Gliomatosis cerebri: a brain tumour which is too difficult to treat?

Gliomatosis cerebri is a rare form of primary diffuse brain tumour first described by Nevin in 1938. It was originally considered to be a post-mortem diagnosis before Troost et al reported a clinically diagnosed case in 1987. However antemortem diagnosis remains difficult due to vague clinical symptoms and often non-specific findings on CT scanning. Gliomatosis cerebri has been classified by the World Health Organization as an infiltrative tumoural process, which involves at least two, and usually three, lobes of the brain. Magnetic resonance (MR) imaging shows a diffuse infiltrative process with possible mass effect but no necrosis. Histology is usually of a low grade astrocytic neoplasm which seemingly infiltrates out of proportion to the degree of anaplasia. We report two patients who presented over the past year, whose clinical and radiological features prompted a preoperative diagnosis of gliomatosis cerebri, confirmed by biopsy.

A glycine-rich RNA-binding protein gene is differentially expressed during acute hypersensitive response following Tobacco Mosaic Virus infection in tobacco

During efforts for cloning disease resistance-responsive genes, a cDNA encoding a putative Nicotiana glutinosa glycine-rich RNA binding protein (ngRBP) was isolated from TMV induced cDNA library. Northern blot hybridization revealed that ngRBP gene is negatively regulated during early hours of TMV induced acute hypersensitive response (HR). Under greenhouse conditions induced expression of ngRBP gene was observed after 24 h following TMV infection. Salicylic acid and copper also induced ngRBP mRNA expression. Our findings are suggestive of some possible role for ngRBP in plant-pathogen interaction.

Identification of binding sites for bepridil and trifluoperazine on cardiac troponin C

The solution structure of cardiac troponin C (cTnC) (Sia, S., Li, M. X., Spyracopoulos, L., Gagne, S. M., Liu, W., Putkey, J. A. & Sykes, B. D. (1997) J. Biol. Chem. 272, 18216-18221) challenges existing structure/function models for this critical regulatory protein. For example, it is clear that the closed conformation of the regulatory N-terminal domain in Ca2+-bound cardiac troponin C (cTnC) presents a much different binding surface for Ca2+-sensitizing compounds than previously thought. We report here the use of Met methyl groups as site-specific structural markers to identify drug binding sites for trifluoperazine and bepridil on cTnC. Drug dependent changes in the NMR heteronuclear single-quantum coherence spectra of [methyl-13C]Met-labeled cTnC indicate that bepridil and trifluoperazine bind to similar sites but only in the presence of Ca2+. There are 3-4 drug binding sites in the N- and C-terminal domains of intact cTnC that exhibit fast exchange on the NMR time scale. Use of a novel spin-labeled phenothiazine and detection of isotope-filtered nuclear Overhauser effects allowed identification of drug binding sites in the shallow hydrophobic cup in the C-terminal domain and on two hydrophobic surfaces on the N-terminal regulatory domain. The data presented here, coupled with our previous study using covalent blocking groups, support a model in which the Ca2+-sensitizing binding site includes Met-45 in helix B of site I, and Met-60 and -80 in helices B and C of the regulatory site II. This subregion in cTnC makes a likely target against which to design new and selective Ca2+-sensitizing compounds.

Endoscopic sigmoidopexy: a safer way to treat sigmoid volvulus?

Sigmoid volvulus may be treated by sigmoidoscopic reduction and elective sigmoidopexy or resection at a later stage, provided there is no evidence of peritonitis, perforation or rectal bleeding. However, operative treatment, whether urgent or elective, is associated with a relatively high morbidity and mortality. An endoscopic technique of sigmoidopexy is reported which is relatively quick and straightforward to perform, and is likely to have a lower rate of morbidity and mortality than conventional techniques for the treatment of sigmoid volvulus.

