Effect of delayed argatroban treatment on intracerebral hemorrhage-induced edema in the rat

Studies indicate that thrombin plays an important role in intracerebral hemorrhage (ICH) induced edema formation. However, the time window for administration of a thrombin inhibitor to reduce ICH-induced edema is unknown. Nor is it known whether this time window extends beyond the period when a thrombin inhibitor might exacerbate rebleeding. This study examines whether a thrombin inhibitor, argatroban, can reduce edema formation following intracerebral infusion of 100 microl of blood in the rat, the therapeutic time window for argatroban, and whether argatroban promotes rebleeding. Intracerebral injection of argatroban 3 hours after ICH caused a significant reduction in edema measured at 48 hours. The systemic administration of argatroban (0.9 mg/h) starting 6 hours after ICH also significantly reduced edema formation. There was no protection when the onset of argatroban administration was delayed to 24 hours after ICH. Argatroban did not increase collagenase-induced hematoma volume when given into the clot after 3 hours or given systemically at 6 hours. Our data suggest argatroban may be an effective therapy for ICH-induced edema.

Brain edema after intracerebral hemorrhage: the effects of systemic complement depletion

The complement cascade is activated after experimental intracerebral hemorrhage (ICH) and may play an important, role in edema formation. This study investigated the effects of systemic complement depletion on brain edema formation following ICH. Thirty-six pentobarbital-anesthetized Sprague-Dawley rats were used. Treatment animals were complement-depleted with cobra venom factor (CVF) while controls received an equal volume of saline injection (i.p.). In both treatment and control rats, autologous blood (100-microL) was infused stereotactically into the right basal ganglia. Rats were sacrificed one and three days later for brain water and ion content measurements and immunohistochemical studies. Immunohistochemistry was used to detect complement C3d, C5a, and C9. Western blot analysis was applied for C9 semiquantitation. Perihematomal brain edema was reduced by systemic complement depletion at one and three days. The water content of the cerebellum (a tissue distant from the hematoma site) was unaffected by complement depletion. Immunocytochemistry found complement depletion significantly reduced perihematomal C9 deposition, C3d production, and C5a positive cell accumulation. In conclusion, complement depletion by CVF attenuates brain edema in ICH perhaps by inhibiting the inflammatory response and membrane attack complex (MAC) formation.

Experimental intracerebral hemorrhage: effect of lysed erythrocytes on brain edema and blood-brain barrier permeability

Understanding the mechanism of edema formation following intracerebral hemorrhage (ICH) is important for developing treatment protocols for this condition. This study examines the role of red blood cell (RBC) lysis and hemoglobin in edema formation following ICH. Significant brain edema developed after 24 hours in rats infused with lysed RBCs and this was associated with a 3-fold increase blood brain barrier (BBB) permeability to alpha-aminoisobutyric acid. We have previously shown that intracerebral injection of packed RBCs does not cause edema formation at one day but does at three days. In this study, we found that packed RBCs did not cause significant BBB disruption at one day but produced a 4-fold increase in BBB permeability at three days. These studies show that following ICH the leakage of substances inside the RBC, facilitated by cellular lysis, results in delayed edema. This was confirmed by both experimentally induced lysis and naturally occurring in-vivo lysis.

Effect of ischemic preconditioning on edema formation and cerebrovascular injury following focal cerebral ischemia

Many studies have shown that a brief period of ischemia can protect against a subsequent severe ischemic event and this has been termed ischemic preconditioning (IPC). Most studies have been focused on neuroprotection, with only a little attention on cerebrovascular effects. This study examines the effect of IPC, induced by 15 minutes of middle cerebral artery occlusion (MCAO) in the rat, on brain edema formation and cerebrovascular injury induced by a permanent MCAO induced three days later. Brain edema formation was significantly reduced in IPC treated rats compared to non-IPC treated rats. IPC-treated rats also had reduced blood-brain barrier disruption and reduced cerebrovascular expression of heat shock protein 70, a marker of cell stress. These results indicate that IPC reduces cerebrovascular injury from subsequent permanent focal cerebral ischemia. Understanding the mechanisms involved may provide new therapeutic strategies for stroke.

