Familial polyposis coli: an unusual case in West Africa. We describe a case very rare in the West African sub-region, Familial Polyposis Coli, presenting with rectal prolapse. Symptoms appeared at an unusual age of three years. Histological examination of four polyps excised at random showed all to have undergone malignant change. While the patient was being built up for surgery, she developed marked abdominal distension, hyperpyrexia, respiratory distress and vomiting. She died within 24 hours of this acute illness. This is the first reported case, to our knowledge, of Familial Polyposis Coli in the West African sub-region.


Intracellular cyclic AMP produces effects opposite to those of cyclic GMP and calcium on shape and motility of neuroblastoma cells. We have directly evaluated the effects of various intracellular second messengers including cyclic nucleotides, calcium ion, and inositol polyphosphates on shape and motility of differentiating mouse neuroblastoma cells. The messengers were microinjected into cells and the responses of the soma, neurite, and growth cone were monitored using time-lapse video microscopy. Each messenger altered cell shape and motility in a characteristic manner. Cyclic AMP promoted lamellipodial expansion, neurite outgrowth, and motility. The other injected messengers opposed motility. Cyclic GMP caused motile structures to freeze and to retract permanently, while the inhibitory effects of calcium injection were concentration-dependent. Small calcium injections affected specifically actin-containing motile structures which froze and retracted temporarily. Intermediate calcium injections caused a strong contraction at the site of injection in all cells. With large injections, cells retracted long neurites, rounded up, and frequently began vigorous blebbing that continued to cell death. Injections of the inositol polyphosphates IP3(1,4,5) and IP4(1,4,5,6) mimicked the effects of small calcium injections, as did electrical stimulation that elicited action potentials. The results suggest that in mouse neuroblastoma cells, intracellular cAMP elevation increases cytoskeletal organization and promotes neurite extension perhaps through an enhancement of cell-substratum adhesion. On the other hand, a rise of intracellular cGMP or intracellular calcium interferes directly with the function and organization of the actin-microfilament system. The integrated action of these second messenger systems may, therefore, operate in vivo to allow substances released from neighboring cells to regulate neuronal architecture.


Unusual presentation of tuberculous meningitis. We present 4 cases of tuberculous meningitis with atypical clinical features and CSF findings. Two patients had initially normal CSF examination, one developed internuclear ophthalmoplegia, while the other had deterioration of consciousness. The third patient presented with paranoid psychosis, and the fourth had a picture mimicking acute bacterial meningitis and he developed right hemianopia due to a tuberculoma detected by MRI. All recovered completely with anti-tuberculous treatment.


Somatosensory evoked potentials (cutaneous nerve stimulation) and electromyography in lumbosacral radiculopathy. In order to evaluate the usefulness of SEP with cutaneous nerve stimulation in lumbosacral radiculopathy, we investigated 19 patients by EMG including H-reflex and SEP. All patients had radiculopathy proven by myelography and/or CT scan and, if indicated, operative treatment. The findings by EMG and SEP were compared with operative and radiological findings. In this preliminary study, SEP was as sensitive as EMG in detecting lumbosacral radiculopathy. Further investigation seems justified.


Management of cerebellar infarction with associated occlusive hydrocephalus. We review here 10 cases of cerebellar infarction and associated occlusive hydrocephalus. Surgical therapy consisted of placement of a permanent shunt in 4, and a temporary external ventricular drainage in 6 individuals. This treatment regimen was effective in 9 cases and remained without adequate response in only 1 patient with multiple supra- and infratentorial infarctions. These results and similar reports from the literature suggest that treatment of the hydrocephalus alone might be sufficient in most cases and should therefore constitute the primary treatment of choice in patients presenting with cerebellar infarction and obstruction of cerebrospinal fluid (CSF) pathways.


The prognostic value of intra-operative observations during thalamotomy for parkinsonian tremor. Data from 27 thalamotomies were analyzed with respect to possible correlations between certain intra-operative observations and the long-term effect on parkinsonian tremor. Tremor reduction caused by mechanical impact of the electrodes in the target area was not correlated with the long-term effect on the tremor. The same was true for the threshold intensities during the intra-operative electrical stimulation of the target area, stimulation that facilitates and/or inhibits the tremor. In a minority of the patients, all with good long-term results, a combination of a pronounced tremor inhibition from the electrode insertion and a low threshold intensity was observed. Variations in other lesion parameters were not correlated with the outcome. The results are discussed within the framework of a "tremor" vs. a "tonus" mechanism underlying the thalamotomy effect.


Chronic inflammatory demyelinating polyradiculoneuropathy with membranous glomerulonephritis: report of one case. A case of chronic inflammatory demyelinating poly radiculoneuropathy (CIDP) associated with membranous glomerulonephritis (MGN) is presented. Immunological implications are discussed. This is the first case report describing such an association.


A spinal haematoma occurring in the subarachnoid as well as in the subdural space in a patient treated with anticoagulants. A 75-year-old man on anticoagulant therapy suddenly experienced an excruciating back pain and subsequently developed a paraplegia. At operation a subarachnoid and a subdural haematoma were found, extending between the levels of the vertebrae T3 and L2. This extremely rare combination of haematomas may have been caused either by rupture of a small vessel in the arachnoid membrane or by rupture of the arachnoid membrane itself, secondary to a massive haemorrhage in the subarachnoid space.


Purulent meningitis due to aspergillosis in a patient with systemic lupus erythematosus. We report a 39-year-old female patient with systemic lupus erythematosus under immunosuppressive therapy who developed persistent neutrophilic meningitis, for which no infectious agent could be identified. Intensifying the immunosuppressive therapy induced a short amelioration of the clinical picture. At autopsy, basal meningitis was found to be due to Aspergillus sp.


Epidermoid cyst in association with subcutaneous meningioma. A 17-year-old female presented with a non-tender, firm and fixed swelling in the right frontal region. Skull x-rays revealed soft tissue shadow and mild hyperostosis of the underlying frontal bone. Histopathological examination after excision showed it to be a meningioma with an epidermoid cyst.


Is there involvement of the central nervous system in hereditary sensory radicular neuropathy? There is pathological evidence that hereditary sensory radicular neuropathy (HSN type I) is a disorder related to multi-system atrophy with marked cell loss in the cerebral cortex, thalamus, brain stem and cerebellum. We report here a clinical study of a case of HSN-I including audiometric testing, autonomic functions, electromyography, transcranial magnetic stimulation and magnetic resonance imaging of the brain. There were no signs of central nervous system involvement. It is stated that HSN-I remains a disorder of dorsal root ganglia and sensory nerves, leading to painless perforating ulceration and mutilation, within the course of the disease peripheral motor nerve involvement, but without involvement of central motor pathways.


Intraspinal juxta-facet cysts: a case of bilateral ganglion cysts. Juxta-facet cysts are relatively uncommon intraspinal lesions, causing radiculopathy, neurogenic claudication or myelopathy. To the best of our knowledge, only 4 cases of bilateral synovial or ganglioncysts were described. We report the 5th case of bilateral ganglioncysts of the lumbar spine. Generally, juxta-facet cysts should be differentiated from other intraspinal lesions, such as herniated discs, meningiomas and neurinomas. Correct preoperative diagnosis is necessary for adequate treatment, namely the (microscopic) resection of the cyst. After adequate treatment, complete recovery may be expected.


Dermoid cyst mimicking hematoma in the posterior fossa. Intracranial dermoid cysts are usually reported to be associated with long lasting or waxing-waning symptoms. Computer tomography (CT) scans usually depict such neoplasms as well-defined areas of low density. This report is about a case of a dermoid cyst, the acute clinical features and CT hyperdensity of which mimicked a hematoma in the posterior fossa. The association of acute onset with CT hyperdensity makes this case of dermoid cyst very unusual.


POEMS syndrome: follow-up study of a case. We report here the case of a 20-year-old man with POEMS syndrome (polyneuropathy, organomegaly, endocrinopathy, M proteins, skin changes). This rare syndrome followed a 3-year history of a syndrome that mimics a chronic inflammatory demyelinating polyneuropathy (CIDP). Treatment with cyclophosphamide induced regression of the syndrome and improved peripheral nerve conduction.


Spinal subarachnoid hemorrhage due to a filum terminale ependymoma. We present a case of spinal subarachnoid hemorrhage due to an ependymoma of the filum terminale in a 23-year-old male. Clinical signs indicating a spinal origin of the subarachnoid hemorrhage are discussed. Subarachnoid hemorrhages are only rarely caused by an intraspinal tumor, most of which are located in the cauda equina. Our findings in this case proved the value of MRI examination in tumors of the cauda equina.


Quantitation and mapping of integrated human papillomavirus on human metaphase chromosomes using a fluorescence microscope imaging system. Integrated human papillomavirus type 16 (HPV-16) DNA was directly visualized on metaphase chromosomes in the two human cervical carcinoma cell lines SiHa and CaSki by fluorescence in situ hybridization with a biotinylated DNA probe (7.9 kb). The fluorescence intensities of hybridization signals from single copies and dispersed clusters of integrated HPV-16 DNA were quantified using a microscope equipped with a cooled-CCD camera that was interfaced to an image processor and host computer. Hybridization signals were localized on chromosomes using separate, registered images of 4',6-diamidino-2-phenylindole (DAPI) or propidium iodide stained metaphase chromosome spreads. In both SiHa and CaSki spreads, a single fluorescein signal was observed on one or both chromatids of chromosome 13, which was identified by simultaneous hybridization with a biotinylated centromere probe specific for chromosomes 13 and 21. Ratios of the distance from 13pter to the HPV-16 signals to the entire chromosome length were approximately 0.63 +/- 0.05 in both SiHa and CaSki cells, indicating the possibility of a common integration domain on chromosome 13. In SiHa cells, no additional signals were observed on other chromosomes. This observation, taken together with literature reports that SiHa cells contain 1 to 2 copies of the HPV-16 genome in this region of chromosome 13, suggests that each fluorescein signal on chromosome 13 represents one equivalent of the HPV-16 genome. The total integrated fluorescence intensity in isolated CaSki metaphase chromosome spreads was approximately two orders of magnitude greater than that of a single copy of HPV-16 DNA in SiHa cells, indicating an increase in HPV-16 copy number.(ABSTRACT TRUNCATED AT 250 WORDS)


Dose effects of LPS on neutrophils in a whole blood flow cytometric assay of phagocytosis and oxidative burst. Whole blood phagocytosis (P) and oxidative burst (OB), a rapid and sensitive flow cytometric method for quantifying neutrophil activation, was modified for single laser systems by using propidium iodide labeled Staphylococcus aureus and 2',7' dichlorofluorescein diacetate. The purpose of the present study was to characterize this assay with respect to the stimulatory activity of bacterial lipopolysaccharide (LPS) on phagocytosis. Blood from healthy donors was preincubated with log doses of bacterial LPS B (0.1-1,000 ng/ml) or sterile pyrogen-free saline at 37 degrees C from 0-120 minutes. LPS increased both P and OB in a dose-dependent manner (up to 62 and 121%, respectively) at all time points tested, and this effect on P and OB could be detected even with no preincubation. This LPS-induced phagocytic activity could be blocked by the addition of polymyxin B (10 micrograms/ml) during preincubation. The priming effect of LPS was maximal at 45 min. P and OB were inhibited by preincubation with EDTA at doses greater than 2 mM (60 and 80% inhibition, respectively). These observations are consistent with the exquisite sensitivity of the neutrophil to endotoxin. This method can evaluate neutrophil response to immunomodulatory and chemotherapeutic agents in a physiological milieu. These findings re-emphasize the necessity of using pyrogen-free reagents in any study of neutrophil function.


