The H3K27M mutation alters stem cell growth, epigenetic regulation, and differentiation potential

BACKGROUND

Neurodevelopmental disorders increase brain tumor risk, suggesting that normal brain development may have protective properties. Mutations in epigenetic regulators are common in pediatric brain tumors, highlighting a potentially central role for disrupted epigenetic regulation of normal brain development in tumorigenesis. For example, lysine 27 to methionine mutation (H3K27M) in the H3F3A gene occurs frequently in Diffuse Intrinsic Pontine Gliomas (DIPGs), the most aggressive pediatric glioma. As H3K27M mutation is necessary but insufficient to cause DIPGs, it is accompanied by additional mutations in tumors. However, how H3K27M alone increases vulnerability to DIPG tumorigenesis remains unclear.

RESULTS

Here, we used human embryonic stem cell models with this mutation, in the absence of other DIPG contributory mutations, to investigate how H3K27M alters cellular proliferation and differentiation. We found that H3K27M increased stem cell proliferation and stem cell properties. It interfered with differentiation, promoting anomalous mesodermal and ectodermal gene expression during both multi-lineage and germ layer-specific cell specification, and blocking normal differentiation into neuroectoderm. H3K27M mutant clones exhibited transcriptomic diversity relative to the more homogeneous wildtype population, suggesting reduced fidelity of gene regulation, with aberrant expression of genes involved in stem cell regulation, differentiation, and tumorigenesis. These phenomena were associated with global loss of H3K27me3 and concordant loss of DNA methylation at specific genes in H3K27M-expressing cells.

CONCLUSIONS

Together, these data suggest that H3K27M mutation disrupts normal differentiation, maintaining a partially differentiated state with elevated clonogenicity during early development. This disrupted response to early developmental cues could promote tissue properties that enable acquisition of additional mutations that cooperate with H3K27M mutation in genesis of DMG/DIPG. Therefore, this work demonstrates for the first time that H3K27M mutation confers vulnerability to gliomagenesis through persistent clonogenicity and aberrant differentiation and defines associated alterations of histone and DNA methylation.

Endogenous metabolic markers for predicting the activity of dihydropyrimidine dehydrogenase

Five‐fluorouracil (5‐FU) is a chemotherapeutic agent that is mainly metabolized by the rate‐limiting enzyme dihydropyrimidine dehydrogenase (DPD). The DPD enzyme activity deficiency involves a wide range of severities. Previous studies have demonstrated the effect of a DPYD single nucleotide polymorphism on 5‐FU efficacy and highlighted the importance of studying such genes for cancer treatment. Common polymorphisms of DPYD in European ancestry populations are less frequently present in Koreans. DPD is also responsible for the conversion of endogenous uracil (U) into dihydrouracil (DHU). We quantified U and DHU in plasma samples of healthy male Korean subjects, and samples were classified into two groups based on DHU/U ratio. The calculated DHU/U ratios ranged from 0.52 to 7.12, and the two groups were classified into the 10th percentile and 90th percentile for untargeted metabolomics analysis using liquid chromatography‐quantitative time‐of‐flight‐mass spectrometry. A total of 4440 compounds were detected and filtered out based on a coefficient of variation below 30%. Our results revealed that six metabolites differed significantly between the high activity group and low activity group (false discovery rate q‐value < 0.05). Uridine was significantly higher in the low DPD activity group and is a precursor of U involved in pyrimidine metabolism; therefore, we speculated that DPD deficiency can influence uridine levels in plasma. Furthermore, the cutoff values for detecting DPD deficient patients from previous studies were unsuitable for Koreans. Our metabolomics approach is the first study that reported the DHU/U ratio distribution in healthy Korean subjects and identified a new biomarker of DPD deficiency.

