Enhanced expression of granulosa cell low density lipoprotein receptor activity in response to in vitro culture conditions

Previous studies have shown that the B/E (low density lipoprotein [LDL]) receptor pathway plays a minor role in cholesterol uptake in the intact rat ovary, but when granulosa cells are isolated and maintained in culture, the cells develop a fully functional B/E receptor system. In the current study we examined the development of the B/E receptor over time (96 h) in culture and compared its physiological function, expression of mRNA and protein levels, and morphological events to the upregulation induced in 24 h by hormone (human chorionic gonadotropin [hCG] or Bt2cAMP). With both protocols, increased progestin production occurs and is associated with elevated binding, uptake, and degradation of LDL in the medium although the impact of Bt2cAMP stimulation on all these measurements is several times that observed with time alone. Only the hormone-stimulated LDL receptor response was associated with an increase in receptor protein (Western blot) or mRNA levels (RNase protection assay). We conclude that unstimulated granulosa cells show posttranslational increases in B/E receptor activity with time in culture, but transcriptional changes in B/E receptor follow stimulation with trophic hormone or its second messenger, cAMP.

Is clumsiness a marker for Asperger syndrome?

Although Asperger syndrome (AS) has been included in the ICD-10 as a distinct category within the pervasive developmental disorders, it is still unclear to what extent it differs from normal-intelligence autism (high-functioning autism; HFA). Persons with AS are said to be particularly clumsy. To test the hypothesis that clumsiness can reliably distinguish AS from autism, the present authors compared 11 patients with AS (ICD-10; 10 males; mean age, 13.6 years; mean IQ, 98) with nine patients with HFA (ICD-10/DSM-III-R; eight males; mean age, 12.9 years; mean IQ, 84). Clumsiness was assessed by the Bruininks-Oseretsky test. Both groups showed problems with coordination and the distribution of standard scores was virtually identical. This suggests that motor clumsiness, as measured by tests of coordination, may not reliably distinguish AS from HFA. However, qualitative differences may occur between the two groups in the manner in which movements are performed. Further research with larger samples may elicit differences into the pattern of motor deficits that occur in autism and AS.

Mutations affecting the pattern of the PNS in Drosophila reveal novel aspects of neuronal development

Through a systematic genetic screen, we have identified 55 mutations that affect the development of the PNS of Drosophila embryos. These mutations specify 13 novel and 5 previously characterized genes and define new phenotypes for 2 other known genes. Five classes of mutant phenotypes were identified in the screen: gain of neurons, loss of neurons, abnormal position of chordotonal neurons, aberrant neuronal trajectories, and abnormal morphology of neurons. Phenotypic analyses of mutations identified in this study revealed three novel aspects of PNS development. First, we have identified a novel gene that may be required to define glial versus neuronal cell identity. Second, our data indicate that neuronal migration plays an important role in pattern formation in the embryonic PNS. Third, we have identified mutations that cause a lack of sensory organs, but unlike mutations in proneural genes, do not affect the formation of sensory organ precursors. These genes may be required for key aspects of neuronal differentiation. Our studies suggest that approximately 70 essential genes are required for proper PNS development in Drosophila embryos.

Effect of okadaic acid on utilization of lipoprotein-derived cholesteryl esters by rat steroidogenic cells

This study examines various functional, biochemical, and structural changes in rat adrenocortical and ovarian granulosa cells that could account for the decline in lipoprotein-supported hormone production after cell treatment with the protein phosphatase inhibitor, okadaic acid. Although the steroidogenic pathway enzymes in these cells are not in themselves affected by okadaic acid, the intracellular transport of cholesterol to important cellular processing sites is defective. That is, okadaic acid does not interfere with the internalization of lipoprotein-derived cholesteryl esters, but the mitochondrial utilization of cholesterol obtained from intracellular cholesterol storage sites is 50% reduced as compared to control cells. Two-dimensional electrophoresis gels from okadaic acid-treated cells demonstrate a number of hyperphosphorylated proteins. Morphological examination of the affected cells reveal completely disrupted Golgi complexes with attendant structures, but otherwise the cells appear unchanged. The results suggest that some necessary sterol transport protein (or cofactor or associated membrane) is adversely phosphorylated by okadaic acid, and is rendered dysfunctional.

