Effects of prostaglandin E2, forskolin and cholera toxin on cAMP production and in vitro LH-RH release from the rat hypothalamus

The present study attempts to elucidate the possible role of adenosine 3',5'-monophosphate (cAMP) and prostaglandin E2 (PGE2) in the function of the neural luteinizing hormone-releasing hormone (LH-RH) apparatus. To this end, in vitro LH-RH release from superfused hypothalamic fragments and cAMP production by hypothalamic P2 membrane fractions were measured. Immature female rats (day 28) were ovariectomized and implanted with Silastic capsules containing estradiol (235 micrograms/ml). Two days later, animals were sacrificed and the mediobasal hypothalamic preoptic area (hypothalamic units or fragments) were removed. To examine in vitro LH-RH release from superfused hypothalamic fragments, effluents were collected into tubes on ice at 10-min intervals and LH-RH concentration was determined by radioimmunoassay (RIA). Following a 50-min control period, a step-wise increment in several doses of PGE2 (each dose for a 50-min interval) evoked a dose-related increase in LH-RH release. PGE2 induced significant (P less than 0.01) increments in LH-RH release at doses of 5.68 X 10(-7), 5.68 X 10(-6), and 5.68 X 10(-5) M, respectively. When adenylate cyclase activators, such as forskolin and cholera toxin were infused in a step-wise manner (each dose for a 50-min interval) following a 50-min control period, a dose-related increase in LH-RH release was also obtained; forskolin and cholera toxin significantly (P less than 0.01) stimulated LH-RH release at doses of 1 X 10(-4) and 5.4 X 10(-10) M, respectively. These two substances were ineffective in stimulating LH-RH release when hypothalamic fragments were superfused in calcium-free plus EGTA (10 mM) containing medium.(ABSTRACT TRUNCATED AT 250 WORDS)

Copy-number of broad host-range plasmid R1162 is regulated by a small RNA

We have shown previously [Kim, K. and Meyer, R.J. (1985) J. Mol. Biol. 185,755-767] that copy-number of the broad host-range plasmid R1162 is controlled by the amounts of two proteins, encoded by cotranscribed genes comprising a region of the plasmid called RepI. We have now demonstrated that expression of RepI is negatively regulated by a 75 base RNA that is complementary to a segment of the RepI message. Increased intracellular amounts of RNA molecules that include this segment relieve the inhibition of RepI gene expression, suggesting that the target for regulation is the mRNA itself. A mutation decreasing the amount of the 75 base RNA results in elevated plasmid copy-number. Thus, consistent with our previous observations, regulation of the expression of the RepI genes is a factor in controlling plasmid copy-number.

The percentage of dense red cells does not predict incidence of sickle cell painful crisis

To test the hypothesis that the tendency of hemoglobin S (HbS) to polymerize within cells is the major determinant of the incidence of vaso-occlusive episodes, we have examined the effect of the percentage of dense cells (as measured by Percoll-Stractan continuous density gradient centrifugation) on the frequency of painful crises in a group of 36 patients with sickle cell disease. No correlation was found between the percentage of dense cells and admissions for crisis. Among the patients with known alpha-gene status (n = 25), the strong correlation between decreased dense cells and alpha-thalassemia (-alpha/alpha alpha) reported previously was confirmed (P less than .001). In addition, in this small subset, patients with alpha-thalassemia (-alpha/alpha alpha) appeared to have a marginally increased number of admissions for sickle cell crisis (t = 2.1910, P less than .05), which was independent of the percentage of dense cells. We conclude that the percentage of dense sickle cells cannot predict the incidence of painful crisis, suggesting that other factors (microcirculatory regulation or other humoral and cellular factors) are more important in the generation maintenance of painful crises than the necessary, but not sufficient, tendency of HbS-containing red cells to sickle.

