Pharmacokinetics of aminolevulinic acid after intravesical administration to dogs

PURPOSE

To examine the stability and systemic absorption of aminolevulinic acid (ALA) in dogs during intravesical administration.

METHODS

Nine dogs received an intravesical dose of ALA either with no prior treatment, after receiving ammonium chloride for urinary acidification, or after receiving sodium bicarbonate for urinary alkalinization. Urine and blood samples collected during and after administration were monitored for ALA using an HPLC assay developed in our laboratories. Concentrations of pyrazine 2,5-dipropionic acid, the major ALA degradation product, and radiolabeled inulin, a nonabsorbable marker for urine volume, were also determined.

RESULTS

Less than 0.6% of intravesical ALA doses was absorbed into plasma. Urine concentrations decreased to 37% of the initial concentration during the 2 hour instillation. Decreases in urinary ALA and radiolabeled inulin concentrations were significantly correlated, indicating that urine dilution accounted for over 80% of observed decreases in urinary ALA. ALA conversion to pyrazine 2,5-dipropionic acid was negligible.

CONCLUSIONS

These studies demonstrate that ALA is stable and poorly absorbed into the systemic circulation during intravesical instillation. Future studies utilizing intravesical ALA for photodiagnosis of bladder cancer should include measures to restrict fluid intake as a means to limit dilution and maximize ALA concentrations during instillation.

Taxol-induced meiotic maturation delay, spindle defects, and aneuploidy in mouse oocytes and zygotes

To increase our understanding about the potential risks of chemically-induced aneuploidy, more information about the various mechanisms of aneuploidy induction is needed, particularly in germ cells. Most chemicals that induce aneuploidy inhibit microtubule polymerization. However, taxol alters microtubule dynamics by enhancing polymerization and stabilizing the polymer fraction. We tested the hypothesis that taxol induces meiotic delay, spindle defects, and aneuploidy in mouse oocytes and zygotes. Super-ovulated ICR mice received 0 (control), 2.5, 5.0, and 7.5 mg/kg taxol intraperitoneally immediately after HCG. Females were paired (1:1) with males for 17 h after taxol treatment. Mated females were given colchicine 25 h after taxol and their one-cell zygotes were collected 16 h later. Ovulated oocytes from non-mated females were collected 17 h after taxol. Chromosomes were C-banded for cytogenetic analyses. Oocytes were also collected from another group of similarly treated females for in situ chromatin and microtubule analyses. Taxol significantly (p<0.01) enhanced the proportion of oocytes exhibiting parthenogenetic activation, chromosomes displaced from the meiotic spindle, and sister-chromatid separation. Moreover, 7.5 mg/kg taxol significantly (p<0.01) increased the proportions of metaphase I and diploid oocytes and polyploid zygotes. A significant (p<0.01) dose response for taxol-induced hyperploidy in oocytes and zygotes was found. These results support the hypothesis that taxol-induced meiotic delay and spindle defects contribute to aneuploid mouse oocytes and zygotes.

Biochemical and anatomical characterization of forepaw adjusting steps in rat models of Parkinson's disease: studies on medial forebrain bundle and striatal lesions

Deficits in forepaw adjusting steps in rats have been proposed as a non-drug-induced model of the akinesia associated with Parkinson's disease. The present study examined the relationship between contralateral forepaw adjusting steps and dopamine depletion after medial forebrain bundle lesions with 6-hydroxydopamine. Depletion of striatal dopamine by >80% resulted in dramatic reductions in the ability of rats to make adjusting steps, but rats with < 80% dopamine depletion had no detectable deficit. The deficit in forepaw adjusting steps was evident by three days after lesions and did not recover for up to 13 weeks. Compared to apomorphine-induced rotation, the deficit in adjusting steps was evident at milder dopamine depletion. Discrete striatal lesions were also utilized to localize the striatal subregions that mediate forepaw adjusting steps. Forepaw adjusting steps were reduced after lesions of dorsolateral, ventrolateral or ventrocentral striatum, but not after lesions of dorsomedial, dorsocentral or ventromedial striatum. The reductions in adjusting steps after the discrete striatal lesions were not as severe as after medial forebrain bundle lesions. Furthermore, none of the discrete striatal lesions resulted in rotation after apomorphine administration, although a few resulted in increase in amphetamine-induced rotation. Administration of L-3,4-dihydroxyphenylalanine partially reversed the reductions of forepaw adjusting steps in both sets of lesion experiments. Together, these results suggest that forepaw adjusting step deficits in the rat provide a good model for the akinesia of Parkinson's disease both in medial forebrain bundle and striatal lesions, and would be a useful tool for investigating the efficacy of various therapeutic strategies.

