Non-Labeled, Stable Labeled, or Radiolabelled Approaches for Provision of Intravenous Pharmacokinetics in Humans: A Discussion Piece

A review of the use of microdoses and isotopic microtracers for clinical intravenous pharmacokinetic (i.v. PK) data provision is presented. The extent of application of the varied approaches available and the relative merits of each are highlighted with the aim of assisting practitioners in making informed decisions on the most scientifically appropriate design to adopt for any given new drug in development. It is envisaged that significant efficiencies will be realized as i.v. PK data in humans becomes more routinely available for suitable assets in early development, than has been the case prior to the last decade.

Recommendations on the Use of Multiple Labels in Human Mass Balance Studies

The administration of radiolabeled drug candidates is considered the gold standard in absorption, distribution, metabolism, and excretion studies for small-molecule drugs since it allows facile and accurate quantification of parent drug, metabolites, and total drug-related material independent of the compound structure. The choice of the position of the radiolabel, typically 14C or 3H, is critical to obtain relevant information. Sometimes, a biotransformation reaction may lead to cleavage of a part of the molecule. As a result, only the radiolabeled portion can be followed, and information on the fate of the nonlabeled metabolite may be lost. Synthesis and administration of two or more radiolabeled versions of the parent drug as a mixture or in separate studies may resolve this issue but comes with additional challenges. In this paper, we address the questions that may be considered to help make the right choice whether to use a single or multiple radiolabel approach and discuss the pros and cons of different multiple-labeling strategies that can be taken as well as alternative methods that allow the nonlabeled part of the molecule to be followed. SIGNIFICANCE STATEMENT: Radiolabeled studies are the gold standard in drug metabolism research, but molecules can undergo cleavage with loss of the label. This often results in discussions around potential use of multiple labels, which seem to be occurring with increased frequency since an increasing proportion of the small-molecule drugs are tending towards larger molecular weights. This review provides insight and decision criteria in considering a multiple-label approach as well as pros and cons of different strategies that can be followed.

Evobrutinib pathway to its major metabolite M463-2 and insights from a biotransformation and DDI perspective

Evobrutinib is a highly selective, covalent, central nervous system-penetrant Bruton's tyrosine kinase (BTK) inhibitor, currently in Phase III trials for the treatment of relapsing multiple sclerosis. One major circulating metabolite of evobrutinib has been previously identified as the racemic dihydro-diol M463-2 (MSC2430422) in a Phase I human mass balance study.Phenotyping experiments were conducted to confirm the metabolic pathway of evobrutinib to M463-2. Ratio of the enantiomers was determined by enantioselective liquid chromatography with tandem mass spectrometry analysis of plasma samples from humans and preclinical species. Drug-drug interaction (DDI) characterisation, evaluation of pharmacological activity on BTK, and off-target screening experiments followed assessing safety of the metabolite.The biotransformation of evobrutinib to M463-2 was determined to be a two-step process with a CYP-mediated oxidation acting to form an epoxide intermediate, which was further hydrolysed by soluble and mitochondrial epoxide hydrolase. Only the (S)-enantiomer was determined to be a major metabolite, the (R)-enantiomer was minor. In vitro studies demonstrated the (S)-enantiomer lacked clinically relevant pharmacological activity, off-target effects and DDIs.The biotransformation of evobrutinib to its major metabolite has been elucidated, with the major (S)-enantiomer being shown to pose no on/off target or DDI risks.

Considerations for Human ADME Strategy and Design Paradigm Shift(s) - An Industry White Paper

The human absorption, distribution, metabolism, and excretion (hADME) study is the cornerstone of the clinical pharmacology package for small molecule drugs, providing comprehensive information on the rates and routes of disposition and elimination of drug-related material in humans through the use of 14 C-labeled drug. Significant changes have already been made in the design of the hADME study for many companies, but opportunity exists to continue to re-think both the design and timing of the hADME study in light of the potential offered by newer technologies, that enable flexibility in particular to reducing the magnitude of the radioactive dose used. This paper provides considerations on the variety of current strategies that exist across a number of pharmaceutical companies and on some of the ongoing debates around a potential move to the so called "human first/human only" approach, already adopted by at least one company. The paper also provides a framework for continuing the discussion in the application of further shifts in the paradigm.