Enteric virome negatively affects seroconversion following oral rotavirus vaccination in a longitudinally sampled cohort of Ghanaian infants

Rotavirus vaccines (RVVs) have substantially diminished mortality from severe rotavirus (RV) gastroenteritis but are significantly less effective in low- and middle-income countries (LMICs), limiting their life-saving potential. The etiology of RVV’s diminished effectiveness remains incompletely understood, but the enteric microbiota has been implicated in modulating immunity to RVVs. Here, we analyze the enteric microbiota in a longitudinal cohort of 122 Ghanaian infants, evaluated over the course of 3 Rotarix vaccinations between 6 and 15 weeks of age, to assess whether bacterial and viral populations are distinct between non-seroconverted and seroconverted infants. We identify bacterial taxa including Streptococcus and a poorly classified taxon in Enterobacteriaceae as positively correlating with seroconversion. In contrast, both bacteriophage diversity and detection of Enterovirus B and multiple novel cosaviruses are negatively associated with RVV seroconversion. These findings suggest that virome-RVV interference is an underappreciated cause of poor vaccine performance in LMICs.

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Longitudinal analysis of microbiota of Ghanaian infants receiving rotavirus vaccine

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Streptococcus and Enterobacteriaceae taxa positively associate with RVV seroconversion

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Enterovirus B, Cosavirus A, and phage richness negatively associate with RVV serostatus

Changes in the gut microbiome influence the hypoglycemic effect of metformin through the altered metabolism of branched-chain and nonessential amino acids

AIMS

Although metformin has been reported to affect the gut microbiome, the mechanism has not been fully determined. We explained the potential underlying mechanisms of metformin through a multiomics approach.

METHODS

An open-label and single-arm clinical trial involving 20 healthy Korean was conducted. Serum glucose and insulin concentrations were measured, and stool samples were collected to analyze the microbiome. Untargeted metabolomic profiling of plasma, urine, and stool samples was performed by GC-TOF-MS. Network analysis was applied to infer the mechanism of the hypoglycemic effect of metformin.

RESULTS

The relative abundances of Escherichia, Romboutsia, Intestinibacter, and Clostridium were changed by metformin treatment. Additionally, the relative abundances of metabolites, including carbohydrates, amino acids, and fatty acids, were changed. These changes were correlated with energy metabolism, gluconeogenesis, and branched-chain amino acid metabolism, which are major metabolic pathways related to the hypoglycemic effect.

CONCLUSIONS

We observed that specific changes in metabolites may affect hypoglycemic effects through both pathways related to AMPK activation and microbial changes. Energy metabolism was mainly related to hypoglycemic effects. In particular, branched-chain amino acid metabolism and gluconeogenesis were related to microbial metabolites. Our results will help uncover the potential underlying mechanisms of metformin through AMPK and the microbiome.

Assessment of Oral Vancomycin-Induced Alterations in Gut Bacterial Microbiota and Metabolome of Healthy Men

Several classes of antibiotics have reduced the mortality caused by infectious diseases; however, orally administered antibiotics alter the composition of gut microbiota, leading to dysbiosis-related disease. Therefore, in this study, we used 16S rRNA gene sequencing- and metabolomics-based approaches to investigate the effects of oral vancomycin on gut bacterial microbiota and the metabolome in biospecimens collected from healthy men. Samples collected from 11 healthy men were analyzed using 16S rRNA gene sequencing and metabolomics. 16S rRNA gene sequencing was performed to analyze the gut bacterial microbiota, and GC-TOFMS-based untargeted metabolomics was performed to analyze fecal, urine, and plasma metabolomics. Spearman's rank correlation was utilized to explore the associations between gut bacterial microbiota and metabolome. Fecal 16S rRNA gene sequencing analysis showed decreased relative abundance of genera belonging to the phyla Bacteroidetes and Firmicutes, and increased relative abundance of genera of the phyla Proteobacteria and Fusobacteria. Fecal metabolomics analysis showed that levels of uracil, L-aspartic acid, lithocholic acid, and deoxycholic acid were significantly higher at baseline, whereas that of dihydrouracil was significantly higher after vancomycin administration. No significant metabolic markers were selected from urine and plasma metabolomics analysis. This study demonstrates that oral vancomycin administration induces alterations in gut bacterial microbiota and metabolome. Correlation analysis between our two datasets shows that alteration of the gut bacterial microbiota, induced by oral vancomycin, potentially affected the systemic activity of dihydropyrimidine dehydrogenase. This correlation should be further examined in future studies to define the effects of gut bacterial microbiota on drug-metabolizing enzymes, thereby contributing to the development of personalized therapy.