Disorders of platelet function.

Disorders of platelet function. Platelets provide for primary hemostasis by forming a hemostatic plug at sites of vascular damage. They also provide a surface for the assembly of the coagulation protein complexes that generate thrombin, serve as a nidus for fibrin clots, and secrete factors involved in wound repair. Normal platelet function can be divided into four phases: adhesion, aggregation, secretion, and expression of procoagulant activity. Platelet adhesion initiates plug formation as platelets adhere to the connective tissue at the edges of a wound within seconds after vascular damage. When damage occurs in regions of slow blood flow, platelets adhere to subendothelial collagen, fibronectin, and laminin. However, when damage occurs in regions of rapid flow, platelet adhesion requires the presence of subendothelial von Willebrand factor (vWf) and a specific platelet receptor, the glycoprotein Ib/IX (GPIb/IX) complex. Following initial adhesion, platelets aggregate to complete the formation of a hemostatic plug. Platelet aggregation requires active platelet metabolism, platelet stimulation by agonists such as ADP, thrombin, collagen, or epinephrine; the presence of calcium or magnesium ions and specific plasma proteins such as fibrinogen or vWf; and a platelet receptor, the glycoprotein IIb/IIIa (GPIIb/IIIa) complex. Thus, platelet stimulation results in the generation of intracellular second messengers that transmit the stimulus back to the platelet surface, exposing protein binding sites on GPIIb/IIIa. Fibrinogen (or vWf) then binds to GPIIb/IIIa and crosslinks adjacent platelets to produce platelet aggregates. Platelet stimulation also results in platelet secretion and the elaboration of platelet procoagulant activity. During secretion, substances are released to propagate the aggregation response and to promote wound healing; the expression of procoagulant activity localizes thrombin generation to the site of vascular damage. Disorders of platelet function can be divided into those of congenital and those of acquired origin. Although congenital disorders are uncommon, acquired disorders are encountered frequently in clinical practice. Congenital absence of GPIb/IX and GPIIb/IIIa results in the Bernard-Soulier syndrome (BSS) and Glanzmann thrombasthenia (GT), respectively. Each is an autosomal recessive bleeding disorder in which absence of a protein complex renders the affected platelets incapable of undergoing either vWf-mediated adhesion (BSS) or fibrinogen-mediated aggregation (GT).(ABSTRACT TRUNCATED AT 400 WORDS)


The possible mechanism of action of ethanol on rat thymus. Alcohol is a known suppressant of the immune system and alcoholics frequently have impaired humoral and cell-mediated immunity. The purpose of this study was to investigate the effect of a single dose of ethanol on the thymus and the possible mechanism of its action. Adult female Wistar rats were divided into three groups which were treated with: (a) ethanol (4 g/kg i.p.), (b) naltrexone (5 mg/kg i.p.) and 45 min later with ethanol, (c) naltrexone alone. Untreated rats served as controls. The animals were killed 20 h after administration of alcohol. Thymuses were removed and fixed in Bouin's solution. Paraffin sections were stained with hematoxylin-eosin and analysed using stereological measurements. Our results showed that a single dose of ethanol significantly decreased the volume of the thymus especially affecting the cortex. This effect was blocked by pretreatment with naltrexone. Therefore, it seems that the effect of ethanol on the thymus is mediated by an opioid-dependent mechanism.


Cue-evoked arousal in cocaine users: a study of variance and predictive value. Thirty-six cocaine abusers in treatment and 16 non-using controls were exposed to visual cocaine cues; measurements included changes in skin conductance and a rating of psychological arousal (persisting cocaine thoughts and images during the 24 h following the experiment). The GSI score of the HSCL-58 was used as an indicator of psychological distress. Probands showed arousal responses significantly higher than the controls. Skin conductance readings correlated positively with HSCL-58 scores and with severity of craving in the week prior to the trial. Unexpectedly, they correlated negatively with duration of cocaine use and did not vary as a function of the severity of cocaine addiction or the duration of cocaine abstinence prior to the test. Neither cocaine addiction measurements nor arousal responses were found to predict cessation of use (a minimum of 3 months of sustained abstinence) 1 year after the test.


Relapse to opiate use provokes biphasic changes of blood pressure in heroin-withdrawn addicts treated with clonidine. The effect of relapse to opiate use on blood pressure and heart rate has been studied in heroin-withdrawn addicts treated with clonidine in an outpatient detoxification procedure. The daily dose of clonidine was established according to body weight and amount of heroin usually consumed at the onset of treatment. Patients who returned to heroin use were detected by increased urinary levels of opiates. Clonidine elicited significant reductions of blood pressure and heart rate reaching a plateau in the second day of treatment. Heroin consumption was found to provoke a further decrease of both systolic and diastolic pressure when the time interval between the relapse and the cardiovascular determinations was about 3 h as estimated by the patients. At longer intervals (16 h) this effect was reversed and both the hypotensive and the bradycardiac actions of clonidine seemed to be impaired. The possible impact of endogenous opioids and alpha-2 receptor sensitivity on these biphasic alterations is discussed.


Selenite is a substrate for calf thymus thioredoxin reductase and thioredoxin and elicits a large non-stoichiometric oxidation of NADPH in the presence of oxygen. The thioredoxin system, comprising NADPH, thioredoxin reductase and thioredoxin reduces protein disulfides via redox-active dithiols. We have discovered that sodium selenite is a substrate for the thioredoxin system; 10 microM selenite plus 0.05 microM calf thymus thioredoxin reductase at pH 7.5 caused a non-stoichiometric oxidation of NADPH (100 microM after 30 min). In contrast, thioredoxin reductase from Escherichia coli showed no direct reaction with selenite, but addition of 3 microM E. coli thioredoxin also resulted in non-stoichiometric oxidation of NADPH, consistent with oxidation of the two active-site thiol groups in thioredoxin to a disulfide. Kinetically, the reaction was complex with a lag phase at low selenite concentrations. Under anaerobic conditions the reaction stopped after 1 mol selenite had oxidized 3 mol NADPH; the admission of air then resulted in continued consumption of NADPH consistent with autooxidation of selenium intermediate(s). Ferricytochrome c was effectively reduced by calf thymus thioredoxin reductase and selenite in the presence of oxygen. Selenite caused a strong dose-dependent inhibition of the formation of thiol groups from insulin disulfides with either the E. coli or calf-thymus thioredoxin system. Thus, under aerobic conditions selenite catalyzed, NADPH-dependent redox cycling with oxygen, a large oxygen-dependent consumption of NADPH and oxidation of reduced thioredoxin inhibiting its disulfide-reductase activity.


Dependence of the adenovirus tripartite leader on the p220 subunit of eukaryotic initiation factor 4F during in vitro translation. Effect of p220 cleavage by foot-and-mouth-disease-virus L-protease on in vitro translation. The adenovirus tripartite leader (TPT) 5' untranslated region (5'UTR) allows translation in poliovirus-infected cells, in which the p220 subunit of eukaryotic initiation factor 4F is degraded. This p220-independent translation was investigated by measuring in vitro translation in a reticulocyte lysate of a reporter gene, chloramphenicol acetyltransferase, coupled to the TPT 5'UTR. The p220 subunit was degraded by translation of a foot-and-mouth-disease L-protease construct. Surprisingly, the TPT 5'UTR was dependent on intact p220, as are other naturally capped mRNA species. Translation of encephalomyocarditis virus RNA was p220 independent, as expected from its ability to support internal, cap-independent initiation. In vitro protein-synthesis experiments with purified initiation factors confirmed the dependence of TPT mRNA translation on eukaryotic initiation factor 4F. The relationship between adenovirus TPT-5'UTR-directed translation and poliovirus-induced host cell shut-off is discussed.


Escherichia coli Rep protein and helicase IV. Distributive single-stranded DNA-dependent ATPases that catalyze a limited unwinding reaction in vitro. Rep protein and helicase IV, two DNA-dependent adenosine 5'-triphosphatases with helicase activity, have been purified from Escherichia coli and characterized. Both enzymes exhibit a distributive interaction with single-stranded DNA as DNA-dependent ATPases in a reaction that is relatively resistant to increasing NaCl concentration and sensitive to the addition of E. coli single-stranded DNA binding protein (SSB). The helicase reaction catalyzed by each protein has been characterized using a direct unwinding assay and partial duplex DNA substrates. Both Rep protein and helicase IV catalyzed the unwinding of a duplex region 71 bp in length. However, unwinding of a 119-bp or 343-bp duplex region was substantially reduced compared to unwinding of the 71-bp substrate. At each concentration of protein examined, the number of base pairs unwound was greatest using the 71-bp substrate, intermediate with the 119-bp substrate and lowest using the 343-bp substrate. The addition of E. coli SSB did not increase the fraction of the 343-nucleotide fragment unwound by Rep protein. However, the addition of SSB did stimulate the unwinding reaction catalyzed by helicase IV approximately twofold. In addition, ionic strength conditions which stabilize duplex DNA (i.e. addition of MgCl2 or NaCl), markedly inhibited the helicase reaction catalyzed by either Rep protein or helicase IV while having little effect on the ATPase reaction. Thus, these two enzymes appear to share a common biochemical mechanism for unwinding duplex DNA which can be described as limited unwinding of duplex DNA. Taken together these data suggest that, in vitro, and in the absence of additional proteins, neither Rep protein nor helicase IV catalyzes a processive unwinding reaction.


