Experiences and intentions of patients undergoing medically indicated oocyte or embryo cryopreservation: a qualitative study.

STUDY QUESTION: What structural (logistical) and psychological challenges do patients who cryopreserve oocytes or embryos for medical reasons face, including possible barriers to using their frozen materials? SUMMARY ANSWER: The majority of women who underwent oocyte or embryo cryopreservation for medical reasons reported a desire to use their frozen oocytes or embryos but had been impeded by ongoing medical issues, the need for a gestational carrier, or the lack of a partner. WHAT IS KNOWN ALREADY: Current data suggest that many women who have frozen oocytes or embryos for medical indications are concerned about the prospect of infertility and have unique emotional and financial needs that differ from patients with infertility. Further, most patients have not returned to use their cryopreserved materials. STUDY DESIGN, SIZE, DURATION: This is a qualitative interview study of 42 people who cryopreserved between January 2012 and December 2021. Interviews were conducted between March 2021 and March 2022. PARTICIPANTS/MATERIALS, SETTING, METHODS: All participants were cisgender women who had undergone oocyte or embryo cryopreservation for medical indications at an academic fertility center. Participants were invited to interview by email if they were younger than 40 years old when their oocytes or embryos were cryopreserved. Interviews were conducted over the internet and transcribed verbatim. Data were analyzed using thematic analysis with the constant comparison method. MAIN RESULTS AND THE ROLE OF CHANCE: Saturation was reached at 42 interviews. The median age of participants was 35 years old (range 28-43) at interview and 31 years old (range 25-39) at cryopreservation. Of the 42 women, 30 had a cancer diagnosis, while 7 had non-cancer chronic medical conditions, and 5 had hereditary cancer susceptibility syndromes. There were 12 women who banked embryos and 30 who banked oocytes. The majority of women indicated a desire to use their cryopreserved materials, but many were unsure about how or when. Four had already used their frozen oocytes or embryos, while another four had conceived without assisted reproduction. The cryopreservation experience was described by the majority as highly emotionally challenging because they felt out of place among couples receiving infertility treatment and, for cancer patients, overwhelmed by the complex decisions to be made in a short time period. Common reported barriers to using frozen materials included ongoing medical issues preventing pregnancy, the need for a gestational carrier, the lack of a partner, and the desire for unassisted conception. Some were glad to have frozen oocytes or embryos to allow more time to meet a partner or if they were considering becoming single parents. LIMITATIONS, REASONS FOR CAUTION: The majority of participants had their oocytes or embryos frozen at a single, urban, academic fertility center, which may limit generalizability. We also could not calculate a response rate because the snowball technique was used to identify additional participants, so did not know the total number of people invited to participate. Like other interview studies, our study may be subject to response bias because those who agreed to participate may have particularly positive or negative views about their experiences. Furthermore, the mean follow-up time since freezing was relatively short (3.3 years, median 2.7 years), which may not have been enough time for some patients to use their frozen materials. WIDER IMPLICATIONS OF THE FINDINGS: Learning about the experiences of patients undergoing medically indicated oocyte and embryo cryopreservation can help clinicians better counsel these patients regarding decisions and hurdles they may encounter. We found that most patients had not returned to use their frozen materials because of ongoing medical issues, the need for a gestational carrier, lack of a partner, or the desire to attempt unassisted reproduction. STUDY FUNDING/COMPETING INTEREST(S): This study did not receive any funding. The authors of this study have no conflicts of interest to declare. TRIAL REGISTRATION NUMBER: N/A.

Cortical GABA markers identify a molecular subtype of psychotic and bipolar disorders.