Increasing the Reuse of Protein Non-Naïve Nonhuman Primates in Pharmaceutical Drug Discovery and Development: An Overview and Industry Position on the Challenges and Benefits

The IQ Consortium NHP Reuse Working Group (WG) comprises members from 15 pharmaceutical and biotechnology companies. In 2020, the WG developed and distributed a detailed questionnaire on protein non-naïve NHP reuse to the WG member companies. The WG received responses from key stakeholders including principal investigators, facility managers, animal welfare officers and research scientists. This paper's content reflects the consolidated opinion of the WG members and the questionnaire responses on the subject of NHP reuse within nonclinical programs at all stages of research and development. Many of the pharmaceutical companies represented in the working group or participating in the questionnaire have already achieved some level of NHP reuse in their nonclinical programs, but the survey results suggested that there is significant potential to increase NHP reuse further and a need to understand the considerations involved in reuse more clearly. The WG has also focused carefully on the inherent concerns and risks of implementing protein non-naive NHP reuse and has evaluated the best methods of risk assessment and decision-making. This paper presents a discussion on the challenges and opportunities surrounding protein non-naïve NHP reuse and aims to stimulate further industry dialogue on the subject and provide guidance for pharmaceutical companies to establish roadmaps and decision trees enabling increased protein non-naïve NHP reuse. In addition, this paper represents a solid basis for collaborative engagement between pharmaceutical and biotechnology companies with contract research organizations (CROs) to discuss how the availability of protein non-naïve NHP within CROs can be better leveraged for their use within nonclinical studies.

Multi-Well Array Culture of Primary Human Hepatocyte Spheroids for Clearance Extrapolation of Slowly Metabolized Compounds

Accurate prediction of human pharmacokinetics using in vitro tools is an important task during drug development. Albeit, currently used in vitro systems for clearance extrapolation such as microsomes and primary human hepatocytes in suspension culture show reproducible turnover, the utility of these systems is limited by a rapid decline of activity of drug metabolizing enzymes. In this study, a multi-well array culture of primary human hepatocyte spheroids was compared to suspension and single spheroid cultures from the same donor. Multi-well spheroids remained viable and functional over the incubation time of 3 days, showing physiological excretion of albumin and α-AGP. Their metabolic activity was similar compared to suspension and single spheroid cultures. This physiological activity, the high cell concentration, and the prolonged incubation time resulted in significant turnover of all tested low clearance compounds (n = 8). In stark contrast, only one or none of the compounds showed significant turnover when single spheroid or suspension cultures were used. Using multi-well spheroids and a regression offset approach (log(CL_int) = 1.1 × + 0.85), clearance was predicted within 3-fold for 93% (13/14) of the tested compounds. Thus, multi-well spheroids represent a novel and valuable addition to the ADME in vitro tool kit for the determination of low clearance and overall clearance prediction. Graphical Abstract.

Metabolic profiling of S-praziquantel: Structure elucidation using the crystalline sponge method in combination with mass spectrometry and nuclear magnetic resonance

Praziquantel (PZQ) is the drug of choice for treatment of the neglected tropical disease schistosomiasis. Although the drug has been extensively used over several decades and its metabolism well studied (several oxidative metabolites are known from literature), the knowledge of the complete structure of some of its metabolites remains elusive. Conventional techniques like nuclear magnetic resonance (NMR) or liquid chromatography mass spectrometry (LC-MS) were used in the past to investigate phase I and phase II metabolites of PZQ. These techniques are either limited to provide the complete molecular structure (LC-MS) or require large amount of sample material (NMR), which are not always available when in vitro systems are used for investigation of the metabolites. In this study, we describe new structures of S-PZQ metabolites generated in vitro from human liver microsomes (HLM) using the crystalline sponge method (CS-XRD). After chromatographic separation and purification of the oxidative metabolites, ultra-performance liquid chromatography (UPLC)-quadrupole time-of-flight mass spectrometry (qTOF) analysis was conducted to narrow down the position of oxidation to a certain part of the molecule. To determine the exact position of hydroxylation, singe-crystal X-ray diffraction (SC-XRD) analysis of the crystalline sponges (CS) and absorbed analyte was used to identify the structure of S-PZQ and its metabolites. CS-XRD allowed for complete structure elucidation of the known metabolites S-trans-4'-hydroxy PZQ (M1), S-cis-4'-hydroxy PZQ (M2) and S-/R-11b-hydroxy PZQ (M6) as well as the unknown metabolites S-9-hydroxy PZQ (M3) and S-7-hydroxy S-PZQ (M4). For comparison of structural elucidation techniques, one metabolite (M3) was additionally analyzed using NMR. Significance Statement The information content of the metabolic pathway of praziquantel is still limited. The crystalline sponge method allowed the complete structural elucidation of three known and two unknown metabolites of S-praziquantel, using only trace amounts of analyte material, as demonstrated in this study.

Identification of Clinical Candidate M2698, a Dual p70S6K and Akt Inhibitor, for Treatment of PAM Pathway-Altered Cancers

Herein, we report the discovery of a novel class of quinazoline carboxamides as dual p70S6k/Akt inhibitors for the treatment of tumors driven by alterations to the PI3K/Akt/mTOR (PAM) pathway. Through the screening of in-house proprietary kinase library, 4-benzylamino-quinazoline-8-carboxylic acid amide 1 stood out, with sub-micromolar p70S6k biochemical activity, as the starting point for a structurally enabled p70S6K/Akt dual inhibitor program that led to the discovery of M2698, a dual p70S6k/Akt inhibitor. M2698 is kinase selective, possesses favorable physical, chemical, and DMPK profiles, is orally available and well tolerated, and displayed tumor control in multiple in vivo studies of PAM pathway-driven tumors.