Thrombin exacerbates brain edema in focal cerebral ischemia

Thrombin contributes to edema formation after intracerebral hemorrhage. Recent studies suggest that thrombin may also play a role in ischemic brain damage. In the present study, adult male Sprague-Dawley rats were anesthetized with pentobarbital. Middle cerebral artery (MCA) was occluded using the suture method. We found that brain thrombin activity was elevated after permanent MCA occlusion as was prothrombin messenger RNA expression. Intracerebral injection of a thrombin inhibitor, hirudin, reduced neurological deficits following cerebral ischemia. In contrast, intracerebral administration of exogenous thrombin (at a dose that is non-toxic to normal brain), markedly exacerbated brain edema after transient focal cerebral ischemia. These results indicate that extravascular thrombin inhibition may be a new therapeutic target for cerebral ischemia.

A thrombin inhibitor reduces brain edema, glioma mass and neurological deficits in a rat glioma model

Although thrombin is a critical enzyme in the coagulation cascade, it has become apparent that it has many other effects. Thus, it may induce brain edema formation, angiogenesis and cell proliferation. Because of the importance of these three factors in the extremely poor prognosis of glioma patients, the present study examined the role of thrombin in that disease state. We found that thrombin activity is increased in a rat glioma model and thrombin positive cells were present in the tumor. Anti-thrombin treatment with argatroban reduced brain edema, tumor growth, and tumor-related neurological deficits. Our results suggest that thrombin is a new target for glioma treatment.

Thrombin preconditioning upregulates transferrin and transferrin receptor and reduces brain edema induced by lysed red blood cells

Pretreatment with a low dose of thrombin reduces brain edema after both hemorrhagic and ischemic stroke. We call this phenomenon thrombin preconditioning (TPC) or thrombin-induced brain tolerance. The present study examines whether TPC can attenuate the brain edema induced by lysed red blood cells (RBCs) to determine whether thrombin production early in an intracerebral hemorrhage (ICH) might alter potentially injurious events associated with clot resolution. It also examines whether TPC might be protective by altering iron handling within the brain, particularly through modulating transferrin (Tf) and transferrin receptor (TfR) levels. Brain edema was measured by wet/dry weight. Western blot analysis and immunohistochemistry were used for Tf and TfR measurements. We found that TPC reduces lysed RBC-induced brain edema and upregulates both Tf and TfR levels in the brain. Thrombin formation after an ICH may be part of a signaling cascade that acts to limit potentially injurious events associated with clot resolution through altering iron-handling proteins.

Changes in cerebral oxygenation in children undergoing surgical repair of ventricular septal defects

There have been few published studies on changes in cerebral oxygenation during paediatric cardiac surgery as measured by conventional near-infrared spectroscopy. We studied changes in cerebral oxygenation in 16 children undergoing surgical repair of ventricular septal defects. Fifteen of the patients showed similar patterns of changes: brain tissue concentrations of oxyhaemoglobin decreased significantly during cardiopulmonary bypass, whereas there was no significant change in brain tissue concentrations of deoxyhaemoglobin. In the remaining patient, who suffered decreased blood flow to the lower body during surgery, the pattern of changes was different to that of the other subjects. This patient suffered postoperative respiratory and renal failure. This study suggests that conventional near-infrared spectroscopy may be useful for clinical monitoring during ventricular septal defect repair.

Effects of mild and moderate hypothermia on apoptosis in neuronal PC12 cells

BACKGROUND

There is still a possibility that mild hypothermic therapy may be useful as a neuroprotective tool during the intraoperative period, although the mechanism of cerebral protection by mild hypothermia is not well understood. We hypothesized that mild hypothermia may be protective against cerebral ischaemia by inhibiting post-ischaemia apoptosis. In this study, we used serum-deprived PC12 cells as the neuronal apoptotic model and examined the direct effects of mild and moderate hypothermia.

METHODS

Apoptosis was induced by depriving the cell culture medium of serum, which is one of the most representative methods to induce apoptosis, but not necrosis, in PC12 cells. Effects of mild (35 and 33 degrees C) and moderate (31 and 29 degrees C) hypothermia on apoptosis were evaluated. Cytotoxicity (lactate dehydrogenase leakage) and the percentage of apoptotic cells (calculated by flow cytometry with propidium iodide) were evaluated 4 days after induction of apoptosis. As a control, cells without induction of apoptosis were incubated under the same conditions as the apoptosis group.