Mobilization of blood-derived stem and progenitor cells in normal subjects by granulocyte-macrophage- and granulocyte-colony-stimulating factors

BACKGROUND

It was previously reported that the combination of granulocyte-macrophage-colony-stimulating factor (GM-CSF) and granulocyte-CSF (G-CSF) for 4 days mobilized more primitive CD34+ subsets than did either G-CSF or GM-CSF alone.

STUDY DESIGN AND METHODS

The studies determine the optimal number of days of growth factor dosing for mobilization and collection of peripheral blood progenitor cells, by increasing the days of administration of GM-CSF and/or G-CSF or employing the sequential administration of GM-CSF followed by G-CSF. Sixty normal subjects were given injections of G-CSF or GM-CSF alone; GM-CSF and G-CSF concurrently for 4, 5, or 6 days; or a sequential regimen of GM-CSF for 3 or 4 days followed by G-CSF for 2 or 3 days. A 10-L apheresis was performed 24 hours after the last dose.

RESULTS

The three most efficacious mobilization regimens consisted of sequential GM-CSF for 3 days followed by G-CSF for either 2 or 3 days and G-CSF alone for 5 days. Each of these regimens resulted in the collection of significantly greater numbers of CD34+ cells by apheresis than any of the 4-day dosing regimens with G-CSF and/or GM-CSF (sequential GM-CSF/G-CSF: 3 days/2 days = 3.58 +/- 0.53 x 106 CD34+ cells/kg; GM-CSF/G-CSF: 3 days/3 days = 4.45 +/- 1.08 x 10(6) CD34+ cells/kg; G-CSF: 5 days = 3.58 +/- 0.97 x 10(6) CD34+ cells/kg; all p<0.05 vs. G-CSF and/or GM-CSF for 4 days). Clonogenic assays generally paralleled the level of CD34+ cells. Regimens containing GM-CSF resulted in a higher percentage of the cells from primitive CD34+/CD38-/HLA-DR+ subset than G-CSF alone.

CONCLUSION

Compared with 4-day dosing regimens with G-CSF and/or GM-CSF, mobilization of CD34+ cells in normal subjects using sequential GM-CSF for 3 days followed by G-CSF for 2 or 3 days or using G-CSF alone for 5 days increased the number CD34+ cells that can be collected by a single 10-L apheresis 24 hours after the last dose of cytokine.

Artificial neural networks applied to the in vitro-in vivo correlation of an extended-release formulation: initial trials and experience

Artificial neural networks applied to in vitro-in vivo correlations (ANN-IVIVC) have the potential to be a reliable predictive tool that overcomes some of the difficulties associated with classical regression methods, principally, that of providing an a priori specification of the regression equation structure. A number of unique ANN configurations are presented, that have been evaluated for their ability to determine an IVIVC from different formulations of the same product. Configuration variables included a combination of architectural structures, learning algorithms, and input-output association structures. The initial training set consisted of two formulations and included the dissolution from each of the six cells in the dissolution bath as inputs, with associated outputs consisting of 1512 pharmacokinetic time points from nine patients enrolled in a crossover study. A third formulation IVIVC data set was used for predictive validation. Using these data, a total of 29 ANN configurations were evaluated. The ANN structures included the traditional feed forward, recurrent, jump connections, and general regression neural networks, with input-output association types consisting of the direct mapping of the dissolution profiles to the pharmacokinetic observations, mapping the individual dissolution points to the individual observations, and using a "memorative" input-output association. The ANNs were evaluated on the basis of their predictive performance, which was excellent for some of these ANN models. This work provides a basic foundation for ANN-IVIVC modeling and is the basis for continued modeling with other desirable inputs, such as formulation variables and subject demographics.