BACKGROUND: Deficits in gamma aminobutyric acid (GABA) neuron-related markers, including the GABA-synthesizing enzyme GAD67, the calcium-binding protein parvalbumin, the neuropeptide somatostatin, and the transcription factor Lhx6, are most pronounced in a subset of schizophrenia subjects identified as having a 'low GABA marker' (LGM) molecular phenotype. Furthermore, schizophrenia shares degrees of genetic liability, clinical features and cortical circuitry abnormalities with schizoaffective disorder and bipolar disorder. Therefore, we determined the extent to which a similar LGM molecular phenotype may also exist in subjects with these disorders. METHOD: Transcript levels for GAD67, parvalbumin, somatostatin, and Lhx6 were quantified using quantitative PCR in prefrontal cortex area 9 of 184 subjects with a diagnosis of schizophrenia (n = 39), schizoaffective disorder (n = 23) or bipolar disorder (n = 35), or with a confirmed absence of any psychiatric diagnoses (n = 87). A blinded clustering approach was employed to determine the presence of a LGM molecular phenotype across all subjects. RESULTS: Approximately 49% of the subjects with schizophrenia, 48% of the subjects with schizoaffective disorder, and 29% of the subjects with bipolar disorder, but only 5% of unaffected subjects, clustered in the cortical LGM molecular phenotype. CONCLUSIONS: These findings support the characterization of psychotic and bipolar disorders by cortical molecular phenotype which may help elucidate more pathophysiologically informed and personalized medications.

The Ageing Brain: Age-dependent changes in the electroencephalogram during propofol and sevoflurane general anaesthesia.

BACKGROUND: Anaesthetic drugs act at sites within the brain that undergo profound changes during typical ageing. We postulated that anaesthesia-induced brain dynamics observed in the EEG change with age. METHODS: We analysed the EEG in 155 patients aged 18-90 yr who received propofol (n=60) or sevoflurane (n=95) as the primary anaesthetic. The EEG spectrum and coherence were estimated throughout a 2 min period of stable anaesthetic maintenance. Age-related effects were characterized by analysing power and coherence as a function of age using linear regression and by comparing the power spectrum and coherence in young (18- to 38-yr-old) and elderly (70- to 90-yr-old) patients. RESULTS: Power across all frequency bands decreased significantly with age for both propofol and sevoflurane; elderly patients showed EEG oscillations ∼2- to 3-fold smaller in amplitude than younger adults. The qualitative form of the EEG appeared similar regardless of age, showing prominent alpha (8-12 Hz) and slow (0.1-1 Hz) oscillations. However, alpha band dynamics showed specific age-related changes. In elderly compared with young patients, alpha power decreased more than slow power, and alpha coherence and peak frequency were significantly lower. Older patients were more likely to experience burst suppression. CONCLUSIONS: These profound age-related changes in the EEG are consistent with known neurobiological and neuroanatomical changes that occur during typical ageing. Commercial EEG-based depth-of-anaesthesia indices do not account for age and are therefore likely to be inaccurate in elderly patients. In contrast, monitoring the unprocessed EEG and its spectrogram can account for age and individual patient characteristics.

Developments in the field of allergy in 2011 through the eyes of Clinical and Experimental Allergy.

As in previous years, we felt it would be of value to our readership to summarize the new information provided by the authors who have published in Clinical and Experimental Allergy in 2011 and set this in the context of recent advances in our understanding of the pathogenesis and management of allergic disease in all its many manifestations. In 2011, about 210 articles were published in Clinical and Experimental Allergy including editorials, reviews, opinion articles, guidelines, letters, book reviews and of course at the heart of the journal, papers containing original data. As before, this review is divided into sections based on the way the journal is structured, although this year we have grouped together all the papers dealing with mechanisms of allergic disease, whether they involve patients (clinical mechanisms), pure in vitro studies (basic mechanisms) or animal models (experimental models), as we felt this was a more coherent way to deal with the subject. In the field of asthma and rhinitis, the relationship between airway inflammation and airway dysfunction was of perennial interest to investigators, as were phenotypes and biomarkers. Aspirin hypersensitivity appeared in studies in several papers and there was new interest in asthma in the elderly. The mechanisms involved in allergic disease describe advances in our understanding of T cell responses, the relationship between inflammation and disease, mast cell and basophil activation, steroid resistance and novel therapies. In the section dealing with epidemiology, studies seeking to identify risk factors for allergic disease including vitamin D are prominent, as once again are studies investigating gene-environment interactions. The clinical allergy section focuses on drug allergy, food allergy and immunotherapy. The area of oral immunotherapy for food allergy is well covered and we were grateful to Stephen Durham for guest editing an outstanding special issue on immunotherapy in the centenary year of Leonard Noon's pioneering work. Lastly, in the field of allergens, the interest in component-resolved diagnosis continues to grow and there are also articles describing important novel cultivars and the effect of food processing on the allergenic properties of foods. Another terrific year, full of important and high-quality work,which the journal has been proud to bring to the allergy community.

