Fast algorithms for the estimation of motion vectors

In this correspondence, a fast motion estimation algorithm, based on the successive elimination algorithm (SEA) of Li and Salari (1995), is studied. This fast motion estimation algorithm finds the same displacement vectors as the exhaustive search algorithm with a reduced computational load. A modified fast motion estimation algorithm introducing negligible distortion into a transform coder, but providing for a further computational load reduction, is developed. Implementation issues are also discussed and compared. Results show that the number of searching operations can be reduced dramatically with the help of fast motion estimation algorithms.

Assessment of rapid morphological changes associated with elevated cAMP levels in human orbital fibroblasts

Orbital fibroblasts exhibit a phenotype distinct from that of other types of fibroblasts. Addition of prostaglandin E2 (PGE2) to culture medium elicits a dramatic change in orbital fibroblast morphology. That response is mediated through the generation of cAMP. Orbital fibroblasts can generate high levels of PGE2 through induction by proinflammatory cytokines of prostaglandin endoperoxide H synthase-2 (PGHS-2). Here we compare the influence on fibroblast morphology of exogenous PGE2, forskolin, and 8-br-cAMP to that mediated through PGHS-2 induction by a lymphocyte-derived cytokine. Within a few hours, orbital fibroblasts treated with any of these test compounds appear under phase-contrast microscopy to exhibit a stellate morphology. When these changes were assessed quantitatively by electric cell-substrate impedance sensing (ECIS), it became evident that 8-br-cAMP, forskolin, and PGE2 initiated shape changes within 30 min of addition to the culture medium, while effects of the cytokine were first evident after approximately 3.5 h. Dermal fibroblasts failed to respond to any of these compounds with regard to changes in cellular morphology. Analysis of micromotion, manifested as small impedance fluctuations, revealed that orbital fibroblasts treated with 8-br-cAMP exhibit less motion than did untreated cells. These results suggest that orbital fibroblast shape can be altered by several compounds known to alter intracellular cAMP levels. They demonstrate the utility of ECIS in the assessment of very rapid and dynamic cellular events associated with changes in cell morphology.

KCNQ2 and KCNQ3 potassium channel subunits: molecular correlates of the M-channel

The M-current regulates the subthreshold electrical excitability of many neurons, determining their firing properties and responsiveness to synaptic input. To date, however, the genes that encode subunits of this important channel have not been identified. The biophysical properties, sensitivity to pharmacological blockade, and expression pattern of the KCNQ2 and KCNQ3 potassium channels were determined. It is concluded that both these subunits contribute to the native M-current.

Preeclampsia is associated with reduced serum levels of placenta growth factor

OBJECTIVES

Adequate vascular development of the placental bed is essential for normal pregnancy. We assessed serum levels of placenta growth factor, an angiogenic factor, throughout normal pregnancy and determined its association with preeclampsia.

STUDY DESIGN

Serum samples were collected from (1) 308 healthy pregnant women throughout normal gestation, (2) at delivery from 30 each gestational age-matched patients with normal pregnancy and preeclampsia, and (3) maternal and cord blood samples from normal deliveries with and without labor (n = 37 each). Placenta growth factor levels were determined with an antigen-capture enzyme-linked immunosorbent assay.

RESULTS

Maternal placenta growth factor levels during normal pregnancy increased from the first trimester to the late second trimester; they subsequently declined from 30 weeks' gestation to delivery. Significantly less maternal placenta growth factor (P <.0001) was found in pregnancies complicated by preeclampsia, and labor significantly lowered placenta growth factor levels in both maternal (P =.0189) and cord serum samples (P <.0001).

CONCLUSION

Decreased levels of placenta growth factor during preeclampsia could influence endothelial cell and trophoblast function, thereby contributing to the pathogenesis of the disease.

