[Online measurement of retinal artery branches in type II diabetic patients. Initial clinical trials before and after laser coagulation]

By the use of a new online measuring system the effect of argon-laser coagulation in diabetics on the diameters of retinal arteries was measured.

METHOD

The vessel diameter of retinal branch arteries were measured in patients with type-II diabetes before and after (0.5 h) argon-laser coagulation. Ten patients without previous laser treatment were included in this study. Measurements were taken in all four quadrants by the use of a new automatic online measuring system.

RESULTS

The new technique allowed measurements to be made within an acceptable period of time and with little strain on patients. After argon-laser coagulation 56.7% of retinal arteries showed a significant vasodilation. No significant changes in vessel diameter were found in 18.9% of these arteries, whereas 24.3% showed significant vasoconstriction.

CONCLUSION

The new online measuring system is able to measure the effects of photocoagulation on an individual basis with a noninvasive technique. The first findings presented here confirm previous studies of larger groups, with a considerable reduction in efforts required.

Early experience with intravenous immunoglobulin treatment in Wegener's granulomatosis with ocular involvement

BACKGROUND

Pooled intravenous gammaglobulin (IVIg) was reported to be effective in the treatment of Wegener's granulomatosis (WG). No reports have been made on the effects of this new treatment on ocular manifestations of WG.

METHOD

IVIg treatment was given to two patients suffering from WG with ocular involvement after several other treatment regimes had failed.

RESULTS

Although the systemic disease was under control, the ocular symptoms of both patients worsened during and after IVIg treatment. In one case an adverse effect consisting of retinal vasculitis was noted on two occasions.

CONCLUSION

Although beneficial effects of IVIg treatment on WG have been previously described, the two cases with ocular involvement presented here did not reveal any positive response. Paradoxical and unpredictable reactions cannot be ruled out. Thus, patients treated with IVIg should be closely surveyed by an ophthalmologist.

[Haptic position of iris-fixed posterior chamber lenses. Determination by ultrasound biomicroscopy]

In eyes lacking adequate posterior capsular support, fixation of posterior chamber intraocular lenses (IOL) by iris sutures has become one of the methods available. Ultrasound biomicroscopy (UBM) allows detection of the haptic position postoperatively and determination of its relationship to adjacent intraocular structures.

METHODS

Thirteen patients with iris-sutured IOLs were examined pre- and postoperatively with UBM. The examination included locating the haptic and tracing the haptic to the position closest to other uveal structures.

RESULTS

The position of all 26 haptics was determined. All haptics were in touch with the iris. In the 12-clock position 11 haptics did not touch other intraocular structures. In one case the haptic was located in the ciliary sulcus, and in another case it touched the ciliary body. In the 6-clock position two haptics were located in the sulcus region, and seven were located posterior to the ciliary processes. Four haptics did not touch any other intraocular structures.

CONCLUSIONS

In most cases surgical placement of iris-fixed lenses is a blind procedure. UBM is an adequate method of determining the position of IOL haptics postoperatively.

Correlation between loss of middle ear bones and altered goosecoid gene expression in the branchial region following retinoic acid treatment of mouse embryos in vivo

The homeobox gene goosecoid marks the Spemann organizer in vertebrate gastrula embryos, and is expressed in the craniofacial region, body wall and limbs during organogenesis. Mouse mutants of goosecoid displayed a variety of phenotypes related to the expression pattern at mid-embryogenesis. These defects included loss of the tympanic ring and malformation of the malleus, phenotypes which were reminiscent of the teratogenic effects of retinoic acid (RA). Here we investigated the correlation of goosecoid gene expression and RA-teratogenicity following treatment of mouse embryos in vivo at embryonic day (E) 8 + 5 h. We found that goosecoid was specifically affected at E10.5 in branchial arches I and II. Expression was either reduced to background levels or restricted to the branchial cleft region. This change in goosecoid gene expression correlated with a loss of middle ear ossicles and a partial or complete deletion of the tympanic ring, suggesting a role for goosecoid in executing the RA teratogenic effects.

Nasal and pharyngeal abnormalities caused by the mouse goosecoid gene mutation

The Goosecoid (gsc) gene is a homeobox-containing gene expressed first in the gastrula, and later during organogenesis in development. The gsc gene transcript is found in the first and second branchial arches, frontonasal mass in its late phase of expression. We have previously shown that targeted mutation of the mouse gsc gene leads to neonatal death and craniofacial defects. In this study, we performed histological studies on craniofacial phenotypes in order to elucidate the processes underlying the neonatal death of gsc mutant mice. We found that gsc mutant mice have aplastic nasal cavities and lack the Sinus Paranasalis. We also showed that secretory olfactory glands in the basal layers are aplastic. This is suggested to be essential defects for olfaction. gsc mutant mice also show several pharyngeal phenotypes, including defects in the pharyngeal muscles and the pharyngeal mucosa. It is therefore suggested that mutant mice develop lethal gastro-intestinal phenotypes caused by defects in breathing and sucking of milk as a consequence of these craniofacial disorders. These results should help elucidating the molecular genetic programs essential to the neonatal development of mammals.

The dorsalizing and neural inducing gene follistatin is an antagonist of BMP-4

Specific signaling molecules play a pivotal role in the induction and specification of tissues during early vertebrate embryogenesis. BMP-4 specifies ventral mesoderm differentiation and inhibits neural induction in Xenopus, whereas three molecules secreted from the organizer, noggin, follistatin and chordin dorsalize mesoderm and promote neural induction. Here we report that follistatin antagonizes the activities of BMP-4 in frog embryos and mouse teratocarcinoma cells. In Xenopus embryos follistatin blocks the ventralizing effect of BMP-4. In mouse P19 cells follistatin promotes neural differentiation. BMP-4 antagonizes the action of follistatin and prevents neural differentiation. In addition we show that the follistatin and BMP-4 proteins can interact directly in vitro. These data provide evidence that follistatin might play a role in modulating BMP-4 activity in vivo.

Protein synthesis-dependent and -independent mechanisms for the regulation of GnRH RNA transcript levels in GT1 cells

The cellular mechanism for the suppression of GnRH gene expression by the phorbol ester PMA was investigated in GT1 cells. The protein synthesis inhibitor cycloheximide decreased GnRH primary transcript levels, indicating a protein synthesis requirement for basal GnRH transcription. PMA decreased GnRH primary transcript levels even in the presence of cycloheximide, indicating that the PMA suppression of GnRH gene transcription is protein synthesis-independent. In contrast, the PMA-inhibitory effect on GnRH cytoplasmic mRNA levels was significantly reduced or inhibited in the presence of cycloheximide or RNA synthesis inhibitors given within 4 h of PMA, suggesting a protein/RNA synthesis-dependent mechanism for the regulation of GnRH mRNA levels by PMA. Thus, the mechanism for the PMA inhibition of GnRH primary transcript is mediated through a protein and RNA synthesis-independent mechanism, while the decrease in GnRH mRNA levels occurs through a mechanism that involves the induction of new RNA and protein synthesis that happens within 4 h of PMA administration.