Discovery of Covalent Bruton's Tyrosine Kinase Inhibitors with Decreased CYP2C8 Inhibitory Activity

Bruton's tyrosine kinase (BTK) is a member of the Tec kinase family that is expressed in cells of hematopoietic lineage. Evidence has shown that inhibition of BTK has clinical benefit for the treatment of a wide array of autoimmune and inflammatory diseases. Previously we reported the discovery of a novel nicotinamide selectivity pocket (SP) series of potent and selective covalent irreversible BTK inhibitors. The top molecule 1 of that series strongly inhibited CYP2C8 (IC₅₀ =100 nM), which was attributed to the bridged linker group. However, our effort on the linker replacement turned out to be fruitless. With the study of the X-ray crystal structure of compound 1, we envisioned the opportunity of removal of this liability via transposition of the linker moiety in 1 from C6 to C5 position of the pyridine core. With this strategy, our optimization led to the discovery of a novel series, in which the top molecule 18 A displayed reduced CYP inhibitory activity and good potency. To further explore this new series, different warheads besides acrylamide, for example cyanamide, were also tested. However, this effort didn't lead to the discovery of molecules with better potency than 18 A. The loss of potency in those molecules could be related to the reduced reactivity of the warhead or reversible binding mode. Further profiling of 18 A disclosed that it had a strong hERG (human Ether-a-go-go Related Gene) inhibition, which could be related to the phenoxyphenyl group.

Crystalline sponge affinity screening: A fast tool for soaking condition optimization without the need of X-ray diffraction analysis

Structural elucidation of small molecules only available in low quantity (nanogram) is one of the big advantages of the crystalline sponge method. The optimization of various soaking parameters is crucial for effective analyte absorption and repetitive positioning in the pores of the crystal. Time-consuming X-ray diffraction measurements are necessary for data collection and confirmation of successful guest inclusion. In this work, we report a screening method to select optimal soaking conditions without the need of single-crystal X-ray diffraction analysis for individual compounds and mixtures. 14 substances were chosen as test compounds. Parallel guest soaking of individual compounds and mixtures was conducted using various soaking conditions. After evaporation of solvent, excessive material was removed, and guest molecules released through dissolution of the framework. Liquid chromatography-tandem mass spectrometry allowed the estimation of analyte trapped in the pores and the selection of optimal soaking condition dependent on the highest amount of analyte to crystal size (affinity factor). The tool allowed subsequent crystallographic analysis of ten compounds with minimal experiment time. Additionally, a study to examine the lower limit of detection of the crystalline sponge method was conducted. Determination of two target analytes was possible using only 5 ng of sample. Our study shows the potential of an affinity screening to prioritize soaking parameters by estimation of the guest concentration in a single crystal for one or multiple target compounds within a short period of time.

Deconvolution of Cytochrome P450 Induction Mechanisms in HepaRG Nuclear Hormone Receptor Knockout Cells

Pregnane X receptor (PXR), constitutive androstane receptor (CAR), and PXR/CAR knockout (KO) HepaRG cells, as well as a PXR reporter gene assay, were used to investigate the mechanism of CYP3A4 and CYP2B6 induction by prototypical substrates and a group of compounds from the Merck KGaA oncology drug discovery pipeline. The basal and inducible gene expression of CYP3A4 and CYP2B6 of nuclear hormone receptor (NHR) KO HepaRG relative to control HepaRG was characterized. The basal expression of CYP3A4 was markedly higher in the PXR (10-fold) and CAR (11-fold) KO cell lines compared with control HepaRG, whereas inducibility was substantially lower. Inversely, basal expression of CYP3A4 in PXR/CAR double KO (dKO) was low (10-fold reduction). Basal CYP2B6 expression was high in PXR KO (9-fold) cells which showed low inducibility, whereas the basal expression remained unchanged in CAR and dKO cell lines compared with control cells. Most of the test compounds induced CYP3A4 and CYP2B6 via PXR and, to a lesser extent, via CAR. Furthermore, other non-NHR-driven induction mechanisms were implicated, either alone or in addition to NHRs. Notably, 5 of the 16 compounds (31%) that were PXR inducers in HepaRG did not activate PXR in the reporter gene assay, illustrating the limitations of this system. This study indicates that HepaRG is a highly sensitive system fit for early screening of cytochrome P450 (P450) induction in drug discovery. Furthermore, it shows the applicability of HepaRG NHR KO cells as tools to deconvolute mechanisms of P450 induction using novel compounds representative for oncology drug discovery. SIGNIFICANCE STATEMENT: This work describes the identification of induction mechanisms of CYP3A4 and CYP2B6 for an assembly of oncology drug candidates using HepaRG nuclear hormone receptor knockout and displays its advantages compared to a pregnane X receptor reporter gene assay. With this study, risk assessment of drug candidates in early drug development can be improved.