The role of propranolol in the preoperative preparation of patients with Graves' disease

From March 1980 to August 1982, 108 patients with Graves' disease participated in a prospective study at Yonsei University College of Medicine. Preoperatively, 22 patients were prepared with propranolol alone (group 1) and 86 with propranolol and propylthiouracil (PTU) (group 2). The duration of preparation averaged 11.5 days for group 1 and 10.8 days for group 2. Bilateral subtotal thyroidectomy was performed, leaving 4 to 6 grams at both upper poles. No significant difference was noted in the average weight of the removed gland or the amount of blood loss between both groups. During the operation, the pulse rate of group 1 was significantly faster than that of group 2 but evened out by the day of discharge. The incidence of high fever during and immediately after operation was 27.3 per cent in group 1 which is greater than the 17.4 per cent in group 2. In group 1, the incidence of postoperative transient hypocalcemia was 27.3 per cent, transient or prolonged hypothyroidism was 13.6 per cent and recurrence of thyrotoxicosis was 4.5 per cent. In group 2, the values were 22.1, 18.6 and 4.7 per cent, respectively. High fever developed in one patient from group 1 during operation and this patient died on the third day postoperatively. From the results of our study, it appears to be more beneficial to administer both propranolol and PTU as preoperative medication to patients with Graves' disease prior to undergoing operation.

In vitro LHRH release from superfused hypothalamus as a function of the rat estrous cycle: effect of progesterone

The present study examines the effect of progesterone (P) on in vitro LHRH release from hypothalamic fragments from intact adult rats throughout the estrous cycle. Estrous cyclicity was monitored by daily vaginal smears, and animals which exhibited at least two consecutive 4-day estrous cycles were used. Animals were sacrificed between 10.00 and 13.00 h and the mediobasal hypothalamic-preoptic area-suprachiasmatic nucleus units were removed and transferred into superfusion chambers (one unit/chamber). Following a 2-hour control period, in which the spontaneous LHRH release was established, P (10 ng/ml) was infused in an intermittent mode (10 min-on, 20 min-off). Effluents were collected at 10-min intervals and LHRH concentrations were determined by RIA. The spontaneous LHRH release from control preparations was episodic throughout all stages of the estrous cycle with a significant low release rate and low LHRH amplitude only during estrus. Interestingly, intermittent infusion of P significantly stimulated LHRH release solely in hypothalamic fragments derived from proestrous rats. The P-stimulated LHRH release during the 1st-hour period after P infusion was significantly higher (p less than 0.05) than that observed in the control preparations during the same time period as well as from its own basal pre-P values (1-hour post-P: 4.26 +/- 0.96 vs. 1-hour control and pre-P: 2.34 +/- 0.38 and 2.32 +/- 0.57 pg/10 min, respectively). P administration did not stimulate in vitro LHRH release during the other stages of the estrous cycle.(ABSTRACT TRUNCATED AT 250 WORDS)

Nonenzymatic cleavage of proteins by reactive oxygen species generated by dithiothreitol and iron

Many enzymes, represented by yeast glutamine synthetase, are inactivated and degraded in the presence of dithiothreitol (DTT), oxygen, and catalytic amounts of iron salts. The roles of DTT and iron can be replaced by ascorbate and copper, respectively. Experimental data suggest that reactive oxygen species, likely hydroxyl radicals, are generated locally around irons bound at specific sites on enzymes, and these species are responsible for the inactivation and degradation. Since many biochemicals are contaminated with metal salts in quantities sufficient for some hydroxyl radical formation to occur, the possibility of oxidative modification and degradation should be considered when an enzyme is exposed to DTT.

Copy number of the broad host-range plasmid R1162 is determined by the amounts of essential plasmid-encoded proteins

DNA of the broad host-range plasmid R1162 contains a 1700 base-pair segment essential for plasmid maintenance. This region, RepI, consists of two cotranscribed genes encoding polypeptides with molecular weights of 29,000 and 31,000. Fusion of RepI to the strong tac promoter results in greatly increased amounts of at least one of these polypeptides. In trans, this construction has two other properties: it can raise the copy number of R1162, and it can protect this plasmid from loss due to incompatibility. Both effects require intact RepI genes. These properties of the RepI region, along with those of an origin-linked region described earlier, are discussed with respect to current models for control of plasmid copy number.