An atlas vertebra with a centrum? A case report of an abnormal atlas and axis

This case report represents the finding of an abnormal atlas vertebra during dissection of 34 cadavers. The case which we describe appeared to have an atlas with a mass at a position similar to that of a centrum. This mass may have been a developmental abnormality of the centrum of the atlas or may have represented a congenital abnormality, known as the os odontoideum. Alternatively the abnormality may have been due to non-union of an odontoid fracture, with subsequent fusion to the atlas. The case report will discuss which of these three alternatives is more probable, and the embryology and phylogenesis of the atlas and axis, leading us to believe in a congenital hypothesis as an explanation for the malformation.

Evidence for autocrine inhibition of gonadotropin-releasing hormone (GnRH) gene transcription by GnRH in hypothalamic GT1-1 neuronal cells

To examine whether an ultrashort feedback mechanism of gonadotropin-releasing hormone (GnRH) operates at the level of gene transcription, we studied the effects of GnRH analogs on GnRH promoter activity and GnRH mRNA level in hypothalamic GT1-1 neuronal cells. Treatment of GT1-1 cells with buserelin, a GnRH agonist, or native GnRH for 24 h significantly decreased GnRH promoter activity and its mRNA level, whereas that with GnRH antagonists, antide or [D-Phe2,D-Ala6]-GnRH, showed no effect. The inhibitory effects of buserelin on GnRH gene transcription and GnRH mRNA level were dose-related, and a significant inhibition was observed in cells treated with buserelin at concentrations higher than 0.1 microM. Time-course experiments showed that significant decreases in GnRH promoter-driven luciferase activity and GnRH mRNA level were observed within 12 h and sustained up to 48 h. Moreover, treatment with GnRH agonist for 12 h significantly decreased the transcription rate of the mouse GnRH gene, as revealed by nuclear run-on transcription assay. The promoter analysis with the 5'-deletional constructs demonstrated that cis-acting elements important for GnRH autoregulation by GnRH agonist reside within -854 bp upstream from the transcription start site. These data clearly demonstrate that GnRH can exert autocrine regulation at the level of GnRH gene transcription.

Expression of galectin-1 mRNA in the mouse uterus is under the control of ovarian steroids during blastocyst implantation

Galectin-1 is a member of beta-galactoside-binding lectins expressed in a variety of mammalian tissues. We report here that galectin-1 mRNA is abundantly expressed in the mouse reproductive organs such as the uterus and ovary. Uterine expression of galectin-1 mRNA is specifically regulated in the embryonic implantation process. Its expression increased at a high level on the fifth day post coitum (dpc 5) when embryos hatched into the endometrial epithelial cells. In the absence of embryos, however, galectin-1 expression in the mouse uterus decreased on dpc 5. In the delayed implantation mice, galectin-1 mRNA levels was augmented by the termination of the delay of implantation. Ovarian steroids progesterone and estrogen differentially regulated galectin-1 mRNA level in uterine tissues. Treatment with RU486, a progesterone receptor antagonist, blocked progesterone-induced galectin-1 mRNA level in uterine tissues of ovariectomized mouse. ICI182780, a pure estrogen receptor antagonist, clearly blocked the estrogen effect. Taken together, galectin-1 gene expression in the uterine tissues was regulated by ovarian steroids and this regulation correlated with the implantation process.

Expression of laminin chain-specific gene transcripts in mouse uterine tissues during peri-implantation period

