Showing papers by "University of Gothenburg published in 1988"

Effects of enalapril on mortality in severe congestive heart failure: Results of the Cooperative North Scandinavian Enalapril Survival Study (CONSENSUS)

Abstract: To evaluate the influence of the angiotensin-converting enzyme inhibitor, enalapril (2.5 to 40 mg/day), on the prognosis of severe congestive heart failure, defined as New York Heart Association functional class IV, a double-blind study was undertaken in which 253 patients were randomized to receive either placebo (n = 126) or enalapril (n = 127) in addition to conventional treatment, including vasodilators. Follow-up averaged 188 days (range 1 day to 20 months). The reduction in crude mortality within 6 months (primary objective) was 40% in the enalapril-treated group (from 44 to 26%, p = 0.002) and within 1 year 31% (p = 0.001). By the end of the study, 68 subjects in the placebo group and 50 in the enalapril group had died--a reduction of 27% (p = 0.003). The entire reduction in total mortality (50%) was found in patients dying from progressive heart failure, whereas no difference was seen in the incidence of sudden cardiac death. There was a significant improvement in New York Heart Association classification in the enalapril group, together with a reduction in heart size and a reduced requirement for other heart failure medication. It is concluded that the addition of enalapril to conventional therapy in patients with severe congestive heart failure can reduce mortality and improve symptoms. The effect seems to be due to a reduction in death from progression of heart failure.

Healing of bone defects by guided tissue regeneration.

Abstract: In this study we describe a principle for the accomplishment of bone regeneration based on the hypothesis that different cellular components in the tissue have varying rates of migration into a wound area during healing By a mechanical hindrance, using a membrane technique, fibroblasts and other soft connective-tissue cells are prevented from entering the bone defect so that the presumably slower-migrating cells with osteogenic potential are allowed to repopulate the defect Defects of standard size were created bilaterally through the mandibular angles of rats On one side of the jaw the defect was covered with Teflon membranes, whereas the defect on the other side served as control Histologic analysis after healing demonstrated that on the test (membrane) side, half the number of animals showed complete bone healing after 3 weeks and all animals showed complete healing after 6 weeks Little or no sign of healing was evident on the control side even after an observation period of 22 weeks

Osseointegrated Oral Implants

Abstract: Fourteen Swedish teams outside the University of Gothenburg, each with minimally three years' experience in the Nobelpharma osseointegrated implant participated in a retrospective multiclinic study. The total number of consecutively inserted implants at the 14 clinics was 8139. The outcome of every implant was reported and all implant failures, irrespective of when they occurred, were published. The success criteria included absence of implant mobility, absence of radiolucent zones on x-rays, and an annual bone loss after the first year of less than 0.2 mm. In the mandible 334 implants were followed for five to eight years, with only three failures, for a success rate of 99.1%. In the maxilla 106 implants were followed for five to seven years, with a success rate of 84.9%. In irradiated and grafted mandibles, 56 implants were inserted and none was lost during a follow-up of up to five years. In the irradiated maxilla there were 16 implants inserted with three reported failures and in the grafted upper jaw 71 implants were inserted with 12 failures. The proportions of mandibular and maxillary sleeping implants were 0.8 and 0.3%, of patient drop-out implants 0.3 and 0.6%, and of patient death implants 0.9 and 1.2%, respectively. It was concluded that the osseointegrated implant, if inserted according to the guidelines of Branemark, results in a very high degree of clinical success, thereby meeting any published oral implant success criteria.

Thin Stage I Primary Cutaneous Malignant Melanoma

Abstract: Although wide surgical excision is the accepted treatment for thin malignant melanomas, there is reason to believe that narrower margins may be adequate. We conducted a randomized prospective study to assess the efficacy of narrow excision (excision with 1-cm margins) for primary melanomas no thicker than 2 mm. Narrow excision was performed in 305 patients, and wide excision (margins of 3 cm or more) was performed in 307 patients. The major prognostic criteria were well balanced in the two groups. The mean thickness of melanomas was 0.99 mm in the narrow-excision group and 1.02 mm in the wide-excision group. The subsequent development of metastatic disease involving regional nodes and distant organs was not different in the two groups (4.6 and 2.3 percent, respectively, in the narrow-excision group, as compared with 6.5 and 2.6 percent in the wide-excision group). Disease-free survival rates and overall survival rates (mean follow-up period, 55 months) were also similar in the two groups. Only three patients had a local recurrence as a first relapse. All had undergone narrow excision, and each had a primary melanoma with a thickness of 1 mm or more. The absence of local recurrence in the group of patients with a primary melanoma thinner than 1 mm and the very low rate of local recurrences indicate that narrow excision is a safe and effective procedure for such patients.