Activation of human orbital fibroblasts through CD40 engagement results in a dramatic induction of hyaluronan synthesis and prostaglandin endoperoxide H synthase-2 expression. Insights into potential pathogenic mechanisms of thyroid-associated ophthalmopathy

Human orbital fibroblasts play a putative role in the pathogenesis of thyroid-associated ophthalmopathy (TAO). We hypothesize that the hyaluronan accumulation and inflammation in TAO derive from enhanced biosynthetic activities of orbital fibroblasts. CD40, a member of the tumor necrosis factor-alpha receptor superfamily, is a critical signaling molecule expressed by B lymphocytes. Engagement of CD40 with CD154 or CD40 ligand results in the activation of target genes. Orbital fibroblasts also display CD40. Here we report that CD40 engagement leads to substantial increases in hyaluronan synthesis in orbital fibroblasts. The increase is approximately 5-fold above control values, is comparable to the induction elicited by IL-1beta and could be attenuated with dexamethasone but not by SC 58125, a prostaglandin endoperoxide H synthase-2 (PGHS-2)-selective inhibitor. PGHS-2 is also induced by CD40 engagement in a time-dependent manner, and this is mediated through increases in levels of steady-state mRNA. The induction of PGHS-2 leads to a dramatically enhanced prostaglandin E2 production that can be blocked by SC 58125 and dexamethasone. CD40 ligand up-regulates the synthesis of IL-1alpha, and blocking this cytokine with exogenous IL-1 receptor antagonist (IL-1ra) or with IL-1alpha neutralizing antibodies partially attenuates the induction of PGHS-2. In contrast, CD40 ligand up-regulation of hyaluronan synthesis is unaffected by IL-1ra. CD40 cross-linking enhances mitogen-activated protein kinase activation, and interrupting this pathway attenuates the PGHS-2 induction. Thus the CD40/CD40 ligand bridge represents a potentially important activational pathway for orbital fibroblasts that may underlie the cross-talk between these cells and leukocytes. These findings may be relevant to the pathogenesis of TAO and provide insights into previously unrecognized, potential therapeutic targets.

Outcome of pregnancy after radioactive iodine treatment for well differentiated thyroid carcinomas

This study sought to determine the outcome of pregnancy in female patients with differentiated thyroid carcinoma who became pregnant after radioactive iodide treatment. A total of 779 female thyroid cancer patients were treated at Chang Gung Medical Center in Linkou between January 1977 and December 1995. The medical records of these patients were reviewed retrospectively. Thirty-seven of these patients had well differentiated thyroid carcinoma receiving 131I treatment and conceived at a mean age of 27.97 +/- 3.49 year-old. A total of 58 pregnancy episodes were recorded during this study period. Among these 37 patients, 3 episodes of artificial abortion, 8 episodes of spontaneous abortion and 2 threatened abortions were observed. These patients delivered a total of 47 babies including 3 premature babies. Seven of these patients conceived within 6 months after the last administration of 131I, including 2 cases within 1 month, 4 cases within 4 months, and 1 patient within 5 months. Of these 7 patients, only one patient who conceived within 6 months after the last administration of 131I (14.3%) had a spontaneous abortion. The present results suggest that previous administration of 131I in female patients with well differentiated thyroid cancer does not result in demonstrable adverse effects in subsequent pregnancies. However, further studies involving long-term follow-up of children delivered by mothers who became pregnant within 6 months after the last administration of 131I is needed to further elucidate the possible chronic effects and sequelae of 131I therapy on subsequent pregnancies.

Serpin=serine protease-like complexes within neurofilament conglomerates of motoneurons in amyotrophic lateral sclerosis

Neurofilamentous conglomerates (NfCg), as axonal spheroids or conglomerates in motoneurons, are the histopathologic hallmarks for early stages of amyotrophic lateral sclerosis (ALS). We hypothesize that NfCg may be formed by post-translational modifications of altered Nf proteins that include: (1) hyperphosphorylation, (2) glycosylation (or glycoxidation), (3) nitration, (4) ubiquitination and/or (5) crosslinking by the Ca++-dependent transglutaminase (TGase). These, as well as other changes, are predicted to be initiated or accentuated by oxidative damage. The damaged Nf proteins then activate cascades of intracellular protein degradation which include ATP-dependent ubiquitin/proteasome proteolysis. Other proteolytic systems, either Ca++-dependent or independent, may also be activated, such as serine and cysteine protease systems. These enzymes, either lysosomal or non-lysosomal may also participate in the degradation of damaged Nf proteins being balanced by their cognate inhibitors. Protein complexes formed by these protease=inhibitor systems, along with damaged Nf proteins, may accumulate within the cell bodies as neuronal inclusions, since a number of intracellular inclusions are found in motor neurons in ALS. In the current study, we investigated the involvement of serine proteases and their serpins in NfCg formation. Pairs of three serine proteases (trypsin, chymotrypsin and thrombin) and their cognate serpins (alpha1-anti-trypsin, alpha1-anti-chymotrypsin, and protease nexin I) were probed in motoneurons with their antibodies for both NfCg and inclusions. Positive immunoreactivities for all serine proteases and their cognate serpins support the contention that the imbalance of serine proteases and internalized serpins may have a role in formation of NfCg and inclusions, and hence, the pathogenesis of ALS.

