Peri-implant diseases. A systematic review of the literature

Peri-implantitis surrounding oral implants is an inflammatory process affecting the soft and hard tissues resulting in rapid loss of supporting bone associated with bleeding and suppuration. The etiopathogenesis of early and late peri-implantitis is less well understood and seems to be related to the peri-implant environment and to the soft tissues/implant interface, to patient-related factors (smoke, systemic diseases, plaque control) and to host-parasite equilibrium. However, there is wide scientific evidence that demonstrates the direct correlation between oral microbiota and peri-implant mucositis or peri-implantitis. In particular, adherence and colonization of microbiota on plaque-exposed biomaterials, like c.p. titanium, are discriminant factors for the development of infection. Regenerative or resective surgical approaches are proposed for the treatment of peri-implantitis depending on the morphology and the shape of bone defects. The therapeutical approach of peri-implantitis surrounding dental implants comprises several aspects such as the removal of supra-gingival bacterial plaque, an appropriate surgical approach, the removal of granulation tissue and detoxification of the exposed implant surface, the elimination of the anaerobic ecosystem by the removal of peri-implant pocket (gingivectomy or apically repositioned flap) or by the regeneration of the peri-implant hard tissues and, finally, the establishment of an efficient plaque control regimen.

Decreased plasma and cerebrospinal fluid content of neuroactive steroids in Parkinson’s disease

The levels of the neuroactive steroids allopregnanolone (THP) and 5alpha-dihydroprogesterone (DHP) were quantified in the plasma of 11 (group 1) and in the liquor of 12 (group 2) Parkinson's disease (PD) patients using a gas-chromatographic/mass-spectrometric method. When compared with controls, both groups showed a significant decrease in DHP and THP concentrations. These decreases could be a useful marker of PD. Moreover, in view of the importance of GABA-ergic transmission to substantia nigra (SN) neurons and GABA-ergic modulation exerted by the two neuroactive steroids, our data indicate a global dysregulation of the SN GABA-ergic system in PD patients. Moreover, a lack of neuroprotective factors (i. e., GDNF, BDNF), promoted by DHP, may contribute to dopaminergic cell death.

GABA(A) receptor active steroids are altered in epilepsy patients with tuberous sclerosis

BACKGROUND

The neuroactive steroid 3alpha, 5alpha-tetrahydroprogesterone is the most potent endogenous positive modulator of gamma-amino-butyric acid (GABA)(A) receptors. There is evidence for a relation between neuroactive steroids and seizure susceptibility.

OBJECTIVE

To evaluate the putative role of counteregulator neuroactive steroids in the occurrence of seizures in patients with tuberous sclerosis.

METHODS

Plasma concentrations of the enantiomers 3alpha, 5alpha- and 3alpha, 5beta-tetrahydroprogesterone (3alpha(s)-THP), which are positive modulators of GABA(A) receptors, were measured in 18 patients, along with their endogenous functional antagonists 3beta, 5alpha- and 3beta, 5beta-THP (3beta(s)-THP), to assess their possible modification compared with control subjects. Neuroactive steroids were assayed using a highly sensitive and specific gas chromatographic/mass spectrometric method.

RESULTS

In the tuberous sclerosis patients with poorly controlled seizures, there was a significantly lower 3alpha(s)/3beta(s)-THP ratio than in seizure-free patients or control subjects.

CONCLUSIONS

The reduced 3alpha(s)/3beta(s)-THP ratio may decrease GABAergic tone, contributing to the appearance of seizures in tuberous sclerosis patients with epilepsy.

Neuroactive steroids: molecular mechanisms of action and implications for neuropsychopharmacology