The Complex Interactions Between Rotavirus and the Gut Microbiota

Human rotavirus (HRV) is the leading worldwide cause of acute diarrhea-related death in children under the age of five. RV infects the small intestine, an important site of colonization by the microbiota, and studies over the past decade have begun to reveal a complex set of interactions between RV and the gut microbiota. RV infection can temporarily alter the composition of the gut microbiota and probiotic administration alleviates some symptoms of infection in vivo, suggesting reciprocal effects between the virus and the gut microbiota. While development of effective RV vaccines has offered significant protection against RV-associated mortality, vaccine effectiveness in low-income countries has been limited, potentially due to regional differences in the gut microbiota. In this mini review, we briefly detail research findings to date related to HRV vaccine cohorts, studies of natural infection, explorations of RV-microbiota interactions in gnotobiotic pig models, and highlight various in vivo and in vitro models that could be used in future studies to better define how the microbiota may regulate RV infection and host antiviral immune responses.

Urinary metabolic markers reflect on hepatic, not intestinal, CYP3A activity in healthy subjects

Intestinal cytochrome P450 3A (CYP3A) plays an important role in oral drug metabolism, but only endogenous metabolic markers for measuring hepatic CYP3A activity were identified. Our study evaluated whether hepatic CYP3A markers reflected intestinal CYP3A activity. An open-label, three-period, six-treatment, one-sequence clinical trial was performed in 16 healthy Korean males. In the control phase, all subjects received a single dose of intravenous (IV) and oral midazolam (1 mg and 5 mg, respectively). Clarithromycin (500 mg) was administered twice daily for 4 days to inhibit hepatic and intestinal CYP3A, and 500 mL of grapefruit juice was given to inhibit intestinal CYP3A. Clarithromycin significantly inhibited total CYP3A activity, and the clearance of IV and apparent clearance of oral midazolam decreased by 0.15- and 0.32-fold, respectively. Grapefruit juice only reduced the apparent clearance of oral midazolam by 0.84-fold, which indicates a slight inhibition of intestinal CYP3A activity. Urinary markers, including 6β-OH-cortisol/cortisol and 6β-OH-cortisone/cortisone, were significantly decreased 0.5-fold after clarithromycin administration but not after grapefruit juice. The fold changes in 6β-OH-cortisol/cortisol and 6β-OH-cortisone/cortisone did not correlate to changes in intestinal availability but did correlate to hepatic availability. In conclusion, endogenous metabolic markers are only useful to measure hepatic, but not intestinal, CYP3A activity.

The utility of CYP3A activity endogenous markers for evaluating drug-drug interaction between sildenafil and CYP3A inhibitors in healthy subjects

Cytochrome P450 (CYP) 3A-related drug-drug interaction (DDI) studies are needed during drug development to determine clinical interaction effects. We aimed to evaluate DDI between sildenafil and two CYP3A inhibitors, clarithromycin and itraconazole, regarding the changes in pharmacokinetics and endogenous markers. An open-label, one-sequence, one-period, two-treatment parallel study was conducted in 32 healthy Korean subjects. Each of 16 subjects were randomly assigned to the clarithromycin and itraconazole groups. Both groups received a single dose of sildenafil 25 mg as a control, and either clarithromycin 250 mg or itraconazole 100 mg was administered four times to inhibit CYP3A activity. Pharmacokinetics of sildenafil showed the similar magnitude of inhibitory effects of the two inhibitors on total CYP3A activity; both inhibitors similarly increased systemic exposure of sildenafil by 2-fold. Urinary 6β-OH-cortisone/cortisone and plasma 4β-OH-cholesterol were significantly decreased after clarithromycin administration but not after itraconazole. A significant correlation between sildenafil CL/F and metabolic markers of CYP3A activity was observed after clarithromycin administration. We confirmed that sildenafil has moderate pharmacokinetic interaction with clarithromycin and itraconazole. Endogenous markers well reflected the CYP3A inhibition of clarithromycin, suggesting possible utility in DDI study with moderate to strong CYP3A inhibition; however, there are limitations in predicting intestinal CYP3A mediated DDI.