RESULTS

Without induction at 37 degrees C, cytotoxicity and the percentage of apoptotic cells were over 60 and 90%, respectively. At each temperature examined below 35 degrees C, significant decreases in cytotoxicity and the percentage of apoptotic cells were observed. Mean cytotoxicity at 31 and 29 degrees C was 50.2 (SD 4.2)% and 47.9 (4.4)%, respectively. The percentage of apoptotic cells at 31 and 29 degrees C was 42.5 (7.4)% and 36.5 (7.3)%, respectively. In the control group, cytotoxicity and the percentage of apoptotic cells were significantly higher at 29 degrees C than at 37 degrees C.

CONCLUSIONS

Mild and moderate hypothermia (29-35 degrees C) inhibited apoptosis, although hypothermia below 30 degrees C may induce apoptosis in intact cells.

Intravenous C-type natriuretic peptide augments behavioral and endocrine effects of cholecystokinin tetrapeptide in healthy men

Given the anxiogenic effects of the type-B natriuretic peptide receptor agonist C-type natriuretic peptide (CNP) in rodents, we investigated the influence of CNP pretreatment upon the behavioral and endocrine action of the panicogen cholecystokinin tetrapeptide (CCK-4) in healthy men. In a randomized double-blind balanced design, 20 male volunteers were given an intravenous infusion of 300 microg of CNP vs. placebo followed by 25 microg of CCK-4. The behavior was assessed using panic, anxiety, and dissociation questionaires before the infusion and after the CCK-4 stimulus. Furthermore, the stress-sensitive hormones adrenocorticotropic hormone (ACTH), cortisol, and prolactin were measured. CNP pretreatment enhanced the anxiogenic and prodissociative effects of CCK-4 and significantly augmented the ACTH surge after CCK-4. However, no effect of CNP was seen upon panic symptoms. Our preliminary data support a role of type-B natriuretic peptide receptors in anxiety modulation in normal man.

Delayed first injection of the once-a-month injectable contraceptive containing 25 mg medroxyprogesterone acetate and 5 mg estradiol-cypionate: effects on cervical mucus

The objectives of this study were to assess whether women who were administered the first injection of the once-a-month contraceptive containing estradiol cypionate and 25 mg depot-medroxyprogesterone acetate (MPA+E(2)C) on Day 7 of their menstrual cycle (delayed injection) exhibit the same degree of cervical mucus changes as women who receive it on Day 5 of their menstrual cycle. This was a multicenter, randomized, controlled clinical trial. A total of 158 women, aged between 18 and 38 years (inclusive), who, were willing to use MPA+E(2)C as their contraceptive method participated in the trial. Participants received a MPA+E(2)C injection on Day 5 (control group, n = 41) or Day 7 (delayed-injection group, n = 117) of their menstrual cycle. Participants who received MPA+E(2)C on Day 5 of their menstrual cycle (control group) exhibited fair or poor mucus quality and poor sperm penetration. Of those women who received MPA+E(2)C on Day 7 of their menstrual cycle (delayed-injection group), 3 (3%) showed good mucus or good sperm penetration at some time point during follow-up. It is possible to conclude that the first injection of MPA+E(2)C given on Day 7 of a menstrual cycle does not provide the same degree of inhibition of mucus quality and sperm penetration as that observed if it is administered on Day 5. However, the theoretical risk of pregnancy after receiving MPA+E(2)C on Day 7 would be expected to be low.

Mechanisms of edema formation after intracerebral hemorrhage: effects of extravasated red blood cells on blood flow and blood-brain barrier integrity

BACKGROUND AND PURPOSE

Red blood cell (RBC) lysis contributes to brain edema formation after intracerebral hemorrhage (ICH), and RBC hemolysate (oxyhemoglobin) has been implicated to be a spasminogen in subarachnoid hemorrhage. Whether cerebral ischemia contributes to brain edema formation after ICH remains unclear, however. The aims of this study were to test whether extravasation of RBCs induces cerebral ischemia and/or blood-brain barrier disruption in a rat ICH model characterized by perihematomal brain edema.

METHODS

In this study, 87 pentobarbital-anesthetized Sprague-Dawley rats were used. In each animal, saline, packed RBCs, or lysed RBCs were injected into the right caudate nucleus. Sham injections served as controls. Regional cerebral blood flow, brain water and ion contents, blood-brain barrier integrity, and plasma volume were measured.