The deficit syndrome in first-admission patients with psychotic and non-psychotic disorders

The authors study the frequency of primary enduring negative symptoms in first-admission patients with schizophrenic and non-schizophrenic disorders. Carpenter's criteria for distinguishing the primary, enduring negative symptoms from the more transient negative symptoms (secondary to different factors) were applied. Furthermore, they compare negative symptom complexes between first-admission patients and patients with recurrent hospitalizations (within 5 years after first admission). There was a trend for patients with recurrent admissions to show more frequently a deficit syndrome than first-admission patients. Nevertheless, this difference was not significant (χ2 = 0.90). First-admission patients with deficit syndrome had significantly higher affective blunting (P < 0.05) and anhedonia (P < 0.001) than those with recurrent admissions. First-admission subjects with psychotic disorders had significantly higher frequency of deficit syndrome than those first-admission patients with non-psychotic disorders (P < 0.05). These results show that negative symptoms observed in first-admitted non-schizophrenic patients can also be enduring and primary. Thereby this work does not contribute to support the specificity of primary enduring negative symptoms for schizophrenia. Moreover, data suggest, that primary anhedonia and affective blunting can decrease within the first 5 years after discharge.

Changes in PTGS1 and ALOX12 Gene Expression in Peripheral Blood Mononuclear Cells Are Associated with Changes in Arachidonic Acid, Oxylipins, and Oxylipin/Fatty Acid Ratios in Response to Omega-3 Fatty Acid Supplementation

Introduction

There is a high degree of inter-individual variability among people in response to intervention with omega-3 fatty acids (FA), which may partly explain conflicting results on the effectiveness of omega-3 FA for the treatment and prevention of chronic inflammatory diseases. In this study we sought to evaluate whether part of this inter-individual variability in response is related to the regulation of key oxylipin metabolic genes in circulating peripheral blood mononuclear cells (PBMCs).

Methods

Plasma FA and oxylipin profiles from 12 healthy individuals were compared to PBMC gene expression profiles following six weeks of supplementation with fish oil, which delivered 1.9 g/d eicosapentaenoic acid (EPA) and 1.5 g/d docosahexaenoic acid (DHA). Fold changes in gene expression were measured by a quantitative polymerase chain reaction (qPCR).

Results

Healthy individuals supplemented with omega-3 FA had differential responses in prostaglandin-endoperoxide synthase 1 (PTGS1), prostaglandin-endoperoxide synthase 2 (PTGS2), arachidonate 12-lipoxygenase (ALOX12), and interleukin 8 (IL-8) gene expression in isolated PBMCs. In those individuals for whom plasma arachidonic acid (ARA) in the phosphatidylethanolamine (PE) lipid class decreased in response to omega-3 intervention, there was a corresponding decrease in gene expression for PTGS1 and ALOX12. Several oxylipin product/FA precursor ratios (e.g. prostaglandin E₂ (PGE₂)/ARA for PTGS1 and 12-hydroxyeicosatetraenoic acid (12-HETE)/ARA for ALOX12) were also associated with fold change in gene expression, suggesting an association between enzyme activity and gene expression. The fold-change in PTGS1 gene expression was highly positively correlated with ALOX12 gene expression but not with PTGS2, whereas IL-8 and PTGS2 were positively correlated.

Conclusions

The regulation of important oxylipin metabolic genes in PBMCs varied with the extent of change in ARA concentrations in the case of PTGS1 and ALOX12 regulation. PBMC gene expression changes in response to omega-3 supplementation varied among healthy individuals, and were associated with changes in plasma FA and oxylipin composition to different degrees in different individuals.

Trial Registration

clinicaltrials.gov NCT01838239

Discovery of potent, orally bioavailable, small-molecule inhibitors of WNT signaling from a cell-based pathway screen

WNT signaling is frequently deregulated in malignancy, particularly in colon cancer, and plays a key role in the generation and maintenance of cancer stem cells. We report the discovery and optimization of a 3,4,5-trisubstituted pyridine 9 using a high-throughput cell-based reporter assay of WNT pathway activity. We demonstrate a twisted conformation about the pyridine-piperidine bond of 9 by small-molecule X-ray crystallography. Medicinal chemistry optimization to maintain this twisted conformation, cognisant of physicochemical properties likely to maintain good cell permeability, led to 74 (CCT251545), a potent small-molecule inhibitor of WNT signaling with good oral pharmacokinetics. We demonstrate inhibition of WNT pathway activity in a solid human tumor xenograft model with evidence for tumor growth inhibition following oral dosing. This work provides a successful example of hypothesis-driven medicinal chemistry optimization from a singleton hit against a cell-based pathway assay without knowledge of the biochemical target.