Chronic recurrent multiple evanescent white dot syndrome

PURPOSE

Multiple evanescent white dot syndrome (MEWDS) is usually unilateral, self-limited, and monophasic. The purpose of this study was to demonstrate that a chronic recurring form of the disease exists.

METHODS

Three patients with otherwise typical MEWDS were observed for 4 to 5 years. Their ocular histories and physical findings were recorded.

RESULTS

Multiple recurrences (5-7) involving both eyes were noted in each of the three patients. Classic clinical findings were seen, including granularity to the macula, white dots, and optic disc changes. Despite these recurrences, the patients still retained visual acuity of 20/20 in each eye.

CONCLUSION

A chronic recurrent form of MEWDS exists. The cause of MEWDS remains unknown, and it is unclear why these patients demonstrated this atypical clinical course.

Spinal posture, sagittal mobility, and subjective rating of back problems in former female elite gymnasts

This study analyzed posture, spinal sagittal mobility, and subjective back problems in former female elite gymnasts in comparison with matched control subjects. The former gymnasts had less thoracic kyphosis than the control subjects. No difference in thoracic range of motion was found. In the lumbar spine there was no difference as to either posture or sagittal motion. The former gymnasts did not report a higher frequency of current back problems. In the former gymnasts 27% had subjective back problems. In the control subjects the corresponding value was 38%. We did not find any correlation between posture or range of motion and subjective rating of back problems in either of the groups. In conclusion, former female elite gymnasts did not have more back problems than an age matched control group.

Role of native disulfide bonds in the structure and activity of insulin-like growth factor 1: genetic models of protein-folding intermediates

Insulin and insulin-related proteins contain three motif-specific disulfide bonds. Here we examine the role of these disulfide bonds in the folding and function of one family member, human insulin-like growth factor 1 (IGF-1). Analogues containing pariwise Cys-->Ser or Cys-->Ala substitutions were expressed in Escherichia coli, purified, and analyzed with respect to receptor-binding, solution structure, and thermodynamic stability. An analogue lacking all three disulfide bonds (designated des-Cys-IGF-1) is inactive and unfolded. Introduction of the [18-61] disulfide bond, previously shown to occur in an early intermediate in oxidative refolding [Miller, J. A., Owers-Narhi, L., Hua, Q. X., Rosenfeld, R., Arakawa, T., Rohde, M., Prestrelski, S., Lauren, S., S. Stoney, K. S., Tsai, L., & Weiss, M. A. (1993) Biochemistry (preceding paper in this issue)], results in a compact partially folded state with low but significant biological activity. Additional but incomplete structural organization and biological activity are observed following introduction of either the [6-48] or the [47-52] disulfide bonds. Native function, structure, and stability require the presence of all three disulfide bonds. These analogues provide genetic models of IGF-1 protein-folding intermediates. Their characterization suggests that bifurcation of the IGF-1 folding pathway reflects alternative late steps in the folding of a molten-globule intermediate.

Oxidative refolding of insulin-like growth factor 1 yields two products of similar thermodynamic stability: a bifurcating protein-folding pathway