Mobilization of peripheral blood progenitor cells for human immunodeficiency virus-infected individuals

Gene therapy is becoming one of the most promising modalities for the treatment of acquired immunodeficiency syndrome. The purpose of this study was to investigate the mobilization and collection of peripheral blood progenitor cells from human immunodeficiency virus (HIV)-infected individuals using granulocyte colony-stimulating factor (G-CSF). A total of 10 patients (9 male, 1 female; median age 36.5 years) with varying circulating CD4+ cell counts (13.9-1467/microL) were administered 10 microg/kg G-CSF daily for 6 days. Peripheral white blood cells (WBCs), CD34+ cell counts, lymphocyte subsets, and plasma viremia were monitored before each G-CSF injection. An average sixfold increase in WBCs was observed, which stabilized on day 4 or thereafter. The level of CD34+ cells was increased by 20-fold, and did not differ between days 5 and 6. Smaller increases in CD4+, CD8+, and CD4+CD8+ cells were observed. HIV viral load, as measured by RNA copy number in plasma, was not significantly altered by G-CSF administration. The leukapheresis product (LP), collected on day 7, contained an average of 6.25+/-4.52 (mean +/- standard deviation) x 10(10) WBCs and 3.08+/-2.98 x 10(6) CD34+ cells/kg. The levels of different CD34+ cell subsets were similar to those in the LPs of G-CSF-mobilized healthy individuals from an earlier study. Primitive hematopoietic cells (CD38- and CD38-HLA-DR+ cells) were detected in LPs (1.19+/-0.46% and 0.87+/-0.23%, respectively, of CD34+ cells). All parameters (WBC counts, lymphocyte populations, CD34+ cells, and HIV-1 RNA copies) measured 3 weeks after leukapheresis returned to baseline values. The administration of G-CSF was well tolerated by the HIV patients; side effects included bone pain, headache, flulike symptoms, and fatigue. There were no correlations between baseline CD4+ cell count and the WBCs, mononuclear cells, or CD34+ cells collected in the LP. Similarly, no correlation existed between baseline CD4+ and CD34+ cells, peak CD34+ cells, or days to achieve peak CD34+ cell counts after G-CSF mobilization. Our results showed that: (1) maximal mobilization can be achieved after 4 days of G-CSF administration; (2) therapeutic quantities of hematopoietic cells can be collected and used for gene therapy; and (3) G-CSF administration is well tolerated and does not cause a clinically significant increase in viremia.

The concept mapping method. An alternative to focus group inquiry in general practice

BACKGROUND

The concept mapping rationale and process are explained step by step. The concept mapping method produces a two dimensional conceptual map of ideas produced by the group which can be analysed at the level of individual statements, clusters of statements, and groups of similar clusters. An example of concept mapping conducted with four general practitioner (GP) groups from different practice types and demographic locations is provided. A total of 51 participating GPs were asked to complete an 'evaluation questionnaire' at the end of each group session. The majority of GP participants (68%) rated the method as highly useful.

OBJECTIVE

To describe the concept mapping method and its interpretation for use in general practice research. To report on its perceived usefulness and acceptability by general practitioners.

DISCUSSION

Concept mapping is a very useful method combining benefits from qualitative and quantitative approaches for exploring the breadth of a topic in its entirety, especially for abstract concepts. GPs found the concept mapping method to be efficient for group inquiry, rating it high on utility. There is scope to refine the method, reducing time spent in some stages of the session, and substituting more time on final analysis.