RESULTS

Intraparenchymal infusion of lysed RBCs caused severe brain edema by the first day but did not induce ischemic cerebral blood flows. In contrast, blood-brain barrier permeability increased during the first day after infusion of lysed RBCs (a 3-fold increase) and 3 days after infusion of packed RBCs (a 4-fold increase).

CONCLUSIONS

These results suggest that ischemia is not present at 24 or 72 hours after hematoma induction by injection of intact or lysed RBCs. RBC constituents that appear after delayed lysis, however, increase blood-brain barrier permeability, which contributes to edema formation.

Effects and mechanisms of H(2)O(2) on production of dicarboxylic acid

The system of producing long chain dicarboxylic acid (DCA) by Candida tropicalis is an aerobic and viscous fermentation system. A method to overcome the gas-liquid transport resistance and to increase oxygen supply is by adding hydrogen peroxide (H(2)O(2)) to the fermentation system. Here we report that the H(2)O(2) not only can enhance the oxygen supply but also change the metabolism by inducing cytochrome P450, the key enzyme of a, o-oxidation. When C. tropicalis was cultivated in a 3-L bioreactor using the combination of aeration and H(2)O(2) feeding, DCA production rates increased by about 10% after a short period of decrease at the beginning. Furthermore, the experiments showed that the maximum activities of P450 could be induced at 2 mM H(2)O(2), and the inducible mechanisms are also discussed. Moreover, we suggest that alkane might be oxidized through the "peroxide shunt pathway" when H(2)O(2) is present. By adding H(2)O(2), the DCA yield in a 22-L bioreactor could increase by 25.3% and reach 153.9 g/L.

[A study on the change of caries activity of children with fixed orthodontic treatment]

OBJECTIVE

To investigate the change of caries activity in children with fixed appliance.

METHODS

30 children of permanent dentition were treated with edgewise appliance. CAT was used to test the degree of caries activity before the orthodontic treatment, at the first week, at the first month, at the third month and at the sixth month of appliance bonding respectively.

RESULTS

Compared with pre-treatment, there was a significant difference of CAT at the first, third and sixth month of treatment; compared with the first week of treatment, there was also a significant difference of CAT at the third and sixth month of treatment.

CONCLUSIONS

The CAT degree increases in children with fixed orthodontic appliance and these children are more sensitive to dental caries.

Differential cellular expression of neurotrophins in cortical tubers of the tuberous sclerosis complex

Neurotrophins and their receptors modulate cerebral cortical development. Tubers in the tuberous sclerosis complex (TSC) are characterized histologically by disorganized cortical cytoarchitecture and thus, we hypothesized that expression of neurotrophin mRNAs and proteins might be altered in tubers. Using in situ transcription and mRNA amplification to probe cDNA arrays, we found that neurotrophin-3 (NT3) and trkB mRNA expression were reduced whereas neurotrophin-4 (NT4) and trkC mRNA expression were increased in whole tuber sections. Alterations in mRNA abundance were defined in single microdissected dysplastic neurons (DNs) and giant cells (GCs). NT3 mRNA expression was reduced in GCs and trkB mRNA expression was reduced in DNs. NT4 mRNA expression was increased in DNs and trkC mRNA expression was increased in both DNs and GCs. In three patients, TSC2 locus mutations were confirmed and the mean tuberin mRNA expression levels was reduced across all nine cases. Consistent with these observations, NT3 mRNA expression was reduced but trkC mRNA expression was increased in vitro in human NTera2 neurons (NT2N) transfected with a tuberin antisense construct that reduced tuberin expression. Western analysis of tuber homogenates and computer-assisted densitometry of immunolabeled sections confirmed the neurotrophin mRNA expression data in whole sections and single neurotrophin immunoreactive cells. We conclude that alterations in NT4/trkB and NT3/trkC expression may contribute to tuber formation during brain development as downstream effects of the hamartin and tuberin pathway in TSC.

Attenuation of intracerebral hemorrhage and thrombin-induced brain edema by overexpression of interleukin-1 receptor antagonist

OBJECT

Adenovirus-mediated overexpression of interleukin-1 receptor antagonist (IL-1ra) attenuates the inflammatory reaction and brain injury that follows focal cerebral ischemia. Recently, an inflammatory reaction after intracerebral hemorrhage (ICH) was identified. In this study the authors examine the hypothesis that overexpression of IL-1ra reduces brain injury (specifically edema formation) after ICH.