Can one protein sequence encode two structures? Oxidative folding of human insulin-like growth factor 1 (IGF-1), a globular protein of 70 residues, is shown to yield two products of similar thermodynamic stability. This observation is of particular interest in light of the recent demonstration that two of the three disulfide bonds in native IGF-1 rearrange in the presence of dithiothreitol [Hober, S., et al. (1992) Biochemistry 31, 1749-1756]. Kinetics of the IGF-1 folding pathway were monitored by high-performance liquid chromatography (rp-HPLC). Disulfide-pairing schemes of intermediates and products were established by peptide mapping. Two disulfide isomers were obtained as products: one with native insulin-like pairing [6-48; 18-61; 47-52] (designated native IGF-1; 60% yield) and the other with alternative pairing [6-47; 18-61; 48-52] (designated IGF-swap; 40% yield). The predominant early intermediate contains the single disulfide 18-61, which is shared in common by the two products. Relative yields of native IGF-1 and IGF-swap are independent of protein concentration under dilute conditions. In the absence of an added thiol reagent, each isomer is stable indefinitely at neutral pH; in the presence of an added thiol reagent, the two isomers interconvert with an Arrhenius activation barrier of 12 kcal/mol. Interconversion does not require complete reduction and yields the same ratio of products as initial folding, demonstrating thermodynamic control. Spectroscopic studies using circular dichroism (CD), infrared spectroscopy (FTIR), two-dimensional 1H-NMR (2D-NMR), and photochemical dynamic nuclear polarization (photo-CIDNP) suggest that IGF-1 and IGF-swap adopt similar secondary structures but distinct tertiary folds. Implications of these observations for understanding the topology of protein-folding pathways are discussed.

Pseudoverdin, a compound related to the pyoverdin chromophore from a Pseudomonas aeruginosa strain incapable to produce pyoverdins

From a genetically manipulated strain of Pseudomonas aeruginosa ATCC 15692 (PAO1 strain) a compound named pseudoverdin, 3-formylamino-6,7-dihydroxycoumarin, was obtained which is related to the typical pyoverdin chromophore and thus allows to shed some light on the biogenesis of the latter.

Basal concentrations of anabolic and catabolic hormones in relation to endurance exercise after short-term changes in diet

This study aimed to use a classical model to analyse whether alterations in performance due to short-term changes in diet are reflected in peripheral basal anabolic and catabolic hormone concentrations. Six healthy students (two women and four men) performed a cross-over study including three test situations. The reference test was preceded by each subject's normal unrestricted diet of western type (N). After this, three of the subject's were provided a carbohydrate-rich diet (CHO) for 3 days followed by the second test. Following this test, a carbohydrate deficient, protein/fat rich diet (F) was provided for another 3 days followed by the third test. The remaining three subjects had these diets in reverse order. Basal concentrations of cortisol (C), sex hormone-binding globulin (SHBG), insulin-like growth factor (IGF-I), total-testosterone and non-SHBG-bound-testosterone (NST), the NST:C ratio and an ergometer cycle endurance test with measurements of submaximal as well as measurements of maximal oxygen uptake, heart rate, respiratory exchange ratio (R), free fatty acids (FFA), glycerol and lactate were investigated. All the subjects were involved in athletics for recreation and during the study they performed daily physical exercise according to their normal routine. After the F diet only two of the subjects completed the test. One woman dropped out after 16 min, two men dropped out after 14 min and one after 13 min of cycling. After the CHO diet all six subjects completed the ergometer cycle test. Considering the whole group, there were no significant differences in lactate or glycerol concentrations during the study.(ABSTRACT TRUNCATED AT 250 WORDS)

Inactivation of glucose-6-phosphate dehydrogenase by 4-hydroxy-2-nonenal. Selective modification of an active-site lysine

Incubation of glucose-6-phosphate dehydrogenase from Leuconostoc mesenteroides with 4-hydroxy-2-nonenal (HNE) results in a pseudo first-order loss of enzyme activity. The pH dependence of the inactivation rate exhibits an inflection around pH 10, and the enzyme is protected from inactivation by glucose 6-phosphate. Loss of enzyme activity corresponds with the formation of one carbonyl function per enzyme subunit and the appearance of a lysine-HNE adduct. The data presented in this paper are consistent with the view that the epsilon-amino group of a lysine residue in the glucose 6-phosphate-binding site reacts with the double bond (C3) of HNE, resulting in the formation of a stable secondary amine derivative and loss of enzyme activity. We have described a mechanism by which HNE may, in part, mediate free radical damage. In addition, a method for the detection of the lysine-HNE adduct is introduced.