The pH in reversed micelles as imposed by the dihydrogen/proton redox couple and indicated by viologens and cytochrome c3 using hydrogenase as redox catalyst. The pH values in reversed micelles were measured, making use of the hydrogenase enzyme as redox catalyst short-circuiting the viologen oxidized/semiquinone redox states. The hydrogenases from Desulfovibrio vulgaris (Hildenborough) and from Megasphaera elsdenii were applied. The observed pH values in reversed micelles were not dependent on the type of hydrogenase. Two cationic [cetyltrimethylammonium bromide and dodecylammonium propionate (DAP)] and two anionic sodiumdodecyl sulphate, sodium di(ethylhexyl)sulfosuccinate types of reversed micelles were used in combination with viologens having distinguishable valencies. It was observed that, in the cationic-reversed micelles, the dissociation constant for the semiquinone dimer had about the same value as compared to bulk water, while this value was significantly higher in the anionic-reversed micelles. Furthermore, the dissociation constant was independent of the concentration of viologen semiquinone in the reversed micelle, indicating that exchange kinetics are faster than the dimerisation process. With the exception of DAP, a linear relation exists, pH = a.pHrm + b, between the pH of the bulk water and the pH as measured in the reversed micelle (pHrm). In all these cases the value of a is smaller than unity, the value of b ranges between 1.6-2.7. For DAP the pHrm is always around 7. In DAP-reversed micelles, the counter-ion propionate probably serves as an internal buffer. Using cytochrome c3 as pH indicator in combination with N,N'-di(3-aminopropyl)-4,4'-bipyridinium)4+ to take care of electron transfer, in cetyltrimethylammonium-bromide-reversed micelles the pHrm is about the same as indicated by the viologen; in SDS-reversed micelles the pHrm is always lower than that indicated by N,N'-di(3-aminopropyl)4,4'-pyridinium4+. In contrast to cytochrome c3 from D. vulgaris, which in reversed micelles cannot become reduced directly by its D. vulgaris hydrogenase, the hydrogenase of M. elsdenii is able to reduce its ferredoxin directly.


Insulin stimulates phosphatidylinositol-3-kinase activity in rat adipocytes. Phosphatidylinositol (PtdIns) 3-kinase is thought to participate in the signal transduction pathways initiated by the activation of receptor tyrosine kinases including the insulin receptor. To approach the physiological relevance of this enzyme in insulin signaling, we studied the activation of PtdIns-3-kinase in adipocytes, a major insulin target tissue for glucose transport and utilisation. To analyze possible interactions of the enzyme with cellular proteins, immunoprecipitations with the following antibodies were performed: (a) anti-phosphotyrosine antibodies, (b) two antibodies to the 85-kDa subunit of PtdIns-3-kinase (p85) and (c) an antibody to the 185-kDa major insulin receptor substrate (p185). We show that in cell extracts from adipocytes exposed to insulin, and after immunoprecipitation with an anti-phosphotyrosine antibody and an antibody to p85, we are able to detect a PtdIns-3-kinase activity stimulated by the hormone. Similarly, after immunoprecipitation with an antibody to p185, an increase in the PtdIns-3-kinase activity could be demonstrated. Taken together these results suggest that, upon insulin stimulation of fat cells, PtdIns-3-kinase itself is tyrosine phosphorylated and/or associated with an insulin receptor substrate, such as p185, which could function as a link between the insulin receptor and PtdIns-3-kinase. The PtdIns-3-kinase was activated within 1 min of exposure to insulin, and the half-maximal effect was reached at the same concentration, i.e. 3 nM, as for stimulation of the insulin receptor kinase. Subcellular fractionation showed that PtdIns-3-kinase activity was found both in the membranes and in the cytosol. Further, immunoprecipitation with an antibody to p85, which possesses the capacity to activate PtdIns-3-kinase, suggests that the presence of the enzyme in the membrane may be due to an insulin-induced recruitment of the PtdIns-3-kinase from the cytosol to the membrane. Finally, we used isoproterenol, which exerts antagonistic effects on insulin action. This drug was found to inhibit both the PtdIns-3-kinase and the insulin receptor activation by insulin, suggesting that the activation of the PtdIns-3-kinase was closely regulated by the insulin receptor tyrosine kinase. The occurrence of an insulin-stimulated PtdIns-3-kinase in adipocytes leads us to propose that this enzyme might be implicated in the generation of metabolic responses induced by insulin.


Cyclic nucleotides and intracellular-calcium homeostasis in human platelets. The relationship between agonist-sensitive calcium compartments and those discharged by the Ca(2+)-ATPase inhibitor thapsigargin were studied in human platelets. In this context, calcium mobilization from intracellular pools and manganese influx was investigated in relation to the effect of altered cyclic-nucleotide levels. For maximal calcium release from intracellular stores, thapsigargin, compared to a receptor agonist like thrombin, requires the platelet's self-amplification mechanism, known to generate thromboxane A2. With this lipid mediator formed, thapsigargin released calcium and stimulated manganese influx in a manner similar to thrombin. Blocking the thromboxane receptor by addition of sulotroban (BM13.177) or, alternatively, increasing platelet cAMP or cGMP using prostacyclin or sodium nitroprusside, dramatically reduced the ability of thapsigargin to release calcium from intracellular compartments. The same experimental conditions significantly reduced the rate of manganese influx initiated by thapsigargin compared to thrombin. The experiments indicate that thapsigargin-sensitive compartments play only a minor role in inducing manganese influx compared to the receptor-sensitive compartment. Cyclic nucleotides accelerate the redistribution of an agonist-elevated platelet calcium into the thapsigargin-sensitive compartment, from which calcium can be released by inhibition of the Ca(2+)-ATPase. In human platelets, thapsigargin-induced calcium increase and influx were responsible for only part the calcium release resulting from inhibition of the corresponding ATPase; another part results from the indirect effect of thapsigargin acting via thromboxane-A2-receptor activation. Cyclic nucleotides are therefore an interesting regulatory device which can modify the thapsigargin response by not allowing the self-amplification mechanism of platelets to operate.


Reaction of myeloperoxidase with its product HOCl. The reaction of human myeloperoxidase with its product, hypochlorous acid was investigated using both rapid-scan spectrophotometry and the stopped-flow technique. In the reaction of myeloperoxidase with hypochlorous acid a primary compound is found with properties similar to that of compound I and which is converted into compound II. The primary reaction is strongly pH-dependent. At pH 7.2 the reaction is too fast to be measured but at higher pH values it is possible to determine the apparent second-order rate constant. Its value decreases to about 2 x 10(7) M-1.s-1 at pH 8.3 and to 2.3 (+/- 0.4) x 10(6) M-1.s-1 at pH 9.2, respectively. The dissociation constant for the formation of the primary compound is 25.7 (+/- 15.3) microM at pH 9.2 and about 2.5 microM at pH 8.3. The apparent second-order rate constant for the formation of compound II is hardly affected by pH and varies between 2 to 5 x 10(4) M-1.s-1 at pH 10.2 and pH 8.3, respectively. Reaction of myeloperoxidase with hypochlorous acid also resulted in irreversible partial bleaching of the chromophore. Chloride, which is a substrate of the enzyme not only protects myeloperoxidase against bleaching by hypochlorous acid but also competitively inhibits the binding of hypochlorous acid to myeloperoxidase, a process which also has been observed in the reaction with hydrogen peroxide. It is concluded that hypochlorous acid binds at the heme iron to form compound I.


Characterization and purification of a membrane-bound archaebacterial pyrophosphatase from Sulfolobus acidocaldarius. Plasma membranes of the thermoacidophilic archaebacterium Sulfolobus acidocaldarius (DSM 639) display a pyrophosphate-hydrolyzing activity [M. Lübben & G. Schäfer (1987) Eur. J. Biochem. 164, 533-540]. In our present work, we solubilized and purified this pyrophosphatase to homogeneity. It consists of a single subunit with a molecular mass of 17-18 kDa, forming an oligomer of 70 kDa under native conditions. Edman degradation revealed 30 amino acids of the N-terminus. The enzyme cleaves phosphoric-acid-anhydride bonds independently of monovalent or divalent cations. Temperature and pH optima of 75 degrees C and 3.5-3.7, respectively, characterize it as an ectoenzyme. Membrane lipids of Sulfolobus stimulate the activity. The dolichol-pyrophosphate-complexing peptide-antibiotic bacitracin inhibited growth of Sulfolobus. A possible function of the acid pyrophosphatase is the hydrolysis of dolichol pyrophosphate in connection with glycosylation reactions of membrane proteins.


Evidence for polynuclear aggregates of ferric daunomycin. A Mössbauer, EPR, X-ray absorption spectroscopy and magnetic susceptibility study. The interaction of the antitumor agent daunomycin (DN) with ferric iron has been analysed by Mössbauer spectroscopy, EPR, extended X-ray absorption fine structure (EXAFS), and magnetic susceptibility measurements. In contrast to literature data, at millimolar iron and anthracycline concentrations no solitary Fe(DN)3 complexes are formed in appreciable amounts. The Mössbauer spectroscopic analysis revealed severe dependencies on temperature, on the preparation procedure, the time allowed for equilibration, and on the metal/ligand ratio. The Mössbauer spectra exhibit two components: a broad magnetic sextet and a quadrupole doublet at an Fe/DN molar ratio of 1:3 and exclusively a doublet at a molar ratio of 1:20, indicating an equilibrium of these two spectral components. The EPR spectra are dominated by a signal at g(eff) = 2. Double integration of the EPR signals enabled the determination of their spin density and a correlation between EPR and Mössbauer spectra. The Mössbauer sextet species is EPR invisible and corresponds to magnetically ordered polynuclear aggregates with high magnetic anisotropy. EXAFS and susceptibility measurements provide additional evidence for the formation of polynuclear aggregates of ferric daunomycin. The quadrupole doublet species in the Mössbauer spectra correlates with the g = 2 signal in EPR. This species is also related to a magnetically ordered system, exhibiting, however, superparamagnetic behavior due to less magnetic anisotropy. Since daunomycin forms dimers in aqueous solution at millimolar concentrations, we conclude that the cooperative phenomena observed in EPR and Mössbauer spectra are a consequence of its stacking effects.


Importance of beta-adrenoceptor function in fat cells for lipid mobilization. The role of peripheral catecholamine sensitivity in lipid mobilization was investigated in 78 healthy non-obese subjects by comparing beta-adrenergic regulation of lipolysis in isolated adipocytes with circulating catecholamines and glycerol (lipolysis index). Small intra-individual variations (5-7%) in adipocyte lipolytic beta-adrenoceptor sensitivity (ED50) for isoprenaline were found. However, large inter-individual variations (almost 10(5)-fold) in isoprenaline ED50 were observed in abdominal or gluteal adipocytes, which correlated (r = 0.52) negatively with the resting plasma noradrenaline levels. A correlation was also observed between circulating noradrenaline and adipocyte ED50 for noradrenaline (r = -0.38). In subjects with high (ED50 less than 10(-11) mol l-1) as compared to low isoprenaline sensitivity (ED50 greater than 10(-10) mol l-1) physical exercise induced a two times greater increase in plasma glycerol (P less than 0.01), in spite of a 50% less marked increase of plasma noradrenaline (P less than 0.01). Findings with beta-adrenoceptor mRNA and with total beta-adrenoceptor number or affinity for agonist did not show any strong correlation with the resting plasma noradrenaline level (r less than 0.25). In conclusion, inter-individual variations in beta-adrenoceptor sensitivity and its relation to circulating noradrenaline can be ascribed to specific modulations of either BAR-subtypes or in the postreceptor activation of lipolysis. These variations in adipocyte beta-adrenoceptor sensitivity may participate in the regulation of peripheral nervous activity and play a putative role in lipolysis during exercise when subjects with high beta-adrenoceptor sensitivity increased their ability to mobilize lipids despite a reduced noradrenaline response.


