Acute Immobilization Stress and Intraventricular Injection of CRF Suppress Naloxone-Induced LH Release in Ovariectomized Estrogen-Primed Rats

The present study was undertaken to evaluate the role and possible interaction of the endogenous opioid peptide (EOP) and corticotropin-releasing factor (CRF) in the acute stress-induced suppression of gonadotropin secretion in ovariectomized estrogen-primed rats. An intravenous (i.v.) injection of naloxone (10 or 20  mg/kg), an EOP antagonist, significantly elevated serum luteinizing hormone (LH) levels within 10  min in non-stressed animals. The naloxone-induced LH release was completely eliminated when tested 30  min after the onset of acute immobilization. In a subsequent study, it was found that suppression of the naloxone-induced LH release occurred as early as 5  min after the stress onset, and was still evident 60  min after the end of a 30-min period of immobilization. The effect of naloxone was restored 3  h after liberation of the animal from the 30-min immobilization. An intraventricular (i.c.v.) injection of CRF (1 or 5  μg) also significantly suppressed, in a dose-related manner, the effect of a subsequent i.v. injection of naloxone. However, an i.c.v. injection of α -helical CRF(9-41) (25 or 50  μg), a CRF antagonist, prior to immobilization, could not interfere with the suppressive effect of stress on naloxone-induced LH release. These results suggest that both acute immobilization stress and CRF can inhibit the LH secretory activity without mediation by EOP neurons. However, the stress-related suppression may involve non-CRF mechanism(s).     

Organization of the trigeminal and facial motor nuclei in the hagfish, Eptatretus burgeri: a retrograde HRP study

We studied the trigeminal and facial motor nuclei of the hagfish by the retrograde HRP method. We distinguished 4 components in a single column of the motor nuclei of the trigeminal nerve and the facial nerve, viz., the pars magnocellularis of the trigeminal motor nucleus (mVm), the anterior part of the pars parvocellularis of the trigeminal motor nucleus (mVp1), the posterior part of the pars parvocellularis of the trigeminal motor nucleus (mVp2) and the facial motor nucleus (mVII). Although in Nissl preparations only the mVm could be distinguished from the rest of the nucleus, the boundaries of the other 3 components were clearly demarcated in HRP preparations. Intramuscular injections into two representative antagonistic jaw muscles revealed that there was no apparent topological organization of the neurons pertaining to the opening and closing muscles in the mVm and mVp1, but both antagonistic muscles were innervated bilaterally. Although the hagfish does possess a cartilaginous jaw, the organization pattern of the motor nuclei of the jaw muscles seems to be the most primitive of all living vertebrates.     

Implications of Popliteal Lymph Node Detected by Sentinel Lymph Node Biopsy

BACKGROUND: Although there is lymphatic flow into the popliteal fossa from a skin tumor located in the lower leg, popliteal metastasis is extremely rare. Recently, sentinel lymph nodes outside traditional nodal basins have been identified. This study investigated the incidence of sentinel nodes in the popliteal region and the indication for biopsy. METHODS: Fourteen patients with various skin cancers involving the lower extremities (nine melanomas, four squamous cell carcinomas, and one sweat gland carcinoma) underwent lymphoscintigraphy and excision with sentinel lymph node biopsy. RESULTS: In all 14 patients, hot spots showed accumulation in the groin region. Five of 14 patients (36%) demonstrated popliteal sentinel nodes in addition to the inguinal nodes. Three of five popliteal sentinel nodes were histologically studied. A patient with acral melanoma demonstrated micrometastasis of melanoma cells in a popliteal node but not in the groin node. CONCLUSION: This study demonstrates that sentinel lymph nodes located in the popliteal fossa are frequently detected by lymphoscintigraphy and that biopsy should be performed if popliteal nodes are identified.     