Perinatal asphyxia-induced changes in rat brain tyrosine hydroxylase-immunoreactive cell body number: effects of nicotine treatment

Perinatal asphyxia (15-22 min) was induced to male Sprague-Dawley rat pups during the last day of gestation and the surviving pups were sacrificed at 4 weeks of age. Brain sections were stained for tyrosine hydroxylase immunoreactivity and Cresyl violet. With increasing duration of perinatal asphyxia a reduction in the number of tyrosine hydroxylase immunoreactive (TH-IR) nerve cell bodies was found in the locus ceruleus, probably reflecting an increased death of noradrenaline nerve cell bodies. In contrast, perinatal asphyxia (15-20 min) resulted in an increased number of TH-IR nerve cell bodies in the A9 (zona compacta of the substantia nigra) and the A10 (ventral tegmental area) regions of the mesencephalon, probably reflecting an increased survival of dopamine nerve cell bodies. Perinatal asphyxia for longer than 20 min periods reduced the number of TH-IR cell bodies in the 4 week old rat, even below those found in control animals, indicating that when asphyxia is induced for a period leading to almost 100% mortality, a long-term reduction of the number of mesencephalic dopamine neurons is produced. It has previously been shown that a 4 week postnatal nicotine (0.2 micromol/kg per h) treatment counteracts the asphyxia-induced increase in TH-IR cell body number in the substantia nigra and ventral tegmental area. Such nicotine treatment did not influence the reduction in TH-IR cell bodies in the locus ceruleus following 15-20 min of perinatal asphyxia.

[Outcome of cataract operation with reduction of myopia in myopia magna]

Patients with high myopia represent a risk group in cataract surgery. They are suspected of having a higher incidence of retina problems after cataract surgery. In addition, IOL calculations may be difficult.

METHOD

In a retrospective study data of 97 eyes of 60 high myopic patients were analyzed. The inclusion criterion was an axial length of > 26 mm. All eyes underwent cataract extraction and PC IOL implantation between 1991 and 1995. Evaluation focused on visual outcome, precision of the IOL power calculation and the rate of complications.

RESULTS

Visual acuity increased from 0.18 to 0.46 postoperatively. On average, myopia was reduced from -13.6 D to -3.0 D;66% of the patients were +/-1 D;86% were +/-2 D within the predicted calculation of postoperative refraction. During a follow-up period of 14.8 months no retinal detachment occurred.

CONCLUSION

Cataract extraction and IOL implantation showed good functional results, and prediction of postoperative refraction was satisfactory. Our data support the studies reporting a low incidence of retinal problems in patients with high myopia.

Age-related changes of the ciliary sulcus: implications for implanting sulcus-fixated lenses

PURPOSE

To examine age-related anatomical changes of the ciliary sulcus and the implication of these changes for placement of posterior chamber intraocular lenses (IOLs).

SETTING

Department of Ophthalmology, University of Heidelberg, Germany.

METHODS

In this study, 64 human autopsy eyes from 38 donors were divided by age into six groups from younger than 40 years (Group 1) to 80 years and older (Group 6) in 10 year increments. External diameter, capsular bag size, and lens thickness were determined for each eye. The horizontal and vertical diameters of the ciliary sulcus were measured and histological sectioning, staining, and light microscopy performed.

RESULTS

The external diameters of the eyes showed no age correlation; the lenses exhibited the expected increase in thickness with age. The mean vertical diameter of the ciliary sulcus decreased in all age groups from 12.02 mm +/- 0.12 (SD) to 10.71 +/- 0.91 mm and the mean horizontal diameter, from 11.36 +/- 0.24 mm to 10.33 +/- 0.76 mm. Statistical analysis confirmed the overall significance (P < .05) of the differences among age groups.

CONCLUSION

The ciliary sulcus became smaller with age. This might affect the size of sulcus-implanted IOLs and should be noted for transsclerally sutured IOLs.

Randomised crossover trial of naltrexone in uraemic pruritus

BACKGROUND

Most dialysis patients develop pruritus, for which current treatment is unsatisfactory. Endogenous opioids may be involved in this pruritus. We studied the effect of the opioid antagonist naltrexone on the pruritus of haemodialysis patients.

METHODS

Naltrexone 50 mg per day by mouth was given to 15 haemodialysis patients with severe resistant pruritus in a randomised, double-blind, placebo-controlled crossover trial. The naltrexone or placebo periods lasted 7 days each with a 7-day washout between the two periods. Pruritus was assessed by the patients on a visual analogue scale from 0 (no pruritus) to 10 (maximum), and mean daily scores were calculated. Plasma histamine and beta-endorphin levels were measured, and spontaneous and stimulated basophil histamine-release were determined.

FINDINGS

The median pruritus scores at the end of the naltrexone treatment were 2.1 (interquartile range 1.5-2.15) for the naltrexone-placebo sequence and 1.0 (0.4-1.15) for the placebo-naltrexone sequence. The respective values before naltrexone was given were 9.9 (9.85-9.95) and 9.9 (9.3-10.0). Plasma beta-endorphin levels were normal and remained unchanged during the study. Plasma histamine levels were high (mean 2.32 [SD 0.11] ng/mL, normal < 1.0) and decreased after naltrexone (to 1.8 [0.09], p < 0.01). Basophils from haemodialysis patients stimulated by interleukin-3 plus IgE antibodies released high amounts of histamine. The increase was 78.3 (19.3)% compared with 26.6 (16.3)% for five normal controls (p < 0.01). Incubation of the basophils with naloxone, another opioid antagonist, prevented this effect.

INTERPRETATION

Our data suggest short-term efficacy with few side-effects for the amelioration of uraemic pruritus with naltrexone.

Characterization of gonadotropin-releasing hormone gene transcripts in a mouse hypothalamic neuronal GT1 cell line

We have characterized the nuclear and cytoplasmic RNA transcripts derived from the gonadotropin releasing hormone (GnRH) gene in a mouse hypothalamic neuronal GT1 cell line. Analyses of nuclear GnRH RNA precursors present in the GT1 cells by RNase protection assay show that there is no particular order of intron excision, suggesting the existence of multiple processing pathways. A similar pattern is observed in mouse preoptic area-anterior hypothalamus (POA-AH). In GT1 cells, approximately 5% of the total GnRH RNA transcripts are found in the nucleus. In contrast, in the POA-AH of mice, nuclear transcripts comprise 40% of the total GnRH transcripts. Thus the GT1 cells, while similar in overall GnRH RNA processing to mouse hypothalamic GnRH neurons, do not exhibit the high abundance of nuclear GnRH RNA transcripts seen in the rodent GnRH neuron in vivo. Quantitative analysis of the nuclear RNA species shows that the GnRH primary transcript comprises more than 90% of the total nuclear GnRH mRNA precursors in both GT1 cells and mouse POA-AH and thus GnRH processing intermediates account for fewer than 10% of these precursors. Using these probes, we have examined changes in GnRH primary transcript expression in GT1-7 cells. In the presence of RNA synthesis inhibitors, the half-life of the GnRH primary transcript was found to be quite short, approximately 18 min, suggesting that the level of primary transcript would reflect levels of GnRH gene transcription. When GT1-7 cells are treated with the phorbol ester PMA (phorbol, 12-myristate, 13-acetate) for 1 h, GnRH primary transcript levels decrease by approximately 70%. Supporting the hypothesis that GnRH primary transcript is a good indicator of GnRH gene transcription is the finding that 1 h of PMA treatment results in a similar (approximately 50%) decrease in GnRH gene transcription, as assayed by nuclear run-on assay. Our observation that GT1 cells resemble mouse hypothalamic GnRH neurons in their pattern of intron excision and in the ratio of primary transcript to other nuclear transcripts emphasizes the utility of these cells for studying the regulation of GnRH gene expression in this immortalized hypothalamic cell line.