Cloning of a mammalian elk potassium channel gene and EAG mRNA distribution in rat sympathetic ganglia

1. Three new members of the EAG potassium channel gene family were identified in rat and the complete coding sequence of one of these genes (elk1) was determined by cDNA cloning. 2. The elk1 gene, when expressed in Xenopus oocytes, encodes a slowly activating and slowly deactivating potassium channel. 3. The elk1 gene is expressed in sympathetic ganglia and is also expressed in sciatic nerve. 4. Six of the seven known EAG genes were found to be expressed in rat sympathetic ganglia, suggesting an important functional role for these channels in the sympathetic nervous system.

The changing pattern of intestinal tuberculosis: 30 years' experience

SETTING

Although the incidence of tuberculosis had been decreasing for many years, it has recently risen.

OBJECTIVES

To investigate the changes in the pattern and distribution of intestinal tuberculosis and to alert surgeons to the importance of maintaining a high index of suspicion for this disease entity.

DESIGN

Retrospective analysis of 134 patients with intestinal tuberculosis discharged from the Veterans General Hospital in Taipei from 1965 to 1995. All records, bacteriological examinations and pathological specimens were reviewed and extracted onto a standard questionnaire.

RESULTS

A decline in the case numbers of intestinal tuberculosis was noted after 1975. However, there seems to be a slight rise in case numbers since 1990. The average age of those patients after 1990 (64.8 years) is higher than those before 1990 (44.4 years). None of our patients had clinical signs of human immunodeficiency virus (HIV) infection. Most patients (81.3%, 109/134) had not received a definite diagnosis until surgery. Active pulmonary tuberculosis was found in 37 patients (29.1%).

CONCLUSION

The possible reasons for the rise in cases of intestinal tuberculosis in our patients may be linked to an increased life expectancy, the reappearance of some formerly 'silent' tuberculosis cases, and relapse in patients having received incomplete antituberculosis chemotherapy. Its insidious and non-specific clinical presentation makes the diagnosis of intestinal tuberculosis difficult. An increased index of suspicion and greater familiarity with the disease may shorten the time of diagnosis and may also prevent some unnecessary operations.

Advanced glycation endproducts in neurofilament conglomeration of motoneurons in familial and sporadic amyotrophic lateral sclerosis

BACKGROUND

Massive neurofilament conglomeration in motor neurons has been described to occur in the early stages of both familial and sporadic amyotrophic lateral sclerosis (ALS). Previously, neurofilament conglomerates were immunolabeled for both superoxide dismutase (SOD1) and nitrotyrosine, suggesting the potential for oxidative nitration damage to neurofilament protein by peroxynitrite. Long-lived neurofilaments may also undergo modification by advanced glycation endproducts (AGEs) with concomitant generation of free radicals, including superoxide. This radical species may then react with nitric oxide to form the potent oxidant, peroxynitrite, which in turn can nitrate neurofilament protein. Such a glycated and nitrated neurofilament protein may become resistant to proteolytic systems, forming high-molecular-weight protein complexes and cytotoxic, neuronal inclusions.

MATERIALS AND METHODS

Paraffin sections containing both neurofilament conglomerates and neuronal inclusions were obtained from patients with sporadic (n = 5) and familial (n = 2) ALS and were probed with specific antibodies directed against the AGEs cypentodine/piperidine-enolone, arginine-lysine imidazole, pentosidine, and pyrraline.

RESULTS

Neurofilament conglomerates, but not neuronal inclusions, were intensely immunolabeled with each of the anti-AGE antibodies tested. The immunoreactivity was selective for neurofilament conglomerates and suggested that AGEs may form inter- or intramolecular cross-links in neurofilament proteins.

CONCLUSIONS

These data support the hypothesis that AGE formation affects neurofilament proteins in vivo and is associated with the concomitant induction of SODI and protein nitration in neurofilament conglomerates. AGE formation in neurofilament protein may not only cause covalent cross-linking but also generate superoxide and block nitric oxide-mediated responses, thereby perpetuating neuronal toxicity in patients with ALS.