Is high and fluctuating muscle nerve sympathetic activity in the sleep apnoea syndrome of pathogenetic importance for the development of hypertension

Abstract: Muscle nerve sympathetic activity was recorded in six patients with the sleep apnoea syndrome (SAS). Compared with age- and sex-matched control patients, an increased activity during wakefulness was found. Sleep apnoic events were associated with sequencies of progressively increasing sympathetic activity followed by a sudden reduction of activity. The high sympathetic activity associated with SAS may be important in the development of the systemic hypertension commonly seen in these patients.

A double-blind cross-over 12-month study of L-thyroxine treatment of women with 'subclinical' hypothyroidism.

Abstract: Twenty women, who had been randomly selected from women with subclinical hypothyroidism identified in a population study were treated with L-thyroxine and placebo in a double-blind cross-over design during 2 x 6 months. Three women did not complete the study, one because she moved to another part of the country, and two because of nervousness and sense of tachycardia. None of these 'drop-outs' had any objective signs of overtreatment; they had normal pulse rate and a serum T3 concentration within the reference interval. During L-thyroxine treatment serum procollagen-III-peptide concentration increased in 13 women out of the 17 women completing the study and at the end of treatment the mean concentration was significantly raised (P less than 0.001). Serum concentrations of procollagen-III-peptide then correlated with those of free thyroxine (P less than 0.01), total thyroxine (P less than 0.05), and reverse triiodothyronine (P less than 0.05). The same comparison revealed little or no effect on the concentrations of serum creatine kinase activity, transcortin or sex-hormone binding globulin. Heart rate-corrected preejection period and symptom score decreased (P less than 0.05). Four women starting with L-thyroxine showed a marked and prolonged (4-6 months) rise in thyrotrophin concentration during the subsequent placebo period, but remained clinically euthyroid. Four women (of 17) improved during therapy as judged by psychometric testing and their own rating. We could not by pretreatment observations identify these four women apart from serum free and total 3,5,3'-triiodothyronine concentrations in the lower part of the health-associated reference interval. Subclinical hypothyroidism is common among middle-aged and old women, and our findings indicate that approximately one woman in four with this 'subclinical' condition will benefit from L-thyroxine treatment.

Risk factors for type 2 (non-insulin-dependent) diabetes mellitus. Thirteen and one-half years of follow-up of the participants in a study of Swedish men born in 1913

Abstract: This report presents data on antecedents of Type 2 (non-insulin-dependent) diabetes mellitus in a homogeneous sample of randomly selected 54-year-old men from an urban Swedish population with a diabetes incidence of 6.1% during 13.5 years of follow-up. The increased risk leading to diabetes for those in the top quintile compared to the lowest quintile of the distribution of statistically significant risk factors were: body mass index = 21.7, triglycerides = 13.5, waist-to-hip circumference ratio = 9.6, diastolic blood pressure = 6.7, uric acid = 5.8, glutamic pyruvic transaminase = 3.9, bilirubin = 3.2, blood glucose = 2.7, lactate = 2.4 and glutamic oxaloacetic transaminase = 2.0. Those with a positive family history of diabetes had 2.4-fold higher risk for developing diabetes than those without such a history. In a multivariate analysis glutamic pyruvic transaminase, blood glucose, body mass index, bilirubin, systolic blood pressure, uric acid and a family history of diabetes were all significantly associated with the development of diabetes. Our study demonstrates the great importance of adiposity and body fat distribution for the risk of diabetes. A number of established risk factors for coronary heart disease are risk factors for diabetes as well. Disturbed liver function and increased levels of lactate are early risk factors for diabetes - presumably indicators of the presence of impaired glucose tolerance and/or hyperinsulinaemia.