Laminin may be involved in uterine re-organization and embryo attachment to the uterine wall during the peri-implantation period. In the present study using a competitive reverse transcription-polymerase chain reaction (RT-PCR), the precise expression patterns of laminin chain (A, B1, and B2)-specific mRNAs were examined in mouse uterine tissues during the peri-implantation period. Although Northern blot hybridization failed to detect laminin A chain mRNA in mouse uterus, RT-PCR analysis showed that laminin A chain mRNA was present even at the lower level compared with B1 and B2 chain mRNA levels. Competitive RT-PCR revealed that approximately 3 x 10(6), 3.6 x 10(7), and 4 x 10(8) copies of A, B1, and B2 chain mRNA transcripts were present in 1 microgram of total RNA isolated from the uterus. During pregnancy, the A chain mRNA level was significantly increased only from day 6 after post-hCG when embryo attachment and decidualization started. Elevated level of A chain mRNA was sustained thereafter. Laminin A chain mRNA synthesized at this period was mainly originated from stroma decidual cells. The discrete elevation of laminin A chain mRNA level was also observed after estrogen stimulation in the delayed implantation model. Estrogenic stimulation to ovariectomized, progesterone-treated pregnant mice resulted in about a three-fold increase of laminin A chain mRNA levels. In contrast to A chain mRNA, both B1 and B2 chain mRNA levels were insignificantly altered during the peri-implantation period and delayed implantation by an estrogenic stimulation. Taken together, our results for the first time demonstrate that: (1) laminin A chain mRNA as well as B chain mRNAs is expressed in mouse uterus, (2) its mRNA level is significantly increased along with implantation process, and (3) ovarian steroids, especially estrogen, are likely to be involved in the regulation of laminin gene expression in the uterus.

Lung mechanical behavior during one-lung ventilation

OBJECTIVE

Switching from two-lung to one-lung ventilation would be expected to have large effects on lung mechanical properties, and these effects may depend on tidal volume and respiratory frequency. These changes in lung mechanics with one-lung ventilation may be similar to pulmonary edema. Deteriorating lung mechanics during pulmonary edema have been attributed to a loss of ventilated lung units. Therefore, changes in lung mechanics caused by one-lung ventilation were measured and compared with those previously seen during pulmonary edema.

DESIGN

Prospective study.

SETTING

Research laboratory.

INTERVENTIONS

After induction of anesthesia, beagle dogs' tracheas were intubated with an endotracheal tube with a bronchial blocker (Univent System Corp, Tokyo, Japan) to apply one-lung ventilation. The proper position of the bronchial blocker during one-lung ventilation was confirmed with a fiberoptic bronchoscope.

MEASUREMENTS AND MAIN RESULTS

Lung elastance (EL) and resistance (RL) were calculated from measurements of airway pressure, esophageal pressure, and airway flow in five anesthetized, paralyzed dogs during sinusoidal forcing at a constant mean airway pressure of 10 cmH2O in a wide range of breathing frequencies (0.2 to 1.0 Hz in intervals of 0.2) and tidal volumes (50, 100, 200, and to 300 mL). Measurements were made before and after the left mainstem bronchus was occluded with the bronchial blocker. During ventilation of both lungs, EL and RL depended relatively little on frequency, and both EL and RL were independent of tidal volume. During one-lung ventilation, EL doubled and, at most frequencies, RL increased; frequency dependences were not increased, and no dependence on tidal volume was observed.

CONCLUSIONS

The lack of tidal volume dependence in EL and lack of large-frequency dependence in RL during one-lung ventilation are inconsistent with changes induced by severe pulmonary edema. Although decreases in ventilatable lung volume may contribute to increases in lung elastance, other characteristics of mechanical behavior during one-lung ventilation differ from those of pulmonary edema; therefore, other additional mechanisms must be involved in determining lung mechanical properties during severe pulmonary edema.

Degenerate and specific PCR assays for the detection of bovine leukaemia virus and primate T cell leukaemia/lymphoma virus pol DNA and RNA: phylogenetic comparisons of amplified sequences from cattle and primates from around the world

Degenerate and specific PCR assays were developed for bovine leukaemia virus (BLV) and/or primate T cell leukaemia/lymphoma viruses (PTLV). The degenerate assays detected all major variants of the BLV/PTLV genus at a sensitivity of 10-100 copies of input DNA; the specific systems detected 1-10 copies of input target. Sensitivity was 100% in specific DNA-PCR assays done on peripheral blood from seropositive BLV-infected cattle and HTLV-I- or HTLV-II-infected humans, and 62% in RNA/DNA-PCR assays on sera from BLV seropositive cattle. The pol fragments from 21 different BLV strains, isolated from cattle in North and Central America, were cloned and sequenced, and compared to other published BLV and PTLV pol sequences. BLV and PTLV sequences differed by 42%. Sequence divergence was up to 6% among the BLV strains, and up to 36% among the PTLV strains (with PTLV-I and PTLV-II differing among themselves by 15% and 8%, respectively). Some cows were infected with several BLV strains. Among retroviruses, BLV and PTLV sequences formed a distinct clade. The data support the interpretation that BLV and PTLV evolved from a common ancestor many millennia ago, and some considerable time before the PTLV-I and PTLV-II strains diverged from each other. The dissemination of the BLV strains studied probably resulted from the export of European cattle throughout the world over the last 500 years. The relatively similar mutation rates of BLV and PTLV, after their various points of divergence, suggest that there could be a much wider genetic range of BLV than has currently been defined.