Besides their binding to cognate intracellular receptors gonadal steroids may also act as functional antagonists at the 5-HT3 receptor. A structure-activity relationship for the actions of a variety of steroids at the 5-HT3 receptor was elaborated that differed considerably from that known for GABA(A) receptors. Steroids appear to interact allosterically with ligand-gated ion channels at the receptor membrane interface. The functional antagonism of gonadal steroids at the 5-HT3 receptor may play a role for the development and course of nausea during pregnancy and of psychiatric disorders. Moreover, we could demonstrate that 3alpha-reduced neuroactive steroids concurrently modulate the GABA(A) receptor and regulate gene expression via the progesterone receptor after intracellular oxidation. Animal studies showed that progesterone is converted rapidly into GABAergic neuroactive steroids in vivo. Progesterone reduces locomotor activity in a dose dependent fashion in male Wister rats. Moreover, progesterone and 3alpha,5alpha-tetrahydroprogesterone produce a benzodiazepine-like sleep EEG profile in rats and humans. In addition, there is a dysequilibrium of such 3alpha-reduced neuroactive steroids during major depression which is corrected by successful treatment with antidepressants. Neuroactive steroids may further be involved in the treatment of depression and anxiety with antidepressants in patients during ethanol withdrawal. First studies in patients with panic disorder suggest that neuroactive steroids may also play a pivotal role in human anxiety. The genomic and non-genomic effects of steroids in the brain contribute to the pathophysiology of psychiatric disorders and the mechanisms of action of antidepressants. Neuroactive steroids affect a broad spectrum of behavioral functions through their unique molecular properties and may constitute a yet unexploited class of drugs.

Implant-retained mandibular overdentures with Brånemark System MKII implants: a prospective comparative study between delayed and immediate loading

This study was designed to compare the results of immediate and delayed loading of implants with implant-retained mandibular overdentures. Ten patients (test group) received 40 Brånemark System MKII implants (4 per patient) placed in the interforaminal area of the mandible. Standard abutments were immediately screwed to the implants, rigidly connected with a bar, and immediately loaded with an overdenture. Ten patients (control group) received the same type and number of implants in the same area, but the implants were left to heal submerged. Four to 8 months later, standard abutments were screwed to the implants and the same prosthetic procedure was applied. Each implant was evaluated at the time of prosthetic loading and at 6, 12, and 24 months after the initial prosthetic load with the following parameters: modified Plaque Index (MPI), modified Bleeding Index (MBI), probing depth (PD), and Periotest. Peri-implant bone resorption was evaluated on panoramic radiographs taken 12 and 24 months after initial prosthetic loading. No significant differences were found between the 2 groups regarding MPI, MBI, Periotest, peri-implant bone resorption, and PD at 6 and 24 months (P > .05). The only difference was found regarding PD values on the mesial and lingual sites at 12 months (P < .05). The cumulative success rate of implants was 97.5% in both groups. Results from this study showed that immediate loading of endosseous implants rigidly connected with a U-shaped bar does not seem to have any detrimental effect on osseointegration. Conversely, this method significantly shortens the duration of treatment with relevant satisfaction for the patients.

Increased behavioral neurosteroid sensitivity in a rat line selectively bred for high alcohol sensitivity

Acute administration of a neurosteroid 5beta-pregnan-3alpha-ol-20-one induced a greater impairment in motor performance of the selectively bred alcohol-sensitive (ANT) than alcohol-insensitive (AT) rats. This difference was not associated with the sensitivity of gamma-aminobutyrate type A (GABA(A)) receptors, as 5alpha-pregnan-3alpha-ol-20-one (allopregnanolone) decreased the autoradiographic signals of t-butylbicyclophosphoro[35S]thionate binding to GABA(A) receptor-associated ionophores more in the brain sections of AT than ANT rats. Nor was the difference associated with baseline levels of neuroactive progesterone metabolites, as 5alpha-pregnan-3,20-dione (5alpha-DHP) and 5alpha-pregnan-3alpha-ol-20-one were lower in the ANT rats. After ethanol (2 g/kg, i.p.) administration and the subsequent motor performance test, the increased brain concentrations of these metabolites were still lower in the ANT than AT rats, although especially in the cerebellum the relative increases were greater in the ANT than AT rats. The present data suggest that the mechanisms mediating neurosteroid-induced motor impairment are susceptible to genetic variation in rat lines selected for differences in ethanol intoxication.

Vertical distraction osteogenesis of edentulous ridges for improvement of oral implant positioning: a clinical report of preliminary results

This study examined the opportunities offered by intraoral distraction osteogenesis to vertically elongate insufficient alveolar ridges and thereby improve local anatomy for ideal implant placement. Eight patients presenting with vertically deficient edentulous ridges were treated by means of the distraction osteogenesis principle with an intraoral alveolar distractor. Two to 3 months after consolidation of the distracted segments, 26 implants were placed in the distracted areas. Four to 6 months later, abutments were connected and prosthetic loading of the implants was started. The mean follow-up after initial prosthetic loading was 14 months. In all patients, the desired bone gain was reached at the end of distraction (mean vertical bone gain of 8.5 mm). Probing depth, Bleeding Index, and Plaque Index around implants were evaluated, and Periotest values were also calculated. The cumulative success rate of implants was 100%. Radiographic examinations 12 months after functional loading of implants showed a significant increase in the density of the newly generated bone in the distracted areas. This technique seems to be reliable, and the regenerated bone has withstood the functional demands of implant loading. Success rates of implants, periodontal indices of peri-implant soft tissues, and Periotest values were consistent with those reported in the literature regarding implants placed in native bone.