The earlier the colonization by mutans streptococci, the higher the caries prevalence at 4 years of age

Abstract: Seventy-eight 4-year-old children, examined earlier for the presence of mutans streptococci at 4-month intervals from 15 months of age, were recalled for recording of dental caries and salivary sampling. The saliva samples were analysed for the presence of mutans streptococci, including the species Streptococcus mutans and Streptococcus sobrinus and lactobacilli. The results showed that the earlier the mutans streptococci had been detected in the children, the higher the caries experience. Eighty-nine percent of the children colonized at 2 years of age had experienced caries and had a mean dfs of 5.0 compared with 25% of the non-colonized 4-year-olds with a mean dfs of 0.3. S. mutans was the predominant species. S. sobrinus was usually found in combination with S. mutans, except in 2 children where S. sobrinus was the only species detected. More children with multiple species had higher numbers of total mutans streptococci and a tendency to higher caries prevalence than children with only S. mutans.

Soft tissue reactions around percutaneous implants: a clinical study of soft tissue conditions around skin-penetrating titanium implants for bone-anchored hearing aids.

Abstract: Some patients with hearing impairment cannot use conventional hearing aids. One solution for these patients is the use of bone conduction hearing aids; however, this kind of equipment is associated with several problems related to the necessity for a good contact between the transducer and the temporal bone. Direct bone contact would be an ideal solution provided that safe and reaction-free skin penetration and a safe and permanent bone anchorage could be achieved. Branemark et al have developed a procedure to furnish edentulous patients with fixed bridges using titanium implants. This report is focused on the clinical status of the soft tissue adjacent to the 67 skin-penetrating devices in 60 patients. The patients have been followed between 3 and 96 months on 313 occasions, which represents a total observation time of 1515 months of clinical performance. Only one implant was extracted due to adverse skin reaction, giving a failure rate of 0.07% per month. This is comparable with the failure rate of cardiac pacemakers 0.02-0.04% per month).

Peripheral Sympathetic Neural Activity in Conscious Humans

Abstract: Hagbarth & Vallbo made the first direct microneurographic recordings of postganglionic sympathetic nerve discharges in man (32). Since then per­ cutaneously inserted microelectrodes have been used extensively for the study of human sympathetic function. Apart from a recent study of sympathetic activity in trigeminal nerve branches (44), the microneurographic exploration of sympathetic mechanisms has bcen confined to nerves of the extremities. Two different types of sympathetic outflow have been recognized in multifi­ ber recordings: muscle nerve sympathetic activity (MSA) and skin nerve sympathetic activity (SSA). The former is dominated by vasoconstrictor signals; the latter is a mixture of sudomotor and vasoconstrictor and probably sometimes includes pilomotor and vasodilator impulses. Thus only two sub­ divisions of the anatomically multifaceted sympathetic nervous system are accessible to study. Despite this limitation, the results have allowed a number of conclusions, not only about peripheral sympathetic function but also about reflex patterns and hence general principles of sympathetic regulation.

The effect of immunotherapy on bronchial hyperresponsiveness and eosinophil cationic protein in pollen-allergic patients

Abstract: The effect of immunotherapy (IT) on bronchial response to histamine and on eosinophil cationic protein (ECP) in 40 birch pollen-allergic patients with a history of rhinoconjunctivitis and wheezing during the birch season was examined. Twenty patients started IT with birch extract (Pharmacia, Uppsala, Sweden) before the season. The other 20 patients were not treated with IT. Histamine-challenge tests were performed before, at the start, at pollen peak, at the end, and after the birch-pollen season. Blood samples for determination of ECP were collected at the same time. Skin prick tests and nasal provocation tests were also performed before and after the season. A significant increase in bronchial hyperresponsiveness was noted in the group treated with IT and in the untreated group during the season. The increase was greatest in the untreated group with the maximal difference between the two groups at the end of the pollen season ( p p p

Muscle and Adipose Tissue Morphology and Metabolism in Cushing's Syndrome*

Abstract: Femoral and abdominal adipose tissue cellularity and metabolism as well as muscle morphology and metabolism were examined in women with Cushing’s syndrome and compared with those in nonobese women and obese women with the android and gynoid types of fat distribution. Cushing’s syndrome was characterized by abdominal obesity and enlarged abdominal fat cells, with adipose tissue lipoprotein lipase activity elevated 2–3 times that in normal women and low lipolytic capacity. Muscle tissue in women with Cushing’s syndrome had a relatively low proportion of type I (30%) and a high proportion of type IIB (32%) muscle fibers, similar to those in android obesity (45% and 25%, respectively) and in contrast to fiber composition in gynoid obesity (55% and 12%, respectively). Glycogen synthase activity in the lateral vastus muscle was very low. We suggest that the enlargement of abdominal fat depots in women with Cushing’s syndrome is at least partially due to elevated adipocyte lipoprotein lipase activity and low lip...