The pleiotypic response to amino acid deprivation is the result of interactions between components of the glycolysis and protein synthesis pathways. Several diverse metabolic events become compromised when mammalian cells are made deficient in essential amino acids or when charging of their tRNA is blocked by amino acid analogs. This rapid general demise of cell function can be due to inhibition of phosphofructokinase (PFK) by uncharged tRNA. It has now been demonstrated that when tRNA is added to PFK in an assay dependent upon the reassociation of inactive, dissociated enzyme subunits, nanomolar concentrations cause complete inhibition. The model for control suggests that charged tRNA becomes associated with EF-1, which is specific for aminoacyl-tRNAs and is present in sufficiently high concentrations in cells to sequester that charged forms from an inhibitory role. Support for this model include: (1) the rapid onset of inhibition of glycolysis and glucose uptake upon amino acid deficiency; (2) the unique role of the product of PFK activity, fructose-1,6-diphosphate, in reactions of peptide chain initiation, particularly its role as a co-factor for purified eIF-2B, the GDP/GTP exchange factor; (3) the correlations of this interaction with the cellular and molecular lesions of insulin insufficiency; (4) the recognition that the anomalous role of high concentrations of cAMP as a stimulant of peptide chain initiation in energy depleted or gel-filtered cell lysates correlates with its stimulatory action on PFK as an analog for the positive effector, adenosine-5'-monophosphate; and (5) the role of fructose-1,6-diphosphate in the formation of glyceraldehyde-3-phosphate, a substrate for synthesis of ribose-5-phosphate via the non-oxidative portion of the pentose phosphate pathway, which, as a precursor of phosphoribosylpyrophosphate, is essential for nucleic acid synthesis.


Ordered phosphorylation of a duplicated minimal recognition motif for cAMP-dependent protein kinase present in cardiac troponin I. Cardiac troponin I contains two adjacent serines in sequence after three arginine residues thus making up a minimally duplicated recognition motif for cAMP-dependent protein kinase. In a synthetic peptide, PVRRRSSANY, the two serine residues are phosphorylated sequentially with the intermediate formation of a monophosphorylated species according to the following reaction sequence: Peptide k1----Peptide-P k2----Peptide-P2. The calculated rat constants are: k1 = 0.435.min-1 and k2 = 0.034.min-1. Sequence analyses of the monophosphopeptide and its tryptic fragments show that the predominant monophosphoform carries phosphate at the second serine.


Effects of solubilization and vanadate/glutathione complex on inhibitor potencies against eosinophil cyclic AMP-specific phosphodiesterase. Treatment of membranes from guinea-pig peritoneal eosinophils with deoxycholate and NaCl solubilized greater than 95% of the particulate cyclic AMP-specific phosphodiesterase (PDE IV). Solubilized PDE IV was at least 10 times more potently inhibited by selective PDE IV inhibitors (e.g. rolipram, denbufylline) than bound enzyme. Vanadate/glutathione complex (V/GSH) activated membrane-bound PDE IV and also increased potencies of these same inhibitors by at least 10-fold. Neither solubilization nor V/GSH markedly influenced the inhibitory activities of non-selective inhibitors (e.g. trequinsin, dipyridamole). Inhibitor effects on solubilized PDE IV and cyclic AMP accumulation in intact cells were strongly correlated. These results suggest a biologically important site on eosinophil PDE IV which is concealed or partially concealed in freshly prepared membranes and is exposed by solubilization or V/GSH.


Site-directed mutants of human myeloperoxidase. A topological approach to the heme-binding site. Two site-directed mutants of human promyeloperoxidase, MPO(His416----Ala) and MPO(His502----Ala), have been expressed in Chinese hamster ovary cells and purified. Overall purification yields and apparent molecular masses of the mutant proteins were similar to those of the wild-type enzyme. Both mutant species were analyzed spectroscopically to check the presence of the hemic iron in the proteins and were assayed for peroxidase activity. The data show that substitution of His502 leads to the loss, or to an inappropriate configuration, of the heme together with the loss of activity, suggesting that this residue could be the proximal His involved in the binding to the iron centers. On the other hand, substitution of His416 by alanine had no effect on either of the studied parameters.


The proteasome/multicatalytic-multifunctional proteinase. In vivo function in the ubiquitin-dependent N-end rule pathway of protein degradation in eukaryotes. Proteinase yscE, the proteasome/multicatalytic-multifunctional proteinase of yeast had been shown to function in stress response and in the degradation of ubiquitinated proteins [(1991) EMBO J. 10, 555-562]. A well-defined set of proteins degraded via ubiquitin-mediated proteolysis are the substrates of the N-end rule pathway [(1986) Science 234, 179-186; (1989) Science 243, 1576-1583]. We show that mutants defective in the chymotryptic activity of proteinase yscE fail to degrade substrates of the N-end rule pathway. This gives further proof of the proteasome being a central catalyst in ubiquitin-mediated proteolysis.


Expression of myogenic factors in skeletal muscle and electric organ of Torpedo californica. Fish electric organ is a skeletal muscle homolog in which many muscle-specific genes are inhibited while acetylcholine receptor is expressed at high levels. The molecular mechanisms underlying this discoordinate regulation have not yet been explored. We have obtained partial sequences for MyoD, myogenin, and myf5 from Torpedo californica and have measured their mRNAs in several organs, using ribonuclease protection. We have found that MyoD and myf5 are expressed at comparable levels in muscle and electric organ, whereas myogenin transcripts could not be detected in either tissue. Acetylcholine receptor alpha subunit mRNA, on the other hand, is two orders of magnitude more abundant in electric tissue. We conclude that neither the loss of contractile proteins from, nor the enhanced expression of acetylcholine receptor genes in, the differentiating electrocyte is a simple consequence of the abundance of myogenic factor messages.


A novel non-peptide endothelin antagonist isolated from bayberry, Myrica cerifera. A potent non-peptide ET receptor antagonist, myriceron caffeoyl ester (50-235), was isolated from the bayberry, Myrica cerifera. This compound selectively antagonized specific binding of [125I]ET-1, but not of [125I]ET-3, to rat cardiac membranes, ET-1-induced increase in the intracellular free calcium concentration in Swiss 3T3 fibroblasts, and ET-1-induced contraction of rat aortic strips. Thus, 50-235 is the first non-peptide ET(A) receptor antagonist. This compound can be useful for studying the physiological role of endothelin and exploring its role in various diseases.


Modulation of cardiac Ca2+ channels in Xenopus oocytes by protein kinase C. L-Type calcium channel was expressed in Xenopus laevis oocytes injected with RNAs coding for different cardiac Ca2+ channel subunits, or with total heart RNA. The effects of activation of protein kinase C (PKC) by the phorbol ester PMA (4 beta-phorbol 12-myristate 13-acetate) were studied. Currents through channels composed of the main (alpha 1) subunit alone were initially increased and then decreased by PMA. A similar biphasic modulation was observed when the alpha 1 subunit was expressed in combination with alpha 2/delta, beta and/or gamma subunits, and when the channels were expressed following injection of total rat heart RNA. No effects on the voltage dependence of activation were observed. The effects of PMA were blocked by staurosporine, a protein kinase inhibitor. beta subunit moderate the enhancement caused by PMA. We conclude that both enhancement and inhibition of cardiac L-type Ca2+ currents by PKC are mediated via an effect on the alpha 1 subunit, while the beta subunit may play a mild modulatory role.


Codon context effect in virus translational readthrough. A study in vitro of the determinants of TMV and Mo-MuLV amber suppression. To assess the role of codon context on the efficiency of eukaryotic suppression of termination codons, we have compared, in a rabbit cell-free translation system, the readthrough efficiency related to two synthetic transcripts differing by the codon context around an amber codon. The codon contexts are derived from tobacco mosaic virus (TMV) and Moloney murine leukemia virus (Mo-MuLV) RNAs. The Mo-MuLV-like codon context does not promote suppression. Substituting TMV-derived triplets in the Mo-MuLV-like codon context shows that the two codons downstream from the TMV UAG signal are important determinants of suppression, as recently demonstrated in vivo.


Y2 receptor proteins for peptide YY and neuropeptide Y. Characterization as N-linked complex glycoproteins. Affinity labeling using [125I-Tyr36]PYY and homobifunctional affinity crosslinking reagents of the rabbit Y2 receptor for peptide YY(PYY) results in specifically labeled proteins of both M(r) = 50,000 to 60,000 and M(r) = 96,000 to 115,000 [1,2]. In this work the glycoprotein nature of affinity labeled Y2 receptor proteins were investigated by enzymatic deglycosylation using neuraminidase, endoglycosidase F (endo F), N-glycosidase F (PNGase F), and O-glycanase treatment. Only N-glycosidase F and neuraminidase increased the electrophoretic mobility of the radiolabeled receptor bands, whereas all other glycosidases did not. PNGase F treatment of both radiolabeled receptor bands electroeluted from gel slices reduced the apparent molecular mass of by 16-17 kDa units, that is M(r) = 96,000 to 79,000 and M(r) = 60,000 to 44,000, indicating removal of N-linked oligosaccharide chains of similar size from both species. Neuraminidase treatment caused slight increases in the electrophoretic mobilities suggesting the presence of terminal sialic residues. It is concluded that the Y2 binding proteins are N-linked complex (sialo)glycoproteins with a minimal core protein size of M(r) = 44,000. Furthermore, based on this sensitivity pattern of the glycosidases, the Asn-linked carbohydrate may be of the tri- or tetra-antennary complex type containing terminal sialic acid residues.


Cellobiose oxidase from Phanerochaete chrysosporium. Stopped-flow spectrophotometric analysis of pH-dependent reduction. Cellobiose oxidase (CBO) from Phanerochaete chrysosporium can utilize dichlorphenol-indophenol (Cl2Ind) and cytochrome c as effective electron acceptors for the oxidation of cellobiose. However, the pH dependencies of activity for these electron acceptors are significantly different. Both compounds act as effective electron acceptors at pH 4.2, whereas only dichlorophenol-indophenol is active at pH 5.9. To explain this discrepancy, the pH dependencies of the reduction rates of FAD and heme, respectively, in CBO by cellobiose have been investigated by stopped-flow spectrophotometry. Both FAD and heme are reduced with a high rate constant at pH 4.2. In contrast, at pH 5.9, only FAD reduction is fast, while the reduction of the heme is extremely slow. As a conclusion, the reduction of cytochrome c by CBO is dependent on heme, which functions at a lower pH range compared to reduction of FAD.


The receptor for the plasminogen activator of urokinase type is up-regulated in transformed rat thyroid cells. Five rat thyroid cell lines were tested for the expression of the cell surface receptor for urokinase type plasminogen activator (uPA). All tested lines were found to bind uPA, but transformed 1-5G and Ki-Mol cells, which are also high uPA producers, bound at least ten times more uPA, as compared to non-producers, 'normal' TL5 cells. Moreover, it was possible to remove membrane-bound uPA by treating the cells with phosphatidylinositol-specific phospholipase C, suggesting that rat uPAR, like its human counterpart, is linked to the membrane by a glucosyl-phosphatidylinositol anchor. The specificity of the binding was tested by competition with three different synthetic peptides corresponding to amino acids 14-37 of human, rat and mouse uPA. The results indicate also that the receptor binding region of rat uPA is located within the growth factor domain of the molecule and that its expression may be dependent on the transformed state of the cells.