Nasal mucosal expression of the leukotriene and prostanoid pathways in seasonal and perennial allergic rhinitis.

BACKGROUND: Leukotrienes (LTs) and prostanoids are potent pro-inflammatory and vasoactive lipid mediators implicated in airway disease, but their cellular sources in the nasal airway in naturally occurring allergic rhinitis (AR) are unclear. OBJECTIVE: To quantify cellular expression of enzymes of the 5-lipoxygenase (5-LO) and cyclooxygenase (COX) pathways by immunohistochemistry in nasal biopsies from patients with symptomatic perennial AR (PAR, n = 13) and seasonal AR (SAR, n = 14) and from normal subjects (n = 12). METHODS: Enzymes of the 5-LO pathway (5-LO, FLAP, LT A4 hydrolase, LTC4 synthase) and the COX pathway (COX-1, COX-2, prostaglandin D2 synthase) were immunostained in glycol methacrylate resin-embedded inferior turbinate biopsy specimens, quantified in the lamina propria and epithelium, and co-localized to leucocyte markers by camera lucida. RESULTS: In the lamina propria of PAR biopsies, median counts of cells expressing FLAP were fourfold higher than in normal biopsies (Mann-Whitney, P = 0.014), and also tended to be higher than in SAR biopsies (P = 0.06), which were not different from normal. PAR biopsies showed threefold more cells immunostaining for LTC4 synthase compared with SAR biopsies (P = 0.011) but this was not significant compared with normal biopsies (P = 0.2). These changes were associated with ninefold more eosinophils (P = 0.0005) with no differences in other leucocytes. There were no significant differences in the lamina propria in immunostaining for 5-LO, LTA4 hydrolase, COX-1, COX-2 or PGD2 synthase. Within the epithelium, increased expression of COX-1 was evident in PAR biopsies (P = 0.014) and SAR biopsies (P = 0.037), associated with more intra-epithelial mast cells in both rhinitic groups (P < 0.02). CONCLUSIONS: In the nasal biopsies of PAR subjects, increased expression of regulatory enzymes of the cysteinyl-LT biosynthetic pathway was associated with lamina propria infiltration by eosinophils. Seasonal rhinitis biopsies shared only some of these changes, consistent with transient disease. Increased intra-epithelial mast cells and epithelial COX-1 expression in both rhinitic groups may generate modulatory prostanoids.

Evidence of temporal cortical dysfunction in rhesus monkeys following chronic cocaine self-administration.

Cocaine abusers show impaired performance on cognitive tasks that engage prefrontal cortex. These deficits may contribute to impaired control and relapse in abusers. Understanding the neuronal substrates that lead to these deficits requires animal models that are relevant to the human condition. However, to date, models have mostly focused on behaviors mediated by subcortical systems. Here we evaluated the impact of long-term self-administration of cocaine in the rhesus monkey on cognitive performance. Tests included stimulus discrimination (SD)/reversal and delayed alternation tasks. The chronic cocaine animals showed marked deficits in ability to organize their behavior for maximal reward. This was demonstrated by an increased time needed to acquire SDs. Deficits were also indicated by an increased time to initially learn the delayed alternation task, and to adapt strategies for bypassing a reliance on working memory to respond accurately. Working memory per se (delay dependent performance) was not affected by chronic self-administration. This pattern of cognitive deficits suggests dysfunction that extends beyond localized prefrontal cortical areas. In particular, it appears that temporal cortical function is also compromised. This agrees with other recent clinical and preclinical findings, and suggests further study into addiction related dysfunction across more widespread cortical networks is warranted.