Insulin-like growth factor-I-mediated amplification of follicle-stimulating hormone-supported progesterone accumulation by cultured rat granulosa cells: enhancement of steroidogenic enzyme activity and expression

A body of information now supports the existence of an ovarian intrafollicular insulin-like growth factor (IGF)-I system concerned with the amplification of FSH action at the level of the rat granulosa cell. In this study we examined the ability of IGF-I to modulate the basal and FSH-supported activity and expression of key steroidogenic enzymes concerned with progesterone generation and metabolism in cultured granulosa cells from immature rats. The provision of IGF-I stimulated FSH-supported (20 ng/ml) accumulation of progesterone in a dose-dependent manner, reaching a plateau at an IGF-I dose of 50 ng/ml. This dose of IGF-I substantially enhanced FSH action over a broad range of FSH concentrations, reaching a maximum at an FSH dose of 20 ng/ml. Pulse labeling of FSH-pretreated cells with [3H]pregnenolone revealed relatively rapid (< 5 h) transformation to [3H]progesterone and other distal products that was accelerated by the concurrent addition of IGF-I. These changes in progesterone metabolism were associated with IGF-I-mediated enhancement of the activities and expression of key steroidogenic enzymes. Specifically, treatment with IGF-I produced significant augmentation of the FSH-stimulated activities of cholesterol side-chain cleavage (P450scc) and 3 beta-hydroxysteroid dehydrogenase/ isomerase (3 beta-HSD) enzymes (2.4- and 1.8-fold, respectively). Similarly, P450scc and type I 3 beta-HSD transcripts were elevated by FSH in a dose-dependent manner, the concurrent addition of IGF-I further increasing expression (up to an additional 3-fold) in the range of 1-5 ng/ml (but not at the maximally stimulating dose of 20 ng/ml FSH). The addition of IGF-I also increased basal levels of type I 3 beta-HSD transcripts (3.8-fold). IGF-I enhanced FSH-stimulated 20 alpha-HSD activity and transcripts (2.3-fold and 1.8-fold, respectively) and increased the basal levels of 20 alpha-HSD transcripts (3-fold). Basal levels of 5 alpha-reductase were slightly elevated (1.3-fold) by IGF-I, but the FSH-attenuated activity was unchanged. Taken together, these findings suggest that IGF-I enhances the FSH-supported accumulation of progesterone in cultured granulosa cells through up-regulation of the expression and activity of key enzymes in the steroidogenic pathway. The acceleration of progesterone accumulation reflects a newly established steady state, favoring the activities of progesterone-forming over progesterone-metabolizing enzymes.

Activin-attenuated expression of transcripts encoding granulosa cell-derived insulin-like growth factor binding proteins 4 and 5 in the rat: a putative antiatretic effect