Bone marrow metastasis in astrocytic gliomata

With the increasing survival time of many pediatric patients with malignancies, unexpected symptoms or signs require diligent search for rare complications or second cancers related to the disease or treatment. We recently encountered a patient with extensive glioblastoma multiforme who developed pancytopenia six months after completion of treatment with craniospinal radiation and chemotherapy with etoposide and cyclophosphamide. Bone marrow aspirate and biopsy confirmed bone marrow metastasis from the brain tumor. He showed good partial remission with chemotherapy with carmustine and cis-platinum as demonstrated by serial bone marrow aspirate for cytology and cytogenetics and enjoyed good quality of life for eight months. 14 other patients with astrocytic glioma, two of whom are children, are reported in the literature to have diffuse bone marrow metastasis. Therefore, in patients with malignant astrocytic tumor, bone marrow metastasis, though not common, should be considered when bone pain or cytopenias occur, especially when prolonged.

Microtubule-interfering agents activate c-Jun N-terminal kinase/stress-activated protein kinase through both Ras and apoptosis signal-regulating kinase pathways

The essential cellular functions associated with microtubules have led to a wide use of microtubule-interfering agents in cancer chemotherapy with promising results. Although the most well studied action of microtubule-interfering agents is an arrest of cells at the G2/M phase of the cell cycle, other effects may also exist. We have observed that paclitaxel (Taxol), docetaxel (Taxotere), vinblastine, vincristine, nocodazole, and colchicine activate the c-Jun N-terminal kinase/stress-activated protein kinase (JNK/SAPK) signaling pathway in a variety of human cells. Activation of JNK/SAPK by microtubule-interfering agents is dose-dependent and time-dependent and requires interactions with microtubules. Functional activation of the JNKK/SEK1-JNK/SAPK-c-Jun cascade (where JNKK/SEK1 is JNK kinase/SAPK kinase) was demonstrated by activation of a 12-O-tetradecanoylphorbol-13-acetate response element (TRE) reporter construct in a c-Jun dependent fashion. Microtubule-interfering agents also activated both Ras and apoptosis signal-regulating kinase (ASK1) and coexpression of dominant negative Ras and dominant negative apoptosis signal-regulating kinase exerted individual and additive inhibition of JNK/SAPK activation by microtubule-interfering agents. These findings suggest that multiple signal transduction pathways are involved with cellular detection of microtubular disarray and subsequent activation of JNK/SAPK.

Expression of insulin-like growth factor-binding protein-1 (IGFBP-1) mRNA in embryos and endometrial stromal cells

The objective of the present study was to investigate the effects of insulin-like growth factor-binding protein-1 (IGFBP-1) on the interaction between mouse embryos and endometrial stromal cells in co-culture systems. To explore quantitatively the changes in expression of IGFBP-1 mRNA from endometrial stromal cells cultured alone or co-cultured with embryos, a combination of reverse transcription-polymerase chain reaction (RT-PCR) and Southern blotting followed by a densitometric analysis was used. In co-culture systems, development of embryos was significantly improved and the production of IGFBP-1 from endometrial stromal cells was stimulated by the embryos. Quantitative analysis showed that expression of IGFBP-1 mRNA in endometrial stromal cells co-cultured with embryos was higher on days 3,5 and 8 (1.6-, 4.5- and 2.3-fold respectively) than in endometrial stromal cells cultured alone. In addition, intensity of PCR products for IGFBP-1 mRNA in endometrial stromal cells co-cultured with embryos was higher on day 5 than on days 3 and 8. However, the expression of IGFBP-1 mRNA in embryos cultured alone was very low. In conclusion, co-culture of embryos with endometrial stromal cells improved the development of embryos and may be associated with the production of IGFBP-1 by the co-cultured endometrial stromal cells. A combination of RT-PCR and Southern blotting followed by a densitometric analysis appeared to be a sufficiently quantitative method to determine changes in IGFBP-1 mRNA values.

Identification of two nervous system-specific members of the erg potassium channel gene family

Two new potassium channel genes, erg2 and erg3, that are expressed in the nervous system of the rat were identified. These two genes form a small gene family with the previously described erg1 (HERG) gene. The erg2 and erg3 genes are expressed exclusively in the nervous system, in marked contrast to erg1, which is expressed in both neural and non-neural tissues. All three genes are expressed in peripheral sympathetic ganglia. The erg3 channel produces a current that has a large transient component at positive potentials, whereas the other two channels are slowly activating delayed rectifiers. Expression of the erg1 gene in the sympathetic nervous system has potential implications for the etiology of the LQT2 form of the human genetic disease long QT syndrome.