Overexpression of leukotriene C4 synthase in bronchial biopsies from patients with aspirin-intolerant asthma.

Aspirin causes bronchoconstriction in aspirin-intolerant asthma (AIA) patients by triggering cysteinyl-leukotriene (cys-LT) production, probably by removing PGE2-dependent inhibition. To investigate why aspirin does not cause bronchoconstriction in all individuals, we immunostained enzymes of the leukotriene and prostanoid pathways in bronchial biopsies from AIA patients, aspirin-tolerant asthma (ATA) patients, and normal (N) subjects. Counts of cells expressing the terminal enzyme for cys-LT synthesis, LTC4 synthase, were fivefold higher in AIA biopsies (11.5+/-2.2 cells/mm2, n = 10) than in ATA biopsies (2.2+/-0.7, n = 10; P = 0. 0006) and 18-fold higher than in N biopsies (0.6+/-0.4, n = 9; P = 0. 0002). Immunostaining for 5-lipoxygenase, its activating protein (FLAP), LTA4 hydrolase, cyclooxygenase (COX)-1, and COX-2 did not differ. Enhanced baseline cys-LT levels in bronchoalveolar lavage (BAL) fluid of AIA patients correlated uniquely with bronchial counts of LTC4 synthase+ cells (rho = 0.83, P = 0.01). Lysine-aspirin challenge released additional cys-LTs into BAL fluid in AIA patients (200+/-120 pg/ml, n = 8) but not in ATA patients (0. 7+/-5.1, n = 5; P = 0.007). Bronchial responsiveness to lysine-aspirin correlated exclusively with LTC4 synthase+ cell counts (rho = -0.63, P = 0.049, n = 10). Aspirin may remove PGE2-dependent suppression in all subjects, but only in AIA patients does increased bronchial expression of LTC4 synthase allow marked overproduction of cys-LTs leading to bronchoconstriction.

Regional specificity of chandelier neuron axon terminal alterations in schizophrenia.

BACKGROUND: The axon terminals of GABAergic chandelier cells form linear arrays, termed cartridges, that synapse on the axon initial segment of neocortical pyramidal cells. These cartridges are immunoreactive for the GABA membrane transporter-1, and the density of GABA membrane transporter-1-immunoreactive cartridges in the prefrontal cortex has been reported to be reduced in schizophrenia. The goal of this study was to determine if reductions in the density of GABA membrane transporter-1-immunoreactive cartridges in schizophrenia are restricted to the prefrontal cortex. METHODS: Relative GABA membrane transporter-1-immunoreactive cartridge density was determined in auditory association area 42, a region previously implicated in the pathophysiology of schizophrenia, in 14 matched pairs of subjects with schizophrenia and normal comparison subjects. The results were compared with similar data from prefrontal area 46 in the same subjects. RESULTS: Mean GABA membrane transporter-1-immunoreactive cartridge density in area 42 was decreased by 9.8% in layers II-IIIa, and by 11.9% in layer VI in subjects with schizophrenia, although these differences did not achieve statistical significance. However, the magnitude of the reductions in the density of GABA membrane transporter-1-immunoreactive cartridges in area 42 of the subjects with schizophrenia was not significantly smaller than those in area 46. CONCLUSIONS: In subjects with schizophrenia, alterations in chandelier neuron axon cartridges appear to be more marked in the prefrontal cortex than in another cortical region implicated in the illness, although such changes might not be restricted to the prefrontal cortex.