The effect of estrogen replacement therapy on plasma serotonin and catecholamines of postmenopausal women

We examined the effect of estrogen replacement therapy (ERT) on plasma serotonin (5HT) and norepinephrine (NE) and their correlation with serum estradiol, luteinizing hormone (LH) and follicle-stimulating hormone (FSH) in 12 postmenopausal women. Plasma 5HT and NE, estrogen, progesterone, LH and FSH were examined every 4 days for 2 consecutive months (before and during ERT). Serotonin values were low (32.29 +/- 38.36 nmol/l) and showed an intrinsic spontaneous cyclicity with a nadir every 10-11 days. Plasma NE was similar to that observed during the follicular phase of the ovulatory cycle (1,216.8 +/- 503.4 pmol/l) and showed no cyclicity. ERT significantly increased mean (+/- SD) serum estrogen values (from 95.40 +/- 73.31 to 390.72 +/- 347.17 pmol/l, P = 0.0001), significantly decreased serum FSH (from 84.04 +/- 14.97 to 52.97 +/- 20.74 mIU/ml, P = 0.0001) and LH (from 35.35 +/- 13.82 mIU/ml to 29.69 +/- 16.46 mIU/ml, P = 0.03). Plasma 5HT levels showed a tendency to rise under the influence of ERT, but this increase was not statistically significant. Plasma NE decreased significantly from 1,216.8 +/- 503.4 to 994.1 +/- 353.89 pmol/l, P <0.05. In conclusion, plasma serotonin in postmenopausal women has a 10-11 day cycle and is significantly lower than in the follicular phase of ovulating women. Plasma NE shows no cyclicity and is significantly decreased by ERT.

Nitric oxide in ischaemic acute renal failure of streptozotocin diabetic rats

Changes in nitric oxide (NO) levels were determined in ischaemic acute renal failure in streptozotocin-induced diabetes mellitus rats. Two weeks after streptozotocin administration and immediately after right nephrectomy, the left renal artery was occluded for 60 min. Similar procedures were carried out in non-diabetic rats. The nitrite (NO2) + nitrate (NO3) levels were measured in plasma and urine. The effects of chronic oral supplementation with L-arginine and an NO synthase inhibitor (N-omega-nitro-L-arginine) were also studied in both diabetic and non-diabetic rats before and after renal artery clamping. The rats with diabetic acute renal failure had a much lower creatinine clearance (90 +/- 22 microliters.min-1. 100g body weight-1, p < 0.005), and higher fractional excretion of sodium (FENa)% (10.90 +/- 4.2, p < 0.001) and protein excretion (2078 +/- 69 micrograms/ml creatinine clearance, p < 0.001) compared with the respective values in the non-diabetic groups (163 +/- 30; 1.46 +/- 86; 453.3 +/- 31). The plasma and urine NO2 + NO3 levels were significantly higher in the untreated diabetic rats compared with the untreated normal rats before ischaemia (p < 0.001). The ischaemic acute renal failure in non-diabetic rats increased the plasma and urinary NO2 + NO3 excretion after ischaemia. The urinary excretion of these metabolites decreased significantly and their plasma levels remained unchanged in the ischaemic diabetic rats. The L-arginine administration resulted in a small but significantly higher creatinine clearance after clamping in the non-diabetic rats. The NO synthase inhibitor caused deterioration in renal function in all ischaemic and non-ischaemic groups. In summary, the greater vulnerability to ischaemia of the diabetic kidney seems to be associated with both impaired response to and impaired production of NO.

The effect of human recombinant erythropoietin on the growth of a human neuroblastoma cell line

Erythropoietin is a growth factor. Cancer can be described as disturbance of the fine balance of positive and negative growth control mechanisms. The effect of human recombinant erythropoietin (EPO) was studied on the cell growth and differentiation of a human neuroblastoma cell line (h-NMB). Cell growth curves, trypan blue staining and thymidine uptake were used to assess cell proliferation and death. To assess cell differentiation, neutral endopeptidase (cell membrane enzyme marker), creatine kinase (cytosolic enzyme marker), dopamine uptake (dopamine transporter marker) and cell morphology were determined. Specific EPO receptor mRNA, by RT-PCR technique, was demonstrated. The incubation of erythropoietin with the tumor cell line resulted in inhibition of cell proliferation as evidenced in a diminished cell growth. EPO was shown to have induced a differentiation process as seen from the two different enzymatic markers, membranal and cytosolic, and from the cells dopamine uptake studies. However, the morphological changes did not document a full differentiation effect. EPO specific antibodies blocked the effects of EPO on cell proliferation and creatine kinase activity. In this study, EPO did not produce any sign of proliferation in the nervous tumor cell line used.

Nitric oxide in streptozotocin-induced diabetes mellitus in rats

1. The present study was performed to determine the relationship between diabetic glomerular hyperfiltration and nitric oxide as modulated by the chronic administration of L-arginine and/or N-omega-nitro-L-arginine, a known nitric oxide synthase inhibitor in streptozotocin-induced diabetic rats. 2. Normal rats and rats drinking hypertonic glucose (10%) were used as time-controlled groups. Six weeks after administration of streptozotocin the diabetic rats had significantly higher creatinine clearance (667 +/- 53 microliters min-1 100 g-1 body weight) than before and streptozotocin (456 +/- 38 microliters min-1 100 g-1 body weight, P < 0.005) and very high plasma (37.8 +/- 10.9 mumol/l) and urinary (3.492 +/- 0.179 nmol min-1 100 g-1 body weight) nitrite+nitrate (stable metabolites of nitric oxide) values compared with before streptozotocin administration [19.3 +/- 2.8 mumol/l (P < 0.001) and 0.420 +/- 0.051 nmol min-1 100 g-1 body weight (P < 0.001) respectively]. The 6-week diabetic rats had higher systolic blood pressure (124.2 +/- 2.9 mmHg, P < 0.05) than before streptozotocin (108 +/- 8 mmHg), but had a value similar to that of the hypertonic-glucose-drinking rats. 3. The diabetic rats supplemented with L-arginine did not show an increase in creatinine clearance and had a lower urinary excretion of nitrite+nitrate (0.999 +/- 0.27 nmol min-1 100 g-1 body weight, P < 0.005) than the respective untreated streptozotocin-induced diabetic rats. Creatinine clearance increased in the normal and glucose-drinking rats that received L-arginine. The administration of L-arginine resulted in significant reduction in blood pressure in all groups studied. The chronic nitric oxide synthase inhibitor resulted in high blood pressure, and in a significant decrease in creatinine clearance and urinary nitrite+nitrate excretion in all groups studied. In both diabetic and glucose-drinking rats, the L-arginine therapy resulted in significantly lower plasma and urinary glucose levels than in their respective untreated control groups. 4. The nitric oxide synthase inhibitor increased the plasma and urinary glucose concentration in both diabetic and glucose-drinking rats. 5. Our results indicate that diabetic rats are characterized by high plasma concentrations and elevated urinary excretion of nitrite+nitrate, suggesting a state of high nitric oxide production. The vascular response to nitric oxide in diabetic rats may be different at the glomerular and peripheral vascular bed.

Treatment of traumatic cataracts

PURPOSE

To analyze the postoperative outcome and complication rate following cataract extraction because of post-traumatic lens opacification.

SETTING

University medical center.