Isoforms of procarboxypeptidase B, (pancreas-specific protein, PASP) in human serum, pancreatic tissue and juice

Human Pancreas-Specific Protein (PASP) has been described as a useful serum marker for pancreatic graft rejection and acute pancreatitis. By molecular cloning PASP has recently been identified as procarboxypeptidase B (PCPB). By use of SDS-gel electrophoresis and Western blots, PASP isoforms (proteins interacting with PASP-antiserum) have now been explored in serum and pancreatic tissue and juice. In serum from healthy volunteers, six different isoforms could be visualised. Their MW varied as follows: > 100 K, about 100 K, 45 K, 35-40 K (two bands) about 30 K and 16 K. The 45 K band, corresponding to PASP purified from pancreatic tissue, was always the major band. In pancreatic cytosol and pancreatic juice, the major band corresponded to PASP (45 K) but weak bands were also seen at MW of 40, 30 and 16 K. In serum from 15 patients with acute pancreatitis, PASP was highly increased. Bands corresponding to PASP/PCPB as well as carboxypeptidase B (CPB) were seen simultaneously. During recovery PASP in serum was normalised and the CPB band disappeared. During 12 episodes of pancreatic graft rejection, PASP in serum was also increased but no changes of isoforms in serum were detected. However during these episodes isoforms in pancreatic juice changed dramatically. The band corresponding to PASP disappeared or became much weaker and only bands with lower MW were seen. We have thus observed changes in PASP/PCB serum isoforms during episodes of acute pancreatitis but not at graft rejection episodes although the total increase of PASP in serum was of the same magnitude.(ABSTRACT TRUNCATED AT 250 WORDS)

Arthroscopic surgery of the knee in local anaesthesia. An analysis of age-related pathology

Arthroscopy of the knee joint was performed in 356 consecutive outpatients in local anaesthesia and without premedication. A continuous pressure-irrigation system was used with 0.2% lidocaine chloride solution in the irrigation fluid, following administration of 5-7 ml prilocaine with epinephrine in each portal. All patients had clinical symptoms of internal derangement of the knee, such as meniscal, cruciate ligament injury or osteoarthritis. Associated intra-articular pathology was registered. Intra-articular surgery was performed in 228 cases. This included partial or subtotal meniscectomy in 207 cases and meniscus suture in 3 cases. In 18 of 228 cases (8%) the operative procedure had to be terminated due to patient discomfort. Of the meniscal injuries 84% were medial and 16% lateral. The age distribution of the medial meniscus tears was as follows: bucket handles 33 +/- 9 years; flap tears 42 +/- 10 years and degenerative tears 53 +/- 10 years. For the lateral meniscus the age distribution was: bucket handles 34 +/- 9 years, cleavage and radiating tears 37.5 +/- 12 years, flap tears 29 +/- 7 years, peripheral tears 32 +/- 9 years and degenerative tears 48 +/- 11 years. Osteoarthritis was observed in 52% of all medial degenerative tears, whereas a low frequency was found in the remaining tears. The majority of patients tolerated the procedure well. In summary, 64% of the consecutive arthroscopies were operative, including 3 meniscal sutures. Only 8% of these procedures had to be abandoned due to patient discomfort. Thus, arthroscopic surgery in local anaesthesia with no premedication is an efficient and well-tolerated method in outpatient practice.

Effect of cortisol on the secretion of testosterone and estradiol-17 beta by human granulosa-luteal cell cultures. A model system for analyzing hormonal alterations in female athletes

The combination of hypercortisolism and usually low androgen and estrogen levels is frequently observed in female long distance athletes. In order to find a useful model system for studying the underlying mechanisms, the following studies were performed. The effect of cortisol on the secretion of testosterone (T) and estradiol-17 beta (E2) by human granulosa-luteal cells was studied in vitro in cultures of cells recovered from mature follicles of gonadotrophin stimulated women (participating in the IVF program). Following 24 hours of culture in tissue culture medium without hormonal additives, the granulosa-luteal cells were incubated for 6 hours in media with addition of 4-androstene-3,17-dione (A-4) as precursor and hMG and cortisol in different combinations. The secretion of T was significantly stimulated by cortisol but not by human menopausal gonadotrophin (hMG). Cortisol, but not hMG, also increased the secretion of E2, although this effect was not statistically significant. These in vitro findings make a direct effect of cortisol upon ovarian sex steroid secretion less likely as the mechanism behind the subnormal sex steroid levels in female long distance athletes. Instead, inadequate gonadotrophic stimulation, related to hypothalamic amenorrhea, and/or a selective decrease in the adrenal secretion of precursor steroids, may be an explanation.