[Measurement of 17 OH progesterone in blood in Chilean newborns: antecedents for implementing a grogram for the neonatal detection of congenital adrenal hyperplasia]

BACKGROUND

The early diagnosis and therapy of congenital adrenal hyperplasia (CAH) due to 21-hydroxylase deficiency can prevent adrenal crises and erroneous gender assignment in affected newborns. To achieve this goal neonatal mass-screening programs have been developed, measuring blood 17 alpha-hydroxyprogesterone (17OHP). In Chile there is no experience with this type of screening.

AIM

To develop a method for measuring 17OHP in filter paper blood specimens. To obtain reference ranges and determine neonatal 17OHP threshold levels according to gestational age and birth weight. To analyze factors affecting the cost-efficiency ratio and suggest recommendations for the organization of a neonatal screening program for CAH in Chile.

MATERIAL AND METHODS

Nine hundred twenty two newborns were studied. 17OHP was measured using double antibody radioimmunoassay in filter paper blood samples obtained 48 h after birth. Reference ranges were determined according to gestational age and birth weight and a cutoff point of 25 ng/ml was established.

RESULTS

Seventeen newborns had 17OHP over the cutoff value. They were assessed by a pediatric endocrinologist and in none of them, CAH was confirmed. Therefore the false positive rate of the determination was 1.8%. Among these newborns with elevated 17OHP, 66% had a birth weight below 1.5 kg and 5.8%, a birth weight between 1.5 and 2.5 kg. The cost per reported result was US $ 1. Timing of the recall was between the 3 and 10 days of life. No newborn missed the follow-up.

DISCUSSION

To increase the cost-efficiency ratio of an eventual neonatal screening program, newborns with birth weights below 1.5 kg should be excluded and cutoff points should be defined according to birth weight (Rev Méd Chile 2000; 128: 1113-18).

Fluoxetine decreases concentrations of 3 alpha, 5 alpha-tetrahydrodeoxycorticosterone (THDOC) in major depression

There is evidence for a differential alteration in the concentrations of 3 alpha-reduced neuroactive steroids in major depression. Because it has been suggested that fluoxetine may shift the activity of the 3 alpha-hydroxysteroid oxidoreductase towards the reductive direction, treatment of major depression may be accompanied by a further increase in plasma 3 alpha, 5 alpha-tetrahydrodeoxycorticosterone (THDOC) concentration. We studied eight male depressed patients before and after treatment with fluoxetine and compared them to healthy age-matched control subjects. Blood samples were quantified for 3 alpha, 5 alpha-tetrahydroprogesterone, 3 alpha,5 beta-tetrahydroprogesterone (THP) and THDOC by means of a highly sensitive combined gas chromatography/mass spectrometry analysis. Compared to control subjects, concentrations of THDOC were higher in depressed patients and decreased after fluoxetine treatment. In contrast, THP concentrations were lower in depressed patients and increased after fluoxetine treatment. Our results give further evidence for a disequilibrium of 3 alpha-reduced neuroactive steroids in major depression, which is normalized by treatment with fluoxetine.

Increased neurosteroids synthesis after brain and spinal cord injury in rats

We studied the effect of brain and spinal cord injury induced by fluid-percussion on the local synthesis of neurosteroids as measured by a gas-chromatographic/mass-spectrometric method. In the nervous system of sham operated rats i.v. infusion of pregnenolone (PREGN)-sulfate results in a 2-4 fold increase in PREGN, progesterone (PROG), 5alpha-dehydroprogesterone (5alpha-DHP) and 3alpha-hydroxy-5alpha-pregnan-20-one (3alpha5alpha-THP, allopregnanolone) concentrations, as compared to vehicle treated rats. When PREGN-sulfate was infused 1, 3 or 7 days after brain or spinal cord injury it was observed a large time-dependent increase of PROG, 5alpha-DHP and 3alpha5alpha-THP levels in the peri-focal but not in the focal site. This increase in neurosteroids content may be due essentially to the glial cells hyperplasia in the peri-focal area and to an activation of the pathways involved in the metabolism of PREGN-sulfate to PROG, 5alpha-DHP and 3alpha5alpha-THP.