METHODS

A retrospective analysis was done of 148 eyes with traumatic cataracts operated on between 1978 and 1992. Age, sex, traumatic sequelae, surgical strategies, and postoperative complications were reviewed for all eyes.

RESULTS

In 85 eyes, Group A, a history of blunt trauma could be ascertained. In 63 eyes, Group B, there had been a penetrating injury. Secondary glaucoma was observed more frequently in patients with blunt trauma. A posterior chamber intraocular lens was implanted in 85% of Group A eyes and in 67% of Group B eyes. Mild or moderate postoperative complications occurred in 15% of all cases. Postoperatively, the incidence of glaucoma remained unchanged. Visual acuity improved in 90% of eyes. Ten percent of eyes did not benefit from cataract surgery because of severe traumatic involvement of the retina or optic nerve.

CONCLUSIONS

In this study, a majority of eyes with traumatic cataract were safely rehabilitated with posterior chamber lens implantation. Visual acuity improved in 90% of eyes; complications were seen in 15%.

[Clinical secondary cataract evaluation in pseudophakic eyes. Method and reproducibility]

INTRODUCTION

According to the literature, the frequency of secondary cataract reported following different studies of posterior chamber intraocular lens (IOL) implantation varies widely. The nonstandardized definition of a clinically significant secondary cataract is one of the reasons for this. We present a morphological scoring system for secondary cataract that does not require visual acuity testing.

PATIENTS AND METHODS

Following dilatation of the pupil standardized photographs of the pseudophakic anterior segments were obtained by means of a Zeiss photoslit-lamp (model 40 SL/P). The posterior capsule opacification (PCO) was scored by evaluating retroillumination photographs. The individual PCO score was calculated by multiplying the density of the opacification (graded from 0 to 4) by the area involved behind the IOL optic (calculated between 0 and 1). In order to evaluate the reliability of the morphological scoring system, in experiment A six observers examined photographs of five eyes each (interindividual reliability), and in experiment B the same observers each scored the PCO of three eyes on 5 different days (intraindividual reliability). In experiment C seven different pairs of photographs taken on the same day were scored for PCO by the same observer (influence of photographic variations).

RESULTS

Morphological PCO scores were reliable. With PCO scoring ranging from 0 to 4, interindividual reliability revealed standard deviations between 0.08 and 0.25. The intraindividual reliability showed standard deviations between 0.06 and 0.19 of any individual PCO score. The standard deviation was 0.12 when different photographs of the same eye were scored.

CONCLUSIONS

When the entire area behind the IOL optic is evaluated a larger area of the posterior capsule is taken into account than during testing of visual acuity alone. This method revealed high reliability and only minimal investigator-dependent variations. With a standardized photographic set-up, systematic errors otherwise caused by variations in individual photographs of the same eye are insignificant. Use of this method may help in the achievement of more accurate testing for differences in secondary cataract formation with various types of IOL and different surgical techniques.

Intravenous iron supplementation for the treatment of the anemia of moderate to severe chronic renal failure patients not receiving dialysis

Iron deficiency may develop in hemodialysis patients, especially when erythropoietin is given. The role of iron deficiency in the anemia of predialysis chronic renal failure (CRF), however, is much less clear. We have intravenously (IV) administered iron as ferric saccharate in a total dose of 200 mg elemental iron monthly for 5 months to 33 CRF patients who remained anemic despite oral iron supplementation and who had no laboratory signs of iron overload. None was receiving erythropoietin therapy. In 22 of the patients there was an increase in the hematocrit values by the end of the study. These patients were considered responders to intravenous iron (IV Fe) therapy. In 11 patients the iron administration was not associated with improvement of the anemia (nonresponders). Before onset of the IV Fe therapy there were no differences between the responders and nonresponders with regard to degree of anemia, serum ferritin, iron saturation, renal function, or blood pressure. One additional patient was excluded from the study because of a mild reaction during an IV test dose before the study. No worsening of kidney function and no other side effects were noted. In four patients (three responders and one nonresponder) the control of blood pressure necessitated antihypertensive drug therapy adjustment. In conclusion, IV Fe supplementation in two thirds of anemic CRF patients not receiving dialysis resulted in a significant improvement of the anemia, thus avoiding the necessity of erythropoietin or blood administration. This could be achieved by increasing the plasma ferritin levels to 200 to 400 microns/L and/or increasing the iron saturation to 25% to 35%. Intravenous ferric saccharate appears to be a safe and effective method of administering iron for the correction of anemia in CRF patients not receiving dialysis.

Chronic continuous infusion of (-)nicotine reduces basic fibroblast growth factor messenger RNA levels in the ventral midbrain of the intact but not of the 6-hydroxydopamine-lesioned rat

A negative correlation has been found between smoking and Parkinson's disease. There is evidence to suggest that this correlation appears to be associated with a neuroprotective role of nicotine for dopamine neurons at least in relation to mechanical injury. However, 1-methyl-4-phenyl-1,2,3,6,-tetrahydropyridine (MPTP) neurotoxicity to dopamine neurons is enhanced by chronic continuous (-)nicotine. More recently, basic fibroblast growth factor has been found to possess neurotrophic activities for many nerve cells including the dopamine cells in vivo and in vitro. Therefore, it is of interest to explore a possible effect of nicotine on basic fibroblast growth factor expression in the ventral midbrain of intact and 6-hydroxydopamine-lesioned rats and how treatment with nicotine can alter the 6-hydroxydopamine-induced injury of the nigral dopamine nerve cells as evaluated by dopamine biochemistry. In the present paper, an analysis of the effects of chronic continuous infusion of (-)nicotine via minipumps was carried out on basic fibroblast growth factor expression in the vental midbrain of the intact male rat and of the 6-hydroxydopamine lesioned rat. A quantitative messenger RNA protection assay analysis was used as well as an immunocytochemical analysis in the substantia nigra. Our findings give evidence that a two-week continuous infusion with (-)nicotine in the intact rat leads to substantial and dose-related (0.03-0.3 mg/kg per h) reductions of basic fibroblast growth factor messenger RNA levels in the ventral midbrain. These changes are not associated with changes in neuronal and glial basic fibroblast growth factor immunoreactivity in this region with the antibodies used. However, a one-week continuous infusion with (-)nicotine (0.125 mg/kg per h) failed to significantly alter the basic fibroblast growth factor messenger RNA levels in the ventral midbrain of solvent and 6-hydroxydopamine-injected rats and thus also the 6-hydroxydopamine-induced increase of basic fibroblast growth factor messenger RNA levels in the ventral midbrain of the lesioned side observed at this time-interval and known to be of astroglial origin [Chadi G. et al. (1994) Neuroscience 61, 891-910]. In agreement, the 6-hydroxydopamine-induced depletion of dopamine in the neostriatum was unaltered by the nicotine treatment (0.125 mg/kg per h). Thus, chronic continuous (-)nicotine treatment may lead to a reduced basic fibroblast growth factor trophic tone in the ventral midbrain of the intact but not of the 6-hydroxydopamine-lesioned rat neither on the lesioned nor on the unlesioned side of the ventral midbrain. It seems possible that chronic nicotine treatment mainly reduces basic fibroblast growth factor messenger RNA levels of neuronal origin, since the astroglial messenger RNA levels dominate after the 6-hydroxydopamine-induced lesions.