Impact of Vancomycin-Induced Changes in the Intestinal Microbiota on the Pharmacokinetics of Simvastatin

The pharmacokinetic (PK) properties of drugs are affected in several ways by interactions with microbiota. The aim of this study was to investigate the effects of oral vancomycin on the gut microbiota and, consequently, on the PKs of simvastatin. An open-label, single arm, sequential crossover study was conducted in six healthy Korean male subjects. After 6 days on a control diet, simvastatin 40 mg was orally administered to the subjects before and after 1 week of oral vancomycin treatment. Blood samples for PK analysis and fecal samples for metagenomic and metabolomic analyses were collected. After vancomycin treatment, the richness of microbiota considerably decreased, and the composition was altered. In particular, the relative abundance of Bacteroidetes decreased, whereas that of proteobacteria increased. In addition, changes in fecal metabolites, including D-glucuronic acid, were observed. However, systemic exposure of simvastatin was not changed whereas that of hydroxysimvastatin showed a tendency to increase. The relationship between the change of PKs of simvastatin and the change of gut microbiota and fecal metabolites were not clearly observed.

Quantitative prediction of hepatic CYP3A activity using endogenous markers in healthy subjects after administration of CYP3A inhibitors or inducers

Accurate prediction of cytochrome P450 (CYP) 3A activity in the early stage of drug development and in clinical practice is important. This study aimed to evaluate the previously constructed CYP3A activity prediction model after administration of CYP3A inhibitors and inducers and to modify the model for better prediction of CYP3A activity. Healthy male subjects received the following study drugs during three study periods: midazolam alone (control phase); midazolam with 200 mg of itraconazole (CYP3A inhibition phase); and midazolam with 150 mg of rifampicin (CYP3A induction phase). We quantified the concentrations of several endogenous CYP3A markers in both urine and plasma using gas chromatography-mass spectrometry. The urinary markers, including 6β-hydroxy (OH)-cortisol/cortisol, 6β-OH-cortisone/cortisone, 16α-OH-dehydroepiandrosterone (DHEA)/DHEA, 16α-OH-androstenedione (A-dione)/A-dione and 7β-OH-DHEA/DHEA, were significantly correlated with midazolam clearance in both the CYP3A inhibition and induction phases. We constructed a statistical prediction model after integrating data from a previous study to predict midazolam clearance as follows: Ln(midazolam clearance) = 2.5545 + 0.3988 × ln(7β-OH-DHEA/DHEA) + 0.1984 × ln(16α-OH-DHEA/DHEA) + 0.5031 × ln(6β-OH-cortisol/cortisol) - 0.1261 [ln(7β-OH-DHEA/DHEA) × ln(6β-OH-cortisol/cortisol)] (r² = 0.75). We suggest that quantitating endogenous markers in vivo coupled with the statistical prediction model may be useful for predicting CYP3A parameters.

Comparison of the Plasma Metabolome Profiles Between the Internal Thoracic Artery and Ascending Aorta in Patients Undergoing Coronary Artery Bypass Graft Surgery Using Gas Chromatography Time-of-Flight Mass Spectrometry

BACKGROUND

The left internal thoracic artery (LITA) has been used as the first conduit of choice in coronary artery bypass grafting (CABG) because of excellent long-term patency and outcomes. However, no studies have examined substances other than nitric oxide that could be beneficial for the bypass conduit, native coronary artery or ischemic myocardium. This study was conducted to evaluate differences in metabolic profiles between the LITA and ascending aorta using gas chromatography-time of flight-mass spectrometry (GC-TOF-MS).