METHODS

Adenoviruses expressing IL-1ra (Ad.RSVIL-1ra) or LacZ, a control protein (Ad.RSVlacZ), or saline were injected into the left lateral cerebral ventricle in rats. On the 5th day after virus injection, 100 microl of autologous blood or 5 U thrombin was infused into the right basal ganglia. Rats with ICH were killed 24 or 72 hours later for measurement of brain water and ion content. Thrombin-treated rats were killed 24 hours later for edema measurements and an assessment of polymorphonuclear leukocyte (PMNL) infiltration by myeloperoxidase (MPO) assay, as well as histological evaluation. Compared with saline-treated and Ad.RSVlacZ-transduced controls, Ad.RSVIL-1ra-transduced rats had significantly attenuated edema in the ipsilateral basal ganglia 3 days after ICH (81.5 +/- 0.3% compared with 83.4 +/- 0.4% and 83.3 +/- 0.5% in control animals). Thrombin-induced brain edema was also reduced in Ad.RSVIL-1ra-treated rats (81.3 +/- 0.4% compared with 83.2 +/- 0.4% and 82.5 +/- 0.4% in control rats). The reduction in thrombin-induced edema was associated with a reduction in PMNL infiltration into the basal ganglia, as assessed by MPO assay (49% reduction) and histological examination.

CONCLUSIONS

Overexpression of IL-1ra by using an adenovirus vector attenuated brain edema formation and thrombin-induced intracerebral inflammation following ICH. The reduction in ICH-induced edema with IL-1ra may result from reduction of thrombin-induced brain inflammation.

Intracranial aneurysms: experience in treating 500 patients

OBJECTIVE

To summarize the experience in surgical treatment of patients with intracranial aneurysms.

METHODS

The measures used in the treatment of 500 patients with intracranial aneurysms were retrospectively reviewed with regard to timing of surgery, induced-hypotensive anesthesia, brain protection combined with temporal occlusion of the feeding artery, dynamically monitoring of transcranial Doppler ultrasound, antivasospasm treatment, techniques of direct surgery, and endovascular embolization.

RESULTS

In 465 patients undergoing surgery, intraoperative rupture was observed in 27(6.2%), postoperative death in 13 (2.7%), hemipalsy in 8(2.2%), and vegetative state in 2 (5.0%). The operative mortality was 3.8% in 210 patients before 1990, while 1.9% in 255 patients after 1990.

CONCLUSION

The outcome of patients with intracranial aneurysms can be markedly improved by comprehensive measures.

Thrombin preconditioning, heat shock proteins and thrombin-induced brain edema

Intracerebral injections of high concentrations of thrombin cause brain edema but, in vitro, low concentrations of thrombin may be neuroprotective. This study investigated whether a low dose of thrombin might induce tolerance to subsequent large doses of thrombin (thrombin preconditioning; TPC) in a manner analogous to ischemic preconditioning. The study involved five parts. The first tested the effect of intracerebral infusion of a small dose (1 U) of thrombin on brain water content. In the second part, the effect of such a small dose of thrombin on subsequent edema formation from a large dose of thrombin (5 U) was evaluated. The time course of TPC was examined in the third part. In the fourth part, heat shock protein (HSP) 27, HSP32 and HSP70 were quantitated by Western blotting analysis while the fifth identified the cell types expressing HSPs. Injection of a low dose of thrombin alone did not cause brain edema. However, TPC significantly attenuated the edema induced by a subsequent injection of a large dose of thrombin. This effect of TPC was abolished by co-injection of a thrombin inhibitor, hirudin. The maximal effect of TPC on edema formation was seven days after pretreatment. This time course was similar to that for a marked up-regulation in astrocytic HSP27. TPC also induced HSP32, but this effect occurred earlier than the effect on edema formation. TPC had no effect on HSP70. These results suggest that thrombin-induced brain tolerance may be related to HSP27 induction.