Given the suggestion that intraovarian insulin-like growth factor (IGF)-binding proteins (IGFBPs) may constitute markers of follicular atresia, we investigated the possibility that activin, a putative antiatretic principle, may modulate granulosa cell-derived IGFBPs. Untreated granulosa cells cultured for 72 h exhibited a progressive increase in the steady-state levels of transcripts corresponding to IGFBP-4 and IGFBP-5 (1.5-fold and 12-fold, respectively). Transcript levels corresponding to IGFBP-5 were consistently higher than their IGFBP-4 counterparts. Treatment with activin-A (50 ng/ml) for 72 h produced significant (p < 0.05) decrements in the steady-state levels of IGFBP-4 and IGFBP-5 transcripts (46% and 79%, respectively) as compared to controls. Thus, treatment with activin-A appears to be capable of blocking the spontaneous increase in IGFBP-4 and IGFBP-5 transcripts exhibited by untreated cultured granulosa cells. Consistent activin-A-induced decrements were also observed in the accumulation of the IGFBP-5 (but not the IGFBP-4) protein. Dose-response analysis revealed monophasic dose dependence (half maximal inhibitory doses of 16.2 and 7.8 ng/ml for IGFBP-5 and IGFBP-4 transcripts, respectively). The addition of increasing concentrations of the putative activin-binding protein, follistatin, produced dose-dependent reversal of the activin-A effect on IGFBP transcripts (IGFBP-5 > IGFBP-4). Activin-B was as effective as activin-A in reducing IGFBP-4 transcripts (31% decrement, p < 0.05) whereas it had little or no effect on IGFBP-5 transcripts (21% decrement, p > 0.1). No apparent effect was observed for the corresponding proteins. Activin-A action was specific in that treatment with transforming growth factor (TGF)-beta1, inhibin-A, or Müllerian-inhibiting substance (MIS)--all related peptides--failed to produce statistically significant alterations in the steady-state levels of IGFBP-4 and IGFBP-5 transcripts. Taken together, these observations reveal that activin-A exerts a substantial, relatively rapid, follistatin-neutralizable, dose- and time-dependent inhibitory effect on granulosa cell-derived IGFBP transcripts (IGFBP-5 > IGFBP-4). Other members of the TGFbeta superfamily (e.g., inhibin-A, TGFbeta1, and MIS) were without significant effect on the expression of IGFBP-4 and IGFBP-5. To the extent that the inhibition of IGFBP-4 and IGFBP-5 expression is associated with, and possibly causally related to, the promotion of follicular health, the present observations are in keeping with the proposition that activin may play an antiatretic role in the dynamic process of follicular selection.

Erythropoietin: physico- and biochemical analysis

A hormone, erythropoietin, mainly produced in adult kidneys and fetal livers, acts on bone marrow erythroid progenitor cells to regulate the production of erythrocyte in mammals. As a result, the oxygen carrying capacity of blood increases and the increased oxygen supply raises the cardiac function and physiological working capacity. Erythropoietin is possibly misused by athletes in sports for the purpose of improving performance. Presently there is no discernible and specific method to identify erythropoietin administration for doping control. To address this practical problem, this paper presents a summary of the applications of analytical biotechnology, especially the structural characterization of erythropoietin.

Traumatic cerebrospinal fluid leakage: risk factors and the use of prophylactic antibiotics

Cerebrospinal fluid (CSF) leakage following head trauma is often difficult to diagnose, but is of considerable importance in view of the possibility of fistula formation and meningitis. It is unclear whether specific clinical or radiological signs point to an increased risk of CSF leakage. Previous studies have been largely anecdotal and uncontrolled, leading us to perform a retrospective control study comparing the clinical and radiological features of patients with overt CSF leakage, and those without. Of the 293 patients studied, 115 had clinical CSF leakage and 170 did not, with incomplete documentation in eight patients. The group with CSF rhinorrhoea had significantly greater incidence of periorbital haematoma (chi square = 8.642). This suggests that patients with head injuries and features of periorbital haematoma are at greater risk of unobserved dural tear and delayed CSF leakage. Frontal and ethmoid fractures in particular were also associated with CSF leakage (chi square = 5.46). The use of prophylactic antibiotics was studied. There was a significantly greater incidence of meningitis in the group which received prophylactic antibiotics (p = 0.024). There was no significant difference in the incidence of meningitis in those patients with CSF fistulae treated by surgical or conservative methods.