Identification and optimization of an aminoalcohol-carbazole series with antimalarial properties

Recent observations on the emergence of artemisinin resistant parasites have highlighted the need for new antimalarial treatments. An HTS campaign led to the identification of the 1-(1-aminopropan-2-ol)carbazole analogues as potent hits against Plasmodium falciparum K1 strain. The SAR study and optimization of early ADME and physicochemical properties direct us to the selection of a late lead compound that shows good efficacy when orally administrated in the in vivo P. berghei mouse model.

Serum oxylipin profiles in IgA nephropathy patients reflect kidney functional alterations

Immunoglobulin A nephropathy (IgAN) is a leading cause of chronic kidney disease, frequently associated with hypertension and renal inflammation. ω-3 fatty acids eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) in fish oil (FO) improve kidney function in animal models, but have inconsistent metabolic effects in humans. Oxylipin profiles in serum from IgAN patients supplemented with either FO or corn oil (CO) placebo were analyzed by liquid chromatography coupled to tandem mass spectrometry. EPA cyclooxygenase and lipoxygenase metabolites, and EPA and DHA epoxides and diols were increased in response to FO supplementation, as were total epoxides and epoxide/diol ratios. Several of these metabolites were drivers of separation as assessed by multivariate analysis of FO patients pre- vs. post-supplementation, including 17,18-dihydroxyeicosatrienoic acid, prostaglandin D₃, prostagalandin E₃, Resolvin E1, 12-hydroxyeicosapentaenoic acid, and 10(11)-epoxydocosapentaenoic acid. In patients whose proteinuria improved, plasma total oxylipins as well as several hydroxyoctadecadienoic acids, hydroxyeicosatetraenoic acids, and leukotriene B₄ metabolites were among the metabolites that were significantly lower than in patients whose proteinuria either did not improve or worsened. These data support the involvement of oxylipins in the inflammatory component of IgAN as well as the potential use of oxylipin profiles as biomarkers and for assessing responsiveness to ω-3 fatty acid supplementation in IgAN patients.

[Do individuals with substance use disorders find information for crisis intervention and suicide prevention resources on the Internet?]

BACKGROUND AND OBJECTIVE

Suicidality is an important issue for substance-dependent people. The few studies about Internet searches have provided ambiguous results regarding help and support using suicide-related terms.

MATERIAL AND METHODS

Five popular search engines and several substance use- and suicide-related German search terms were used; the search results were classified as being pro-suicide, anti-suicide, suicide-neutral, websites not associated with suicide or "page could not be loaded".

RESULTS

The majority of identified websites was not associated with suicide at all, whereas websites offering help and support were less frequent. Using suicide-associated search terms (such as "Selbsttötung") almost half of all web pages were help sites. Websites with instructions for committing suicide were very rarely found.

CONCLUSIONS

In view of the difficulties for substance abusers to get immediate and adequate information about help and support in a suicidal crisis via the Internet, it is urgently necessary to extend fast available help sites on the Internet.

Quantitative profiling method for oxylipin metabolome by liquid chromatography electrospray ionization tandem mass spectrometry

Cyclooxygenase, lipoxygenase, and epoxygenase derived oxylipins, especially eicosanoids, play important roles in many physiological processes. Assessment of oxidized fatty acid levels is important for understanding their homeostatic and pathophysiological roles. Most reported methods examine these pathways in isolation. The work described here employed a solid phase extraction-liquid chromatography-electrospray ionization MS/MS (SPE-LC-ESI MS/MS) method to monitor these metabolites. In 21 min, 39 oxylipins were quantified along with eight corresponding internal standards. The limits of quantification were between 0.07 and 32 pg (20 pM-10 nM). Finally, the validated method was used to evaluate oxylipin profiles in lipopolysaccharide-exposed mice, an established septic inflammatory model. The method described here offers a useful tool for the evaluation of complex regulatory oxylipin responses in in vitro or in vivo studies.