Comorbidity of autistic disorder in children and adolescents

Although considerable research has been done on various aspects of autism, information about the prevalence of coincident psychiatric disorders that may complicate this syndrome, is negligible. In this paper, we present preliminary data on the presentation of other psychiatric disorders in children and adolescents with autism. Out of an outpaticent sample of 68 autistic children and adolescents, 6 (9%) presented with an associated psychiatric disorder. Depression was the most common diagnosis. None of the patients was given a diagnosis of schizophrenia. Clinical and research implications of the findings are discussed.

Synthesis of 5-methylaminomethyl-2-selenouridine in tRNAs: 31P NMR studies show the labile selenium donor synthesized by the selD gene product contains selenium bonded to phosphorus

An enzyme preparation from Salmonella typhimurium catalyzes the conversion of 5-methylaminomethyl-2-thiouridine in tRNAs to 5-methylaminomethyl-2-selenouridine when supplemented with selenide and ATP. Similar preparations from a Salmonella mutant strain carrying a defective selD gene fail to catalyze this selenium substitution reaction. However, supplementation of the deficient enzyme preparation with the purified selD gene product (SELD protein) restored synthesis of seleno-tRNAs. In the absence of the complementary enzyme(s), the SELD protein catalyzes the synthesis of a labile selenium donor compound from selenide and ATP. 31P NMR studies show that among the products of this reaction are AMP and a compound containing selenium bonded to phosphorus. The reaction is completely dependent on the addition of both selenide and magnesium. The dependence of reaction velocity on ATP concentration shows sigmoidal kinetics, whereas dependence on selenide concentration obeys Michaelis-Menten kinetics indicating a Km value of 46 microM for selenide.

Depression in autistic disorder

Depressive illness in a patient with Down's syndrome and autism responded to fluoxetine. The importance of diagnosing superimposed depression in people with developmental disorders is emphasised.

Cortisol and androgen concentrations in female and male elite endurance athletes in relation to physical activity

To evaluate the effect of variations in physical activity on selected hormone concentrations in male versus female athletes, fasting serum concentrations of cortisol (C), total-testosterone, free-testosterone, non sex hormone binding globulin (SHBG) bound testosterone, dehydroepiandrosterone, 4-androstene-3,17-dione and SHBG were studied. The tests were performed in nine male and seven female elite endurance athletes during the off-season (test 1), early in the competition season (test 2) and at the end of the competition season (test 3). The C concentration increased significantly during the competition season in women but not in men. Further, the mean C concentrations at test 3 as well as the mean level during the whole observation period (tests 1, 2, 3) were significantly higher in women than in men. No significant changes were found in androgen concentrations or androgen:cortisol ratios within the two groups. The differences between the sexes in C response may indicate different adaptive mechanisms to similar physical stress.

Okadaic acid interferes with lipoprotein-supported corticosterone production in adrenal cells

Rat adrenocortical cells in culture respond to stimulation by ACTH alone (15 fold over basal) and to ACTH + added lipoproteins (as an exogeneous source of cholesterol), with an additional 25-30 fold rise in steroidogenesis. With the addition of okadaic acid (OKA, 100 nM), a potent protein phosphatase inhibitor, the lipoprotein-induced rise in steroidogenesis is blocked. If 20 alpha-hydroxycholesterol is provided instead of lipoprotein-cholesterol, OKA has no effect suggesting that OKA affects only actively transported cholesterol. Since the OKA block is preceded by specific morphological changes in the cell (i.e., the loss of Golgi-associated microtubules followed by the disruption of the Golgi apparatus itself), it is hypothesized that some OKA-sensitive phosphoprotein associated with the microtubule/Golgi network of adrenocortical cells is critical for lipoprotein-derived cholesterol uptake and/or transport during steroidogenesis.