The anticonvulsant activities of functionalized N-benzyl 2-acetamidoacetamides. The importance of the 2-acetamido substituent

Recent studies have demonstrated that substituted N-benzyl 2-acetamidoacetamides provide significant protection against maximal electroshock (MES)-induced seizures in mice and rats. In this study, we investigated whether the 2-acetamido moiety was necessary for anticonvulsant activity. Ten derivatives of the known anticonvulsant, N-benzyl 2-acetamido-2-phenyl-acetamide were prepared in which the 2-acetamido group was replaced by hydrogen, methyl, oxygen, and halogen substituents. Evaluation of these compounds in the MES-induced seizure test demonstrated that both the hydroxy and the methexy compounds provided full protection against MES-induced seizures in mice given ip at 100 mg/kg. Moreover, evaluation of the individual stereoisomers for the hydroxy compound showed that the principal activity resided in the (R)-isomer. These findings demonstrated that the 2-acetamido substituent is important but not obligatory for the prevention of MES-induced seizures. Further supporting evidence was provided by comparing the pharmacological activities of N-benzyl 2,3-dimethoxypropionamide with N-benzyl 2-acetamido-3-methoxypropionamide. The ED50 value for the former in the MES test was 30 mg/kg (i.p.), which compared favorably with phenobarbital (ED50 = 22 mg/kg), but the ED50 value for N-benzyl 2-acetamido-3-methoxypropionamide was 8.3 mg/kg.

Molecular cloning of a metallothionein-like gene from Nicotiana glutinosa L. and its induction by wounding and tobacco mosaic virus infection

The cloning and characterization of genes expressed in plant disease resistance could be an initial step toward understanding the molecular mechanisms of disease resistance. A metallothionein-like gene that is inducible by tobacco mosaic virus and by wounding was cloned in the process of subtractive cloning of disease resistance-response genes in Nicotiana glutinosa. One 530-bp cDNA clone (KC9-10) containing an open reading frame of 81 amino acids was characterized. Genomic Southern blot hybridization with the cDNA probe revealed that tobacco metallothionein-like genes are present in few or in one copy per diploid genome. Northern blot hybridization detected strong induction of a 0.5-kb mRNA by wounding and tobacco mosaic virus infection, but only mild induction was detected when copper was tested as an inducer. Methyl jasmonate, salicylic acid, and ethylene were also tested as possible inducers of this gene, but they had no effect on its expression. The possible role of this gene in wounded and pathogen-stressed plants is discussed.

The serpin-enzyme complex receptor recognizes soluble, nontoxic amyloid-beta peptide but not aggregated, cytotoxic amyloid-beta peptide

There is now extensive evidence that amyloid-beta peptide is toxic to neurons and that its cytotoxic effects can be attributed to a domain corresponding to amyloid-beta 25-35, GSNKGAIIGLM. We have shown recently that the serine proteinase inhibitor (serpin)-enzyme complex receptor (SEC-R), a receptor initially identified for binding of alpha1-antitrypsin (alpha1-AT) and other serine protease inhibitors, also recognizes the amyloid-beta 25-35 domain. In fact, by recognizing the amyloid-beta 25-35 domain, SEC-R mediates cell surface binding, internalization, and degradation of soluble amyloid-beta peptide. In this study, we examined the possibility that SEC-R mediates the neurotoxic effect of amyloid-beta peptide. A series of peptides based on the sequences of amyloid-beta peptide and alpha1-AT was prepared soluble in dimethyl sulfoxide or insoluble in water and examined in assays for SEC-R binding, for cytotoxicity in neuronal PC12 cells and murine cortical neurons in primary culture, and for aggregation in sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) analysis. The results show that amyloid-beta peptide 25-35 and amyloid-beta peptide 1-40 prepared soluble in dimethyl sulfoxide compete for binding to SEC-R, are nontoxic, and migrate as monomers in SDS-PAGE analysis. In contrast, the same peptides aged in water did not compete for binding to SEC-R but were toxic and migrated as aggregates in SDS-PAGE. An all-D-amyloid-beta 25-35 peptide was not recognized at all by SEC-R but retained full toxic/aggregating properties. Using a series of deleted, substituted, and chimeric ambeta/alpha1-AT peptides, toxicity correlated well with aggregation but poorly with SEC-R recognition. In a subclone of PC12 cells which developed resistance to the toxic effect of aggregated amyloid-beta 25-35 there was a 2.5-3-fold increase in the number of SEC-R molecules/cell compared with the parent PC12 cell line. These data show that SEC-R does not mediate the cytotoxic effect of aggregated amyloid-beta peptide. Rather, SEC-R could play a protective role by mediating clearance and catabolism of soluble, monomeric amyloid-beta peptide, if soluble amyloid-beta peptide proves to be an in vivo precursor of the insoluble, toxic peptide.