Variation in preparation for gastroscopy: lessons towards safer and better outcomes.

OBJECTIVE: To identify the methods employed within the UK practice prior to diagnostic gastroscopy and compare with published guidelines for patients undergoing general anaesthesia. DESIGN: National Health Service (NHS) endoscopy units were invited to take part in a structured telephone survey to determine the length of time patients are kept nil-by-mouth (NBM) for food and fluids prior to gastroscopy, and whether a preprocedure mucolytic drink was used. METHODS: 212 NHS Trusts providing endoscopy services were identified from the Joint Advisory Group on GI Endoscopy. Trusts were excluded if they were children's hospitals (n=5). RESULTS: 207 NHS Trusts were telephoned. 193 completed the survey (93%), 11 Trusts declined and there was no response from 3 Trusts. 13 separate policies regarding NBM timings were identified. 51 Trusts (21%) used the timings ratified by Surgical and Anaesthetic Societies (6 h NBM for food, 2 h for clear fluid). 135 Trusts (70%) used a policy which starved patients in excess of the standard surgical guidelines. No Trust used a mucolytic drink prior to gastroscopy. CONCLUSIONS: The survey revealed large variation in NHS Trust's policies regarding the times patients were starved prior to gastroscopy. Results of surgical studies demonstrate increased risk of significant pulmonary aspiration with increased fluid-starvation periods, 68% of NHS endoscopy policy would be deemed excessive by surgical practice. There is no routine use of a mucolytic drink to improve mucosal visualisation in the UK practice.

Effects of combined angiotensin II and endothelin receptor blockade with developing heart failure: effects on left ventricular performance.

BACKGROUND: The goal of this study was to determine the comparative effects of angiotensin II type 1 (AT(1)) receptor inhibition alone, endothelin-1 (ET) receptor blockade alone, and combined receptor blockade on left ventricular (LV) function, contractility, and neurohormonal system activity in a model of congestive heart failure (CHF). METHODS AND RESULTS: Pigs were randomly assigned to each of 5 groups: (1) rapid atrial pacing (240 bpm) for 3 weeks (n=9), (2) concomitant AT(1) receptor blockade (valsartan, 3 mg/kg per day) and rapid pacing (n=8), (3) concomitant ET receptor blockade (bosentan, 50 mg/kg BID) and rapid pacing (n=8), (4) concomitant combined AT(1) and ET receptor inhibition and rapid pacing (n=8), and (5) sham-operated control (n=9). LV stroke volume was reduced from the control value after rapid pacing, was unchanged with either AT(1) or ET receptor blockade alone, but was improved with combination treatment. LV peak wall stress was reduced in both groups with ET receptor blockade compared with the rapid pacing group. Plasma norepinephrine levels were increased by >3-fold after rapid pacing, remained increased in the monotherapy groups, but were reduced after combination treatment. LV myocyte velocity of shortening was reduced after rapid pacing-induced CHF, remained reduced after AT(1) receptor blockade, increased after ET receptor blockade (compared with rapid pacing-induced CHF values), and returned to within control values after combined blockade. CONCLUSIONS: Combined AT(1) and the ET receptor blockade in this model of CHF improved LV pump function, and contributory factors included the effects of LV loading conditions, neurohormonal system activity, and myocardial contractile performance. Thus, combined receptor blockade may provide a useful combinatorial therapeutic approach in CHF.

Decreased glutamic acid decarboxylase67 messenger RNA expression in a subset of prefrontal cortical gamma-aminobutyric acid neurons in subjects with schizophrenia.