Intravenous ferric saccharate as an iron supplement in dialysis patients

In the present prospective study we examined the long-term effect of intravenous supplementation with ferric saccharate (IV Fe) in the treatment of the anemia of chronic dialysis patients. All patients, 64 on chronic hemodialysis (HD) and 9 on chronic ambulatory peritoneal dialysis (CAPD), were treated intravenously with this preparation in a dose of 100 mg elemental iron twice monthly. There were five groups. Group 1: 41 HD patients who were receiving erythropoietin (EPO) for at least 6 months prior to the addition of IV Fe. In this group, when IV Fe was given over 6 months, the hematocrit (Hct) increased from a mean of 28.7 to 33.7%. Over the next 6 months, the EPO dose was gradually reduced by a mean of 61.1%, but the mean Hct remained unchanged. Group 2: 11 HD patients who started IV EPO simultaneously with the IV Fe. In this group, over 6 months, the mean Hct increased from 28.1 to 34.1. Over the next 6 months, the EPO dose was gradually reduced by 75.7%, but the mean Hct remained unchanged. Group 3: 12 HD patients who received IV Fe alone for 12 months. The mean Hct increased from 30.5 to 37.9%. Group 4: 4 CAPD patients who had been receiving subcutaneous EPO for at least 6 months prior to IV Fe therapy. Over the subsequent 6 months of IV Fe, the mean Hct increased from 28.4 to 33.3%. Group 5: 5 CAPD patients not on EPO who received IV Fe for 6 months. The mean Hct increased from 27.7 to 35.6%. No adverse effects were seen in any patients throughout the study. In conclusion, adequate Fe supplementation may allow the target Hct of about 33% to be reached without, or with only very low doses of EPO. IV Fe as ferric saccharate is a new and safe form of parenteral iron therapy of the anemia of chronic dialysis patients.

Improvement of cardiac performance by intravenous infusion of L-arginine in patients with moderate congestive heart failure

OBJECTIVES

The aim of this study was to evaluate the hemodynamic effect of L-arginine infusion in patients with congestive heart failure.

BACKGROUND

Endothelium-dependent vasodilation is impaired in patients with congestive heart failure. Nitric oxide, which was identified as endothelium-derived relaxing factor, is generated by nitric oxide synthase from L-arginine. Our hypothesis was that administration of L-arginine in patients with congestive heart failure may increase nitric oxide production and have a beneficial hemodynamic effect.

METHODS

Twelve patients with congestive heart failure (New York Heart Association class II or III) due to coronary artery disease (left ventricular ejection fraction < 35%) were given 20 g of L-arginine by intravenous infusion over 1 h at a constant rate. Stroke volume, cardiac output and left ventricular ejection fraction were determined with Doppler echocardiography at baseline and at 30 and 60 min and 1 h after the end of infusion. Blood and urinary levels of nitrite/nitrate (NO2/NO3), stable metabolites of nitric oxide, were measured and clearance was calculated.

RESULTS

One hour of infusion of L-arginine resulted in a significant increase in stroke volume (from 68 +/- 18 ml to 76 +/- 23 ml [mean +/- SD], p = 0.014) and cardiac output (from 4.07 +/- 1.22 liters/min to 4.7 +/- 1.42 liters/min, p = 0.006) without a change in heart rate. Mean arterial blood pressure decreased (from 102 +/- 11 mm Hg to 89 +/- 9.5 mm Hg, p < 0.002), and systemic vascular resistance decreased significantly. Within 1 h after cessation of L-arginine infusion, blood pressure, stroke volume, cardiac output and systemic vascular resistance were statistically not different from baseline values. Clearance of NO2/NO3 increased significantly during L-arginine administration (from 13.28 +/- 0.42 ml/min to 29.97 +/- 1.09 ml/min, p < 0.001).

CONCLUSIONS

Infusion of L-arginine in patients with congestive heart failure results in increased production of nitric oxide, peripheral vasodilation and increased cardiac output, suggesting a beneficial hemodynamic and possibly therapeutic profile.

GDNF mRNA expression in normal postnatal development, aging, and in Weaver mutant mice

Glial cell line-derived neurotrophic factor (GDNF) has been demonstrated to enhance the survival and process outgrowth of mesencephalic dopamine neurons. A nuclease protection assay was utilized to determine whether GDNF mRNA is expressed in the ventral mesencephalon and/or striatum during normal mouse postnatal development. While no GDNF mRNA was detected in the ventral mesencephalon, expression was detected in the striatum throughout postnatal development and maturity with the peak of expression being in the second postnatal week. In the process of normal aging, no change in the levels of GDNF mRNA was observed in the striatum, while a 10-fold increase in glial fibrillary acid protein (GFAP) mRNA was detected in 24-month-old relative to either 4.5- or 11-month-old mice. Further analysis addressed whether there are changes in GDNF gene expression associated with the neurodegeneration of dopamine neurons that occurs in the weaver mutant mouse. A transient 65% increase in the expression of GDNF mRNA was observed in weaver mutant striatum on postnatal day 22. The results of this study suggest that GDNF could provide target derived of dopaminergic neurotrophic support and stimulate fiber outgrowth during development and that decreased levels of GDNF expression are not responsible for either aging-associated decreases in dopaminergic neuronal plasticity or neurodegeneration in the weaver mutant mouse.

Targeted mutation of the murine goosecoid gene results in craniofacial defects and neonatal death

The goosecoid gene encodes a homeodomain-containing protein that has been identified in a number of species and has been implicated in a variety of key developmental processes. Initially suggested to be involved in organizing the embryo during early development, goosecoid has since been demonstrated to be expressed during organogenesis-most notably in the head, the limbs and the ventrolateral body wall. To investigate the role of goosecoid in embryonic development, we have inactivated the gene by gene targeting to generate mice mutant for the goosecoid gene. Mice that are homozygous for the goosecoid mutation do not display a gastrulation phenotype and are born; however, they do not survive more than 24 hours. Analysis of the homozygotes revealed numerous developmental defects affecting those structures in which goosecoid is expressed during its second (late) phase of embryonic expression. Predominantly, these defects involve the lower mandible and its associated musculature including the tongue, the nasal cavity and the nasal pits, as well as the components of the inner ear (malleus, tympanic ring) and the external auditory meatus. Although the observed phenotype is in accordance with the late expression domains of goosecoid in wild-type embryos, we suggest that the lack of an earlier phenotype is the result of functional compensation by other genes.

Epidermal growth factor and basic fibroblast growth factor protect dopaminergic neurons from glutamate toxicity in culture

In this report we characterize the toxicity of the excitatory amino acid L-glutamate with respect to dopaminergic neurons cultured from embryonic rat mesencephalon. We also demonstrate that two growth factors, epidermal growth factor (EGF) and basic fibroblast growth factor (bFGF), can protect these neurons from damage. Micromolar concentrations of L-glutamate, as well as agonists that specifically activate N-methyl-D-aspartate (NMDA) and non-NMDA receptors, are all toxic to dopamine neurons in a concentration-dependent manner, as reflected by decreases in high-affinity dopamine uptake and confirmed by decreases in numbers of tyrosine hydroxylase-immunoreactive neurons. Although the non-NMDA receptor antagonist 6-cyano-7-nitroquinoxaline-2,3-dione could attenuate the effects of quisqualate, treatment with this antagonist could not eliminate the effects of glutamate itself. Similarly, (+/-)-2-amino-5-phosphonopentanoic acid was effective against NMDA toxicity but could not protect cells from quisqualate toxicity. Thus, each type of receptor could mediate neurotoxicity independently of the other. The presence of EGF or bFGF in the culture medium conferred a relative resistance of dopaminergic neurons to glutamate and quisqualate neurotoxicity by increased glutamate transport. However, treatment of the cultures with L-trans-pyrrolidine-2,4-dicarboxylic acid, an inhibitor of glutamate transport, attenuated but did not eliminate the protective effects of both growth factors against glutamate toxicity. When cultures were incubated with conditioned medium from growth factor-treated cultures, neuroprotection was also achieved. These results suggest that both EGF and bFGF can protect neurons from neurotoxicity in culture by increasing the capacity of the culture for glutamate uptake as well as by the secretion of soluble factors into the medium.