Dibutyryl cyclic adenosine monophosphate stimulates in vitro luteinizing hormone-releasing hormone release only from median eminence derived from ovariectomized, estradiol-primed rats

The present study examined the effect of intermittent infusion of dibutyryl cyclic AMP (dbcAMP; 10(-7) M; 10 min on, 20 min off) on in vitro luteinizing hormone-releasing hormone (LH-RH) release from the rat median eminence (ME) derived from immature rats: intact females, intact males, ovariectomized (OVX) females, castrated (CAST) males, ovariectomized, estradiol primed (OVX + E2) females and castrated, estradiol primed (CAST + E2) males. In intact, OVX and CAST conditions, spontaneous LH-RH release from MEs was not modified by dbcAMP infusion. However, E2 implants in OVX and CAST rats selectively affected the responsiveness of MEs to dbcAMP: ME from OVX + E2 were highly responsive to dbcAMP; contrarily, MEs from CAST + E2 were unresponsive to this nucleotide. Therefore, these differences in MEs responsiveness to dbcAMP-induced LH-RH release appear to be dependent upon a critical effect of E2 priming on this tissue in female but not in male rats.

[Evaluation of the effectiveness and safety in the use of cold-diltiazem-potassium cardioplegia in coronary artery bypass surgery: a first clinical trial]

The effectiveness and safety of diltiazem (DIL), a slow channel calcium blocker, added in cold potassium cardioplegic (CP) solution was evaluated in coronary artery bypass graft (CABG) surgery for 2 purposes; (1) protection of ischemic myocardium during cardiac arrest and (2) prevention of perioperative coronary artery spasm (PCS). Diltiazem of 15 mg was added to a liter of CP which was administered 10 ml/kg B.W. initially and 5mg/kg thereafter. The serum concentration of DIL was 570 ng/ml at the time of aortic declamping, 210 ng/ml at cardioversion and 150 ng/ml one hour after surgery. The left ventricular stroke work index was increased significantly (p less than 0.05) in patients treated by DIL-CP, compared with the patients treated by regular CP without DIL. However, CPK-MB values were not significantly different in either group. The incidence of PCS has decreased from 9.1% to 0.8% (p less than 0.01) after the use of DIL-CP. Perioperative myocardial infarction rate has also decreased from 5.5% to 1.6%. No major or long-lasting side-effects were encountered. We consider that DIL-CP is a safe and excellent CP in CABG surgery and we are now utilizing this CP in all patients requiring CABG surgery.

Choroid plexus carcinoma. Report of a case with cytopathologic differential diagnosis

The cytopathologic features of choroid plexus carcinoma in the cerebrospinal fluid of a 13-month-old male infant were reviewed and compared with those of other small-cell malignant neoplasms of childhood and young adulthood involving the central nervous system. The cytologic features of the choroid plexus carcinoma (tight spatial clusters and isolated anaplastic cells with striking nuclear lobulation) were distinct from those of lymphoma, leukemia, neuroblastoma, ependymoma and pineal germinoma. However, the cells had a striking resemblance to those of anaplastic ependymoma and metastatic adenocarcinoma.

Severe Kawasaki heart disease treated with an internal mammary artery graft in pediatric patients. A first successful report

Two Japanese boys, 6 and 10 years old, required operation for severe Kawasaki heart disease. Both had multiple coronary arterial aneurysms and stenoses, and one had mitral regurgitation as well. The operations consisted of anastomosis between the left internal mammary artery and the left anterior descending artery and insertion of an autologous saphenous vein between the aorta and the posterior descending artery in both patients. The mitral valve was replaced in the one with mitral regurgitation. Angina pectoris has been completely relieved as confirmed by postoperative angiocardiography. Late results of coronary bypass grafting with the saphenous vein in pediatric patients with Kawasaki disease have been less than satisfactory because of the high occlusion rate of the graft. The internal mammary artery may be superior, at least theoretically, to the saphenous vein graft because it is a "living graft" with a high possibility of growing and with less susceptibility to degeneration. This is the first report of successful operation utilizing an internal mammary artery graft in coronary bypass for Kawasaki disease.

Pineal germinoma with widespread extracranial metastases

A case of primary pineal germinoma with widespread extracranial metastasis in a 36-year-old man is presented. A clinical work-up revealed bilateral pleural effusions, ascites, and metastatic lesions involving the lung. Cytology and electron microscopic study of the pleural and ascitic fluid and of the fine needle aspiration material revealed metastatic germinoma. Although the cytologic features were not distinct from those of anaplastic carcinoma, they were distinguishable from those of glial neoplasms, lymphoma, and sarcoma. The computed tomography findings, elevated human chorionic gonadotropin level, and electron microscopic features contributed significantly to the diagnosis of extracranial metastasis of the pineal germinoma. Metastatic spread most likely occurred via the ventriculoperitoneal shunt.