BACKGROUND: Markers of gamma-aminobutyric acid (GABA) neurotransmission seem to be altered in the prefrontal cortex (PFC) of subjects with schizophrenia. We sought to determine whether the expression of the messenger RNA (mRNA) for the synthesizing enzyme of GABA, glutamic acid decarboxylase67 (GAD67), is decreased in the PFC of subjects with schizophrenia, whether this change is present in all or only some GABA neurons, and whether long-term treatment with haloperidol decanoate contributes to altered GAD67 mRNA expression. METHODS: Tissue sections from 10 pairs of subjects with schizophrenia and control subjects and 4 pairs of haloperidol-treated and control monkeys were processed for in situ hybridization histochemical analysis with sulfur-35-labeled oligonucleotide probes for GAD67 mRNA and exposed to nuclear emulsion. Within each layer of PFC area 9, neurons expressing a detectable level of GAD67 mRNA were quantified for cell density and the relative level of mRNA expression per cell (grain density per neuron). RESULTS: In subjects with schizophrenia, the density of labeled neurons was significantly (P<.05) decreased by 25% to 35% in cortical layers 3 to 5. In contrast, the mean grain density per labeled neuron did not differ across subject groups. Similar analyses in monkeys revealed no effect of long-term haloperidol treatment on either the density of the labeled neurons or the grain density per labeled neuron. CONCLUSIONS: These findings indicate that in subjects with schizophrenia, GAD67 mRNA expression is relatively unaltered in most PFC GABA neurons but is reduced below a detectable level in a subset of GABA neurons. Altered GABA neurotransmission in this subset may contribute to PFC dysfunction in subjects with schizophrenia.

Decreased somal size of deep layer 3 pyramidal neurons in the prefrontal cortex of subjects with schizophrenia.

BACKGROUND: Schizophrenia is associated with deficits in working memory, a cognitive function that depends on the connections of the prefrontal cortex (PFC) with the thalamus and other cortical regions. Pyramidal neurons in PFC deep layer 3 play a central role in both thalamocortical and corticocortical circuitry. Given that somal size tends to be associated with both the dendritic and axonal architecture of a neuron, abnormalities in these circuits in schizophrenia may be associated with a change in the somal size of deep layer 3 pyramidal neurons. METHODS: We used design-based stereology to estimate the somal volume of pyramidal neurons in deep layer 3 of PFC area 9 in 28 subjects with schizophrenia, each of whom was matched to 1 normal comparison subject for sex, age, and postmortem interval. RESULTS: The geometric mean of the somal volume estimates in the subjects with schizophrenia was significantly (P =.02) decreased by 9.2%. This decrease was associated with a shift in the distribution of somal volumes toward smaller sizes. Neither antipsychotic medication treatment history nor duration of illness was associated with somal size. CONCLUSIONS: These findings independently replicate previous reports of decreased somal size in the PFC in schizophrenia. The reduction in size of deep layer 3 pyramidal neurons is consistent with abnormalities in thalamocortical and corticocortical circuitry, suggesting that disruption of these circuits may contribute to cognitive abnormalities in schizophrenia.

Prenatal diagnosis of ductus arteriosus aneurysm.

The ductus arteriosus holds major functional importance within the fetal circulation, and anomalies within the ductus arteriosus may interfere with the integrity of the fetal circulation. Ductus arteriosus aneurysm, previously considered a rare lesion, is now a well-reported finding in infancy with some reports describing this finding in the prenatal period. Postnatally, most ductus arteriosus aneurysms resolve spontaneously; however, a small group of infants show complications such as connective-tissue disorders, thrombo-embolism, compression of surrounding thoracic structures and life-threatening spontaneous rupture requiring surgical correction. As such, postnatal assessment in this group is recommended.

Promoter polymorphism influences the effect of dexamethasone on transcriptional activation of the LTC4 synthase gene.