Glutamate regulation of GDNF gene expression in the striatum and primary striatal astrocytes

The aim of this study was to investigate the regulation of glial cell line-derived neurotrophic factor (GDNF) mRNA by activation of glutamate receptors in the rat striatum. We observed an increase in GDNF mRNA levels in the adult rat striatum after administration of subseizure doses of N-methyl-D,L-aspartic acid (NMA) and kainic acid. Since it is unclear whether the upregulation of GDNF occurred in neurons or astrocytes within the striatum, we further investigated whether GDNF gene expression in primary striatal astrocytes in culture could be regulated by glutamate receptor activation. We found that treatment of the cultures with NMA and kainic acid similarly upregulated GDNF gene expression as observed in vivo, suggesting that striatal astrocytes express functional glutamate receptors. Immunocytochemical and nuclease protection analysis revealed that striatal astrocytes expressed the NMDA-R1 subunit. These findings suggest the regulation of GDNF mRNA in the striatum may be mediated by excitation of glutamate receptors via glutamatergic cortical afferents.

Oral administration of L-arginine and captopril in rats prevents chronic renal failure by nitric oxide production

The effect of oral supplementation of L-arginine, the substrate of nitric oxide, (1.25 g/liter water) and captopril (15 mg/liter water) was studied in 5/6 nephrectomized rats for a period of three months. N-omega-nitro L-arginine, a nitric oxide synthase inhibitor, was given orally (70 mg/liter water) with or without L-arginine or captopril. The urinary excretion of nitrite (NO2) + nitrate (NO3), the known metabolites of nitric oxide, was taken as an index of nitric oxide production. Chronic renal failure rats were characterized by a low creatinine clearance, high FENa%, proteinuria, hypertension and a low urinary excretion of NO2 + NO3; 0.152 +/- 0.06 (P < 0.001) nmol/micrograms creatinine compared with 0.481 +/- 0.004 (P < 0.001) in normal rats and 0.479 +/- 0.11 (P < 0.001) in untreated sham-operated rats. Both L-arginine and captopril were effective in the normalization of all these parameters. The combination of L-arginine and captopril had no additive effects. The nitric oxide synthase inhibitor significantly diminished the captopril beneficial effect. It is concluded that chronic renal failure in rats is a low nitric oxide production state. The supplementation of L-arginine is shown to overcome this condition. It is suggested that the beneficial effect of captopril on chronic renal failure is through a specific L-arginine--nitric oxide synthase--nitric oxide pathway.

Striatal TGF-alpha: postnatal developmental expression and evidence for a role in the proliferation of subependymal cells

Transforming growth factor alpha (TGF-alpha) is expressed in the brain and affects cells by binding to the epidermal growth factor receptor (EGF-R). Using a ribonuclease protection assay, we found that TGF-alpha steady state mRNA levels in the mouse striatum peak during the first week of postnatal life. Temporally this peak correlates with the height of gliogenesis in the subependymal layer (SEL), which lies along the striatal border of the lateral ventricle. In vitro studies demonstrate that TGF-alpha can stimulate the proliferation of astrocytes, so glial fibrillary acidic protein (GFAP) mRNA levels were measured as well and it was observed that the peak of GFAP expression followed that of TGF-alpha by 1 week. Furthermore, in a TGF-alpha deficient mouse, waved-1 (wa-1), a significant reduction of GFAP mRNA levels and immunostaining for GFAP was found in the striatum. Bromodeoxyuridine labeling combined with immunohistochemistry of normal postnatal day 6 brain showed that the proliferating cells in the SEL are EGF-R immunoreactive. In the waved-1 SEL, there were fewer BrdU positive cells and there was a reduced level of [3H]thymidine incorporation. EGF-R immunoreactive cells were found in the SEL of the adult mouse brain. Taken together, our data suggest that the TGF-alpha/EGF-R signaling pathway is involved in postnatal mitogenic events in the brain.

Prenatal corticosterone increases spontaneous and d-amphetamine induced locomotor activity and brain dopamine metabolism in prepubertal male and female rats

Recently, both glucocorticoid receptor immunoreactivity and glucocorticoid receptor messenger RNA levels were found in multiple brain areas, especially in the neuroepithelium during the late prenatal development of the rat brain. To better understand the potential influence of stress on fetal brain development by release of maternal adrenocortical steroids, we have investigated the effects of corticosterone administration to pregnant rats on the locomotor activity of their prepubertal offspring. On day 16 of pregnancy female rats were implanted with either placebo or corticosterone pellets (release of 2.4 mg/day for seven days). After birth their offspring were nursed by foster mothers to avoid any postnatal effects of the corticosterone pellets. At three weeks of age, the offspring were tested for spontaneous motor behaviours. Both male and female offspring from corticosterone treated mothers showed significantly increased spontaneous ambulation, motility and rearing compared to placebo treated groups. No significant sex differences were found in locomotor activity between male and female offspring from placebo groups. Following d-amphetamine (1.5 mg/kg) treatment, a preferential dopamine releasing agent, we observed a significant increase in ambulation, motility and rearing activity in the male offspring treated with corticosterone. In the female offspring, only the rearing activity was significantly higher after d-amphetamine treatment in the prenatal corticosterone group compared with the placebo treated group. Basal dopamine metabolism (dihydroxyphenylacetic acid/dopamine ratio) was increased in the dorsal striatum and ventral striatum of male and female offspring from corticosterone-treated dams. In the male offspring, corticosterone treatment was associated with a disappearance of the right side dominance of dopamine metabolism in the dorsal striatum.(ABSTRACT TRUNCATED AT 250 WORDS)

Perinatal asphyxia increases bFGF mRNA levels and DA cell body number in the mesencephalon of rats

The present investigation was undertaken in order to study the long-term effects of perinatal asphyxia on basic fibroblast growth factor (bFGF) gene expression and the number of dopamine nerve cell bodies in the mesencephalon of the rat. Asphyxia was induced during birth for 19-20 min. A 30% increase in the number of tyrosine-hydroxylase immunoreactive (TH-IR) nerve cell bodies (i.e. dopamine-containing neurones) as well as a 50% increase in bFGF gene expression following asphyxia was found in the substantia nigra/ventral tegmental area 4 weeks after birth. The increase in bFGF mRNA levels may underlie the increase found in the number of dopamine cell bodies. The present results indicate that asphyxia during birth can prime the long-term development of the central nervous system.