Altered Soluble Epoxide Hydrolase Gene Expression and Function and Vascular Disease Risk in the Stroke-Prone Spontaneously Hypertensive Rat

Soluble epoxide hydrolase (sEH) metabolizes epoxyeicosatrienoic acids and represents a novel therapeutic target in cardiovascular disease treatment. We investigated the relationship among sequence variation in the sEH gene (Ephx2), sEH function, and risk of end-organ injury in strains of spontaneously hypertensive rat (SHRs) differing in their susceptibility to develop brain vascular disease. Brain Ephx2 expression was significantly lower in stroke-prone (SHR/A3) than in stroke-resistant (SHR/N) SHRs (5-fold; P <0.0001). Resequencing of the Ephx2 promoter in the 2 strains identified 3 polymorphisms that significantly influenced promoter transcriptional activity in vitro. Measurements of brain sEH enzyme activity and plasma levels of arachidonate and linoleate metabolites of sEH further suggested significant differences between the 2 strains. Ratios of epoxyoctadecenoic acids to dihydroxyoctadecenoic acids were significantly higher, indicating a lower sEH activity in SHR/A3 than in SHR/N ( P <0.0001). Plasma dihydroxyeicosatrienoic acid levels were lower in SHR/A3 than in SHR/N ( P <0.0001), but plasma epoxyeicosatrienoic acids levels were similar in the 2 strains. Association analysis of Ephx2 polymorphism in the F2 progeny of an SHR/A3×SHR/N cross showed that animals carrying the SHR/A3 allele of Ephx2 had a greater risk of stroke and associated urinary proteinuria than animals that do not. Investigation of patterns of allelic similarities and differences among multiple stroke-prone and stroke-resistant SHR substrains showed that Ephx2 belongs to a haplotype block shared among all of the stroke-prone but no stroke-resistant substrains. These data support a role for Ephx2 polymorphism on sEH gene expression and function and risk of end-organ injury in the stroke-prone SHR.

[A survey of the psychosocial situation of homeless men in Frankfurt am Main]

In a current field-study a sample of 71 homeless men (mean age 35.4 years) was investigated with a semi-standardized interview. Sociodemographically, a low education level, a high unemployment rate and low income were noted. The income was gained mainly through regular social welfare support. Mostly unmarried and without children, the participants seldom lived in a stable partnership during their life. Psychosocial conflicts (59.2%) were one of the most important causes for homelessness at an average age of 28.1 years. Interpersonal conflicts, release from jail and loss of job were the most frequently reported causes of current homelessness. 42.3% had been treated in psychiatric hospitals in the past, the majority because of alcoholism. In summary the current findings indicate that homeless men experience social isolation early during their maturation and that the frequency of psychiatric disorders is high.

Can response to partial sleep deprivation in depressed patients be predicted by regional changes of cerebral blood flow?

The possible predictive value of regional cerebral perfusion patterns with respect to the response to partial sleep deprivation (PSD) was evaluated in 15 major depressive patients (mean age = 54.9 years, mean Hamilton depression score = 21.6). Patients were studied with single photon emission computed tomography with technetium-99 m-D,L-hexamethyl-propylene amine oxime. Scans were performed on the morning before and after (at 08.00 h) PSD. Responders to PSD had significantly higher perfusion in the right orbitofrontal cortex than did non-responders before PSD. Multiple regression analysis indicated that right orbitofrontal/basal cingulate perfusion (r = -0.77, P < 0.001) before PSD, and left inferior temporal perfusion (r = 0.59, P = 0.01) after PSD, were fairly accurate predictors of change in Hamilton depression scores. Thus, it appears that the orbitofrontal cortex and the cingulate are involved in PSD and may serve as predictors of therapeutic response.

[Subjective diurnal fatigue and sleep deprivation response]

29 major depressive patients, the majority suffering from a melancholic subtype and typical diurnal variation of mood, rated subjective tiredness on a 100 mm analogous scale before and after total sleep deprivation (TSD). In study A every four hours during the day before and after TSD and every 2 hours during the TSD-night ratings were performed, in study B at 8.00 a.m. before and after TSD. The mean response rate was 55.2% in the 2 studies. In study A subsequent responders were less tired during the afternoon before TSD. Responding patients were more alert the morning after sleep deprivation than non-responders. A higher inter-individually variability of tiredness ratings in responders before and after sleep deprivation was found in study B, assuming an arousing property and a greater variability in subjective arousal at least during the morning hours. In summary the determination of the subjective arousal level may help to predict response.

Subjective sleepiness and physiological sleep tendency in healthy young morning and evening subjects

The Multiple Sleep Latency Test (MSLT) was performed twice after 8 h and after 4 h of night sleep in 15 healthy young subjects (mean age: 23 y). Seven subjects could be regarded as morning, 8 subjects as evening types. After 8 h of sleep significantly more evening types napped at 08.00 hours and at 12.00 hours. Evening types rated themselves more sleepy on an hourly administered visual analogous scale (VAS). Sleep onset latencies (SOL) decreased, and the amount of Stages 1 and 2 increased in all subjects dependent on the sleep restriction condition. No significant differences between morningness and eveningness concerning SOL and structure of nap structure could be observed. After 4 h of sleep there was a marked increase in subjectively rated sleepiness during the morning hours in both groups.