METHODS

Twenty patients who underwent CABG using the LITA were prospectively enrolled. Plasma samples were collected simultaneously from the LITA and ascending aorta. GC-TOF-MS based untargeted metabolomic analyses were performed and a 2-step volcano plot analysis was used to identify distinguishable markers from two plasma metabolome profiles. Semi-quantitative and quantitative analyses were performed using GC-TOF-MS and enzyme-linked immunosorbent assay, respectively, after selecting target metabolites based on the metabolite set enrichment analysis.

RESULTS

Initial volcano plot analysis demonstrated 5 possible markers among 851 peaks detected. The final analysis demonstrated that the L-cysteine peak was significantly higher in the LITA than in the ascending aorta (fold change = 1.86). The concentrations of intermediate metabolites such as L-cysteine, L-methionine and L-cystine in the 'cysteine and methionine metabolism pathway' were significantly higher in the LITA than in the ascending aorta (2.0-, 1.4- and 1.2-fold, respectively). Quantitative analysis showed that the concentration of hydrogen sulfide (H₂S) was significantly higher in the LITA.

CONCLUSION

The plasma metabolome profiles of the LITA and ascending aorta were different, particularly higher plasma concentrations of L-cysteine and H₂S in the LITA.

Assessment of Hepatic Cytochrome P450 3A Activity Using Metabolic Markers in Patients with Renal Impairment

BACKGROUND

The renal function of individuals is one of the reasons for the variations in therapeutic response to various drugs. Patients with renal impairment are often exposed to drug toxicity, even with drugs that are usually eliminated by hepatic metabolism. Previous study has reported an increased plasma concentration of indoxyl sulfate and decreased plasma concentration of 4β-hydroxy (OH)-cholesterol in stable kidney transplant recipients, implicating indoxyl sulfate as a cytochrome P450 (CYP) inhibiting factor. In this study, we aimed to evaluate the impact of renal impairment severity-dependent accumulation of indoxyl sulfate on hepatic CYP3A activity using metabolic markers.

METHODS

Sixty-six subjects were enrolled in this study; based on estimated glomerular filtration rate (eGFR), they were classified as having mild, moderate, or severe renal impairment. The plasma concentration of indoxyl sulfate was quantified using liquid chromatography-mass spectrometry (LC-MS). Urinary and plasma markers (6β-OH-cortisol/cortisol, 6β-OH-cortisone/cortisone, 4β-OH-cholesterol) for hepatic CYP3A activity were quantified using gas chromatography-mass spectrometry (GC-MS). The total plasma concentration of cholesterol was measured using the enzymatic colorimetric assay to calculate the 4β-OH-cholesterol/cholesterol ratio. The correlation between variables was assessed using Pearson's correlation test.

RESULTS

There was a significant negative correlation between MDRD eGFR and indoxyl sulfate levels. The levels of urinary 6β-OH-cortisol/cortisol and 6β-OH-cortisone/cortisone as well as plasma 4β-OH-cholesterol and 4β-OH-cholesterol/cholesterol were not correlated with MDRD eGFR and the plasma concentration of indoxyl sulfate.

CONCLUSION

Hepatic CYP3A activity may not be affected by renal impairment-induced accumulation of plasma indoxyl sulfate.

Assessment of induced CYP3A activity in pregnant women using 4β-hydroxycholesterol: Cholesterol ratio as an appropriate metabolic marker

AIMS

This study was aimed at evaluating changes in CYP3A activity following and during pregnancy by analyzing metabolic markers for CYP3A activity, which can help avoid unnecessary drug exposure and invasive sampling.