Postprandial intestinal-derived chylomicron and chylomicron remnants in essential hypertensive patients before and after prolonged captopril therapy

The metabolism of the postprandial intestinal-derived lipoproteins, chylomicron and chylomicron remnants, is not known in patients with essential hypertension. After a fat meal, using the vitamin A test as a marker, retinyl palmitate was measured in the total plasma, chylomicron, and chylomicron remnant fractions in 14 untreated nondiabetic essential hypertensive patients with normal fasting lipids and lipoproteins. The vitamin A fat loading test was repeated in eight hypertensive patients after 3 months of captopril therapy. Fifteen matched normotensive subjects were used as controls. The untreated essential hypertensive patients had significantly higher chylomicron fraction concentration curves (AUC 17,469 +/- 2553 micrograms/L/h) P < .001 compared with the control group (AUC 13,208 +/- 1245 micrograms/L/h), by two-way analysis of variance with repeated measurements. After 3 months of captopril therapy, the chylomicron fraction (AUC 9701 +/- 1566 micrograms/L/h), and chylomicron remnants fraction (AUC 3487 +/- 580 micrograms/L/h) were much lower (P < .001) than before captopril therapy. Oral glucose tolerance tests were borderline in five of the eight hypertensives before captopril treatment but returned to normal after 3 months of therapy. In summary, postprandial intestinal-derived lipoprotein metabolism is altered in essential hypertensive patients. Captopril therapy caused significant improvement in the postprandial chylomicron metabolism.

Role of nitric oxide (EDRF) in radiocontrast acute renal failure in rats

This study was undertaken to examine the possible role of endothelium-derived relaxing factor (EDRF), identified as nitric oxide (NO), in the pathogenesis of radiocontrast-induced acute renal failure in rats. Normal and salt-depleted rats were monitored for 60 min or 24 h after radiocontrast administration. The administration of L-arginine to normal rats abolished the immediate decrease in p-aminohippurate clearance (CPAH) and attenuated the decrease in inulin clearance (CIn). The administration of NO synthase inhibitor to the salt-depleted animals resulted in a significantly more pronounced decrease in CPAH compared with both the control and the L-arginine-treated animals. The recovery of CIn 24 h after radiocontrast administration to the salt-depleted rats was significantly better in the L-arginine-treated rats than in either the control or inhibitor-treated groups. The administration of radiocontrast material resulted in a significant decrease in urinary guanosine 3',5'-cyclic monophosphate as well as NO2 + NO3 excretion. This decrease was significantly attenuated by L-arginine. Our results 1) suggest that NO plays a major role in the pathogenesis of radiocontrast-induced acute renal failure and 2) suggest a novel therapeutic approach, i.e., the use of L-arginine in this form of acute renal failure.

Deletion of T lymphocytes in human CD4 transgenic mice induced by HIV-gp120 and gp120-specific antibodies from AIDS patients

CD4, a T cell receptor for major histocompatibility complex class II antigen, is a key regulator of immunological reactivities. When engaged together with the T cell antigen receptor, CD4 enhances immune reactions, whereas when ligated independently of the antigen receptor CD4 inhibits the activation of T cells or initiates their deletion. CD4 serves also as a receptor for the human immunodeficiency virus (HIV), which binds the receptor with high avidity through its envelope molecule, gp120. Studies in tissue culture have shown that its affinity to CD4 gives the virus opportunities to utilize CD4-mediated signaling and to manipulate immunocytes. We show here in human CD4 transgenic mice that appropriately cross-linked HIV envelope protein causes massive deletion of HIV-reactive T cells in vivo.

Epidermal growth factor and basic fibroblast growth factor have independent actions on mesencephalic dopamine neurons in culture

Epidermal growth factor (EGF) and basic fibroblast growth factor (bFGF) are both trophic for dopamine neurons in cultures of dissociated embryonic rat mesencephalon, but the significance of this apparent overlap in neurotrophic activity is not yet known. In this study, we investigated the mechanisms of action of these two growth factors and the potential relationship between them. Using a nuclease protection assay, we determined that bFGF mRNA was expressed in the cultures. Double-label immunocytochemistry revealed that bFGF immunoreactive material could be detected in tyrosine hydroxylase immunoreactive neurons and glial fibrillary acidic protein immunoreactive astrocytes. EGF treatment increased bFGF mRNA content per culture dish. As we have previously demonstrated that EGF exerts its dopaminergic neurotrophic activity via an intermediate cell type, studies were designed to address whether the pathway by which EGF acts on dopaminergic neurons is mediated by the release of bFGF. However, the trophic action of EGF on dopamine neurons, represented by high-affinity neuronal dopamine uptake, could not be blocked by immunoneutralization of bFGF, suggesting that the actions of EGF were not mediated by bFGF release. The time course of the effects of EGF and bFGF on dopamine uptake were similar, with significant increases detectable only after 5 days in culture. Both growth factors were active in the picomolar-to-nanomolar range with maximal trophic activity between 0.4 and 2.5 nM. EGF, however, was the more potent mitogen under these conditions. When cultures were simultaneously incubated with maximal concentrations of EGF and bFGF, the effect on dopamine uptake was significantly greater than with either growth factor alone and, in fact, approximated the sum of the individual effects. On the basis of these results we conclude that these growth factors have independent effects on dopamine neurons of the mesencephalon.

Second messenger regulation of mouse gonadotropin-releasing hormone gene expression in immortalized mouse hypothalamic GT1-3 cells

Using a transgenic mouse derived GnRH expressing neuronal cell line, GT1-3, we studied the effects of activation of cAMP, Ca2+ and protein kinase C pathways by forskolin, ionomycin and the phorbol ester phorbol 12-myristate 13-acetate (PMA), respectively, upon gonadotropin-releasing hormone (GnRH) secretion, cellular peptide content, mRNA and RNA primary transcript levels. Forskolin, ionomycin and phorbol ester all caused an increase in GnRH secretion in GT1-3 cells in a time and dose-dependent manner during a short-term (1 h) static incubation. Prolonged treatment with forskolin (10 microM), ionomycin (1 microM) and PMA (10 nM) for 12 or 24 h resulted in significant decreases in GnRH mRNA levels. Time-course studies showed that the increases in GnRH secretion stimulated by forskolin, ionomycin and PMA were gradually attenuated over time in parallel with the decreases in mRNA expression. In contrast, there were only small and variable changes in the GnRH cellular content. Studies using a GnRH antagonist (100 microM) suggested that the released GnRH has a negative feedback effect on its own secretion. However, co-incubation with the GnRH antagonist did not alter the inhibitory effects on GnRH mRNA levels by the secretagogues. Further studies on the transcriptional effects of forskolin, ionomycin and PMA on GnRH gene expression in GT1-3 cells revealed that all three secretagogues suppressed GnRH RNA primary transcript levels, with forskolin having a slower time course of action. Thus, the inhibition of cytoplasmic GnRH mRNA, and presumably its synthesis, after 12-24 h of secretagogue treatment may be due at least in part to a suppression of GnRH gene transcription.(ABSTRACT TRUNCATED AT 250 WORDS)

[Cerebral tuberous sclerosis and Coats disease]

A 10-year-old boy with known tuberous sclerosis since early childhood suffered from unilateral Coats' disease. Initially his parents noticed a divergent squint. On examination, well-advanced Coats' disease involving almost the entire retina including the macula was found. Visual acuity had decreased to 20/300. Intrascleral diathermy was successfully performed, and after painful secondary glaucoma, cryotherapy of the ciliary body became necessary. Coats' disease has been reported in a number of genetic diseases, most of them quite variable in their clinical manifestations. To the best of our knowledge this is the first description of Coats' disease associated with tuberous sclerosis, which is known to be of genetic origin. Although in Coats' disease no genetic predisposition has been proven to date, the growing list of genetic diseases associated with Coats' disease should be considered in patients presenting with this retinopathy.