Taoistic cognitive psychotherapy for neurotic patients: a preliminary clinical trial

Taoistic cognitive psychotherapy is a cognitive therapy based on Taostic philosophy of life and health. The present preliminary study aims to test clinical significance of the Taoistic cognitive psychotherapy, indicates that type A behavior patterns distorted values and psychopathologies can be improved after a short period (4 weeks) of Taoistic cognitive psychotherapy. The theoretical basis of this psychotherapy is also briefly introduced.

Psychoactive substance use in three sites in China: gender differences and related factors

One year prevalence rates for psychoactive substance use are reported based on community surveys performed in three sites in China: Hunan, Heilongjiang and Jiangsu. The data were gathered on more than 14,000 respondents (15-65 years old). The drinking rates were from 58.3 to 82.6% for men and from 16.3 to 31.4% for women. Smoking rates range from 64.9 to 68.1% for men and from 0.1 to 20.5% for women. Most drinkers were light users and most smokers were heavy users. Illicit drug use was observed at Hunan. Regarding frequency and quantity of psychoactive substance use, women are lighter consumers than their male counterparts except for use of minor tranquilizers and analgesics. The psychosocial factors related to drinking and smoking were also investigated in this study.

Temporal relationships between hormonal and hemodynamic changes in early human pregnancy

BACKGROUND

The systemic hemodynamic profile of human pregnancy is characterized by a decrease in mean arterial pressure, a rise in cardiac output and plasma volume in association with an increase in renal plasma flow and glomerular filtration rate. The factors and the time course responsible for the initial hemodynamic changes seen in human pregnancy have not been completely documented. We hypothesize that systemic and renal hemodynamic changes occur early, prior to the presence of the fetal-placental unit.

METHODS

Thirteen women were studied prior to and immediately following conception in identical fashion at gestational weeks 6, 8, 10, 12, 24 and 36. Individuals underwent mean arterial pressure, cardiac output, inulin and PAH clearance determinations.

RESULTS

Mean arterial pressure decreased by six weeks gestation (mid follicular 81.5 +/- 2.6 vs. six weeks 68.7 +/- 2.0 mm tig, P < 0.001) in association with a significant increase in cardiac output, a decrease in systemic vascular resistance and an increase in plasma volume. Renal plasma flow and glomerular filtration rate increased by six weeks gestation. Plasma renin activity and aldosterone concentration increased significantly by six weeks, whereas norepinephrine levels did not change throughout pregnancy. Atrial natriuretic peptide levels increased later, at 12 weeks gestation. Plasma cGMP levels decreased and cGMP clearance increased by six and eight weeks, respectively.

CONCLUSIONS

Peripheral vasodilation occurs early in pregnancy prior to full placentation in association with renal vasodilation and activation of the renin-angiotensin-aldosterone system. Plasma volume expansion occurs early, followed later by increases in ANP concentration, suggesting that ANP increases in response to changes in intravasular volume.

Candidate hematopoietic stem cells from fetal tissues, umbilical cord blood vs. adult bone marrow and mobilized peripheral blood