Effects of fluoxetine, indomethacine and placebo on 3 alpha, 5 alpha tetrahydroprogesterone (THP) plasma levels in uncomplicated alcohol withdrawal

OBJECTIVE

The purpose of this study was to investigate the effects of fluoxetine (F) and indomethacine (I), two drugs that regulate the synthesis of the GABAergic neurosteroid 3 alpha, 5 alpha tetrahydroprogesterone (allopregnanolone, THP) on THP plasma levels and on symptoms of anxiety and depression in alcoholics during ethanol withdrawal.

METHOD

Patients who met DSM-IV criteria for alcohol abuse were randomly assigned to treatment with F (40 mg/day) plus misoprostol (M) (500 mg/day) or I (100 mg/day) plus M or placebo (PL) plus M. Patients were rated with the Hamilton Anxiety (14-HAS) and Depression (17-HDS) scales on days 1, 5, 7, 15 and 28 of ethanol withdrawal and with a Visual Analogue Scale for Depression (VASD) and a Visual Analogue Scale for Anxiety (VASA) on days 1, 2, 4, 5, 7, 15 and 28 of withdrawal. On the same days a plasma sample was collected to measure the concentrations of THP by means of a very sensitive gas chromatographic mass spectrometric method.

RESULTS

During withdrawal at days 1, 2, 4 and 5, THP plasma values were lower and symptoms of anxiety and depression were significantly higher compared to the late withdrawal phase at days 15 and 28. In the F or I treatment, the depression and anxiety score, measured by VASD and VASA, decreased significantly at day 5-7 whereas THP plasma levels significantly increased compared to PL condition

CONCLUSIONS

Treatment of alcohol withdrawal either with F or I reduced the extent of anxiety and depression and normalised THP plasma levels that were decreased during withdrawal.

Behavior of implants in bone grafts or free flaps after tumor resection

The authors compared bone resorption of autogenous bone grafts and revascularized free flaps used for the reconstruction of mandibular continuity defects following resection for tumors, before and after the placement of endosseous implants. Ten patients (group 1) were treated with autogenous bone grafts taken from the fibula or the anterior iliac crest; 8 patients (group 2) were treated with iliac or fibula revascularized flaps. Four to 8 months later, 72 endosseous implants were placed in the reconstructed areas. After a further healing period of 4-6 months, patients were rehabilitated with implant-borne prostheses. The following parameters were evaluated and compared between the two groups: 1) bone resorption of grafts and free flaps before and after implant placement; 2) peri-implant bone resorption mesial and distal to each implant, immediately after prosthetic rehabilitation and then during yearly follow-ups. Bone resorption before implant placement showed mean values of 3.53 mm in group 1, and 0.96 mm in group 2. Peri-implant bone resorption was: 0.49 mm (39 implants) in group 1, and 0.45 mm (30 implants) in group 2, at time of prosthetic rehabilitation; 0.78 mm (39 implants) in group 1, and 0.89 mm (30 implants) in group 2, 12 months after prosthetic load; 1.16 mm (24 implants) in group 1, and 1.02 mm (13 implants) in group 2, 24 months after the prosthetic load. A significant difference in bone resorption before implant placement was found between the two groups, whereas it was not found after implant placement and prosthetic load. The failure rate according to Albrektsson criteria was 4.9% (2/41 implants) in group 1, and was 3.2% (1/31) in group 2.

Clinical outcome of autogenous bone blocks or guided bone regeneration with e-PTFE membranes for the reconstruction of narrow edentulous ridges