Human thyroid fibroblasts exhibit a distinctive phenotype in culture: characteristic ganglioside profile and functional CD40 expression

Fibroblasts from different regions of the human body exhibit substantial phenotypic diversity, some of which relates to the capacity for cross-talk with cells of the immune system. We examine, for the first time, thyroid fibroblast biology in culture. Thyroid explants were placed in culture, and fibroblasts were outgrown and serially passaged. These fibroblasts take on a morphology in culture resembling cells from other anatomic regions. When treated with PGE2, they assume a stellate morphology similar to that of prostanoid-treated orbital fibroblasts. The ganglioside profile exhibited by these cells is distinct from that observed previously in orbital and dermal fibroblasts. They uniformly express Thy-1, a surface glycoprotein. Messenger RNA encoding CD40, a surface receptor found on bone marrow-derived cells, and CD40 protein were expressed constitutively at low levels. Interferon-gamma (500 U/ml) treatment for 48-72 h resulted in high levels of surface HLA-DR and CD40 display. When CD40 is engaged with CD40 ligand (CD40L), nuclear factor-kappaB binding activity is up-regulated as is interleukin (IL)-6 and IL-8 expression. IL-1beta treatment up-regulates the expression of IL-1alpha, IL-1beta, and PGE2. These observations suggest that thyroid fibroblasts possess the molecular machinery necessary for cross-talk with immunocompetent cells such as lymphocytes and mast cells through the CD40/CD40L complex, as well as through classic cytokine networks, and to participate potentially in the inflammatory response of the thyroid gland.

Aberrant glycosylation/phosphorylation in chromatolytic motoneurons of Werdnig-Hoffmann disease

Chromatolytic motor neurons (cMN) in Werdnig-Hoffmann disease (WHD) were investigated in both spinal anterior horns and hypoglossal nuclei with both immuno- and lectin-histochemistry in six cases (3-9 months; two female and four male) of clinically typical WHD. Most characteristic findings from lectin-histochemistry were central accumulation of N-linked glycopeptides and marked general paucity of O-linked glycopeptides in cMN. Phosphorylated intermediate filaments, developmentally regulated cytoskeletons and cell adhesion molecules were abundant at the periphery of cMN, as visualized with immunohistochemistry. Both N-linked and O-linked glycoproteins were reciprocally absent or scarce at the peripheral zone of cMN. This intriguing phenomenon provided the basis for postulating the pathogenesis of WHD. The reciprocal ('yen-yang') dissociation of phosphorylation and glycosylation of neurofilament proteins was only seen with phosphorylated neurofilaments and seen only in cMN, not in the control or surrounding unaffected motoneurons. The central accumulation of N-linked glycopeptides was in contrast with peripheral absence of O-GlcNAc-linked glycopeptides which would normally be expected to colocalize with phosphorylated neurofilaments. Both O-glycosylation and phosphorylation are considered essential for assembly and network of neurofilaments. Aberrant O-glycosylation and dissociation of O-glycosylation/phosphorylation would not only cause a defect in neurofilament assembly but also neuron-glia adhesion (via a molecule such as Ng-CAM), causing a failure of lower motoneurons to synapse homophilically with the upper motoneurons and also a failure to adhere heterophilically to glia, resulting in the histopathologic tetrad ((i) central chromatolysis, (ii) empty-cell beds, (iii) migratory motoneurons and (iv) glial bundles of spinal roots) typical of WHD.