Gamma-interferon regulates vascular smooth muscle proliferation and Ia antigen expression in vivo and in vitro.

Abstract: A significant fraction of the arterial smooth muscle cells in atherosclerotic plaques and injury-induced intimal thickenings express class II major histocompatibility complex (Ia) antigens. This might be the consequence of gamma-interferon secretion by T lymphocytes also present in these lesions. We have therefore analyzed the effects of gamma-interferon on cultured rat aortic smooth muscle cells. Recombinant gamma-interferon inhibited smooth muscle proliferation in vitro in a dose-response relation; inhibition was detectable down to a concentration of 1 unit/ml. In similar concentrations, gamma-interferon also induced Ia expression by the cells. This suggested that Ia antigens might be selectively expressed by nonproliferating smooth muscle cells. In vivo, there was a strong negative correlation between Ia expression and 3H-thymidine labeling of smooth muscle cells in intimal thickenings induced by balloon catheter injury. In rats receiving continuous infusions of 3H-thymidine for two weeks after injury, Ia-positive 3H-positive cells had undergone fewer rounds of replication than Ia-negative ones. This indicates that Ia-expression both in vivo and in vitro is associated with a reduced proliferative capacity. These results suggest that gamma-interferon, a secretory product of activated T lymphocytes, acts as a natural regulator of smooth muscle cell growth and Ia expression in injury-induced intimal thickenings and atherosclerotic plaques.

Epilepsy in Autism and Autisticlike Conditions: A Population-Based Study

Abstract: • In a population-based study from Goteborg, Sweden, of infantile autism in children under age 10 years, we found epilepsy in 20% of the cases. Twice as many children among those with "autisticlike conditions" had epilepsy. All types of epilepsy were seen. Of the children in the study who had epilepsy, almost 75% (10/ 14) had psychomotor epilepsy. The association between autism—autisticlike conditions and epilepsy seemed to be with the behavioral disorder and not with the often concomitant mental retardation. Abnormalities evidenced on electroencephalograms seemed to be generated from the temporal regions and phylogenetically older parts of the brain in a majority of the cases.

Periodontal status in relation to age and tooth type. A cross-sectional radiographic study.

Abstract: The purpose of the present study was to assess by radiographic means the pattern of destructive periodontal disease within the dentition of individuals of different ages. Full-mouth series of intra-oral radiographs from 531 dentate individuals aged 25-75 years were examined with respect to number and type of remaining teeth, location of the alveolar bone in relation to the cemento-enamel junction and presence of angular bony defects. The assessments of alveolar bone levels and angular bony defects were performed at the approximal surfaces of all teeth present. The results showed that although most individuals had experienced a reduction in alveolar bone height with age, only a small number of subjects had developed advanced breakdown of the periodontium. Hence, pronounced bone loss was observed in only 11% of the subjects and was non-existent in ages below 35 years. 23% of the individuals accounted for 3/4 of the total number of sites with bone level values (bone loss) of greater than or equal to 6 mm. Out of the total number of tooth sites examined, 28% showed no bone loss, while 13% demonstrated pronounced periodontal tissue breakdown. Angular bony defects were found at 8% of all teeth examined and were most frequent at the maxillary first premolars. Teeth in the incisor regions consistently showed the highest frequency of advanced alveolar bone loss and the lowest frequency of normal tissue support, while corresponding figures for teeth in the molar regions were found to be the opposite. However, molars were the most frequently missing teeth.

A Study of Students' Understanding of Electricity in Five European Countries.

Abstract: This paper describes a study of the understanding of basic electrical concepts shown by 15‐17 year‐old students in England, France, The Netherlands, Sweden and West Germany, the same objective test having been administered to samples of students in each of these countries. When within‐country results were averaged across student groups the between‐country differences on many aspects of this subject were quite small. Those electrical principles which yielded significant differences fell into two main groups, one concerned with current, flow of charge and energy, the other with voltage and its relationship to current. The consistency with which these significant differences emerged across a range of problems concerning related principles suggests that these represent real differences between the outcomes of teaching across the five countries but the causes of these differences are not yet clear. Despite the differences that have emerged, the overall impression which the results convey is of substantially th...

Cyclosporin A inhibits smooth muscle proliferation in the vascular response to injury.

