Karl Louis Rewi Jansen

• MD, PhD
• Auckland District Health Board

Hypersexual behaviour is not uncommon in psychiatric presentations. Most available scales that measure hypersexual behaviour are self-rated, often containing sexually explicit questions, unsuitable for use in mentally unwell people. Lack of a clinically suitable instrument may have resulted in under-detection and under-researching of hypersexuality...

We report hypersexuality in three people with schizophrenia after starting risperidone, with evidence suggesting a possible link between risperidone and the hypersexuality. Mrs X, 71 years old, married once and widowed for 20 years, with no known history of hypersexuality, was started on

To examine the impact of 'party pills' (PP; herbal highs) on the Auckland City Hospital Emergency Department Overdose Database 2002-2004, and to present figures for five other substances in that database. Auckland City Hospital's Emergency Department's overdose database was reviewed for 2002, 2003, and 2004 for 'herbal ingestions' and 'party pills'...

The term "date rape drug" has traditionally been applied by the media to powerful sedatives, such as gamma hydroxybutyrate (GHB) and flunitrazepam (Rohypnol), which can render a person unconscious and hence unable to resist and/or recall an assault. However, some law enforcement agents and others have recently obtained convictions by arguing that t...

Methods to estimate weights of children requiring resuscitation appeared to underestimate the weight of Pacific Island and Maori children. This study sought to quantify differences between real and estimated weights, study links with ethnicity and derive a new estimation method for large-for-age children. Data were collected prospectively for 3 mon...

To (1) identify current patterns of non-medical ketamine use; and (2) identify potential harms associated with non-medical ketamine use. Cross sectional survey of lifetime ketamine users. Semi-structured interviews took place in public and private settings in Sydney Australia. One Hundred ketamine users. Self-reported experiences with and attitudes...

This is the second part of a review of the nonmedical use of ketamine. Part one discussed the history of ketamine, the sought-after effects for which it is taken in a nonmedical context, how these are produced, common adverse effects, the ketamine schizophrenia model and the neurotoxicity issue. Part two reviews what is currently known about proble...

Ketamine is a dissociative anesthetic with an accepted place in human medicine. Ketamine also has psychedelic properties, and there has been a recent increase in nonmedical use linked with the growth of the "dance culture." This has attracted little comment in the formal literature but has been the subject of many reports in the media. Myths and mi...

Methylenedioxymethamphetamine (MDMA) is generally described as non-addictive. However, this report describes three cases in which criteria for dependence were met. A wider understanding that MDMA can be addictive in rare cases is important as very heavy use may cause lasting neuronal changes. This risk could be reduced with effective identification...

Near-death experiences (NDEs) can be reproduced by ketamine via blockade of receptors in the brain for the neurotransmitter glutamate, the N-methyl-D-aspartate (NMDA) receptors. Conditions that precipitate NDEs, such as hypoxia, ischemia, hypoglycemia, and temporal lobe epilepsy, have been shown to release a flood of glutamate, overactivating NMDA...

The commentators on my paper raised several interesting issues. Set and setting do influence drug effects, but they also influence near-death experiences (NDEs). Some NDEs are very anxiety-generating, just like some ketamine experiences, though frightening NDEs have been ignored by most researchers. High frequency, compulsive ketamine use is rare....

Near-death experiences (NDEs) can be reproduced by ketamine via blockade of receptors in the brain for the neurotransmitter glutamate, the N-methyl-D-aspartate (NMDA) receptors. Conditions that precipitate NDEs, such as hypoxia, ischemia, hypoglycemia, and temporal lobe epilepsy, have been shown to release a flood of glutamate, overactivating NMDA...

Using quantitative receptor autoradiographic methods we have examined A1 adenosine receptors, adenosine uptake sites, benzodiazepine receptors, NMDA, AMPA, and kainic acid receptors in temporal lobes removed from patients suffering from complex partial seizures and in normal control post-mortem temporal cortex. Binding to A1 adenosine receptors and...

The densities of [3H]1,3-di-o-tolylguanidine ([3H]DTG) binding to sigma binding sites in the CA1 stratum pyramidale region in 7 hippocampi affected by Alzheimer's disease, were compared with densities in 7 normal hippocampi. There was an average reduction of 26% in [3H]DTG binding in this area, which was correlated with an average 29% pyramidal cel...

The effect of haloperidol upon [3H]1,3-di-o-tolylguanidine ([3H]DTG) binding sites was assessed in rat brain and testes. An acute injection (10 mg/kg), in rats culled 2 h later, changed Kd values from 18 +/- 2 to 108 +/- 26 nM (brain) and 14 +/- 1 to 116 +/- 35 nM (testes), with unchanged Bmax values. Rats were injected with 4 mg/kg per day for 7,...

Autoradiography was used to visualise N-methyl-D-aspartate, phencyclidine, strychnine-insensitive glycine, alpha-amino-3-hydroxy-5-methyl-4-isoxazole propionic acid, kainic acid, benzodiazepine, gamma-aminobutyric acid type A, sigma, serotonergic, dopaminergic, alpha 2-adrenergic, beta-adrenergic, muscarinic cholinergic, nicotinic, opioid, neuroten...

This chapter focuses on receptors in human spinal cord. The distribution of benzodiazepine/GABAA receptors in the human spinal cord demonstrates that these receptors are distributed in a consistently similar fashion in the gray matter of the cervical, thoracic, lumbar, and sacral regions of the human spinal cord. Receptor proteins are also detected...