As part of our ongoing effort to identify a rich source of pluripotent progenitor cells for transplantation and gene therapy, we cultured single-sorted CD34+ subpopulations from different human hematopoietic tissues to assess the relationship between immunophenotype expression and functional characteristics. In combination with index sorting, single cell culture permits precise assessment of the colony efficiency (CE), growth characteristics, and replating potential (RP) of each individual phenotype without interference from other cell types. CD34+ cells from fetal liver (FL), fetal bone marrow (FBM), umbilical cord blood (UCB), adult BM (ABM), and mobilized peripheral blood (MPB) were sorted and cultured as single cells according to the coexpression of CD38. With the exception of FL, higher CEs were found among CD34+/CD38+ cells vs. CD34+/CD38- cells from the same cell source. However, colonies with dispersed growth pattern (DGP) and mixed growth pattern (MGP) were found predominantly in the CD34+/CD38- subsets. We next examined the functional characteristics of CD34+ subsets defined by three-color analysis and coexpression of CD38 and HLA-DR or CD38 and CDw90 (Thy-1). Using the combination CD34, CD38, and HLA-DR, the highest CEs, the highest percentages of colonies with DGP/MGP and the maximum RP were found in the CD34+/CD38-/HLA-DR+ subset among samples from FL, FBM, and UCB. The CEs and percentages of colonies with DGP/MGP of single-sorted CD34+/CD38-/HLA-DR+ cells were 72.7+/-11.8% (mean +/- standard deviation) and 20.1+/-10.4%, respectively, in FL; 60.9+/-11.1% and 11.5+/-5.4% in FBM; 57.0+/-16.5% and 24.1+/-7.3% in UCB; 27.2+/-12.8% and 9.0+/-4.9% in MPB, and 9.6+/-7.8% and 4.6+/-3.2% in ABM. Using the combination CD34, CD38, and CDw90(Thy-1), the subset with the highest CEs and highest percentages of colonies with DGP/MGP was found to be CD34+/CD38-/CDw90- in FL and FBM, but colonies with high RP were distributed evenly among CDw90+ and CDw90- subsets derived from FL, FBM, UCB, or MPB. We conclude that the CD34+/CD38-/HLA-DR+ subset contained the highest number of candidate stem cells among the various immunophenotypes, and that FL contained the highest concentration of CD34+ cells (11.4+/-7.5%) and the highest level of CD34+/CD38-/HLA-DR+ subsets (34.7+/-8.2%) among cells from various ontogenic age. Our estimate of candidate stem cells using single cell suspension culture correlated with that obtained by single cell long-term culture-initiating cells. CD34+/CD38-/HLA-DR+ cells from FL appear to represent the best targets for ex vivo stem cell expansion and genetic manipulation.

The impact of formulation and process changes on in vitro dissolution and the bioequivalence of piroxicam capsules

The purpose of this research was to determine the effect of major compositional changes on the bioavailability of piroxicam from immediate-release formulations filled in hard gelatin capsules. The capsules were manufactured according to a 2(5-1) + star point (resolution V) experimental design to investigate the effects of sodium lauryl sulfate level, magnesium stearate level, lactose/microcrystalline cellulose ratio, piroxicam particle size, and lubricant blending time. Sodium lauryl sulfate level, lactose level, and piroxicam particle size were the most important main effects affecting dissolution. Lubricant level and lubricant blending time were either not significant (5% level) or were among the lowest ranking of factors affecting dissolution in standardized pareto analysis. Three of these formulations exhibiting slow, medium, and fast dissolution were compared to a single lot of the Innovator (commercial) product in a small bioavailability study. The slow formulation did not meet the USP dissolution specification for piroxicam capsules. Compositionally, the experimental formulations represented major changes in piroxicam particle size, level of filler, and level of sodium lauryl sulfate. Sixteen healthy volunteers received each formulation (20 mg) in a four-way crossover design. The three Maryland manufactured formulations were bioequivalent with the commercial product and were also bioequivalent among themselves. The major changes incorporated into these formulations did not result in major differences in bioavailability. The dissolution profiles which discriminated between the formulations in vitro did not accurately represent the in vivo bioavailability results. The results of this study are part of the research database that supports SUPAC-IR, an FDA guidance that provides relaxed testing and filing requirements for scale-up and post-approval changes to immediate-release oral solid dosage forms.

Towards automatic cell identification in DIC microscopy

A general method is proposed for constructing templates of cells in differential interference contrast (DIC) microscopy. This takes account of the optics which generate DIC images, and is applicable to both transparent and semi-transparent cells of simple and complex shapes. Then, a template matching methodology is presented, which uses fast Fourier transforms to fit templates of a range of sizes and orientations to images. For illustration, this is used to automatically identify and measure individual Candida yeast cells in clusters.