Involvement of a d-type oxidase in the Na(+)-motive respiratory chain of Escherichia coli growing under low delta mu H+ conditions. An attempt has been made to find out which of the two terminal oxidases, the d-type or the o-type, operates as a Na+ pump in Escherichia coli grown at low delta mu H+ conditions. For this purpose, mutants lacking either d or o oxidase have been studied. It is shown that a d-,o+ mutant grows slowly or does not grow at all under low delta mu H+ conditions (alkaline or protonophore-containing growth media were used). Inside-out subcellular vesicles from the d-,o+ mutant cannot oxidize ascorbate and TMPD, and cannot transport Na+ when succinate is oxidized in the presence of a protonophore. The same vesicles are found to transport Na+ when NADH is oxidized as if the Na(+)-motive NADH-quinone oxidase were operative. On the other hand, a mutant lacking o oxidase (d+,o-) grows at low delta mu H+ conditions as fast as the maternal E. coli strain containing both d and o oxidases. Corresponding vesicles oxidize ascorbate and TMPD as well as succinate, the oxidations being coupled to the protonophore-stimulated Na+ transport. Growth in the presence of a protonophore is found to induce a strong increase in the d oxidase level in the maternal d+,o+ E.coli strain. It is concluded that oxidase of the d-type, rather than of the o-type, operates as a Na+ pump in E. coli grown under conditions unfavorable for the H+ cycle.


The hepatic interleukin-6 receptor. Down-regulation of the interleukin-6 binding subunit (gp80) by its ligand. Interleukin-6 (IL6) exerts its action via a cell surface receptor composed of an 80 kDa IL6-binding protein (gp80) and a 130 kDa polypeptide involved in signal transduction (gp130). We studied the role of gp80 in binding, internalization and down-regulation of the hepatic IL6-receptor (IL6R) by its ligand in human hepatoma cells (HepG2). Comparison of transfected HepG2 cells overexpressing gp80 with parental cells indicate that gp80 is responsible for low affinity binding (Kd = 500 pM) of IL6. Furthermore, gp80 is rate-limiting in internalization and degradation of IL6. Internalization resulted in a rapid down-regulation (t1/2 approximately 15-30 min) of IL6-binding sites at the cell surface. More than 80% of the internalized [125I]rhIL6 was degraded. The reappearance of IL6-binding sites at the cell surface required greater than 8 h and was sensitive to cycloheximide, suggesting that gp80 is not recycled after internalization. The down-regulation of the hepatic IL6R by its ligand might play an important role as a protection against overstimulation.


NMR study of self-paired parallel duplex of d(AAAAACCCCC) in solution. The oligonucleotide d(A5C5) in solution forms a parallel self-duplex at neutral and low pH values. H2O NMR spectra at pH 5.1 indicate the presence of five imino resonances at lower temperatures; and the structure is stable up to 60 degrees C. These signals can arise only from the hemiprotonated C+.C pairs [Westhof, E. and Sundaralingham, M. (1980) Biochemistry 77, 1852-1856; Westhof, E. and Sundaralingham, M. (1980) J. Mol. Biol. 142, 331-361] and constitute the first direct observation of C+.C hemiprotonated pairs in solution. The cross peaks from H1's and more than five distinct AH8's in 500 MHz 1H 2D-NOESY spectra indicate that there are two conformationally different and energetically similar A-tracts. There is good qualitative agreement between NOESY data and two theoretically derived structures in which A-tracts are reverse Watson-Crick and reverse Hoogsteen base-paired, respectively.


Soluble human interleukin-6-receptor modulates interleukin-6-dependent N-glycosylation of alpha 1-protease inhibitor secreted by HepG2 cells. Interleukin-6 (IL-6) induces changes in gene expression and the N-glycosylation pattern of acute-phase proteins in hepatocytes. IL-6 exerts its action via a cell surface receptor complex consisting of an 80 kDa IL-6 binding protein (gp80) and a 130 kDa glycoprotein (gp130) involved in signal transduction. A genetically engineered gp80-derived soluble human IL-6-receptor (shIL-6-R) significantly enhanced the IL-6 effect on N-glycosylation changes (revealed by reactivity with the lectin-concanavalin A) of a1-protease inhibitor (PI) secreted by human hepatoma cells (HepG2). Stable transfection of IL-6-cDNA into HepG2 cells (HepG2-IL-6) resulting in constitutive secretion of 2 micrograms of IL-6 per 10(6) cells in 24 h led to a down-regulation of surface-bound gp80 and subsequent homologous desensitization of HepG2-IL-6 cells towards IL-6. Soluble human IL-6-R functionally substituted membrane-bound gp80 resulting in a reconstitution of responsiveness of HepG2-IL-6 cells.


Differential androgen response to adrenocorticotropic hormone stimulation in polycystic ovarian syndrome: relationship with insulin secretion. To investigate the relationship between insulin and adrenal androgens in patients with polycystic ovarian disease (PCOD). Patients with PCOD and a group of volunteers who attended the department during a period of 6 months were studied. Department of Gynaecology and Obstetrics, Università Cattolica del Sacro Cuore, Roma, Italy. Healthy women with ovulatory cycles (hospital personnel, n = 8) and women affected by PCOD (n = 32) were studied on day 5 to 6 of their follicular phase. All women had an oral glucose tolerance test (OGTT) (75 g) on day 5 to 6 of the cycle. Then plasma samples were collected at 7.00 A.M.; at 11.00 P.M., 2 mg of dexamethasone (DEX) were orally administered with blood samples collected the day after at 7.00 A.M. (effect of DEX). Then adenocorticotropic hormone (ACTH, Synacten; Ciba-Geigy, Varese, Italy) 250 micrograms was injected intravenously (IV) and samples collected 60 minutes later (effect of ACTH). Plasma glucose and insulin concentration were assayed on OGTT samples collected at time 0, 30, 60, 90, 120, 180, and 240 minutes after glucose ingestion. Data are expressed as area under the curve. Cortisol, 17 alpha-hydroxyprogesterone (17-OHP), testosterone (T), androstenedione (A), and dehydroepiandrosterone sulphate (DHEAS) plasma levels were evaluated on the samples collected before and after DEX or ACTH administration. Data are expressed as absolute concentrations and percent increase in respect to values before the treatment. According to the OGTT response, 21 patients were classified as hyperinsulinemic and 11 as normoinsulinemic. The ideal body weight was greater in hyperinsulinemic patients. No differences in baseline hormone levels were found between the two groups. Only sex hormone binding globulin levels were significantly greater in normoinsulinemic patients (P less than 0.05). Also, the plasma concentration of all steroids after DEX were similar in both groups. Intravenous injection of ACTH significantly increased plasma androgens levels. Cortisol, DHEAS, and T enhancement did not differ in normoinsulinemic and hyperinsulinemic patients, whereas significantly greater A (P less than 0.01) and 17-OHP (P less than 0.05) plasma concentrations were observed after ACTH injection in hyperinsulinemic when compared with normoinsulinemic PCOD subjects. Control group after IV ACTH showed an increase of A and 17-OHP similar to those found in normoinsulinemic PCOD group. These data suggest that insulin could be involved in the androgen production by adrenal gland and it could influence the responsiveness of adrenal to its trophic hormones.


[The effects of indigestible dextrin on sugar tolerance: I. Studies on digestion-absorption and sugar tolerance]. It is widely acknowledged that high viscosity water-soluble dietary fibers such as pectin and guar gum affect a lowering of blood glucose levels and a reducing of insulin secretion following a sugar load. However, as dietary fibers vary in origin and in chemical properties, their physiological functions differ as well. In this study the effects of Indigestible Dextrin (PF-C), a low viscosity, water-soluble dietary fiber obtained through acid and heat-treatment of potato starch, on various aspects of sugar tolerance were examined. First, the influence of PF-C on sucrose hydrolysis was examined in rat intestinal mucosa cell homogenate confirming that PF-C did not inhibit sucrase activity. Then, in order to investigate the influence of PF-C on sugar digestion-absorption, an experiment was performed by using the everted intestinal sac of the rat in vitro. PF-C did not have an effect on glucose-transport into the serosal medium, whereas PF-C did inhibit the transport of hydrolyzed-glucose from sucrose, with no change in the hydrolysis of sucrose. Recently, Crane et al. reported that there is a specific route for hydrolyzed glucose from sucrose in glucose-absorption on the enteric surface (disaccharidase related transport system). The possibility exists that PF-C specifically affects this pathway. Further, total glucagon released into the serosal medium stimulated by both glucose and sucrose were reduced by PF-C. On the basis of these results, an oral sugar tolerance test was conducted in both rats and healthy human subjects. In male Sprague-Dawley rats (8 weeks old, 250-280g) concurrent administration of PF-C (0.6g/kg body weight) reduced an increase in plasma insulin levels with no change in glucose levels following a glucose (1.5g/kg body weight) load. Further noted were reductions in increases in both plasma glucose and insulin levels following a sucrose (1.5g/kg body weight) plus PF-C (0.6g/kg body weight) load to that of the sucrose (1.5g/kg body weight) single load. These findings reflect the above mentioned in vitro results. Moreover, in healthy male subjects the increase in both plasma insulin and glucagon-like immunoreactivity (Gut GLI) levels following a Trelan-G75 load were significantly reduced by concurrent administration of PF-C. From these observations it would appear that the effectiveness of reducing insulin secretion by PF-C results due to the decrease in sugar absorption by inhibiting the disaccharidase-related transport system.(ABSTRACT TRUNCATED AT 400 WORDS)


Biochemical correlates of alpha 1-adrenoceptor activation. An impressive body of evidence based on radioligand binding, biochemical, functional and structural data supports the existence of two sub-types of the alpha 1-adrenoceptor (alpha 1a and alpha 1b) in the CNS and in peripheral tissues. Both elevate intracellular Ca2+ concentrations, although by different mechanisms, resulting in a cascade of intracellular events dependent upon the cell type involved.


Multiple histamine receptors: properties and functional characteristics. Recent advances in molecular biological techniques have seen the cloning of the H2-receptor gene from canine parietal cells, and the structural identification and cloning of the H1- and H3-receptors should soon follow. This information will allow the elucidation of the mechanisms responsible for the species and tissue heterogeneity in the H1-receptor binding and functional characteristics. The mechanisms underlying the inhibitory effect of H3-receptor stimulation on neurotransmitter release remains to be established, but this receptor appears to be coupled to its effector system (perhaps an ion channel?) via a G-protein. Patch-clamp studies on histamine receptors in invertebrate neurones have identified a ligand-gated chloride channel at a photoreceptor synapse of the housefly and it remains an intriguing possibility that there is a counterpart in mammalian species.