Autoradiographic distributions of [3H]1,3-di-O-tolylguanidine, [3H]DTG, binding to sigma (sigma) receptors were studied in key human brain regions. High densities occurred in the substantia nigra pars compacta and cerebellum. Pineal and pituitary levels were moderate. In neocortex, binding was high in laminae II-IVA and much lower in the midzone. M...

The autoradiographic distributions of [3H]1,3-di-ortho-tolyguanidine ([3H]DTG), [3H]1-[1-(2-thienyl) cyclohexyl] piperidine ([3H]TCP) and L-[3H]glutamate were studied in the human cerebellum. [3H]DTG is a selective label for the sigma receptor, while L-[3H]glutamate binding was carried out under conditions selective for the N-methyl-D-aspartate (NM...

A comprehensive review is presented of the recreational and accidental ingestion of psychoactive mushrooms in Australia and New Zealand; 15 recognized species are considered from Australia and eight from New Zealand. Common epithets, potency levels, and methods of ingestion are discussed. Legal aspects involving the use of these psychoactive fungi...

The distributions of N-methyl-D-aspartate (NMDA), alpha-amino-3-hydroxy-S-methyl-4-isoxazole propionic acid (AMPA) and kainic acid (KA) receptors were determined in the human cerebellum using autoradiography. In contrast to the cerebral cortex, where KA receptors have a complementary distribution to NMDA and AMPA receptors, AMPA receptors were conc...

Ketamine, a congener of phencyclidine (PCP), can produce a range of psychological effects which have led to its nonmedical use. Recent discoveries concerning the effects of ketamine and similar substances in the brain suggest that they may interfere with memory processes when given acutely and may affect synaptic plasticity when given chronically i...

Unilateral lesions of the rat hippocampus produced by needle insertion lead to ipsilateral accumulation of c-fos protein in dentate granule cells and neurons in the piriform cortex, as well as in glial-like cells in the corpus callosum and in ependymal cells lining the lateral ventricle adjacent to the lesion site. C-fos protein was detected immuno...

The Near-Death Experience (NDE) is a dissociative mental state with characteristic features. These can be reproduced by ketamine which acts at sigma sites and blocks N-methyl-D-aspartate (NMDA) linked phencyclidine (PCP) receptors to reduce ischaemic damage. Endogenous ligands, alpha and beta-endopsychosin, have been detected for these receptors wh...

The distribution of sigma (sigma) receptors in the rat brain was studied with autoradiography using [3H]1,3-di-ortho-tolyl-guanidine ([3H]DTG) as a ligand. The highest concentration of sigma receptors was seen in the pineal gland, an area which has not been previously studied. This result is of interest as both sigma receptors and the pineal gland...

Rats injected with haloperidol, which binds to both D2 dopamine and sigma receptors or the specific D2 dopamine receptor antagonist YM 09151-2, but not the specific D1 dopamine receptor antagonist SCH 23390, showed induction of c-fos protein and c-fos-related antigens in striatal neurons. This effect of haloperidol and YM 09151-2 was inhibited by t...

The following receptors were assessed post-mortem in the hippocampi (anterior region) of eight patients with Alzheimer's disease and nine age-matched controls, using autoradiography: N-methyl-D-aspartate (including glutamate, phencyclidine and glycine binding sites), quisqualate, kainic acid, adenosine A1, benzodiazepine, serotonin (1 and 2), musca...

The regional, cellular and subcellular distribution of GABA, GABA receptors and benzodiazepine receptors was investigated by light and electron microscopy in the human lumbar spinal cord taken post-mortem from eight cases aged 20–76 years. Firstly, the regional distribution of GABA receptors and benzodiazepine receptors was studied using autoradiog...

The phencyclidine (PCP) binding site of the N-methyl-D-aspartate receptor, the kainic acid (KA) receptor and the quisqualate (QA) receptor were visualised, using autoradiography in the human spinal cord and the distributions compared with that of benzodiazepine (BDZ) receptors and substance P (SP). All of the receptor types, and SP, were concentrat...

The distribution of [3H]glycine binding sites was compared with that of N-methyl-D-aspartate (NMDA) receptors labelled with L-[3H]glutamate, and with that of phencyclidine (PCP) receptors labelled with [3H]1-(1-(2-thienyl)-cyclohexyl)piperidine ([3H]TCP) in sections from 7 normal human hippocampi. The results indicate that strychnine-insensitive gl...

The mechanism(s) by which long-term changes are induced and maintained in the nervous system are poorly understood. Kindling is an example of a permanent change in brain function that results from repeated elicitation of seizures. Recently, a class of genes called "immediate-early genes" that were previously thought to be only involved in cell divi...

The excitatory amino acids are probably the major neurotransmitters in the cerebral cortex, and they act through at least three receptors: theN-methyl-d-aspartate, the quisqualate and the kainic acid receptors. Under the appropriate conditions, [³H]1-(1-(2-thienyl)-cyclohexyl)piperidine ([³H]TCP), [³H]glycine andl-[³H]glutamate label different site...

Mitragynine is thus a drug with a highly unusual but nevertheless well-documented history of being described as both a depressant and a stimulant, while at the same time possessing the chemical structure one might expect of a psychedelic. It can suppress the opiate withdrawal syndrome, but it is not reversed by nalorphine. Discovering the sites of...

Anaesthetic studies have generally found no long-term effects, but these studies involved anaesthetic doses in a single episode or limited series, often with effect-moderating drugs such as diazepam. Subanaesthetic doses may have different effects because the former can produce metabolic hyperfrontality (over-activity) like that seen in schizophren...

Thesis (Ph. D.)--University of Oxford, 1993.