In vitro luteinizing hormone-releasing hormone release from superfused rat hypothalami: site of action of progesterone and effect of estrogen priming

The study examined the effect of estrogen priming on progesterone (P4)-induced LHRH release, the tissue site of action of P4, and the effect of 5 alpha-dihydroxyprogesterone (5 alpha-DHP) on LHRH release from hypothalamic fragments superfused in vitro. Immature female rats were ovariectomized (OVX) and, at 28 days of age, Silastic capsules containing estradiol (E2) were implanted. Two days later, animals were killed and hypothalamic fragments were removed and transferred to superfusion chambers. The hypothalamic units received P4 or 5 alpha-DHP delivered in an intermittent mode (10-min on, 20-min off). LHRH was determined in perfusates by RIA. After the input characteristics of different infusion modes (single pulses, intermittent, and continuous) of P4 infused into superfusion chambers were assessed, an intermittent infusion mode (10-min on, 20-min off) was selected for further examinations. In the mediobasal hypothalamic-anterior hypothalamic-preoptic area (MBH-AHA-POA) tissue preparations, we observed: 1) an infusion of 5 alpha-DHP was ineffective in stimulating LHRH release; 2) the release pattern of LHRH in response to three different P4 doses (10, 20, and 50 ng/ml) was similar in terms of percent changes (202% to 219% over control values); and 3) E2 priming was absolutely required for P4-stimulated LHRH release, and this requirement appeared to be dose dependent. Upon an examination of three hypothalamic tissue boundaries [the MBH, the POA-suprachiasmatic nuclei (POA-SCN), and the median eminence (ME)] to better delineate the in vitro site of action of P4 on LHRH release, it was demonstrated that the MBH responded upon P4 infusion, whereas the POA-SCN was unable to do so. The ME also responded upon P4 infusion, and LHRH release followed closely the pulsatile administration of P4 since upon each challenge of the steroid at the concentration of 10 or 20 ng/ml, a significant rise in LHRH release occurred. However, the temporal patterns of LHRH release from the ME appears to be different from those obtained from the MBH as well as the MBH-AHA-POA. These observations demonstrate that an intermittent infusion of P4, but not 5 alpha-DHP, is effective in activating the neural LHRH apparatus. Estrogen is an obligatory requirement for this P4-stimulated LHRH release, and the neural site of action of P4 resides within the MBH. However, this steroid also can act directly upon the ME nerve terminals to release LHRH.

Caffeine-induced reorganization of DNA replicating system occurs on or near nuclear matrix in HeLa cells

Since caffeine reorganizes the DNA replicating system, with several consequences, we studied the effect of caffeine on the DNA replication which normally occurs on or near the nuclear matrix in a variety of eukaryotic cells. When HeLa cells, treated with or without the DNA-damaging agent, neocarzinostatin, were postincubated in the presence or absence of caffeine and then pulse-labeled with [3H]thymidine, the DNA remaining tightly associated with the matrix was enriched in the newly synthesized DNA at the same level as that seen in untreated cells. The nuclear matrix-bound DNA polymerase alpha activity was also the same in these cells. Therefore, in the presence of caffeine, DNA replication, with or without DNA damage, also occurs on or near the nuclear matrix, as is the case in normal DNA replication.

Novel system for recognizing and eliminating foreign DNA in Pseudomonas putida

Derivatives of pQSR49 (R1162::Tn1) containing cloned fragments of Escherichia coli chromosomal DNA are stable in E. coli but unstable in Pseudomonas putida. Similar derivatives containing P. putida chromosomal DNA are stable in both species. Instability is a consequence of plasmid loss during growth and is not due to death or inhibition of growth of plasmid-containing cells. Average copy numbers per cell of the unstable hybrid plasmids are similar to that of pQSR49, indicating that instability is not the result of reduced replication of plasmid DNA. A plasmid unrelated to pQSR49, RK2, becomes unstable in the presence of the unstable hybrids but only when it also contains foreign DNA. The data suggest an inducible mechanism in P. putida active in the elimination of plasmid-borne foreign DNA from the cell.