Gibberellin perception and the Avena fatua aleurone: do our molecular keys fit the correct locks? The plant hormones GA, ABA, and auxin differ from the majority of animal hormones in that they are hydrophobic weak acids. They are soluble in the inter- and intra-cellular environments of plant tissues and their neutral species can cross the plasma membrane by passive diffusion. Auxin transport is mediated by specific uptake and efflux carriers in plasma membranes, and there is some evidence for carrier-mediated uptake of GA and ABA. Because these plant hormones can cross the plasma membrane it is not a prerequisite that receptors for them should be at the protoplast surface. Nevertheless, there is substantial evidence that auxin acts at the plasma membrane, and evidence suggesting that GA may be perceived at the plasma membrane of A. fatua aleurone protoplasts has been reviewed here. It is conceivable that the plant plasma membrane might provide the means to integrate, transduce, and amplify these signals, and that such properties of the plasma membrane, rather than the permeability characteristics of these ligands, may determine the site of perception. Further progress in our understanding of signal transduction pathways that may be involved in the actions of plant hormones is likely to shed light on these questions. It has been proposed that GA receptors involved in cell elongation may be soluble rather than membrane bound. The soluble 50 kDa GA-binding protein observed in aleurone by GA4 photoaffinity labelling may be a good candidate for a soluble GA receptor.(ABSTRACT TRUNCATED AT 250 WORDS)


The cAMP-dependent signalling cascade in the two luteal cell types of the pregnant rat corpus luteum. Corpora lutea of rats, like those of many other species, contain two sub-populations of luteal cells. In this report we sought to determine whether the luteinizing hormone (LH)- and beta-adrenergic cAMP signal transduction pathways known to be present in rat corpora lutea were segregated into separate luteal cell types. Results showed that large rat luteal cells, obtained on day 3 of pregnancy, exhibited elevated LH- and most notably epinephrine-stimulated adenylyl cyclase activities but equivalent cAMP-dependent catalytic protein kinase and total regulatory subunit cAMP binding activities compared to small luteal cells. Progesterone production by the large cell was greater than that by the small cell but both cells were equally sensitive to stimulation of progesterone by LH. However, neither the large nor the small rat luteal cell produced significant progesterone in response to epinephrine despite a marked epinephrine-stimulated adenylyl cyclase in both cell populations. The LH-stimulated progesterone synthetic response of the two sub-populations of rat luteal cells is more similar to that of the developing monkey corpus luteum and contrasts sharply with that of ruminants.


Evidence for a role for protein kinase C in the modulation of bombesin-activated cellular signalling in human breast cancer cells. The phorbol ester 12-O-tetradecanoylphorbol 13-acetate (TPA) is a potent activator of protein kinase C (PKC) and is known to affect a variety of biochemical processes in human breast cancer cells. In the present study we have employed MCF-7 cells to investigate the effects of TPA on inositol lipid signalling, the putative pathway leading to PKC activation and intracellular Ca2+ mobilization. Phosphoinositide hydrolysis in MCF-7 cells was stimulated by bombesin (BN) as evidenced by increases in both inositol phosphate production and cytidine diphosphate diacylglycerol (CDP-DG) accumulation. Pretreatment of MCF-7 cells with TPA caused attenuation of both these BN-induced responses. This inhibitory action of TPA on inositol phosphate production was mimicked by diacylglycerol analogues and was reversed by staurosporine, H-7 and tamoxifen, all known inhibitors of PKC. Furthermore, putative down-regulation of PKC by prolonged TPA pretreatment also reversed the inhibitory action of TPA and enhanced BN-induced phosphoinositide hydrolysis. TPA also inhibited BN-induced increases in cytosolic Ca2+ concentration ([Ca2+]i) and caused a dose-dependent inhibition of epidermal growth factor (EGF) binding in MCF-7 cells. However, EGF receptor occupancy was unaffected by BN. These data support an inhibitory role for PKC in the regulation of phosphoinositide hydrolysis and [Ca2+]i in breast cancer cells and provide a potential mechanism for feedback regulation of this signalling pathway in these cells.


Progressing toward a molecular description of colorectal cancer development. During the past decade, the powerful techniques of molecular biology and genetics have been applied to the study of human cancer. Colorectal tumors have proved to be an excellent system in which to search for and study the mutations involved in the development and progression of a common human cancer because of their natural history and several inherited syndromes that strongly predispose to colorectal cancer. A current view is that colorectal cancer results, at least in part, from the accumulation of multiple mutations in oncogenes and tumor suppressor genes in an affected cell. Although the genetic alterations often occur in a preferred sequence, the total accumulation of changes, rather than their order with respect to one another, appears to be a critical determinant of the biological properties of the tumor cell. Study of the inherited and somatic mutations in colorectal tumor cells may provide insights not only into the pathogenesis of cancer, but may also lead to future understanding of the mechanisms of the origin of mutations and the role of environmental and dietary factors in colorectal tumor development.


Pituitary adenylate cyclase-activating polypeptide stimulates secretion in T84 cells. Pituitary adenylate-cyclase-activating peptide (PA-CAP) and PACAP-27 are novel hypothalamic peptides that can stimulate adenylate cyclase in cultured anterior pituitary cells. Because these peptides are present in the gut and are homologous with vasoactive intestinal peptide (VIP), itself known to stimulate intestinal ion transport, we examined the effects of these peptides on the T84 colonocyte cell line. Using cells grown on semipermeable supports and mounted in Ussing chambers, we showed that PACAP and PACAP-27 potently activate intestinal secretion. The half-maximal secretory response was produced with 0.5 nmol/L PA-CAP and 0.1 nmol/L PACAP-27. PACAP resembled VIP in that it stimulated a secretory response potentiated by carbachol, inhibited by bumetanide and barium chloride, and not further stimulated by the subsequent addition of VIP. Like VIP, PACAP also stimulated 5' cyclic adenosine monophosphate (cAMP) production and the phosphorylation of cellular proteins known to be substrates for cAMP-dependent protein kinase. In addition, PACAP inhibited 125I-VIP binding to T84 cells, and the secretion it stimulated was reduced by the VIP receptor antagonist, L-8-K. Thus PACAP and PACAP-27 potently stimulate colonocyte ion transport via mechanisms mediated by the VIP receptor and cAMP-dependent signaling.


Development of hepatocellular carcinoma associated with increases in DNA synthesis in the surrounding cirrhosis. The relationship between DNA synthesis activity in hepatocytes from cirrhotic tissue and development of hepatocellular carcinoma was studied in 33 posthepatitic patients with Child's grade A cirrhosis. DNA synthesis activity was measured by a bromodeoxyuridine (a thymidine analogue) labeling index, using the bromodeoxyuridine-antibromodeoxyuridine in vitro method, and the patients were followed up prospectively with frequent liver ultrasonography for 2 years. During the 2-year follow-up, 11 of the 33 cirrhotic patients developed hepatocellular carcinoma; they included 8 of the 15 patients (53%) in the high labeling index (greater than 1.5%) group compared with only 3 of the 18 patients (17%) in the low labeling index (less than 1.5) group (P less than 0.05). Five of the latter 18 subsequently had increased synthesis activity. Of these 20 patients who showed high synthesis activities either initially or subsequently, 10 (50%) developed hepatocellular carcinoma, in contrast to 1 of 13 (8%) with persistently low activities (P less than 0.05). Thus, hepatocellular carcinoma seems to develop or may become detectable when DNA synthesis in the background cirrhosis is increasing or remains high.


Posttransfusion hepatitis revisited by hepatitis C antibody assays and polymerase chain reaction. Sera of 40 patients with posttransfusion non-A, non-B hepatitis were tested for hepatitis C and B viral genomes by polymerase chain reaction and for hepatitis C antibodies by synthetic peptide immunoassays. Five were then considered to have chronic hepatitis before transfusion. Six patients without hepatitis C markers and hepatitis B virus DNA recovered. In 29 recipients who became positive for hepatitis C virus RNA, posttransfusion hepatitis C was diagnosed. Of them, 5 were hepatitis B surface antigen carriers. Synthetic peptide immunoassays detected 28 whereas anti-C100 assay detected 23 of the 29 acute hepatitis C patients. Anticapsid antibody appeared earlier than the antinonstructural antibody in 10 seroconverters. They appeared simultaneously in 15 seroconverters but anticapsid antibody appeared later then the antinonstructural antibody in 3 hepatitis B carriers. Transient suppression of hepatitis B surface antigenemia was found in 2, whereas elevated hepatitis B virus DNA was found in 3 carriers during acute hepatitis C superinfection. In 2 carriers whose hepatitis C became chronic, both hepatitis B and C viral genomes persisted throughout 2 years of followup. Therefore these assays define posttransfusion hepatitis C more precisely, and there seems no significant interference between chronic hepatitis B and C virus infections.


[Experiences up to now with the ultrasound dissection instrument in gynecologic oncology]. The energy of high frequency ultrasound is used to disrupt cellular structures. Since the water content of each individual cell is of utmost importance for the physical destruction of the cell, there may be a tissue-selective effect in respect of tissues such as epithelium (high water content) and mesenchyma (low water content). The various therapeutic modalities are described in the following four cases. Ultrasonic tumor destruction was highly effective with regard to maximum reduction of tumor masses, especially for tumor sites which could not be removed by conventional tumor surgery. Blood vessels and nerves surrounded by tumor could be carefully and completely dissected--even in advanced stages. Peritoneal metastases from an ovarian carcinoma could be removed entirely, as well as the metastases within a tumor bulk (e.g. ureter within tumor mass); also the layers of tissue which were lost could be visualized again. So far, no increase in complications during and after surgery has been observed.


Different pathways for chromosomal integration of transfected circular pSVneo plasmids in normal and established rodent cells. The chromosomal integration of transfected circular plasmid pSV2neo molecules was investigated in normal and established mammalian fibroblasts, including two secondary cultures of normal mouse fibroblast lines, one established mouse-hamster hybrid cell line, R44, and the human fibrosarcoma line, HT1080. The physical organization of the integrated molecules was studied by restriction analysis. The results showed that whereas the normal fibroblasts predominantly integrated one head-to-tail partial dimeric molecule, the established cells predominantly integrated distinctly different molecular forms including deleted monomeres (HT1080) and various complex concatemeric molecules (R44), and frequently at more than one chromosomal site (R44). We also constructed a head-to-tail dimeric version of the plasmid, which in the case of the normal fibroblasts again integrated as a partial dimeric molecule in at least 50% of these cells. This result excluded the possibility that the normal mouse transfectants were selected for the integration of two functional neo genes. Thus, it is concluded that the distinctly different molecular forms integrated in normal and established cells demonstrate the operation of different integration pathways, the possible nature of which is discussed.


Transvaginal color Doppler sonography and CA-125 elevation in a patient with ovarian thecoma and ascites. A postmenopausal patient presented with a pelvic mass and ascites. The CA-125 level was 329 U/ml, and transvaginal color Doppler sonography of the tumor vasculature suggested malignancy. At laparotomy, a luteinized thecoma and cytologically benign ascites were found. On rare occasions ovarian thecoma may be associated with ascites without hydrothorax. Preoperative evaluation of the patient with ascites and a pelvic mass may suggest malignancy, but histologic confirmation is necessary to exclude this rare association.


