrophages, and IL-10 acts to destabilize CA-induced KC mRNA and de novo synthesis of an intermediate protein is a part of the IL-10 suppressive mechanism.

Retroperitoneal multilocular bronchogenic cyst adjacent to adrenal gland

Bronchogenic cysts are generally found in the mediastinum, particularly posterior to the carina, but they rarely occur in such unusual sites as the skin, subcutaneous tissue, pericardium, and even the retroperitoneum. A 30-year-old Korean man underwent surgery to remove a cystic adrenal mass incidentally discovered during routine physical checkup. At surgery, it proved to be a multilocular cyst located in the retroperitoneum adjacent to the left adrenal gland. Microscopically, the cyst was lined by respiratory epithelium over connective tissue with submucous glands, cartilage and smooth muscle, thereby histologically confirming bronchogenic cyst. This is the first reported case of retroperitoneal bronchogenic cyst in an adult without other congenital anomalies in Korea.

Idiopathic bronchiolitis obliterans with organizing pneumonia presenting with spontaneous hydropneumothorax and solitary pulmonary nodule

The first case of idiopathic bronchiolitis obliterans with organizing pneumonia (BOOP) presenting as solitary pulmonary nodule with spontaneous hydropneumothorax is reported in a 54-year-old man. A wedge resection of the right lower lobe was performed to show typical histological features of BOOP. This case report demonstrates that BOOP has a very diverse clinical manifestation and stresses the need to include solitary pulmonary nodule with hydropneumothorax in the spectrum of BOOP.

Cyclin D1 overexpression is an indicator of poor prognosis in resectable non-small cell lung cancer

Cyclin D1 is one of the G1 cyclins that control cell cycle progression by allowing G1 to S transition. Overexpression of cyclin D1 has been postulated to play an important role in the development of human cancers. We have investigated the correlation between cyclin D1 overexpression and known clinicopathological factors and also its prognostic implication on resected non-small-cell lung cancer (NSCLC) patients. Formalin-fixed and paraffin-embedded tumour tissues resected from 69 NSCLC patients between stages I and IIIa were immunohistochemically examined to detect altered cyclin D1 expression. Twenty-four cases (34.8%) revealed positive immunoreactivity for cyclin D1. Cyclin D1 overexpression is significantly higher in patients with lymph node metastasis (50.0% vs 14.4%, P = 0.002) and with advanced pathological stages (I, 10%; II, 53.8%; IIIa, 41.7%, P = 0.048; stage I vs II, IIIa, P = 0.006). Twenty-four patients with cyclin D1-positive immunoreactivity revealed a significantly shorter overall survival than the patients with negativity (24.0 +/- 3.9 months vs 50.1 +/- 6.4 months, P = 0.0299). Among 33 patients between stages I and II, nine patients with cyclin D1-positive immunoreactivity had a much shorter overall survival (29.7 +/- 6.1 months vs 74.6 +/- 8.6 months, P = 0.0066). These results suggest that cyclin D1 overexpression is involved in tumorigenesis of NSCLCs from early stage and could be a predictive molecular marker for poor prognosis in resectable NSCLC patients, which may help us to choose proper therapeutic modalities after resection of the tumor.

Risk factors for early filtration failure requiring suture release after primary glaucoma triple procedure with adjunctive mitomycin

PURPOSE

Postoperative release of scleral flap closure suture is useful in trabeculectomy combined with cataract surgery. We determined risk factors for early filtration failure requiring suture release during the first month after primary glaucoma triple procedure.

METHODS

The medical records of 71 consecutive patients with primary open-angle glaucoma who underwent a primary glaucoma triple procedure (primary trabeculectomy, phacoemulsification, and posterior chamber intraocular lens implantation) were reviewed. Suture release had been performed in 24 of the patients for early filtration failure with postoperative intraocular pressure greater than the target value during the first postoperative month. The long-term filtration failure was defined according to 2 criteria based on medical dependency and requirement of additional surgical procedure for intraocular pressure control. Cox proportional hazards multivariate analysis was performed to identify independent risk factors.

RESULTS

African American race (P = .02), more than 2 preoperative glaucoma drugs (P = .02), and intraocular pressure greater than 14 mm Hg during the first postoperative week (P = .006) were identified as significant independent risk factors requiring suture release for filtration failure during the first postoperative month. Their significance was further confirmed by Kaplan-Meier survival analysis with Mantel-Cox log-rank test (P = .03, P = .02, and P = .001, respectively).

CONCLUSIONS

African American race, more than 2 preoperative medications, and intraocular pressure greater than 14 mm Hg in the first postoperative week are major independent risk factors for initial filtration failure requiring suture release during the first month after primary glaucoma triple procedure. Presence of the risk factors may warrant a more aggressive antiproliferative regimen and/or earlier suture release.

Spatial and temporal expression of UDP-galactose: ceramide galactosyl transferase mRNA during rat brain development

We studied the expression of UDP-galactose: ceramide galactosyl transferase (CGT) mRNA in postnatal rat brains using an in situ hybridization technique. From P0 to P16, there was a defined temporal and spatial pattern to the earliest acquisition of CGT mRNA expression. In the forebrain, CGT mRNA-expressing (CGT+) cells were first detected in regions outside the subventricular zone around the lateral ventricle at P2. Cells in the external capsule, internal capsule and corpus callosum were later found to be CGT-positive. At P8 to P16, CGT+ cells were found in the thalamus, striatum, occipital and frontal cortex. In the case of midbrain and hindbrain, the first CGT+ signals were detected in the medullary raphe of the medulla oblongata at P0. CGT+ cells were subsequently located in the cerebellum, midbrain and pons from P4 to P16. That is, in regions closer to the areas in which CGT+ cells were first found, CGT mRNA expression was observed much earlier. These findings support the notion that there are at least two discrete waves of CGT mRNA signal expression in the forebrain and hindbrain.

In situ localization of neuronal nitric oxide synthase (nNOS) mRNA in the rat retina

We performed a comparative study on the distribution of neuronal nitric oxide synthase (nNOS) immunoreactivity and mRNA in a normal rat retina using immunocytochemistry and in situ hybridization technique. As in previous studies, we found NOS immunoreactive (NOS-IR) cells and fibers in inner and outer plexiform layers (IPL and OPL), inner nuclear layer (INL) and inner photoreceptor segment (IPS). However, very little nNOS-IR could be detected in groups of amacrine cells and ganglion cells localized in ganglion cell layer (GCL). However, in situ hybridization showed that intense NOS mRNA signals were mainly found in the GCL and INL while weak or no mRNA signals were detected in IPL, OPL, outer nuclear layer (ONL) and IPS. This difference suggests that nNOS proteins may be transported through axons into the terminals in the IPL and OPL after they were synthesized with nNOS mRNA templates in the INL. In the case of nNOS mRNA in GCL, synthesizing nNOS proteins may move outside the eyeball and carry out tasks in central nervous system. The difference of nNOS mRNA and nNOS IR means that the complete concurrence of nNOS IR and in situ hybridization results may not always occur in the rat retina.