CCAAT-enhancer binding protein alpha is expressed in activated microglial cells after brain injury

Microglial cells play important roles in brain injury and repair and are implicated in diseases such as Alzheimer's disease, Creutzfeldt-Jacob disease, multiple sclerosis, the Aids Dementia Complex and stroke. Despite their importance in neuropathology, the underlying molecular basis for the activation of microglia after brain injury is not understood. We show, using RT-PCR, in situ hybridisation, immunocytochemistry, and electrophoretic mobility shift assay, that the CCAAT-enhancer binding protein alpha (C/EBP alpha), a sequence specific DNA-binding protein, is induced in microglial cells, but not astrocytes or neurons, after hypoxic-ischemic brain injury. These results suggest that C/EBP alpha might regulate gene expression and consequentially have a role in the activation and/or proliferation of microglia following brain injury.

An MTP inhibitor that normalizes atherogenic lipoprotein levels in WHHL rabbits

Patients with abetalipoproteinemia, a disease caused by defects in the microsomal triglyceride transfer protein (MTP), do not produce apolipoprotein B-containing lipoproteins. It was hypothesized that small molecule inhibitors of MTP would prevent the assembly and secretion of these atherogenic lipoproteins. To test this hypothesis, two compounds identified in a high-throughput screen for MTP inhibitors were used to direct the synthesis of a highly potent MTP inhibitor. This molecule (compound 9) inhibited the production of lipoprotein particles in rodent models and normalized plasma lipoprotein levels in Watanabe-heritable hyperlipidemic (WHHL) rabbits, which are a model for human homozygous familial hypercholesterolemia. These results suggest that compound 9, or derivatives thereof, has potential applications for the therapeutic lowering of atherogenic lipoprotein levels in humans.

Peroral gene therapy of lactose intolerance using an adeno-associated virus vector

Gene therapy is usually reserved for severe and medically refractory disorders because of the toxicity, potential long-term risks and invasiveness of most gene transfer protocols. Here we show that an orally administered adeno-associated viral vector leads to persistent expression of a beta-galactosidase transgene in both gut epithelial and lamina propria cells, and that this approach results in long-term phenotypic recovery in an animal model of lactose intolerance. A gene 'pill' associated with highly efficient and stable gene expression might be a practical and cost-effective strategy for even relatively mild disorders, such as lactase deficiency.

The role of the general practitioner in postnatal care: a survey from Australian general practice

BACKGROUND

Despite the practice of routine postnatal check-ups, many women experience problems in the months after childbirth. General practitioners (GPs) are involved in routine postnatal care, yet little research has been undertaken to explore this role.

AIM

To report the views of Australian GPs as to what physical examination and discussion should take place at the routine six week postnatal check-up and to determine the influence of gender on the approach to the check-up.

METHOD

Postal survey of 1104 Australian GPs, yielding an eligible sample of 1022.

RESULTS

A total of 715/1022 (70%) usable surveys returned. Over 65% of GPs recommend routine examination of the abdomen, blood pressure, perineum, vagina, pelvic floor, and breasts at the six week check-up. Fewer than a half the sample believed that physical problems (urine and bowel symptoms, back problems), sexual issues, relationship and parenting issues should be routinely discussed. After controlling for age, practice location, obstetric practice, and qualifications, the sex of the GP remains an important factor influencing the GP's approach to postnatal care. Female GPs are three times more likely to believe that maternal feelings should be discussed routinely and about twice as likely to believe that infant sleeping/behaviour, maternal sleeping/diet/tiredness, coping with other children, relationship with partner, and household work should form part of the routine discussion with all recent mothers.

CONCLUSIONS

Sex of practitioner and older age (60 years or more) are the two most important influences on a GP's approach to postnatal care. This study indicates a need for GPs to shift their focus from routine examination to indicated examination to allow more time to discuss common postnatal problems.