Isolation and structural analysis of the rat MyoD gene. We have cloned and determined the nucleotide (nt) sequence of a 6.5-kb genomic DNA fragment containing the rat MyoD gene (encoding a muscle regulatory factor, MyoD). Mouse fibroblasts transfected with this DNA display a high degree of conversion to a muscle phenotype, suggesting that this genomic clone contains sufficient sequence information to allow the production of the rat MyoD protein in these cells. The 6.5-kb genomic fragment contains the complete coding region of MyoD, distributed over three exons, plus 2.3 kb of 5'-noncoding sequence and 1.4 kb of 3'-noncoding sequence. Based on RNase protection assays, the major transcription start point of MyoD is located 210 nt 5' to a methionine start codon and 26 nt 3' to a TAAATA motif which bears similarity to a consensus recognition sequence (TATA) utilized by eukaryotic RNA polymerase II transcription complexes. The high degree of identity between the amino acid sequence of rat MyoD and the MyoD proteins isolated from other vertebrates indicates that this muscle regulatory protein has been evolutionarily conserved.


The prevalence of HPV16DNA in normal and pathological cervical scrapes using the polymerase chain reaction. Human papillomavirus (HPV) has been implicated in the development of cervical cancer. Newly developed molecular techniques have facilitated HPV identification and typing of cervical lesions. Several studies have suggested a strong correlation between HPV16 and intraepithelial cervical neoplasia. However, there is no agreement on this point since HPV16 is detected also in normal cervical tissue. We have amplified the L1 region of HPV16 DNA using the polymerase chain reaction (PCR) technique and analyzed the HPV16 prevalence in cytological scrapes of 201 Italian sexually active patients. One hundred twenty-four of these women had normal cytologic and colposcopic examination, while seventy-seven women had normal or abnormal cytology and a cervical lesion detectable by colposcopy. Within this latter group, 25 of 77 women (32.4%) were positive for HPV16 DNA, compared to 11 of 124 samples (8.87%) from women with normal cytology and colposcopy. The present results confirm the high efficiency of the PCR technique in detecting HPV16 DNA from cervical scrapes and suggest that this analysis should become a method of choice in clinical studies.


Detection of Epstein-Barr virus DNA from a lymphoma-like lesion of the uterine cervix. The case of a 60-year-old woman in whom a lymphoma-like lesion of the cervix was found during an episode of silent Epstein-Barr virus (EBV) infection is presented. Fractional curettage was performed because of abnormal endometrial smear. The endocervical curettage specimens were diagnosed as highly suggestive of malignant lymphoma, but microscopic examination of a subsequent hysterectomy specimen revealed a benign lymphoid hyperplasia. Those were retrospectively interpreted as a lymphoma-like lesion of the cervix. In the absence of clinical symptoms of infectious mononucleosis, the results of serologic tests for EBV revealed an active EBV infection. EBV DNA was demonstrated in nuclei of large lymphoid cells in endocervical curettage specimens by in situ hybridization. She is alive and well 32 months postoperatively. When female patients with lymphoma-like lesions of the lower genital tract are encountered, examinations for EBV are recommended.


Is human papillomavirus associated with cervical neoplasia in the elderly? There have been no studies in the United States of human papillomavirus (HPV) in elderly women. This paper presents cross-sectional data on HPV and cervical neoplasia among 232 women age 65 or more. HPV deoxyribonucleic acid (DNA) testing was performed using a modified dot-blot hybridization technique. The prevalence of HPV DNA positivity was 3.5% (95% confidence interval (CI) 0.9%, 6.0%). There were six cases of histologic cervical neoplasia. The crude odds ratio for cervical neoplasia among HPV DNA positives was 18.3 (95% CI 2.8, 120.3). The adjusted odds, controlling for age, prior screening history, current sexual activity, and past contraception use, were 12.2 (95% CI 1.2, 122.9). Ever having had a Papanicolaou smear was protective, and there was a trend for the odds of having neoplasia to increase with age. Additional studies with larger samples of elderly women are needed. If confirmed, the results suggest that, independent of past screening, HPV may increase the risk of having cervical neoplasia for elderly women.


The psychological, social, and sexual consequences of gestational trophoblastic disease. Seventy-six women diagnosed with gestational trophoblastic disease (GTD) from 1985 to 1989 completed questionnaires evaluating their status on mood disturbance, marital satisfaction, sexual functioning, psychosocial response to illness, and report of the most stressful event occurring within the past year. Multivariate analyses of variance (MANOVA) were conducted on dependent measures to examine differences between diagnostic groups (partial mole, complete mole, persistent disease), time from diagnosis (less than 1 year, 1-2 years, or 3-5 years from diagnosis), and follow-up status (active disease or remission). MANOVAs revealed no significant differences in the dependent measures based on time from diagnosis, type of medical treatment received, or type of molar disease. The metastatic disease group displayed significantly greater mood disturbance (F(1, 66) = 17.63, P less than 0.0001) and reported suffering clinically significant levels of distress and significantly greater levels of distress in response to the illness (F(33, 39) = 2.32, P less than 0.006). Women with active disease also reported significantly greater levels of distress in response to the illness (F(33, 39) = 2.76, P less than 0.001). Across disease types, GTD patients experience clinically significant levels of anxiety, anger, fatigue, confusion, and sexual problems and are significantly impacted by pregnancy concerns for protracted periods of time.


Resection of a large liver cell adenoma originating in the caudate lobe. A rare case is reported of a large liver cell adenoma originating in the caudate lobe of the liver in a 38-year-old women with no history of liver cirrhosis or use of oral contraceptives: Caudate lobectomy of the liver is described. Passing tapes around the inferior vena cava was useful for controlling the bleeding from a torn short hepatic vein. This resection of a large hepatocellular adenoma originating in the caudate lobe is to our knowledge only the second case to be reported in the English literature.


Biochemical factors involved in the FSH action on amino acid transport in immature rat testes. Testes of 15-day-old rats preincubated and incubated during different times with various doses of FSH (0.2; 2.0 and 20.0 mU/ml) in Krebs-Ringer bicarbonate (KRb) buffer increase the uptake of [14C] methylaminoisobutyric acid and [14C] aminoisobutyric acid. The basal and FSH stimulated amino acid transport occurs at absolute lower levels when the protein or glycoprotein synthesis is inhibited by cycloheximide (350 mumol/l) or tunicamycin (12 mumol/l) or when the microtubules are depolymerized with colchicine (1.2 mumol/l). However, the proportional increase of amino acid transport produced by FSH was maintained. The blockage of the voltage-dependent Ca++ channels with verapamil or the competitive inhibition of the bivalent ion channels by Co++ or Ni++ nullified the stimulatory action of FSH on the amino acid transport. Also quinine, that blocks the ATP dependent K+ channels, abolished the FSH action. It was concluded that in immature rat testes FSH stimulates amino acid transport through a mechanism involving voltage-dependent Ca++ channels and ATP-sensitive K+ channel.


Epstein-Barr virus DNA in Reed-Sternberg cells of Hodgkin's disease is frequently associated with CR2 (EBV receptor) expression. We studied 44 cases of Hodgkin's disease for the presence of Epstein-Barr virus (EBV) DNA, its localization and the expression of the EBV receptor on the tumour cells. EBV DNA was found in 52% (16/31) of the Hodgkin's lymphomas using the polymerase chain reaction. With a very sensitive non-radioactive DNA in situ hybridization technique in combination with immunohistochemistry for CD 30 or CD 15 antigens, EBV DNA was localized to Reed-Sternberg cells and its mononuclear variants. The relationship between the presence of EBV DNA and the expression of the EBV-receptor CR2 (CD 21) on Reed-Sternberg cells was studied using the same techniques and two different monoclonal anti-CD 21 antibodies. CR2 could be detected on a substantial number of the Reed-Sternberg cells in EBV DNA positive Hodgkin's lymphomas (9/12; 75%), whereas in EBV negative cases positivity with anti-CD 21 was rare (1/13; 8%). The results indicate that CR2 expression on Reed-Sternberg cells and the presence of EBV DNA sequences are frequently associated in Hodgkin's lymphomas.


The expression of the EBV latent membrane protein (LMP-1) is independent of CD23 and bcl-2 in Reed-Sternberg cells in Hodgkin's disease. A series of 33 cases of Hodgkin's disease was investigated for the presence of the EBV encoded latent gene product LMP-1 and of CD23 using immunohistochemical techniques. The expression of bcl-2 was examined in a subset of cases. LMP-1 was detected in the Reed-Sternberg cells in 15 cases. Although LMP-1 is known to upregulate CD23 and bcl-2, there was no correlation between the expression of LMP-1 and the detection of CD23 and bcl-2 in Reed-Sternberg cells.


Primary extrarenal Wilms' tumour: identification of a putative precursor lesion. We report a case of primary extrarenal Wilms' tumour which, on histological examination, revealed a zone of hyalinized blastema adjacent to, and within the tumour capsule. The tumour showed a predominant stromal component. The presence of the hyalinized blastema adjacent to the tumour raises the possibility that some cases of extrarenal Wilms' tumour may have a precursor lesion.


Assignment of the human CRABP-II gene to chromosome 1q21 by nonisotopic in situ hybridization. Two highly conserved forms of cellular retinoic acid binding protein (CRABP-I and CRABP-II) have been described, and one, CRABP-II, is highly expressed in human skin. We have utilized a 10-kb fragment containing the human CRABP-II (hCRABP-II) gene (isolated from a human genomic library) to localize hCRABP-II to human chromosome 1 band q21 by fluorescence in situ hybridization. Localization to 1q was confirmed by hybridization of a hCRABP-II cDNA clone against a human-mouse hybrid cell line containing a t(1;6)(q21;q13)) translocation chromosome. The hCRABP-II gene is therefore localized to a band known to contain several other genes that are expressed in the context of epidermal differentiation, including profilaggrin, loricrin, involucrin, and calcyclin.


The prostaglandin E1 analogue, misoprostol, regulates inflammatory cytokines and immune functions in vitro like the natural prostaglandins E1, E2 and E3. We examined whether some immune functions related to the action and production of cytokines could be regulated by the natural prostaglandins E (PGE) and the PGE1 (ester) analogue, Misoprostol. PGE1,2,3 and Misoprostol inhibited: (1) the mitogenic activity of interleukin-1 (IL-1) for mouse thymocytes; (2) spreading of mouse macrophages on glass; (3) tumour necrosis factor (TNF) (alpha and beta) production by human peripheral blood mononuclear cells and rat macrophages; (4) IL-1 production by rat and mouse peritoneal macrophages; and (5) interferon-gamma (IFN-gamma) production by human peripheral blood mononuclear cells. These PGE had little effect on IL-1 production by human monocytes. By contrast, they all enhanced IL-6 production by rat and mouse macrophages and human monocytes. These effects were noted at concentrations below 500 nM (even as low as 10 nM). The relative potency of the prostanoids tested for both inhibitory and stimulatory effects was PGE1 = PGE2 = or greater than PGE3 greater than Misoprostol greater than PGA2 much greater than PGF1-alpha = PGF2-alpha = PGD2 (no effect). There is strong evidence that PGE1,2,3 and Misoprostol bind to the same receptor(s) and trigger the second messenger, cAMP, since dibutyryl cAMP (a lipophilic analogue of cAMP) had the same effects as the PGE. These PGE also induced elevated intracellular cAMP levels in and competed with [3H]PGE2 for binding to human and rat cells with the same relative potencies as described above.