Abstract: The arterial response to injury is dominated by proliferation of smooth muscle cells and infiltration of blood-borne cells in the vascular intima. Arterial smooth muscle cell proliferation is under growth factor control, but how this regulation operates in vivo is unclear. We studied the effect on arterial response to mechanical injury of cyclosporin A, a drug that inhibits T-lymphocyte activation. Cyclosporin A treatment at surgery caused a persistent inhibition of the intimal proliferative lesion. Cyclosporin A also inhibited expression of Ia antigens on smooth muscle cells in situ but had no direct effects on smooth muscle cell proliferation in culture. Therefore, the inhibition of intimal cell proliferation appears to be mediated via the immune system.

Implant fixation improved by close fit. Cylindrical implant-bone interface studied in rabbits.

Abstract: Cylindric titanium implants of three different diameters were inserted and stabilized in a 3.7-mm burr hole in the rabbit tibia. The purpose of the study was to investigate the interfacial reaction to screw- and cylinder-shaped implants, and to determine if there is a critical gap at the insertion between bone and implant that prevents direct cortical bone apposition on the implant. The study indicated that this critical gap approached zero.

Gastrointestinal and colonic segmental transit time evaluated by a single abdominal x-ray in healthy subjects and constipated patients.

Abstract: Gastrointestinal transit time (GITT) and segmental colonic transit times were studied in 56 healthy subjects by repeated daily ingestion of 10 radiopaque markers followed by abdominal x-ray. A seven-day procedure including marker intake for 6 days and a single radiograph on day 7 was found to be a simple method to differentiate between rapid, normal and prolonged transit. Addition of 20 distinguishable markers on day 6 helped to describe transit profiles. Healthy women had longer GITT than men (median 2.4 and 1.9 days, respectively) measured as mean 50% excretion time for the ingested doses of markers. For comparisons with patients percentiles for transit were calculated. In constipated patients the 7-day method demonstrated prolonged GITT as well as transit dysfunction in separate colonic segments. The method seems convenient for clinical use in diagnostic as well as therapeutic studies of colonic transit.

Wide tourniquet cuffs more effective at lower inflation pressures

Abstract: Longitudinal and radial tissue-fluid pressure distributions were determined beneath and adjacent to wide (12 and 18 cm) pneumatic tourniquet cuffs placed on intact human cadaveric arms and legs, re...

Adipose tissue volume determination in males by computed tomography and 40K

Abstract: Seventeen healthy male volunteers with weights ranging from 54 to 145 kg were examined with a Philips Tomoscan 310 The upper attenuation limit of adipose tissue was determined to be -30 HU The lower attenuation limit was set to -190 HU Regional and total adipose tissue volumes were calculated from the adipose tissue areas of 22 scans and from the distances between these scans Three different mathematical formulas were used, which all gave similar results The adipose tissue area of several trunk scans, as well as the elbow, showed very high correlations (r greater than 096) versus the volume determinations based on 22 scans The visceral adipose tissue area of scan L2-L3 showed a higher correlation (r = 0986) than any other single scan versus the visceral adipose tissue volume Total adipose tissue volume determinations with ten selected scans correlated very closely with the results obtained from 22 scans (r = 0997) The adipose tissue volume of the head and neck region was 19 +/- 10 per cent of the total volume Corresponding figures for other regions were: arms 68 +/- 10 per cent, legs 290 +/- 73 per cent, subcutaneous part of the trunk 414 +/- 74 per cent and the visceral region 209 +/- 70 per cent With greater total adipose tissue volumes the percentage of the subcutaneous adipose tissue of the trunk increased (r = 0686; P less than 0005) There was a very strong negative relationship between the fractional amount of adipose tissue in the legs and in the trunk (r = 0993, P less than 0001) The potassium contents of fat-free mass and lean body mass were deduced to be 647 and 710 mmol/kg, respectively These calculations were based on adipose tissue volume determinations by computed tomography, on 40K measurements and on the assumption that the volume proportions of fat, water and protein in adipose tissue were 85:137:13 By using computed tomography (CT) as a standard an optimal weight (W) for height (H) index was constructed by using an iterative correlation technique The optimal index, ie highest correlation and lowest error versus ATCT was found for W/H09

Role of "diseased" root cementum in healing following treatment of periodontal disease. A clinical study.