Induction of colligin may attenuate brain edema following intracerebral hemorrhage

Brain edema plays an important role in the secondary brain injury following intracerebral hemorrhage (ICH). Edema formation after ICH has been linked to thrombin toxicity. Therefore, the induction of endogenous serine protease inhibitors, which inhibit thrombin prior to ICH may limit edema formation. This study examines whether injection of a low dose of thrombin upregulates such inhibitors and induces tolerance to subsequent ICH. Rats received intracerebral infusions of either one unit thrombin or saline into the right caudate nucleus. After seven days, the rats were either (A) used to examine colligin (a serine protease inhibitor) induction by Western blot analysis, immunohistochemistry and immunofluorescent double labeling, (B) to determine brain water content, or (C) they received a second injection of 50 microL blood and brain edema was determined one day later. Intracerebral infusion of thrombin caused a marked upregulation of colligin, a serine protease inhibitor, in the ipsilateral basal ganglia. Immunocytochemistry and immunofluorescent double labeling showed that colligin was induced in astrocytes. Infusion of this dose of thrombin alone did not affect brain water content but it significantly attenuated subsequent ICH-induced brain edema (79.0 +/- 0.5 vs. 81.4 +/- 0.9%, P < 0.01). Our results demonstrate that low doses of thrombin upregulate brain colligin levels and attenuate edema formation induced by ICH.

Three SNARE complexes cooperate to mediate membrane fusion

Soluble N-ethylmaleimide-sensitive factor attachment protein receptor (SNARE) proteins of the syntaxin, SNAP-25, and VAMP families mediate intracellular membrane fusion through the formation of helical bundles that span opposing membranes. Soluble SNARE domains that lack their integral membrane anchors inhibit membrane fusion by forming nonfunctional complexes with endogenous SNARE proteins. In this study we investigate the dependence of membrane fusion on the concentration of a soluble SNARE coil domain derived from VAMP2. The increase in the inhibition of fusion observed with increasing concentration of inhibitor is best fit to a function that suggests three SNARE complexes cooperate to mediate fusion of a single vesicle. These three complexes likely contribute part of a protein and lipidic fusion pore.

Abortion history and breast cancer risk: results from the Shanghai Breast Cancer Study

Studies of the association between induced abortion and breast cancer risk have been inconsistent, perhaps due to underreporting of abortions. Induced abortion is a well-accepted family planning procedure in China, and women who have several induced abortions do not feel stigmatized. The authors used data from a population-based case-control study of breast cancer among women age 25-64 conducted between 1996 and 1998 in urban Shanghai to assess whether a history of and the number of induced abortions were related to breast cancer risk. In-person interviews were completed with 1,459 incident breast cancer cases ascertained through a population-based cancer registry, and 1,556 controls randomly selected from the general population in Shanghai (with respective response rates of 91% and 90%). After adjusting for confounding, there was no relation between ever having had an induced abortion and breast cancer (odds ratio [OR] = 0.9, 95% confidence interval [CI] 0.7-1.2). Women who had 3 or more induced abortions were not at increased risk of premenopausal breast cancer (OR = 0.9, 95% CI 0.6-1.4) or postmenopausal breast cancer (OR = 1.3, 95% CI 0.8-2.3). These results suggest that a history of several induced abortions has little influence on breast cancer risk in Chinese women.

Synthesis and reactivity of the catechol metabolites from the equine estrogen, 8,9-dehydroestrone