[Foreign patients in inpatient treatment in a psychiatric university clinic with community service]

About one third (29.5%) of the population living within the area of Frankfurt, for which the psychiatric university clinic provides psychiatric service, are foreigners. For the better understanding of our foreign psychiatric inpatients treated in our clinic in in 1992, the diagnostic spectrum and the nationalities of these patients were analysed. More than half of them (58%) were raised up in former Yugoslavia, Turkey, Italy, Poland and Marocco. The other foreign patients came from 36 different countries. The diagnostic spectrum comparing german and foreign patients showed marked differences. Paranoid schizophrenia was more common in foreigners (31.5%) compared with german patients (16.8%), as well as female foreigners were admitted to the clinic because of psychoreactive disorders (65.2% of all turkish females) more often. The language barrier limited the treatment in many patients. In addition treatment was also hampered by family induced pressure on our patients. This was mainly due to differences and misunderstanding concerning the nature and treatment strategies. In spite of these difficulties, engagement of the therapeutic teams and treatment outcome did not differ between german and foreign patients. In order to improve treatment modalities, we quote for an increasing number of psychiatrists, who are capable of serbocroatic, turkish, italian, polish or arab language and culture, to work in clinical psychiatry.

[Psychological and physical compromises in patients with organic cerebral psychosyndrome--analysis of treatment success]

The extent of psychic and physical disturbances of patients admitted to the Center of Psychiatry in Frankfurt/M. because of organic psychosyndromes in the year 1988 was analysed. Especially the results of the hospital treatment and the proceeding mode of caretaking were examined. Usually an unspecific state of confusion was the main reason for admittance of most of the patients (n = 59). The majority of the patients suffered from a mid-ranged to marked state of dementia. The results of the treatment for these patients was highly significantly worse compared to patients admitted with a psychosis or a depressive syndrome. A non-significant statistical correlation was found for the results of the medical treatment and medical diseases. Concerning the treatment with psychic drugs a pragmatistic order was used. Analysing the results no advantage of a treatment with up to 4 different drugs compared to a monotherapy could be found. Patients who were not treated with psychic active substances tended to have a poorer outcome. At the end of the stay in the hospital 25.4% of patients were classified with a good outcome after treatment, 49.2% had a slight degree of recovery.

[Quality of day time sleep in the multiple sleep latency tests in patients with narcolepsy, obstructive sleep apnea and psychogenic hypersomnia]

The multiple sleep latency test (MSLT) has proved to be a useful diagnostical tool for patients complaining of excessive daytime sleepiness (EDS). The intention of the present study was to investigate the structure of MSLT naps and in particular sleep spindle and k-complex density in three different groups of EDS patients. MSLT was performed at 8 a.m., 10 a.m. 12 a.m., 2. p.m. and 4 p.m.. Each recording lasted 20 minutes and was not stopped even if sleep occurred before 20 min. Sleep was scored visually. Spindle and k-complex density was determined per minute of S2 sleep. Statistical analysis used ANOVA. Each of the three groups consisted of 15 patients. Diagnosis of narcolepsy, sleep apnea, of EDS due to a psychiatric disorder has been confirmed subsequently. There were 5 female and 10 male narcoleptics (mean age: 43.9 +/- 10.9 years), 2 female and 13 male obstructive sleep apnea patients (mean age: 53.9 +/- 10.9 years) and 7 female and 8 male patients complaining of EDS, in whom a psychiatric disorder was diagnosed (mean age: 38.8 +/- 13.8 years). Narcoleptics sent more than half of the recording time of 100 min asleep (52.9%). Apnea patients slept 41.3% and psychogenic EDS patients 22.7%. The proportion of sleep stages 1 and 2 in narcoleptics (S2/S1 = 1:1) was clearly different from the other two (apnea patients: S2/S1 = 4:1; psychogenic EDS patients: S2/S1 = 3:1). 18.5% of the naps contained stage REM and during the afternoon naps 0.9% of S3 in the narcoleptics. Neither REM nor S3 was observed in the others.(ABSTRACT TRUNCATED AT 250 WORDS)

Evaluation of the effects of total sleep deprivation on cerebral blood flow using single photon emission computerized tomography

HMPAO-single photon emission computerized tomography (SPECT) is a useful technique in studying cerebral blood flow (CBF). This method is suitable to evaluate the differences of CBF with reference to total sleep deprivation (TSD) within 24 h because of the short half-life of the radiopharmaceutical compound. In the present study, CBF before and after TSD was analysed in patients suffering from major depression. The morning before and after TSD, Tc-HMPAO-SPECT was performed in 20 patients. Hamilton Rating Scale for Depression scores and subjective ratings were obtained daily. Eleven patients responded to TSD; 9 were nonresponders. The main finding was a significant left temporal and mainly right parietal increase of CBF, which was observed in the responders only. CBF values and the severity of depression correlated inversely.