Molecular cloning of the human homeobox gene goosecoid (GSC) and mapping of the gene to human chromosome 14q32.1

Goosecoid is a homeobox gene first isolated from a Xenopus dorsal lip cDNA library. Homologous genes have been isolated from mouse, zebrafish, and chick. In all species examined, the gene is expressed and plays an important role during the process of gastrulation in early embryonic development. We report here the cloning of the human goosecoid gene (GSC) from a genomic library and the sequence of its encoded protein. The genomic organization and protein sequence of the human gene are highly conserved with respect to those of its Xenopus and mouse counterparts: all three genes consist of three exons, with conserved exon-intron boundaries; the sequence of the homeodomain is 100% conserved in most vertebrates. Using somatic cell hybrid and chromosomal in situ hybridization, the gene was mapped to chromosome 14q32.1.

Characterization of parvalbumin cDNA clones and gene expression in normal and dystrophic mice of strain 129 ReJ

Parvalbumin is a calcium-binding protein found in fast-twitch skeletal muscles and selected cells in the brain. In several dystrophic mutants in the mouse, the parvalbumin content of skeletal muscles and brain is reduced and this deficiency appears to correlate with the inability of these mice to handle enhanced calcium uptake associated with the dystrophic process. In this study, two overlapping cDNA clones of 392 and 1268 base pairs were isolated from a mouse cDNA library in lambda gt11, characterized, and used as probes to study the involvement of the parvalbumin gene and its expression in various tissues of dystrophic mice of strain 129 ReJ. Southern blot analyses of restriction fragments of genomic DNA from normal and dystrophic mice indicate the same number and size of parvalbumin-specific gene fragments observed by other researchers, suggesting that the size of the Pva gene is the same in both normal and dystrophic mice of strain 129 ReJ. Northern blot analyses of total RNA from hind-limb muscles using cloned parvalbumin cDNA as probes revealed an abundant 800-nucleotide mRNA with lesser amounts of a 1000-nucleotide mRNA transcript in both normal and dystrophic mice of strain 129 ReJ. The amount of these mRNAs was reduced by 65-77% in dystrophic muscles preparations and was similar to the levels of beta-actin mRNA in these animals. These results suggest that parvalbumin gene expression is not down regulated in dystrophic mice of strain 129 ReJ.

Flow-cytometric determination of dehydrogenase activities in primary human gastrointestinal tumor cell lines

The activities of 6 dehydrogenases, lactate dehydrogenase (LDH), glucose-6-phosphate dehydrogenase (G6PDH), isocitrate dehydrogenase (ICDH), glycerol-3-phosphate dehydrogenase (GDH), succinate dehydrogenase (SDH) and glutamate dehydrogenase (GLDH), determined by means of flow cytometry in 13 primary human gastrointestinal tumour cell lines, including 10 esophageal carcinomas, one gastric cancer, and 2 pancreatic cancers. Two-parametric measurements of specific dehydrogenase activities in single cells were performed with DAPI as fluorochrome for the nuclear DNA and with the fluorescent redox system of 5-cyano-2,3-ditolyl-tetrazolium chloride (CTC) which forms brilliant red formazan crystals upon reduction by cellular redox enzymes. Furthermore, with the aid of the calibration procedure reported previously [18] the enzyme activities were expressed as biochemical units. This application of tetrazolium salt technique for demonstrating dehydrogenase activities in human tumour cells by flow cytometry offers an alternative tool to characterize malignant tumors.

Mechanism of pepsin-catalyzed aminotranspeptidation reactions

1. The tetrapeptide Ala2-Nph2 (where Nph = p-nitrophenylalanyl) is treated by porcine pepsin to study the mechanism of aminotranspeptidation reactions. 2. The major initial product is Ala2-Nph and the major transpeptidation products are Nph2 and Nph3 accompanied by some Nph, a little Nph4, Ala2-Nph3 and Ala2-Nph4. 3. Oligomers of Nph greater than tetramers are formed near the end of the reaction. 4. In presence of [3H]Nph, no incorporation of Nph into the transpeptidation products is observed. 5. 18O-labeling shows extensive incorporation of 18O atoms from [18O]water in the carbonyl oxygens of Nph residues.

Effect of chronic cholesterol loading in the development of acute ischemic renal failure in rats

The effect of chronic cholesterol loading and lovastatin administration in renal artery clamping acute renal failure in rats is not known. Acute renal failure was induced by 60-min left renal artery clamping immediately after right nephrectomy. The changes in renal function after renal artery clamping in the hyperlipidemic rats were unexpected. The acute renal failure in the cholesterol-loaded groups was less severe than in the nonhyperlipidemic rats. The lovastatin administration had some favorable effect on renal function after ischemia; however, this effect was not additive to the high dietary cholesterol administration. Our results seems to favor the concept that in this special form of experimental renal ischemic acute renal failure, serum cholesterol levels, elevated through diet, may have protective effects with respect to renal tubular lesions during or following the acute ischemic insult.

Characterization of porcine bone sialoprotein: primary structure and cellular expression

Bone sialoprotein (BSP) is a highly glycosylated and sulphated phosphoprotein that is a major non-collagenous protein of bone. To further characterize the porcine protein and to study its expression during bone formation BSP cDNA clones were isolated from a porcine bone cDNA library. The primary sequence of the protein was derived from the nucleotide sequence of the largest cDNA insert and from the amino-terminal amino acid sequence determined by the automated Edman degradation procedure. When compared with sequences obtained from the human and rat BSPs 74% and 64% of the amino acids, respectively, were identical and a further 11% and 17%, respectively, were conservative replacements. Moreover, 60% of the amino acids in a concensus sequence derived from the primary sequences of mammalian BSPs were conserved with 16% conservative replacements. The two stretches of polyglutamic acid, through which the protein is capable of binding to hydroxyapatite, and an RGD motif that mediates cell attachment are retained in conserved sequences as are a number of potential sites of serine, threonine and tyrosine phosphorylation, glycosylation and tyrosine sulphation. Secondary structure prediction and hydrophilicity analysis indicate that the nascent BSP has an open flexible structure with the potential to form significant amounts of alpha-helix and some beta-sheet. In situ hybridization of fetal porcine bone with cRNA probes to porcine BSP mRNA shows that BSP is specifically expressed in differentiated osteoblasts on the surface of newly-forming bone trabeculae with especially high levels of hybridization at sites of de novo bone formation. The highly conserved features of BSP and its restricted distribution indicate an important role for this sialoprotein in the formation of bone.

Effect of sympathetic block demonstrated by triple-phase bone scan

The triple-phase bone scan is frequently used in the diagnosis of reflex sympathetic dystrophy although the etiology of the abnormal findings is not well established. This study evaluated the effect of increased blood flow secondary to sympathetic block on the triple-phase bone scan. In 15 reflex sympathetic dystrophy patients, all of whom had significant relief with sympathetic block, baseline and postsympathetic block bone scans were analyzed. There was a significant linear relationship between change in counts from baseline to postsympathetic block on the blood pool image and bone uptake image. As the blood pool and bone uptake counts increased, the likelihood of typical reflex sympathetic dystrophy findings on visual inspection also increased. These results strongly support the concept of increased vascular flow as the cause of increased periarticular uptake.