The risk factors for women developing breast and endometrial cancers are all associated with a lifetime of estrogen exposure. Estrogen replacement therapy in particular has been correlated with an increased cancer risk. Previously, we showed that the equine estrogens equilin and equilenin, which are major components of the widely prescribed estrogen replacement formulation Premarin, are metabolized to highly cytotoxic quinoids which caused oxidative stress and alkylation of DNA in vitro [Bolton, J. L., Pisha, E., Zhang, F., and Qiu, S. Chem. Res. Toxicol. 1998, 11, 1113-1127]. In this study, we have synthesized 8,9-dehydroestrone (a third equine estrogen component of Premarin) and its potential catechol metabolites, 4-hydroxy-8,9-dehydroestrone and 2-hydroxy-8,9-dehydroestrone. Both 2-hydroxy-8,9-dehydroestrone and 4-hydroxy-8,9-dehydroestrone were oxidized by tyrosinase or rat liver microsomes to o-quinones which reacted with GSH to give one mono-GSH conjugate and two di-GSH conjugates. Like endogenous estrogens, 8,9-dehydroestrone was primarily converted by rat liver microsomes to the 2-hydroxylated rather than the 4-hydroxylated o-quinone GSH conjugates; the ratio of 2-hydroxy-8,9-dehydroestrone versus 4-hydroxy-8,9-dehydroestrone was 6:1. Also in contrast to experiments with equilin, 4-hydroxyequilenin was not observed in microsomal incubations with 8,9-dehydroestrone or its catechols. The behavior of 2-hydroxy-8,9-dehydroestrone was found to be more complex than 4-hydroxy-8,9-dehydroestrone as GSH conjugates resulting from 2-hydroxy-8,9-dehydroestrone were detected even without oxidative enzyme catalysis. Under physiological conditions, 2-hydroxy-8,9-dehydroestrone isomerized to 2-hydroxyequilenin to form the very stable 2-hydroxyequilenin catechol; however, 4-hydroxy-8,9-dehydroestrone was found to be stable under similar conditions. Finally, preliminary studies conducted with the human breast tumor S-30 cell lines demonstrated that the catechol metabolites of 8,9-dehydroestrone were much less toxic than 4-hydroxyequilenin (20-40-fold). These results suggest that the catechol metabolites of 8,9-dehydroestrone may have the ability to cause cytotoxicity in vivo primarily through formation of o-quinones; however, most of the adverse effects of Premarin estrogens are likely due to formation of 4-hydroxyequilenin o-quinone from equilin and equilenin.

Levels of ovine herpesvirus 2 DNA in nasal secretions and blood of sheep: implications for transmission

A recently developed competitive PCR for ovine herpesvirus 2 (OvHV-2) was used to examine the levels of viral DNA in nasal secretions and peripheral blood leukocytes (PBL) of lambs and adult sheep. Viral DNA first appeared in the PBL of most lambs after about 3 months of age and the levels remained relatively constant thereafter. In most of the lambs (83%, n=12), viral DNA was undetectable by PCR in nasal secretions prior to 5 months of age. A dramatic rise of OvHV-2 DNA levels in the nasal secretions occurred starting at 5-6 months of age, which peaked at approximately 7 months. The highest level recorded in lamb nasal secretions was 7.5x10(8)copies/2microg DNA which were 75,000-100,000-fold higher than the levels in PBL of the same lambs. In adult sheep (n=10), the viral DNA levels in both PBL and nasal secretions were relatively stable over the 13-month period of the study, which included a lambing season. The data strongly suggest that neonatal lambs are not an important source for the transmission of OvHV-2 to clinically susceptible species, and that the nasal cavity is an important portal for shedding of infectious OvHV-2 in sheep. Furthermore, this study failed to identify a seasonal pattern in levels of viral DNA in nasal secretions or PBL of adult sheep that would provide a basis for the traditionally held belief that clinical cases of malignant catarrhal fever are significantly associated with lambing ewes.

Delayed first injection of the once-a-month injectable contraceptive containing 25 mg of medroxyprogesterone acetate and 5 mg of E(2)-cypionate: effects on ovarian function

OBJECTIVE

To assess whether women who were administered the first injection of DMPA+E(2)C on day 7 of their menstrual cycle (delayed injection) exhibit the same degree of ovarian suppression as women who receive it on day 5 of their menstrual cycle.

DESIGN

Multicenter, randomized controlled trial.

SETTING

Reproductive health clinics.

PATIENT(S)

Women aged between 18 and 38 years (inclusive) willing to use DMPA+E(2)C as their method of contraception.

INTERVENTION(S)

Participants received a DMPA+E(2)C injection on day 5 (control group, n = 41) or day 7 (delayed-injection group, n = 117) of their menstrual cycle.

MAIN OUTCOME MEASURE(S)

Ovarian activity and follicular development determined by serial serum progesterone levels and vaginal ultrasound.

RESULT(S)

Participants who received DMPA+E(2)C on day 5 of their menstrual cycle (control group) exhibited no more than limited follicular growth (no follicle >16 mm). Of those women who received DMPA+E(2)C on day 7 of their menstrual cycle (delayed-injection group), 21 (18%) showed some follicular growth, of whom 4 (3%) ovulated.

CONCLUSION(S)

The first injection of DMPA+E(2)C given on day 7 of a menstrual cycle does not provide the same inhibition of ovarian activity as that observed when it is administered on day 5 of the menstrual cycle.