The aim of this study was to analyse the clinical outcome of two different surgical methods for the reconstruction of narrow edentulous ridges before implant installation: guided bone regeneration with e-PTFE membranes and autologous bone chips or grafting of autologous bone blocks without e-PTFE membranes. Thirty partially edentulous patients, presenting insufficient bone width (less than 4 mm) in the edentulous sites for installation of screw-type titanium implants, were selected and assigned to two different treatment modalities. Fifteen patients (group 1) were treated by means of guided bone regeneration with e-PTFE membranes supported by stainless steel screws and autologous bone chips taken from intraoral sites. Fifteen patients (group 2) were treated by means of autologous bone blocks taken from intraoral or extraoral sites (anterior iliac crest and calvaria) and stabilized with titanium microscrews. Six to 8 months later, during re-entry for implant insertion, the gain of ridge width obtained was measured. In group 1 the average amount of bone gain was 2.7 mm, whereas in group 2 the value was 4.0 mm. Five to 6 months after implant placement prosthetic rehabilitation was started. The mean follow-up after prosthetic load has been 22.4 months. Success rates of implants according to Albrektsson criteria has been 93.3% in group 1, and 90.9% in group 2. Although a statistical comparison between the two treatment modalities may not be feasible, due to the bias resulting from the choice of treatment by the clinician and from the differences in donor sites and defect extension, some considerations can be made: 1) both methods are a reliable means for the correction of narrow edentulous ridges; 2) both techniques necessitate overcorrection of the defect because of interposition of connective tissue beneath the membrane in the first group and bone resorption in the second one; 3) the use of semipermeable barriers increases the costs of the surgical procedure, as compared to bone grafting without membranes; 4) guided bone regeneration presents a higher risk of infection because of wound dehiscence and membrane exposure. Therefore, in case of wide edentulous areas, reconstruction of narrow ridges should be performed with bone blocks without membranes.

Concentrations of 3 alpha-reduced neuroactive steroids and their precursors in plasma of patients with major depression and after clinical recovery

BACKGROUND

There is preclinical and clinical evidence that plasma concentrations of 3 alpha-hydroxy-5 alpha-pregnan-20-one (3 alpha,5 alpha-tetrahydroprogesterone; 3 alpha,5 alpha-THP), a neuroactive steroid that is a positive allosteric modulator of the GABAA receptor, are altered in depression and normalize as a result of antidepressant treatment. However, no data are available on the concentrations of 3 alpha,21-dihydroxy-5 alpha-pregnan-20-one (3 alpha,5 alpha-tetrahydrodeoxycorticosterone; 3 alpha,5 alpha-THDOC), another GABA ergic neuroactive steroid, in depression.

METHODS

We studied nine depressed patients before and after treatment with various antidepressants and compared them to healthy matched control subjects. Blood samples were quantified by means of a highly sensitive combined gas chromatography/mass spectrometry analysis.

RESULTS

Compared to control subjects, plasma concentrations of 3 alpha,5 alpha-THDOC and its precursor 5 alpha-dihydrodeoxycorticosterone (5 alpha-DHDOC) were increased in depressed patients and were not significantly influenced by antidepressant treatment. However, 3 alpha,5 alpha-THP plasma concentrations were decreased in depression and clinically effective antidepressant treatment was accompanied by an increase of 3 alpha,5 alpha-THP concentrations in these patients.

CONCLUSIONS

Our results provide the first evidence for a differential alteration in the plasma concentrations of the 3 alpha-reduced neuroactive steroids 3 alpha,5 alpha-THDOC and 3 alpha,5 alpha-THP in major depression, which is only partially reversed by successful antidepressant treatment.

Neuroactive steroid concentrations following metyrapone administration in depressed patients and healthy volunteers

BACKGROUND

There is evidence that treatment with the 11 beta-hydroxylase inhibitor metyrapone may represent an alternative treatment strategy in major depression. As a consequence of inhibition of cortisol synthesis the overdrive of corticotropin leads to an accumulation of precursor steroids. However, the effects of metyrapone on the concentrations of endogenous neuroactive steroids that modulate ion channels, e.g., the GABAA receptor, have not yet been studied systematically.

METHODS

Therefore, we quantified the concentrations of an array of neuroactive steroids following administration of 1.5 g metyrapone before and after pretreatment with 1 mg dexamethasone in 19 patients suffering from severe depression in comparison to 13 healthy controls by means of a highly sensitive gas chromatography/mass spectrometry analysis.

RESULTS

The administration of metyrapone induced a pronounced increase in all neuroactive steroids studied both in patients and controls that was prevented by dexamethasone pretreatment.

CONCLUSIONS

Thus, the psychotropic properties of endogenous neuroactive steroids may contribute to the antidepressant properties of metyrapone in the treatment of major depression.

Effects of antidepressant treatment on neuroactive steroids in major depression

OBJECTIVE

There is evidence from animal studies that fluoxetine may enhance the concentrations of neuroactive steroids. Therefore, the authors investigated whether clinically effective treatment with antidepressants may alter the concentrations of neuroactive steroids in patients suffering from a major depressive episode.