[Utilization of inpatient psychiatric care by patients with cerebral organic psychosyndrome. Cross-sectional analysis for 1988 exemplified by the Psychiatry Center in the routine health care of Frankfurt]

All patients admitted to the Frankfurt Psychiatric Clinic suffering from organic psycho-syndromes were studied in a transversal survey. It was intended to evaluate the importance of clinical treatment within the psychiatric care system of a major city including various aspects of the diseases, psychosociological determinants and the continuation of service for these patients following clinical treatment. For the transversal survey a questionnaire was developed to record the psychopathological syndrome on admission, the order to referring patients to the clinic, outcome of treatment and service following clinical care. Patients suffering from organic psycho-syndromes represent a small quota of 4.2% according to the total admission rate. Within the group of elderly patients over 65 years of age it is remarkable that more cases with an affective psychosis were admitted than with organic psycho-syndromes. This small group of patients is in regard to interdisciplinary diagnostical and therapeutical proposals according to a high rate of multiple morbidity of distinct importance. The results of the presented study indicate the necessity to intensify the efforts of cooperation of psychiatric clinic, nursing homes and ambulatory care services for elderly patients with organic psycho-syndromes.

Incorporation of 14C-arachidonic acid into platelet phospholipids of untreated patients with schizophreniform or schizophrenic disorders

The incorporation rate of 14C-labeled arachidonic acid (14C-AA) into membrane phospholipids was measured in a group of untreated (greater than 6 months) psychiatric patients (n = 33) and healthy controls (n = 31). Platelets from controls and from patients with schizophrenia (n = 10), schizophreniform disorder (n = 11), schizoaffective disorder (n = 6), major depression (n = 2), or an atypical psychosis (n = 4), diagnosed according to DSM-III, were incubated with 14C-AA. Platelets from patients with a schizophreniform and a schizoaffective disorder incorporated greater than 50% less 14C-AA than the platelets from controls. The incorporation rates of platelets from schizophrenic patients were slightly (18%), but not significantly, reduced compared to controls. Characterization of variables affecting arachidonic acid and phospholipid metabolism may be helpful in studies focused on the assessment of first-episode psychotic patients and in long-term outcome studies.

Treatment of severe chronic insomnia with L-tryptophan and varying sleeping times

Twenty-five subjects suffering from severe chronic insomnia were treated for four weeks with 2 g of L-tryptophan in combination with a schedule of varying sleeping times which caused a sleep deficiency at the beginning of treatment. A second four-week period without L-tryptophan was used as a control. Nineteen subjects (76%) experienced a markedly improved sleeping pattern after four weeks; the sleeping behavior of ten of these subjects, however, deteriorated again after the control period. Daily self-rating protocols revealed that the subjects' sleep improved significantly between the 10th and 15th day after starting treatment. Further sleep-related items such as "activity", "mood", "nervous tension", "contentment", and "quality of the preceding day" were also evaluated. This treatment schedule can thus be recommended for the treatment of severe chronic insomnia.

Treatment of severe chronic insomnia with L-tryptophan: results of a double-blind cross-over study

Thirty-nine subjects with chronic insomnia were treated with L-tryptophan (L-TRP) in a double-blind, cross-over study. Instead of a placebo, a very low dose of 0.04 g L-TRP was used. The subjects suffered from a sleeping disorder classified as "psychophysiological, persistent". In the subgroup taking the full L-TRP (2 g) dose first, there was a significant difference between the treatment period with the full L-TRP dose and the ineffective dose (placebo). If the placebo was given first, however, there was no significant difference between the two treatment periods. It is suggested that psychological factors are responsible for the diverging results in the two subgroups of patients. On the basis of subjective ratings, it appears that L-TRP is effective in promoting sleep in cases of chronic insomnia.

Correlation of platelet MAO activity with introversion: a study on a German rural population

Platelet monoamine oxidase (MAO) activity and personality characteristics were correlated in a sample of 52 men (37 +/- SD 13 years) and 54 women (37 +/- SD 15 years) from a rural community. Personality characteristics were measured by using the Freiburger Persönlichkeitsinventar (FPI-A). In males, weak but significant linear correlations (Pearson product-moment and Spearman rank correlations) were found between platelet MAO activity (p-tyramine and benzylamine as substrates) and the extraversion/introversion dimension. In the females, however, there were no consistent significant correlations between MAO activity and FPI test scores. Comparing the top and bottom 25% of the platelet MAO distribution resulted in a significant difference for the second order factor extraversion in the group of men but not in the group of women. The significant correlation between MAO and introversion could not be attributed to cigarette smoking, food consumption, alcohol, or drugs. In accord with previous biochemical-behavior research, it is suggested that reduced platelet MAO activity may, to some extent, reflect an impulsive personality type.