Leukotriene B4 augments interleukin-2 receptor-beta (IL-2R beta) expression and IL-2R beta-mediated cytotoxic response in human peripheral blood lymphocytes. Interleukin-2 can induce cytolytic activity in human peripheral blood lymphocytes and this activation is mediated by the beta chain of the interleukin-2 receptor-beta (IL-2R beta). Leukotriene B4 (LTB4) is a potent lipid inflammatory mediator which induces IL-2 and interferon-gamma (IFN-gamma) production from T cells. We examined the ability of LTB4 to modulate IL-2-induced cytolytic activity. Peripheral blood lymphocytes which had been preincubated for 24 hr in the presence of LTB4 responded to 100-fold lower concentrations of IL-2 with an augmentation of natural killer (NK) cell cytotoxic activity. Furthermore, incubation of lymphocytes with graded concentrations of LTB4 augmented the proportion of IL-2R beta+ cells. Peak activity was seen at 10 nM LTB4 and was comparable to that of PHA. By two-colour cytofluorometry, the increased expression of IL-2R beta was found predominantly on CD56+ cells and to a lesser extent on CD8+ cells, while CD4+ cells were unaffected. These observations were correlated at the messenger RNA (mRNA) level with increased IL-2R beta mRNA accumulation following stimulation of purified CD56+ and CD8+ cells with LTB4. CD56-, CD8- cells did not respond to LTB4 by increased IL-2R beta mRNA accumulation. Our data indicate, for the first time, that LTB4 can markedly increase the sensitivity of non-major histocompatibility complex (MHC)-restricted cytotoxic lymphocytes to IL-2, in terms of IL-2-dependent cytotoxic responses, and that this sensitivity is associated with augmented IL-2R beta gene message and cell surface expression.


Requirements for the production of high-titre C3 nephritic factor (NEF) antibody in vitro. C3 nephritic factor (NEF) is an IgG autoantibody directed against neoantigenic determinants of the alternative C3 convertase (C3b.Bb). Structural and functional studies require important amounts of this antibody, which are difficult to obtain from patients' sera. We have developed a method for increasing NEF production in vitro. Epstein-Barr virus is a herpes virus which transforms B lymphocytes. Some authors were able to induce the production of NEF in vitro after infection with Epstein-Barr virus (EBV). These works were preformed without any previous cellular selection of B cells. We have performed a method of preselecting antigen-binding cells prior to EBV transformation. Non-preselected cells yielded 0.16 U/million cells in culture (U/M) of NEF antibody, whereas enriched cells for NEF antibody in eliminated 8 U/M (sheep erythrocytes coated with anti-IgG, A, M). Specific NEF synthesis can be increased, in peripheral blood mononuclear cells (PBMC) from patients by in vitro stimulation with the antigens recognized by NEF [C3b.Bb, 21,000 MW protein from patients' E membranes and 26,000 MW protein from sheep E membranes (ShE)]. The highest stimulation is induced by the C3b.Bb and by 26,000 MW protein, 21,000 MW protein had lowest stimulatory effect. In this work also we have shown that patients having NEF antibody in sera have an increase of the CD5-CD19 subset, when compared with the controls.


Hepatocellular carcinoma invasive to chest wall. An 88-year-old white man developed hepatocellular carcinoma forming a large subcutaneous mass by direct invasion of the posterior chest wall. Forty-seven cases of cutaneous metastases from primary liver cancer have been reported. These cutaneous metastases showed protean morphologic features with the face and scalp being the most common sites of involvement. The metastatic lesions may be the presenting sign of the cancer. Average survival, after development of a skin metastasis, was 5 months. Skin metastases from primary liver cancer are being reported more frequently. This is due, in part, to more prolonged survival of liver cancer patients, which allows development of skin metastases, and also due to increased awareness by the clinician.


Role of HIV and CMV in the pathogenesis of retinitis and retinal vasculopathy in AIDS patients. Cotton-wool spots and cytomegalovirus (CMV) retinitis are seen frequently in AIDS patients. Human immunodeficiency virus (HIV) infection of the retina has been proposed as a mechanism for the high incidence of retinal pathology. An autopsy study of the eyes from 25 consecutive cases of AIDS was performed using gross examination, light microscopy, trypsin digestion of retinal vasculatures, and immunohistochemistry to evaluate the possible role of HIV, as well as CMV, in the pathogenesis of retinitis and retinal vasculopathy. Brain tissue was studied in the first 20 of these cases to evaluate any correlation between retinal and central nervous system pathology. CMV retinitis was observed in 15 cases (60%). Cotton-wool spots were seen in nine cases (36%). CMV encephalitis was detected in four cases, whereas HIV encephalitis was noted in five cases. We were unable to demonstrate a correlation between CMV retinitis and CMV encephalitis. However, the number of cases studied was small, and the frequency of CMV encephalitis was low. On the other hand, bilateral CMV retinitis demonstrated a correlation to HIV encephalitis (P less than 0.005, Fisher's exact test). HIV infection of the retina was not detected by typical morphologic changes or immunohistochemistry. Immunohistochemistry localized CMV infection solely to areas of active retinitis. These findings suggest that bilateral CMV may serve as a marker of HIV encephalitis, possibly indicating a severely immunodepressed state.(ABSTRACT TRUNCATED AT 250 WORDS)


Persistence of herpes simplex virus DNA in rabbit corneal cells. Corneal cell cultures were established from the corneas of rabbits killed during a period of latency 118 d after ocular infection with the RE strain of herpes simplex virus (HSV). DNA was isolated from frozen cell pellets of 42 cell cultures that did not develop viral cytopathic effects during 44 d in culture. Using the polymerase chain reaction (PCR) to amplify HSV thymidine kinase (TK) gene sequences, HSV-specific DNA was detected in 15 of 42 culture-negative cell cultures. Subsequent reamplification, using nested primers that were complementary to HSV TK sequences internal to the orginal primers, resulted in eight additional culture-negative samples showing positive hybridization for HSV TK DNA. Twenty three of the 42 virus culture-negative corneal cell cultures tested by PCR were found to contain HSV genetic material. Detailed examination of the clinical histories of the eyes from which the corneal cultures were obtained showed no correlation between increased frequency or severity of epithelial disease, stromal disease, or virus shedding and more frequent isolation of virus or detection of HSV-specific DNA. These studies document that HSV DNA residues in the corneas of HSV-infected rabbits up to 118 d post-infection. About 10% of the eyes contained virus that could be reactivated in culture, whereas an additional 55% of the eyes contained DNA sequences homologous to a portion of the HSV TK gene.


Deferoxamine effect on selenite-induced cataract formation in rats. A single subcutaneous dose of 30 nmol of sodium selenite per gram of body weight in 13-day-old rats resulted in posterior subcapsular cataract (PSC) after 24 hr and bilateral nuclear cataracts at 72-96 hr. Within 24 hr of treatment, a 60% decrease in lens glutathione was seen. A loss of calcium homeostasis observed by 48 hr resulted in increased lens calcium (4 mumol/g dry weight), which accompanied nuclear opacification. The iron chelator, deferoxamine (DF), was evaluated as a potential protective agent against these selenite-induced changes. Three doses each consisting of 1.1 mumol DF/g body weight were administered during the initial 24 hr of selenite exposure. Within 96 hr, all lenses from animals treated only with DF remained transparent, but 50% of these lenses showed cortical cataract at 3 wk postinjection. Concurrent administration of DF and selenite protected 80% of rats against PSC after 48 hr and 25% against nuclear cataract after 96 hr. No elevation in lens calcium occurred in the protected lenses. An additional 20% of animals were not protected fully but showed substantially less nuclear opacity than with selenite alone. They had a significant but moderate increase in lens calcium. After 3 wk (animal age, 35-40 d), cataract appeared in these "protected" lenses involving both the nucleus and cortex and loss of ion homeostasis. The glutathione content remained lower in lenses from animals treated with both selenite and DF compared with those from selenite-treated animals.(ABSTRACT TRUNCATED AT 250 WORDS)


Rose bengal inhibits herpes simplex virus replication in vero and human corneal epithelial cells in vitro. Rose bengal dye is thought to highlight corneal lesions induced by herpes simplex virus type 1 (HSV-1) by virtue of its binding to dead or dying HSV-1-infected epithelial cells. However, whether rose bengal binds specifically to damaged versus normal corneal epithelial cells is unclear. To determine the binding properties of rose bengal, the authors compared binding of the dye to HSV-1-infected and uninfected cells, determined the cellular binding sites of the dye, and investigated the effects of rose bengal on HSV-1 replication in dye-treated cells in vitro. Spectrophotometric analysis revealed that uninfected and infected Vero cells bound equivalent amounts of dye at several times post inoculation, indicating that rose bengal does not preferentially bind to HSV-1-infected cells. By light microscopy, rose bengal was found to bind to the cell nuclei and perinuclear region of human corneal epithelial cells (HCEC) and Vero cells. Pretreatment of Vero and HCEC with different concentrations of rose bengal and exposure to 148 microW/cm2 of white light for 2 min reduced the ability of both cell types to support HSV-1 replication. Vero cells, in the absence of rose bengal, supported HSV-1 replication, whereas pre-treatment with 0.05% rose bengal reduced the yield of HSV-1 by 99.99% (P less than 0.000001) and 1% rose bengal completely prevented HSV replication. HCEC supported HSV-1 replication in the absence of rose bengal, but pre-treatment with 1% or 0.05% rose bengal completely prevented HSV-1 replication (P less than 0.000001).(ABSTRACT TRUNCATED AT 250 WORDS)


Enzymic potential for fructose 6-phosphate phosphorylation by guard cells and by palisade cells in leaves of the broad bean Vicia faba L. Guard cells and palisade cells were dissected from freeze-dried leaflets of the broad bean, Vicia faba L. Individual cell samples (6-12 ng) were assayed for ATP-dependent and pyrophosphate-dependent phosphofructokinases. The assay indicator, NADH loss, was monitored in real time in oil droplets with a computer-driven microfluorometer. On a protein basis, both activities were 10-fold higher in guard cells than in palisade cells, indicating (i) elevated carbon metabolism in guard cells to meet demands for energy and carbon skeletons required during stomatal opening, and (ii) parallel glycolytic pathways in guard cells, one responsive to the potent regulatory metabolite fructose 2,6-bisphosphate and the other not. Future work will be devoted to clarifying the roles of the cytosolic and chloroplastic compartments in guard cells.