The molecular mechanisms of corticosteroid action in asthma are gradually being elucidated. The LTC4S gene encodes for LTC(4) synthase, the terminal enzyme in the generation of cysteinyl-leukotrienes (cys-LTs), which are key mediators in the pathogenesis of asthma. We have identified a novel promoter polymorphism in LTC4S at position -1072 (G/A) and a -444 (A/C) polymorphism has previously been reported. We hypothesised that the LTC4S gene promoter may be a potential site of regulation by corticosteroids and that genetic polymorphism may determine their effects at this locus. Using in vitro transfection of promoter-reporter constructs, dexamethasone was shown to increase transcription of LTC4S by more than 50% for the -1072G/-444A, A-C and G-C haplotype constructs (P&<0.02), but to have no effect on the A-A haplotype (P=0.27). These data identify an interesting phenomenon that requires validation in a human study examining ex vivo production of LTC(4) in cells from genotyped asthmatic and nonasthmatic subjects. The 9% of the Caucasian asthmatic population with the A-A haplotype may have genetically predetermined lower cys-LT levels in the presence of corticosteroids compared to other patients. These findings have potential implications in the evaluation of combined corticosteroid and antileukotriene therapy in asthma.

Characterization of the absorption phase of marijuana smoking.

Rapid blood collection, a paced smoking protocol and timely collection of physiologic and behavioral measures were used to characterize the absorption phase of marijuana smoking. Six healthy males smoked a single marijuana cigarette (placebo, 1.75%, or 3.55% delta-9-tetrahydrocannabinol) in a double-blind, randomized, Latin square study design. Rapid blood sampling with a continuous withdrawal pump allowed simultaneous collection with concurrent physiologic and behavioral measures. Mean plasma levels of 7.0 and 18.1 ng/ml delta-9-tetrahydrocannabinol were observed after the first inhalation of a 1.75% and 3.55% delta-9-tetrahydrocannabinol cigarette, respectively. Blood levels increased rapidly and peaked at 9 minutes, before initiation of the last puff sequence at 9.8 minutes. Three of six subjects reported increases in drug "liking" scores after the first puff, and all subjects responded by the second puff of a high dose cigarette. Significant increases in heart rate and diastolic blood pressure occurred shortly after peak blood levels. Previous studies have indicated that there is a substantial time delay between peak plasma levels of delta-9-tetrahydrocannabinol and drug-induced effects. This study showed that behavioral and physiologic effects appear concurrently or within minutes after the rapid appearance of delta-9-tetrahydrocannabinol in blood during marijuana smoking.

GABA transporter-1 mRNA in the prefrontal cortex in schizophrenia: decreased expression in a subset of neurons.

OBJECTIVE: Within the prefrontal cortex of schizophrenic subjects, alterations in markers of gamma-aminobutyric acid (GABA) neurotransmission, including decreased immunoreactivity for the GABA membrane transporter GAT-1, may be most prominent in a subset of inhibitory neurons. In the present study, the authors sought to determine whether the alterations in GAT-1 protein could be attributed to a reduction in GAT-1 mRNA expression. METHOD: Tissue sections containing prefrontal cortex area 9 from 10 matched pairs of schizophrenic and comparison subjects were processed for in situ hybridization histochemistry with (35)S-oligonucleotide probes for GAT-1 mRNA. RESULTS: In the schizophrenic subjects, the relative density of labeled neurons was 21%-33% lower in layers 1-5 of the prefrontal cortex but was unchanged in layer 6. In contrast, cellular levels of GAT-1 mRNA expression, as reflected in grain density per labeled neuron, did not differ by more than 11% between subject groups in any layer. These findings indicate that GAT-1 mRNA expression is relatively unaltered in the majority of prefrontal cortex GABA neurons in schizophrenic subjects but is reduced below a detectable level in a subset of GABA neurons. Furthermore, the magnitude and laminar pattern of these results were strikingly similar to those found in a previous study of mRNA expression for the synthesizing enzyme of GABA, glutamic acid decarboxylase(67), in the same subjects. CONCLUSIONS: Both GABA synthesis and reuptake appear to be altered at the level of gene expression in a subset of GABA neurons, and the resulting changes in GABA neurotransmission may contribute to prefrontal cortex dysfunction in schizophrenia.