Does an early postnatal check-up improve maternal health: results from a randomised trial in Australian general practice

OBJECTIVES

To investigate whether a visit to a general practitioner one week after discharge results in less depression, increased breastfeeding rates, improved patient wellbeing, fewer physical problems and greater satisfaction with general practice care than the traditional six week postnatal check-up.

DESIGN

A randomised controlled trial.

SETTING

Rural and metropolitan Victoria, Australia. Population Women giving birth at one rural and one metropolitan hospital between February and December 1995 inclusive.

METHODS

All women received a letter and appointment date to see a general practitioner for a check-up: the intervention group for one week after hospital discharge, the control group for six weeks after birth. A mail-out survey was conducted at three and six months after birth, including Edinburgh Postnatal Depression Scale and Short Form 36.

RESULTS

1017/1407 (72.3%) women giving birth at participating hospitals were eligible for the trial: 683 (67.2%) gave informed consent. The average response rate to postal follow up at three and six months was 67.5%. No significant differences were found between the groups in: Edinburgh Postnatal Depression and Short Form 36 scores; number of problems; breastfeeding rates; or satisfaction with general practitioner care. Women in the intervention group were less likely to attend for their check-up (76.4% vs 88.4%; P = 0.001), more likely to discuss labour and birth at their check-up (OR= 1.77, 95% CI 1.17-2.68), less likely to have a vaginal examination (OR = 0.51; 95%, CI 0.34-0.77) or pap smear (OR = 0.34; 95% CI = 0.22-0.52) at their check; more likely to report difficulties with low milk supply (OR= 1.72; 95% CI = 1.12-2.66) and adjusting to the demands of a new baby (OR = 1.76; 95% CI 1.13 2.74), more likely to talk to a general practitioner about their baby (68.2% vs 58.0%; P=0.02) and less likely to consult a hospital doctor about their baby (7.3% vs 14.0%, P = 0.02).

CONCLUSIONS

To make clinically important improvements in maternal health more is required than early postnatal review.

HLA-Cw*0602 and HIV-associated psoriasis

The aetiopathogenesis of psoriasis is unknown, but genetic and environmental factors may be involved. Psoriasis may not be one disease but a cutaneous inflammatory reaction pattern consequent upon several different independent or related stimuli in susceptible individuals. There are controversial issues regarding the immunological basis of psoriasis and the role of CD4 vs. CD8 T lymphocytes. Psoriasis has been associated with HLA-Cw6 and Cw7 by serology and specifically with HLA-Cw*0602 by polymerase chain reaction (PCR) typing. Psoriasis is probably no more common in HIV infection than in the general population; however, it may appear for the first time or pre-existing psoriasis may worsen and be difficult to treat in HIV disease. We have investigated the prevalence of HLA-C alleles, in the specific clinical context of HIV infection complicated by type 1 psoriasis, in a case control study of 14 men with HIV disease and type 1 psoriasis and 147 HIV-infected patients without psoriasis. Typing was performed using PCR with sequence-specific amplification primers. Eleven of 14 patients (79%) with psoriasis carried the HLA-Cw*0602 allele compared with 24.5% of those without psoriasis (odds ratio = 11.31; 95% confidence limits 2. 73 to 65.36; P = 0.0001). Two patients without the HLA-Cw*0602 allele carried instead the closely related Cw*0401/3 allele. The results confirm the previously reported association between the HLA-Cw*0602 allele and type 1 psoriasis, and suggest that the association with HLA-Cw*0602 is stronger in HIV-associated psoriasis although this trend needs to be supported by a larger sample. The immunodysregulation resulting from HIV infection may trigger psoriasis in those genetically predisposed by the Cw*0602 allele. As CD8 T cells recognize antigens in the context of class I major histocompatibility complex, the identification of an HLA class I association in HIV-associated psoriasis strengthens the argument for an important role for CD8 + T lymphocytes in the immunopathogenesis of psoriasis. Investigations of the pathogenesis of psoriasis should take account of clinical and other subtypes already identified.