Unexpected and differential effects of Cl- channel blockers on the Kv4.3 and Kv4.2 K+ channels. Implications for the study of the I(to2) current

The Kv4.3 K+ channel is thought to underlie the Ca(2+)-insensitive transient outward current (I(to1)) in ventricular myocytes of canine and human heart and to contribute to the I(to1) in rat myocytes. It has been suggested that there is a second component of the transient outward current in some species that is contributed by a Ca(2+)-activated Cl- current (known as I(to2)). The evidence for the existence of the I(to2) current is based, in part, on the pharmacological effects of various Cl- channel blockers. To test for possible interactions between these compounds and I(to1), the effect of several different Cl- channel blockers on the Kv4.3 channel was examined. The fenamates (niflumic and flufenamic acid) were found to have large effects on the position of the steady state inactivation curve of the Kv4.3 channel. The disulfonic stilbenes (DIDS and SITS) had markedly different effects and were found to greatly reduce the rate of recovery from inactivation of the Kv4.3 channel without large changes in the position of the activation and steady state inactivation curves. Both classes of drugs produced an apparent blockade of the Kv4.3 channel under some recording conditions. Surprisingly, the closely related Kv4.2 channel was found to be markedly less sensitive to these drugs. Caffeine was found to block both the Kv4.3 and Kv4.2 channels to a similar extent. These nonspecific drug effects have implications for the study of the two components of the transient outward current and suggest that purely pharmacological criteria cannot be used to define the physiological role of I(to2).

Role of fibronectin and sulfated proteoglycans in endothelial cell migration on a cultured smooth muscle layer

Endothelial cell (EC) migration is essential for the healing of denudation injuries to the vessel wall. This event occurs in vivo in a pericellular environment and should be regulated in part by juxtacrine and paracrine interactions with underlying smooth muscle cells (SMCs). To investigate the EC migration behavior over SMCs under direct cell-cell contact conditions, we have utilized human umbilical vein endothelial cells (HUVECs) grown to confluence on microcarrier beads and radiolabeled with chromium-51. The EC carrying beads were spread over a confluent human aortic SMC monolayer and cocultured for 48 hr, allowing the EC to migrate from beads onto the underlying SMC monolayer in the presence of sodium chlorate, cycloheximide (CHM), or anti-fibronectin monoclonal antibody (anti-FN mAb). The level of EC migration was quantified by counting the amount of radioactivity on the SMC layer after the removal of the beads. The presence of a SMC layer enhanced EC migration more than threefold (P < 0.05). Furthermore, EC migration was inhibited from 30 to 80% (P < 0.05) by sodium chlorate, CHM, and anti-FN mAb in a dose-dependent fashion. This model has shown that smooth muscle cells augment endothelial motility. Both fibronectin and sulfated proteoglycans released by ECs and SMCs likely play an important role in the regulation of EC migration behavior over SMCs. The method described of using radiolabeled ECs on microcarrier beads should prove to be a useful tool in the study of cell migration in a heterotypic cellular environment.

Large bowel tuberculosis and possible influencing factors for surgical prognosis: 30 years' experience

The incidence of tuberculosis is rising in the United States. Similarly, the incidence of pulmonary tuberculosis in Taiwan is increasing, but that of large bowel tuberculosis in this region has not been reported. The purpose of this study was to investigate the changing disease pattern and to determine some possible surgical prognostic factors for large bowel tuberculosis. Seventy cases of large bowel tuberculosis treated at our institute during the period 1965-1995 were reviewed and analyzed. A steady decline in the case number of large bowel tuberculosis were noted from 1975, but there seems to be a slight increase in cases since 1990. The average age of these patients was 65.1 years, and none had human immunodeficiency virus infection. The ileocecum is the most common region of involvement. Of these 70 patients, 59 had not been definitively diagnosed until surgery. Active pulmonary tuberculosis was found in 18 patients (25.7%). The incidence of postoperative pulmonary complications was higher in patients with active pulmonary tuberculosis or disseminating large bowel tuberculosis. Postoperative abdominal complications, including intestinal obstruction, abdominal cutaneous fistula, and wound infection, were seen in 13 patients, none of whom had active pulmonary tuberculosis. Although the incidence of tuberculosis has been reduced for years, it is now rising. Physicians should bear in mind the possibility of large bowel tuberculosis in patients with intestinal obstruction without specific origin. Postoperative respiratory care is important for patients with pulmonary tuberculosis, with either active or disseminating lesions.