METHODS

Forty-eight pregnant women and 25 non-pregnant women were enrolled in this study. Plasma and urine samples were collected from the pregnant women during each trimester and from the non-pregnant women for evaluation of metabolic markers for CYP3A activity. Metabolic markers for CYP3A activity were measured using GC-MS.

RESULTS

An increased 4β-hydroxycholesterol/cholesterol ratio, consistent with high CYP3A activity, was observed in pregnant women compared with that in non-pregnant women; however, no differences were observed among trimesters. No significant differences were observed in urinary markers.

CONCLUSIONS

We observed an increase in the activity of CYP3A following but not during pregnancy when measured using the 4β-hydroxycholesterol/cholesterol ratio. In addition, based on our results, we suggest that the plasma 4β-hydroxycholesterol/cholesterol ratio be used to measure CYP3A activity in pregnant women.

Distribution of Exogenous and Endogenous CYP3A Markers and Related Factors in Healthy Males and Females

Cytochrome P450 (CYP) 3A is an important drug-metabolizing enzyme in humans. Assessing CYP3A activity is necessary for predicting therapeutic outcomes or the potential adverse events of various therapeutics. This study sought to evaluate the distribution of endogenous and exogenous markers reflecting hepatic CYP3A activity and related factors affecting its activity in healthy male and female. Each subject was given a single 1 mg dose of midazolam intravenously. Pharmacokinetics, pharmacometabolomics, and pharmacogenomics analyses were performed to evaluate CYP3A activity. Urinary and plasma steroids were quantified with gas chromatography coupled with triple-quadrupole mass spectrometry (GC-MS), and the concentrations of midazolam and its metabolites were quantified with liquid chromatography coupled with electrospray tandem mass spectrometry (LC-MS/MS). A total of 100 subjects completed this study. Midazolam clearance (MDZ CL) and the metabolic ratio (MDZ MR) were significantly correlated with 6β-OH-cortisol/cortisol and 6β-OH-cortisone/cortisone. MDZ CL, 6β-OH-cortisol/cortisol, and 6β-OH-cortisone/cortisone decreased with increasing age (Pearson r = -0.333, -0.329, and -0.528, respectively; P < 0.05). When the markers were compared according to sex, MDZ CL and 6β-OH-cortisol/cortisol showed significant difference between sexes. However, MDZ CL was higher in female group than male group and 6β-OH-cortisol/cortisol was higher in male group than female group. No significant differences in markers were found when comparing progesterone levels. Our results indicate that both exogenous and endogenous markers showed decreased CYP3A activity with increasing age, which suggested that age could be a factor that significantly influences CYP3A activity.

Effects of renal impairment on the pharmacokinetics and pharmacodynamics of a novel dipeptidyl peptidase-4 inhibitor, evogliptin (DA-1229)

Evogliptin is a novel potent and selective dipeptidyl peptidase-4 (DPP-4) inhibitor. The aim of the present study was to evaluate the pharmacokinetic (PK) and pharmacodynamic (PD) characteristics of evogliptin in participants with renal impairment (RI). An open-label, parallel-group clinical study was conducted in participants with mild, moderate and severe RI and in matched participants with normal renal function (NRF). A single oral 5-mg dose of evogliptin was administered and serial blood and urine samples were obtained to assess the PK and PD characteristics of evogliptin. Baseline urine samples were collected to evaluate endogenous CYP3A metabolic markers. The plasma exposure to evogliptin and degree of DPP-4 activity inhibition increased with decreasing renal function. The mean areas under the concentration-time curves from 0 to 120 hours were increased 1.2-, 1.8- and 1.98-fold in the mild, moderate and severe RI groups, respectively, compared with the NRF group. The levels of CYP3A metabolic markers were lower in the RI group than in the NRF group. The increase in the plasma concentration of evogliptin is unlikely to result in changes in its efficacy or safety, considering the results of previous clinical studies.