GC/MS analysis of PCB congeners in blood of the harbor seal Phoca vitulina from San Francisco Bay

Here we report a validated technique for quantifying up to 20 specific PCB congeners in 1-2 g samples of whole blood with a detection limit below 1 ng/g (ppb) wet weight. Specimens were analyzed from 14 harbor seals sampled in south San Francisco Bay, California during 1991-1992. Ratios of specific congeners to PCB-153, and other aspects of congener pattern, agreed with published values for PCB's detected in seal blood. PCB-153 constituted 30 percent of our sigma PCB values. The mean sigma PCB concentration for the San Francisco Bay seals was 50 ppb, about three times the average level reported for blood of captive seals fed exclusively on fish from the Baltic's PCB-contaminated Dutch Wadden Sea. Such experimental populations have exhibited depressed reproductive success and impaired immune function. These findings support concerns about the ecological effects of PCB contamination in San Francisco Bay.

Do c-Jun, c-Fos, and amyloid precursor protein play a role in neuronal death or survival?

A unilateral hypoxic-ischemic (HI) episode in immature rat brain was used to investigate the role of the immediate early genes c-fos and c-jun in delayed neuronal death and survival. This HI paradigm results in an apoptotic cell death in selectively vulnerable areas, in particular the hippocampal CA1 pyramidal cell layer. In susceptible regions undergoing delayed neuronal death there was a prolonged induction of both c-Jun and c-Fos (mRNA and protein). This expression occurred in parallel with a pronounced increase in AP-1 DNA binding activity but was not associated with either increased levels of Jun NH2-terminal kinase or phosphorylation of c-Jun (ser-63). In addition to changes in immediate early gene expression, the CA1 neurons showed a delayed increase in the expression of amyloid precursor protein (APP751) mRNA, suggesting that APP, which contains an AP-1 site, might be a down-stream gene regulated by the Jun transcription factor in neurons dying by apoptosis. The surviving dentate granule cells also showed an increase in Fos, Jun, and APP751 although this expression occurred earlier than in the CA1 neurons and declined rapidly. These results are discussed with respect to the role of these proteins in neuronal death and survival.

Quantification of microbial productivity via multi-angle light scattering and supervised learning

This article describes the use of chemometric methods for prediction of biological parameters of cell suspensions on the basis of their light scattering profiles. Laser light is directed into a vial or flow cell containing media from the suspension. The intensity of the scattered light is recorded at 18 angles. Supervised learning methods are then used to calibrate a model relating the parameter of interest to the intensity values. Using such models opens up the possibility of estimating the biological properties of fermentor broths extremely rapidly (typically every 4 sec), and, using the flow cell, without user interaction. Our work has demonstrated the usefulness of this approach for estimation of yeast cell counts over a wide range of values (10(5)-10(9) cells mL-1), although it was less successful in predicting cell viability in such suspensions.

Nicotinic receptor desensitization and sensory gating deficits in schizophrenia

BACKGROUND

Nicotinic receptor dysfunction is a possible mechanism of the abnormal sensory gating observed in schizophrenia with the P50 auditory event-related potential. Although nicotinic receptors normally desensitize after activation by acetylcholine or nicotine, pathologically increased desensitization might cause receptor dysfunction in schizophrenia. To examine this possibility, central cholinergic neuronal activity was diminished by allowing schizophrenic patients to sleep briefly, after which they experienced a transient period of normal P50 gating, consistent with receptor resensitization during the absence of cholinergic stimulation. A critical test of the mechanism is whether this resensitization is blocked by concurrent administration of nicotine, which would provide continuous receptor stimulation.

METHODS

Six schizophrenic patients repeated the sleep experiment during nicotine exposure from a dermal patch, in a double-blind, placebo-controlled design.

RESULTS

The normalization of P50 gating immediately postsleep was replicated in the placebo arm, but this effect was decreased in all six patients during exposure to nicotine.

CONCLUSIONS

The results suggest that nicotinic receptor desensitization is responsible for the loss of P50 gating in schizophrenia.