Spinal cord diameters in cadaveric specimens and magnetic resonance scans, to assess embalming artefacts

It would be valuable to use cadaveric models of cervical vertebrae and spinal cord to assess how varying degrees of traumatic subluxation would relate to neurological damage. However, before such a study may be undertaken, it would be important to assess the degree of shrinkage of expansion of the spinal cord that occurs during the embalming process. This is achieved in this study by comparing diameters of cadaveric spinal cord to that of sagittal magnetic resonance scans of living subjects. The geometric measurements of radiographs in living subjects has been assessed but no direct model for spinal cord injury has been described [1]. If embalmed spinal cord diameters were a good estimator of living spinal cord diameters then cadaveric cervical spines could be used as a model. By reproducing various degrees of fracture and dislocation the extent of corresponding cord compression could be assessed. Our study shows that spinal cord dimensions increase after embalming using the Cambridge procedure [4].

Characterization and hormonal regulation of granulosa cell-derived insulin-like growth factor binding protein-4

OBJECTIVE

Because of the potential importance of insulin-like growth factor binding protein-4 (IGFBP-4) to ovarian physiology and the obvious limitations imposed by in vivo-exclusive experimental paradigms, we set out to delineate the characteristics and hormonal regulation of granulosa cell-derived IGFBP-4 under in vitro circumstances.

METHODS

Granulosa cells obtained by follicular puncture of the ovaries from diethylstilbestrol-primed intact immature rats were subjected to culture for up to 72 hours. Insulin-like growth factor binding protein-4 mRNA extracted from culture was subjected to Northern blot hybridization. Data normalization was assured by reprobing with the hamster Chinese hamster ovary B (CHOB) cDNA, and the IGFBP-4/CHOB ratio was calculated. Conditioned culture media were subjected to Western ligand blot before and after immunoprecipitation with a rat IGFBP-4-directed polyclonal antiserum (alpha-B104).

RESULTS

Immunoprecipitation studies revealed granulosa cell-derived IGFBP-4 to be composed of a major 24-kDa species as well as a relatively minor 27-kDa moiety. Given cultures of untreated granulosa cells from immature estrogen-treated rats, transcripts corresponding to IGFBP-4 displayed an initial temporary decline culminating in a 6-hour nadir (a decrease of 67%; P < .05) followed by relatively prompt recovery (within 24 hours) to levels comparable to those noted at the outset of the culture (time 0). However, additional (albeit statistically insignificant) increments were noted at the 48-hour (but not 72-hour) time point. Treatment of granulosa cells with increasing concentration of FSH resulted in decrements of up to 30% (P < .05) in the steady-state levels of IGFBP-4 transcripts. A modest, biphasic, time-dependent response was noted for IGFBP-4 transcripts after treatment with high-dose FSH (100 ng/mL), an effect characterized by 24- and 48-hour increments (51% [P < .05] and 26% [P = .052] over untrated controls, respectively) and a 72-hour decrement (25%; P = .16). The concurrent provision of the C19 aromatase substrate androstenedione (10(-7) mol/L) to the culture medium from 72 hours enhanced the inhibitory effect of FSH (100 ng/mL) for a maximal decrement in IGFBP-4 transcripts of 49% (P < .05). Treatment with insulin-like growth factor (IGF)-I produced limited inhibition (up to 26%) of the steady-state levels of IGFBP-4 transcripts (P < .05).