METHOD

In the first study, eight drug-naive outpatients with major depression were studied during treatment with fluoxetine. In a complementary study, 11 inpatients with major depression were studied during a severe depressive episode and after recovery following treatment with different antidepressants. Plasma samples were quantified for neuroactive steroids by means of a highly sensitive and specific combined gas chromatography/mass spectrometry analysis.

RESULTS

During depression, there was a significant decrease in 3 alpha, 5 alpha-tetrahydroprogesterone (3 alpha, 5 alpha-THP) and 3 alpha, 5 beta-THP concentrations, both of which are positive modulators of the gamma-aminobutyric acidA receptor, and a concomitant increase in 3 beta, 5 alpha-THP levels. This dysequilibrium of neuroactive steroids could be corrected by treatment with different antidepressants.

CONCLUSIONS

These results provide the first clinical evidence of a possible role of neuroactive steroids in successful antidepressant therapy.

Tridimensional reconstruction of knife-edge edentulous maxillae by sinus elevation, onlay grafts, and sagittal osteotomy of the anterior maxilla: preliminary surgical and prosthetic results

The possibility of placing endosseous implants in the edentulous maxilla is frequently reduced by inadequate bone volume of the residual ridge. In totally edentulous maxillae with knife-edge conformation, insufficient thickness is frequently associated with insufficient height of the residual ridge in the posterior maxilla because of pneumatization of the maxillary sinuses. This surgical method combines grafting of the maxillary sinuses, onlay grafts on the buccal side of maxillary posterior segments, and sagittal osteotomy of the anterior maxilla with interpositional bone grafts. Five to six months after maxillary reconstruction, Brånemark implants were placed and, after osseointegration occurred, implant-supported dental prostheses were fabricated. Three patients have been treated with this method and 22 implants have been placed. The mean follow-up after final prosthetic rehabilitation has been 16 months; survival rate has been 100%. Despite the small number of patients and the short follow-up, preliminary results have shown very promising results.

Allopregnanolone affects sleep in a benzodiazepine-like fashion

Recent research in rats and humans has shown that exogenous progesterone evokes a sleep profile similar to that induced by agonistic modulators of gamma-aminobutyric acid(A) receptors, such as benzodiazepines. This finding suggests the involvement of the neuroactive metabolite of progesterone, allopregnanolone. In the vehicle-controlled study reported here, we assessed the sleep effects of two doses of allopregnanolone (7.5 and 15 mg/kg), mixed with oil, administered intraperitoneally at light onset in 8 rats. The electroencephalogram (EEG) and electromyogram were recorded during the first 6 postinjection hr. Compared with vehicle, both doses of allopregnanolone reduced the latency to non-rapid eye movement sleep (non-REMS) and 15 mg/kg allopregnanolone significantly increased the time spent in pre-REMS, an intermediate state between non-REMS and REMS. Furthermore, allopregnanolone dose-dependently influenced EEG activity during non-REMS and REMS. In non-REMS, EEG activity was decreased in the lower frequencies (< or =7 Hz) and enhanced in the frequencies of > or =13 Hz. In REMS, allopregnanolone enhanced high-frequency EEG activity (> or =17 Hz). The effects were most pronounced during the first postinjection hours and gradually diminished thereafter. Analysis of the plasma and brain concentrations of allopregnanolone in 45 rats revealed long-lasting increases, which reached maximal levels during the first postinjection hour. The sleep effects of allopregnanolone are very similar to those elicited by larger doses of progesterone, which produce comparable brain levels of allopregnanolone. These data indicate that the steroid allopregnanolone has benzodiazepine-like effects on sleep.

Marked decrease of plasma neuroactive steroids during alcohol withdrawal

The neuroactive steroids allopregnanolone (ALLO) and allotet-rahydrodeoxycorticosterone (THDOC) are the most potent endogens positive modulators of gamma-aminobutyric acid (GABA) on GABAA receptors, a receptor system presumably responsible for some behavioral responses to alcohol withdrawal. In a group of nine alcoholic subjects, the levels of plasma ALLO and THDOC were markedly lower than those of control subjects during the early withdrawal phase (day 4 and 5), when anxiety and depression scores were higher. In contrast ALLO and THDOC plasma levels did not differ from those of control subjects during the late withdrawal phase when anxiety and depression scores were low. These results suggest that the decrease of neuroactive steroid biosynthesis may contribute to the withdrawal symptoms.