Production of syngeneic autoreactive monoclonal antibodies specific for isotypic determinants of IgE

Methods are described for the production of syngeneic mouse anti-IgE monoclonal antibodies (mAb). Hybridomas were prepared by using spleen cells from mice immunized with a conjugate of keyhole limpet hemocyanin with monoclonal IgE. Serum titers varied from approximately 40 to 1000 micrograms/ml. The anti-IgE mAb were isolated by affinity chromatography on columns containing immobilized monoclonal IgE. The mAb are specific for isotypic determinants of IgE and do not react with other immunoglobulin isotypes. One of the mAb, which has a high affinity for IgE (Ka = 4.7 X 10(8) M-1), should be useful for studies of regulation of IgE. The applicability of the mAb to quantitative assays for IgE was demonstrated.     

Long-lasting effect of ceruletide on dyskinesia and monoaminergic neuronal pathways in rats treated with iminodipropionitrile

In a model of dyskinesia induced by the administration of iminodipropionitrile (IDPN) in the rat, we evaluated the effects of ceruletide, an analogue of cholecystokinin, on behavioral abnormalities and monoaminergic neuronal function. Vertical head twitching in the IDPN-treated animals was inhibited for over 5 h following a single subcutaneous dose of 160 micrograms/kg ceruletide. In animals dosed daily for 2 or 3 days, the number of head twitches at 24 h after the last dose was about one-third of the number before treatment. After repeated daily doses of ceruletide for 6 days, the number of head twitches was reduced to low levels and remained significantly below pretreatment levels until the 4th posttreatment day. These results indicate that the inhibition of dyskinesia by ceruletide was long-lasting. Assays of monoaminergic neurotransmitters and their metabolites in various brain regions indicate that an imbalance between dopaminergic and serotonergic neuronal systems plays a major role in the pathogenesis of the IDPN-induced dyskinesia, i.e. the ratio of (DOPAC+HVA)/5-HIAA was significantly greater in the striatum but significantly smaller in the hippocampus of the IDPN-treated vs normal animals. This initially abnormal ratio of (DOPAC+HVA)/5-HIAA in the striatum and hippocampus of IDPN-treated animals returned to normal following treatment with ceruletide, corresponding with the reduction of the head twitching. The alterations in monoaminergic neuronal function induced by repeated administration of ceruletide persisted for at least 3 days, even though its plasma half-life is several minutes. Ceruletide also exerted a marked effect on monoaminergic neuronal function in the IDPN-treated rats, in contrast to only a slight effect in normal animals.(ABSTRACT TRUNCATED AT 250 WORDS)     

Gene cluster for assembly of pilus colonization factor antigen III of enterotoxigenic Escherichia coli

The assembly of pilus colonization factor antigen III (CFA/III) of enterotoxigenic Escherichia coli (ETEC) requires the processing of CFA/III major pilin (CofA) by a prepilin peptidase (CofP), similar to other type IV pilus formation systems. CofA is produced initially as a 26.5-kDa preform pilin (prepilin) and then processed to a 20.5-kDa mature pilin by CofP which is predicted to be localized in the inner membrane. In the present experiment, we determined the nucleotide sequence of the whole region for CFA/III formation and identified a cluster of 14 genes, including cofA and cofP. Several proteins encoded by cof genes were similar to previously described proteins, such as the toxin-coregulated pili of Vibrio cholerae and the bundle-forming pili of enteropathogenic E. coli. The G+C content of the cof gene cluster was 37%, which was significantly lower than the average for the E. coli genome (50%). The introduction of a recombinant plasmid containing the cof gene cluster into the E. coli K-12 strain conferred CFA/III biogenesis and the ability of adhesion to the human colon carcinoma cell line Caco-2. This is the first report of a complete nucleotide sequence of the type IV pili found in human ETEC, and our results provide a useful model for studying the molecular mechanism of CFA/III biogenesis and the role of CFA/III in ETEC infection.     