Lamina-specific alterations in the dopamine innervation of the prefrontal cortex in schizophrenic subjects.

OBJECTIVE: Abnormalities in dopamine neurotransmission in the prefrontal cortex have been implicated in the pathophysiology of schizophrenia. However, the integrity of the dopamine projections to the prefrontal cortex in this disorder has not been directly examined. METHOD: The authors employed immunocytochemical methods and antibodies against tyrosine hydroxylase, the rate-limiting enzyme in dopamine biosynthesis, and the dopamine membrane transporter to examine dopamine axons in the dorsomedial prefrontal cortex (area 9) from 16 pairs of schizophrenic and matched control subjects. RESULTS: Compared to the control subjects, the total length of tyrosine hydroxylase-immunoreactive axons was unchanged in the superficial and middle layers of the schizophrenic subjects but was reduced by an average of 33.6% in layer 6. The total length of tyrosine hydroxylase-positive axons in layer 6 was decreased in 13 of the schizophrenic subjects compared to their control subjects. Axons immunoreactive for the dopamine membrane transporter showed a similar pattern of change. In contrast, axons labeled for the serotonin transporter did not differ between schizophrenic and control subjects in any layer examined. In addition, the density of tyrosine hydroxylase-containing axons did not differ between monkeys chronically treated with haloperidol and matched control animals. CONCLUSIONS: These findings reveal that schizophrenia is associated with an altered dopamine innervation of prefrontal cortex area 9 that is lamina- and neurotransmitter-specific and that does not appear to be a consequence of pharmacological treatment. Together, these data provide direct evidence for a disturbance in dopamine neurotransmission in the prefrontal cortex of schizophrenic subjects.

Dopamine transporter immunoreactivity in monkey cerebral cortex: regional, laminar, and ultrastructural localization.

Dopamine (DA) influences a number of cognitive and motor functions that are mediated by the primate cerebral cortex, and the DA membrane transporter (DAT) is known to be a critical regulator of DA neurotransmission in subcortical structures in rodents. To gain insight into the possible functional role of cortical DAT, we compared the regional, laminar, and ultrastructural distribution of DAT immunoreactivity to that of tyrosine hydroxylase (TH), the rate-limiting enzyme in DA synthesis, in the cerebral cortex of macaque monkeys. DAT-immunoreactive (DAT-IR) axons were present throughout the cortical mantle, with substantial differences in density and laminar distribution across cytoarchitectonic areas. In particular, high densities of DAT-IR axons were present in certain regions (e.g., posterior parietal cortex, dentate gyrus) not previously thought to receive a substantial DA input. The laminar distribution of DAT-IR axons ranged from a restricted localization of labeled axons to layer 1 in lightly innervated regions to the presence of axons in all six cortical layers, with a particularly dense plexus in deep layer 3, in highly innervated regions. These regional and laminar patterns paralleled those of TH-IR axons, but several differences in fiber morphology and ultrastructural localization of DAT were observed. For example, in contrast to TH, DAT immunoreactivity in the cortex was localized predominantly to small-diameter profiles, whereas, in the dorsolateral caudate nucleus, DAT and TH immunoreactivities were present in both large-diameter and small-diameter profiles, which may represent varicose and intervaricose axon segments, respectively. Overall, the distribution of DAT-IR axons confirms and extends the results of previous reports, using other markers of DA axons, that the DA innervation of the primate cerebral cortex is global but specialized on both a regional basis and a laminar basis. In particular, these observations reveal an anatomical substrate for a direct and potent influence of DA over neuronal activity in posterior parietal cortex and in certain regions of the temporal lobe. However, due to its predominant distribution to small-diameter profiles, immunoreactivity for DAT may not be an appropriate ultrastructural marker for larger DA varicosities in the primate cortex. Moreover, this distribution of DAT suggests that cortical DA fibers may permit greater neurotransmitter diffusion than subcortical DA axons.