Enhanced immune response in the urinary tract of the rat following vaginal immunization

The immune response in the rat urinary tract was assessed by an enzyme-linked immunosorbent assay for immunoglobulins following vaginal immunization and subsequent intravesical challenge with live E. coli 06. Vaginally immunized rats showed a strong and rapid bladder immune response following intravesical challenge, in contrast to nonimmunized control rats. The immune response was localized to the urinary tract in that antibody to E. coli 06 was not detected in serum, saliva and vaginal washes from immunized rats.

Pre- and postoperative hemodynamic assessments and survival rates in patients with postinfarction ventricular septal perforation

Pre- and postoperative hemodynamics were assessed in 14 consecutive patients who developed ventricular septal perforation (VSP) following acute myocardial infarction (AMI). Results were correlated with the surgical outcome and with postoperative clinical improvements. The patients were divided into 3 groups according to the time intervals between the onset of AMI and the operation; acute (within 2 weeks after AMI), subacute (between 2 and 4 weeks) and chronic (after 4 weeks). In the above groups, 6, 2 and 6 patients were included, respectively. Eleven patients had anteroseptal infarction and 3 patients sustained inferior infarction. The survival rates were 33, 50 and 100% in the acute, subacute and chronic groups, respectively with an overall survival rate of 64%. Hemodynamic comparisons between survivors and non-survivors revealed that the systolic aortic pressure and left ventricular stroke volume index were significantly higher and the right ventricular end-diastolic pressure was significantly lower in survivors than in non-survivors (p less than 0.05). Although no statistical significance was obtained, left ventricular end-diastolic volumes and ejection fractions were higher in survivors. No difference was present between survivors and non-survivors in either Qp/Qs, Pp/Ps, Rp/Rs, systolic pulmonary pressure, left ventricular end-diastolic pressure or cardiac index. Patients with low arterial pressure and high right ventricular end-diastolic pressure under intensive medical regimens, indicating the presence of cardiogenic shock and/or associated right ventricular infarction or severe failure, had a high mortality and should be considered for emergency operation. Postoperative hemodynamics improved significantly in all variables measured (p less than 0.05-0.01). Patients with a VSP should all be considered for surgery unless a definite contraindication exists.

In vitro and in vivo neutralizing activity of human colostrum and milk against purified toxins A and B of Clostridium difficile

The neutralizing activity (NA) of supernates of colostral samples collected postpartum from 55 women and tested against a 50% cytopathic dose of purified toxins A and B of Clostridium difficile was evaluated in Y1 adrenal cells. Thirty-one (56%) of the samples had NA against one or both toxins. Samples of breast milk were collected postpartum from five women-three had colostral NA and two did not. All milk specimens from the three women with colostral NA had NA titers of 1:1-1:4 throughout the study (609 days in one case). Samples from the two women without colostral NA did not exhibit NA during a 60-day follow-up period. In suckling mice either toxin plus human milk with in vitro NA elicited significantly less fluid accumulation than did toxin plus diluent or toxin plus milk without in vitro NA (P less than .025 to P less than .05). Twelve (63%) of 19 milk samples with in vitro NA against toxin A and 15 (65%) of 23 with in vitro NA against toxin B inhibited fluid accumulation caused by the corresponding toxin. In vitro NA against toxin A appeared to reside in the secretory IgA fraction of one milk sample assessed by immune precipitation. The results suggest that human milk may protect newborn infants against toxins A and B of C. difficile.

Idiopathic aldosteronism. A possible disease of the intermediate lobe of the pituitary

A 37-year-old woman with documented primary aldosteronism died of a cerebral hemorrhage. At postmortem examination she was found to have bilateral, adrenal hyperplasia and nodular basophilic hyperplasia of the anterior and intermediate lobe of the pituitary. Based on these findings and experimental evidence suggesting the existence of a pituitary factor that stimulates aldosterone secretion, we postulate that idiopathic aldosteronism is caused by an abnormality of the intermediate lobe of the pituitary gland leading to overproduction of non-adrenocorticotropic hormone peptides derived from pro-opiomelanocortin that increase aldosterone production and cause hyperplasia of the adrenal glands.