CONCLUSION

Findings indicate the existence of heterogeneously-sized IGFBP-4 species, of which the 27-kDa (as distinct from the 24-kDa) IGFBP-4 moiety constitutes a relatively minor component. The steady-state levels of granulosa cell-derived IGFBP-4 transcripts display relatively limited regulation in response to treatment with either FSH or IGF-I.

Synthesis and anticonvulsant activities of N-Benzyl-2-acetamidopropionamide derivatives

Studies have demonstrated that 2-substituted N-benzyl-2-acetamidoacetamides (2) are potent anticonvulsants. A recent investigation has led to the hypothesis that an important structural feature in 2 for maximal anticonvulsant activity is the placement of a small, substituted heteroatom moiety one atom from the C(2) site. This paper validates this hypothesis. Twelve derivatives of N-benzyl-2-acetamidopropionamide have been prepared in which six different heteroatom substituents (chloro, bromo, iodo, oxygen, nitrogen, and sulfur) were incorporated at the C(3) site. Highly potent activities were observed for the two oxygen-substituted derivatives, N-benzyl-2-acetamido-3-methoxypropionamide (18) and N-benzyl-2-acetamido-3-ethoxypropionamide (19). The ED50 values in mice following intraperitoneal (i.p.) dosing for the maximal electroshock-induced seizure test for 18 and 19 were 8.3 and 17.3 mg/kg, respectively. These values compared favorably to the ED50 value found for phenytoin (ED50 = 6.5 mg/kg). Comparable activities were observed for 18 and 19 upon oral (p.o.) administration to rats (18, ED50 = 3.9 mg/kg; 19, ED50 = 19 mg/kg; phenytoin, ED50 = 23 mg/kg). Evaluation of the individual stereoisomers for 18 demonstrated that the principal anticonvulsant activity resided in the (R)-stereoisomer. The ED50 value for (R)-18 was 4.5 mg/kg, and the ED50 for (S)-18 exceeded 100 mg/kg. This difference in activity for the two stereochemical isomers surpassed comparable values for other members within this class of compounds. The protective indices (PI = TD50/ED50) (where TD50 represents a neurotoxic dose impairing rotorod performance) for (R)-18 in mice (i.p.) and in rats (p.o.) were 6.0 and > 130, respectively.

CT of the bronchus intermedius: frequency and cause of a nodule in the posterior wall on normal scans

OBJECTIVE

A focal nodule in the posterior wall of the bronchus intermedius is occasionally observed on normal CT scans. The purpose of this study was to determine the frequency and the anatomic cause of this finding.

MATERIALS AND METHODS

We prospectively analyzed helical CT scans (10-mm collimation and 10-mm/sec table speed) for evaluating nodules in the posterior wall of the bronchus intermedius from 280 consecutive subjects. A focal round elevation in the posterior wall of the bronchus intermedius was considered a nodule. Frequency of visualization of the nodule was recorded. In patients showing such nodularity, additional enhanced CT scans with thinner slices (5-mm collimation and 5-mm/sec table speed) were obtained to elucidate the nature of the nodularity.

RESULTS

Nodularity in the posterior wall of the bronchus intermedius was observed in 14/280 total subjects (5%) on 10-mm collimation CT scans. On thin-section CT scans, the nodularity was caused by a branch of the vein from the posterior segment of the right upper lobe (10/14, 71%) or by a branch of the vein from the superior segment of the right lower lobe (4/14, 29%). The vein from the upper lobe that caused nodularity in the posterior wall of the bronchus intermedius drained into either the inferior pulmonary vein (7/10) or the superior pulmonary vein (3/10). In all patients whose nodularity was caused by the vein from the superior segment of the right lower lobe, the vein drained into the inferior pulmonary vein.

CONCLUSION

Focal nodularity in the posterior wall of the bronchus intermedius was caused by the draining pulmonary vein, and it was observed in 5% of normal subjects. This nodularity should be differentiated from uniform or lobular thickening associated with abnormality in the bronchus intermedius.