Malignant fibrous histiocytoma of the pancreas

An extremely rare case of malignant fibrous histiocytoma In the pancreas Is reported. A 70-year-old man complained of upper abdominal discomfort. A tumor in the head of the pancreas was demonstrated by ultrasonography and computed tomography. The surgical specimen revealed a relatively well demarcated tumor, 9 × 7 × 6.5cm in size. Microscopically, fibroblastic, histiocytic, and muitinucleated giant tumor cells were observed in the myxoid area, but some tumor cells had proliferated in a storiform-pleomorphlc pattern. Immunohtstochemically, some tumor cells were positive for lysozyme, α-1-antitrypsin, α-1-antichymotrypsin, and vimentin. Electron microscopically, tumor cells showed a combination of fibroblastic and histiocytic features. The patient Is currently well with no evidence of recurrence or metastasis 22 months after operation.     

Polymorphous low-grade adenocarcinoma of submandibular gland origin

A case of polymorphous low-grade adenocarcinoma (PLGA) in the submandibular gland is reported. A 72 year old woman presented with a 5 year history of a gradually expanding tumor in the submandibular region. The surgical specimen revealed a relatively well demarcated tumor, 35 × 35 × 20 mm in size. Macroscopically, necrosis and hemorrhage were not seen in the solid tumor. Histologically, the tumor growth pattern was variable, composed of tubular, papillary, solid, trabecular and cribriform structures. Immunohistochemically, some tumor cells were positive for epithelial membrane antigen (EMA), S-100 protein, keratin, and carcino-embryonic antigen (CEA). Electron microscopically, prominent microvilli projected into the luminal spaces, and basal lamina and hemidesmosomes were seen in the tumor cells adjacent to the connective tissues. The submandibular gland is an extremely rare location for PLGA. To the authors' knowledge, this is the first case of its kind reported in the English literature.     

Hyperplastic foci in chronic liver disease: Their proliferative activity assessed by nucleolar organizing region

In the cirrhotic and precirrhotic liver, there may be small foci with increased cellularity and amphophilic cytoplasm. These are microscopic lesions that do not form macroscopically detectable nodules, which differ from the macroscopically apparent nodules of dysplastic nodules. In the present study, we assessed the proliferating activity of 12 hyperplastic foci in 11 patients with cirrhosis or chronic hepatitis, by staining for agyrophilic nucleolar organizing regions (AgNOR). The mean AgNOR count per nucleus in the hyperplastic foci ranged from 0.96 to 1.36 (mean, 1.13; SD 0.12), and from 0.81 to 1.06 (mean, 0.94; SD 0.08) in the controls. The AgNOR count In the hyperplastic foci was significantly higher than that In the controls (P> 30.01). Small hyperplastic foci show Increased proliferative activity. Further study on these foci is required to clarify their relation to hepatocarcinogenesis.     

Application of multiple methods to study the immunization programme in an urban area of Guinea

During 1988-89, studies were conducted to evaluate the immunization system in Conakry, Guinea. The first, a health facility survey, found that health staff screened the vaccination status of only 30% of children who presented for curative care. A sterile syringe and needle were used for less than half of the injections. In the second survey, key informant interviews with vaccinators and health centre chiefs showed that there were minimal lines of communication between health workers and the community, but that health workers did not perceive this to be a problem. Focus group discussions in the community revealed a high level of general knowledge about vaccine-preventable diseases. However, mothers did not know how many vaccinations their children should receive or by what age they should be completed. They complained of long waiting times in health centres, the high costs of vaccination, poor rapport with health workers, and the occurrence of abscesses after vaccination. The final study, a "knowledge, attitudes, and practice" community survey, showed that missed immunization opportunities and inappropriately timed vaccinations reduced potential vaccine coverage by almost 30% among children with vaccination cards. Higher socioeconomic status, delivery in hospital, and whether mothers perceived the vaccinations to be affordable affected whether the child began the immunization series. Once a child had entered the immunization system, completion of the series was determined by the mother's education level, employment status, and experience with vaccination services.