Primary myelolipoma of mediastinum

Myelolipoma is a benign nonepithelial neoplasm composed of mature marrow elements and fat cells. This rare neoplasm is usually discovered by pathologists incidentally at autopsy, and, with rare exceptions, usually occurs in the adrenal glands. One of these exceptional anatomic sites is the mediastinum, and only three cases of primary mediastinal myelolipomas have been documented in the English-language literature (1-3). We are presenting a primary myelolipoma involving the posterior mediastinum that was discovered on routine chest radiographs and successfully resected. Computed tomography (CT) scan findings of this rare mediastinal tumor are also presented. This is the first case report in the English language of primary myelolipoma in the mediastinum that was detected clinically and resected successfully.

Post-stimulus facilitatory and inhibitory effects on respiration induced by chemical and electrical stimulation of thin-fiber muscular afferents in dogs

In anesthetized, vagotomized, paralyzed, and artificially ventilated dogs, respiratory responses to both electrical stimulation of the muscle nerve and chemical stimulation of muscular (polymodal) receptors by means of intra-arterial injection of NaCl solution were studied by recording phrenic nervous discharges. During the period of stimulation both types of stimulation caused intensity-dependent facilitation of neural respiratory outputs. After cessation of stimulation, facilitation persisted for a long time (more than 5 min) with a lower intensity stimulation; however, suppression was observed with a higher intensity stimulation. The present results suggest that afferent inputs from the muscular polymodal receptors activate long-acting central mechanisms for enhancement or suppression of respiration.

Outbreaks of diarrhea associated with Clostridium difficile and its toxin in day-care centers: evidence of person-to-person spread

Clostridium difficile was associated with five outbreaks of diarrhea occurring in three day-care centers caring for children less than 2 years of age during a three and one-half-month period; two centers had one outbreak of diarrhea, and one had three outbreaks. The frequency of isolation of C. difficile and its toxin was determined in stool specimens from 65 children attending the three day-care centers. Twelve of 21 (57%) children who had diarrhea excreted C. difficile and its toxin, whereas only four of 44 (9%) children who did not experience diarrhea yielded the organism and the toxin. Five of the 12 symptomatic children with C. difficile and its toxin had received prior antimicrobial therapy for upper respiratory tract infections. An eight-month prospective study was then carried out in one room of the center where the three outbreaks had occurred. Initially, one child had culture-positive stools for C. difficile. During the first 13-week study period six additional children of the 12 (50%) in the room under study became colonized with C. difficile. Six of the seven children who excreted C. difficile and its toxin experienced diarrhea with C. difficile toxin-positive stools by the end of the 13 weeks. Environmental contamination increased as more children became colonized and developed diarrhea. Electrophoretic evaluation of environmental and stool isolates obtained during one outbreak of diarrhea showed that the isolates had an identical protein pattern. Findings of this study indicate the importance of searching for C. difficile in children in day-care centers who develop diarrhea.

Malignant fibrous histiocytoma. Cytologic, light microscopic and ultrastructural studies

Studies of the cytologic, light-microscopic and electron-microscopic features of three malignant fibrous histiocytomas (MFH) confirmed the presence of histiocytelike and fibroblastlike cells. The ultrastructural features suggest that the neoplasm possibly originates in undifferentiated mesenchymal cells that are capable of differentiating into histiocytic and fibroblastic cells. Cytologic features seen in smears obtained by thin needle aspiration included loose aggregates of markedly pleomorphic, elongated cells, histiocytelike cells and isolated bizarre giant cells. Phosphotungstic acid hematoxylin (PTAH) and oil red O staining of air-dried smears were helpful in differentiating MFH from pleomorphic variants of liposarcoma and rhabdomyosarcoma.

Nuclear magnetic resonance imaging and evaluation of human breast tissue: preliminary clinical trials

In vivo clinical evaluations of human mammary tissue, including normal, dysplastic, and neoplastic breasts, were initiated using the FONAR method of nuclear magnetic resonance (NMR) imaging. Spin-lattice relaxation times (T1) were determined and correlated with other diagnostic modalities including mammography, xeroradiography, and sonography. Normal breasts and breasts with extensive fatty replacement were found to have the lowest T1 values, whereas T1 values of malignant tissue were elevated. T1 values for mammary dysplasia extended over a wide range, and NMR images exhibited lower proton density than normal tissue. In several patients with severely dysplastic breasts, T1 values overlapped those from patients with documented breast neoplasms. Markedly elevated T1 values were obtained from fluid-filled cysts that were well beyond the range of malignancy.