Effects of glucose on placental hormones in the human term placenta in vitro

Glucose intake during pregnancy results in a decrease in endogenous insulin-like growth factor binding protein-1 (IGFBP-1). However, the exact role of glucose on placental secretion of IGFBP-1 is unclear. This study was designed to investigate the direct effects of glucose on the production of IGFBP-1 and other placental hormones, using an isolated placental preparation. Using the dual recirculating perfusion system for an isolated human placenta lobule, a total of 43 experiments were performed over a duration of 6 hours. Twenty placentae were perfused with a medium containing 141 +/- 10 mg/dL (7.83 +/- 0.56 mmol/L) glucose (group I) and 23 placentae with 242 +/- 12 mg/dL (13.43 +/- 0.67 mmol/L) glucose (group II). Levels of insulin, glucose, lactate, insulin-like growth factor (IGF-I), IGFBP-1, human placental lactogen (hPL) and beta-human chorionic gonadotropin (beta-hCG) were measured at 30 minute intervals during perfusion. Insulin and IGF-I were barely detectable in the perfusates and their levels were not modulated by glucose. IGFBP-1 was predominantly detected in the maternal rather than the fetal compartment of the placental circulation. Glucose increased the levels of IGFBP-1 in the maternal circulation in groups I and II during the first two hours of perfusion (188 +/- 58% and 193 +/- 31%, respectively). However, during the subsequent 4 hour period, the increase in IGFBP-1 concentration was significantly higher in group II (926 +/- 427%) than in group I (428 +/- 216%) (p < 0.05). There was no difference in the levels of hPL or beta-hCG between the two groups in the maternal circulation. Thus, glucose stimulates the production of IGFBP-1 in the maternal circulation of a placenta in vitro. This increase in IGFBP-1 by glucose in vitro, as opposed to the decrease of IGFBP-1 in vivo, may be due to a lack of circulatory maternal insulin in the isolated placental preparation. These results also suggest that there may be a functional barrier within the placenta that prevents an increase in the level of IGFBP-1 in the fetal circulation.

Endothelial cells exhibit differential chemokinetic and mitogenic responsiveness to alpha-thrombin

Rapid regeneration of the endothelium is a critical component of vascular wall repair because limitations of this process enhance early thrombotic and vasospastic complications, as well as late sequelae of recurrent lesion formation. We have postulated that direct activation of the thrombin receptor initiates both mitogenic and chemokinetic endothelial behavior which facilitates intimal repair. To characterize the role of the thrombin receptor in human endothelial cell (EC) proliferation and migration, we investigated the effects of both alpha-thrombin (0.5-10 U/ml) and its receptor-activating peptide (TRAP; 1-100 microM). Responses of human aortic (HAEC) and umbilical vein (HUVEC) were characterized using [3H]thymidine and 61Cr microcarrier bead assays of proliferation and migration, respectively. Expression of motility-related genes was evaluated using a ribonuclease protection assay. Thrombin exerts both of its chemokinetic and mitogenic effects differentially in human endothelial cells. Following 2 or 4 days in culture, HUVEC proliferation increased two- to threefold after exposure to thrombin, primarily in the low concentration range (P < 0.05). However, HACE proliferation was inhibited up to 50% after a 4-day incubation period (P < 0.005). These mitogenic effects, including the inhibition of aortic endothelial cell proliferation, were reproduced, in part, by thrombin receptor activation with TRAP. In contrast, thrombin stimulates migratory responses in HAEC, but not HUVEC. However, this behavior was not reproduced by TRAP. It is noteworthy that urokinase-plasminogen activator (u-PA) expression was much more strongly expressed in migrating HAEC than in the HUVEC population. Moreover, when stimulated with thrombin, u-PA gene expression was significantly augmented in HAEC. It has been speculated that an effective human thrombin receptor (HTR) antagonist may reduce the proliferation of vascular smooth muscle cells and the development of a restenotic lesion following arterial wall injury. Our data suggest that such an inhibitor will likely also accelerate intimal regeneration through a dominant effect on limiting the HTR inhibitory effect on endothelial proliferation.

Role of cavum septum pellucidum in akinetic mutism of hydrocephalic children

Two children 9 and 13 years of age with histories of aqueductal stenosis developed akinetic mutism after multiple shunt revisions. The girl had spontaneous relief of her akinetic mutism 1 month later, after parenteral antibiotics and multiple shunt revisions. The akinetic mutism of the boy was resistant to antiparkinsonian therapy before megadosage of bromocriptine (120 mg/day). Both children had a prominent cavum septum pellucidum (CSP), which has rarely been involved in the pathogenesis of akinetic mutism. Because of the rapid shrinkage of the girl's CSP after shunt revision, but not that of the boy even after stereotactic fenestration of the wall of his CSP, their eventual outcomes were different. Wide CSP (WCSP) may play an important role in the occurrence of akinetic mutism in hydrocephalic patients.