Abstract: This clinical trial was undertaken to examine whether root debridement in the treatment of periodontal disease must include the removal of the exposed cementum in order to achieve periodontal health. The study included 11 adult patients with moderate to advanced periodontal disease. In a split-mouth design, the dentition of each patient was by random selection divided into test- and control quadrants comprising the incisors, canines and premolars. Following a baseline examination, all patients were given a case presentation and a detailed instruction in self-performed oral hygiene measures. The patients were then subjected to periodontal surgery. Following reverse bevel incisions, buccal and lingual mucoperiosteal flaps were elevated and all granulation tissue was removed. In 2 jaw quadrants (control quadrants) in each patient, the denuded root surfaces were carefully scaled and planed in order to remove soft and hard deposits as well as all cementum, using hand instruments and flame-formed diamond stones. In the contralateral quadrants (test quadrants) the roots were not scaled and planed but soft microbial deposits were removed by polishing the root surfaces with the but soft microbial deposits were removed by polishing the root surfaces with the use of rubber cups, interdental rubber tips and a polishing paste. Calculus in the test quadrants was removed by the use of a curette, but precaution was taken to avoid the removal of cementum. The flaps were repositioned to their original level and sutured. The patients were following active treatment enrolled in a supervised maintenance care program including "professional tooth cleaning" once every 2 weeks for a 3-month period.(ABSTRACT TRUNCATED AT 250 WORDS)

The cellular response of the human allergic mucosa to natural allergen exposure

Abstract: It has been suggested that the IgE-dependent late-phase reaction to allergen exposure, with the features of an inflammatory cellular infiltration and airway hyperreactivity, is a link between anaphylaxis and continuous allergic airway disease. Our main knowledge of the cellular response to allergen in sensitized individuals has been derived from allergen-challenge models. To explore the dynamics of the cellular response during the actual disease, patients with a strictly seasonal allergic rhinitis were studied during natural allergen exposure. Ten patients suffering from an isolated birch-pollen allergy were followed from a symptom-free state before, during, and to the height of the birch-pollen season. Repeated parallel cell samplings from the nasal mucosa were performed with cytologic imprints on plastic strips, nasal lavages with the recovery of the cells in the lavage fluid with cytocentrifugation on object slides for cytologic study, and scrapings from the nasal surface with a curette for histologic and ultrastructural evaluation. The histamine content was determined in lavage fluid and cell pellets. The tosyl-alpha-tosyl-L-arginine methyl esterase activity of the nasal lavage fluid was also determined as a biochemical marker of the allergic inflammatory reaction. The birch-pollen season was moderate in terms of pollen counts, and this resulted in mild to moderate nasal symptoms that ran parallel to the birch-pollen counts. The total number of cells recovered in the lavage fluid was 1.2 +/- 0.4 (SEM) x 10(6) before and 3.2 +/- 2.0 per 10(6) cells (not significant) during pollen exposure. Most cells were neutrophils and mononuclear cells.(ABSTRACT TRUNCATED AT 250 WORDS)

A regional study of sex differences in rat brain serotonin

Abstract: 1. Male and female rats were compared with respect to serotonin (5-HT), 5-hydroxyindoleacetic acid (5-HIAA), tryptophan, dopamine (DA), 3,4-dihydroxyphenylacetic acid (DOPAC), homovanillic acid (HVA) and 3-methoxytyramine (3-MT) levels in five brain regions (brainstem, hypothalamus/preoptic area, corpora striata, limbic forebrain and cortex). Brain 5-HT synthesis rate was also studied in the two sexes. 2. There were no consistent gender differences in the dopaminergic system. 3. In contrast, the serotonergic system was more expressed in females: 5-HT levels were significantly higher in females than in males in the brainstem and limbic forebrain and tended to be so in the cortex. 5-HIAA levels were significantly higher in females in all five brain regions. The 5-HIAA/5-HT ratios were significantly higher in females in the hypothalamus/preoptic area and limbic forebrain and tended to be so in the striatum and cortex. Tryptophan concentrations were significantly higher in females in the brainstem, striatum and cortex. In no brain region were 5-HT, 5-HIAA or tryptophan levels higher in males. Following L-amino acid decarboxylase inhibition 5-hydroxytryptophan (5-HTP) accumulation was more pronounced in the female rat brain. 4. Taken together these results suggest that the brain 5-HT system has a higher potential in female than in male rats. This sex difference is not restricted to a specific region but seems to exist generally in the brain.