Inhibition of the multidrug and toxin extrusion (MATE) transporter by pyrimethamine increases the plasma concentration of metformin but does not increase antihyperglycaemic activity in humans

We hypothesized that the pharmacodynamic (PD) characteristics of metformin would change with inhibition of the multidrug and toxin extrusion (MATE) transporter, which mediates renal elimination of metformin. Twenty healthy male subjects received two doses (750/500 mg) of metformin, with and without 50 mg of pyrimethamine (a potent MATE inhibitor), with 1 week of washout in between each dose. The PD characteristics of metformin were assessed using oral glucose tolerance tests (OGTTs) before and after the metformin dose. Metformin concentrations in plasma and urine were determined using liquid chromatography-electrospray ionization-tandem mass spectrometry. When metformin was co-administered with pyrimethamine, its area under the concentration-time curve from 0 to 12 h was 2.58-fold greater (p < 0.05), whereas the antihyperglycaemic effects of metformin were decreased. The mean differences (90% confidence interval) in mean and maximum serum glucose concentrations and in 2-h-post-OGTT serum glucose concentration were -0.6 (-1, -0.2), -0.9 (-1.6, -0.3) and -0.5 (-1.1, 0.1) mmol/l, respectively. These findings indicate that the response to metformin is not only related to the plasma exposure of metformin but is also related to other factors, such as inhibition of uptake transporters and the gastrointestinal-based pharmacology of metformin.

Cyclic dipeptides from lactic acid bacteria inhibit proliferation of the influenza A virus

We isolated Lactobacillus plantarum LBP-K10 from the traditional Korean fermented food kimchi. When organic acids were removed, the culture filtrate of this isolate showed high antiviral activity (measured using a plaque-forming assay) against the influenza A (H3N2) virus. Two fractions that were active against influenza A virus were purified from the culture filtrate using a C18 column with high-performance liquid chromatography. These active fractions were crystallized and identified to be the cyclic dipeptides cis-cyclo (L-Leu-L-Pro) and cis-cyclo(L-Phe-L-Pro) using gas chromatography-mass spectrometry; this identification was confirmed by X-ray crystallography. These cyclic dipeptides were identified in the culture filtrate of other lactic acid bacteria, including Lactobacillus spp., Leuconostoc spp., Weissella spp., and Lactococcus lactis.

Eye-head coordination in the guinea pig I. Responses to passive whole-body rotations

Vestibular reflexes act to stabilize the head and eyes in space during locomotion. Head stability is essential for postural control, whereas retinal image stability enhances visual acuity and may be essential for an animal to distinguish self-motion from that of an object in the environment. Guinea pig eye and head movements were measured during passive whole-body rotation in order to assess the efficacy of vestibular reflexes. The vestibulo-ocular reflex (VOR) produced compensatory eye movements with a latency of approximately 7 ms that compensated for 46% of head movement in the dark and only slightly more in the light (54%). Head movements, in response to abrupt body rotations, also contributed to retinal stability (21% in the dark; 25% in the light) but exhibited significant variability. Although compensatory eye velocity produced by the VOR was well correlated with head-in-space velocity, compensatory head-on-body speed and direction were variable and poorly correlated with body speed. The compensatory head movements appeared to be determined by passive biomechanical (e.g., inertial effects, initial tonus) and active mechanisms (the vestibulo-collic reflex or VCR). Chemically induced, bilateral lesions of the peripheral vestibular system abolished both compensatory head and eye movement responses.

A novel diketopiperazine improves functional recovery given after the onset of 6-OHDA-induced motor deficit in rats

BACKGROUND AND PURPOSE

Cyclo-L-glycyl-L-2-allylproline (NNZ-2591), a modified diketopiperazine, is neuroprotective and improves long-term function after hypoxic-ischaemic brain injury in rats. The present studies were designed to examine both the neuroprotective and neurotrophic actions of NNZ-2591 on neurochemical and behavioural changes in a rat model of Parkinson's disease.

EXPERIMENTAL APPROACH

To examine its protective effect, either NNZ-2591 (20 ng.day(-1)) or saline was given intracerebroventricularly for 3 days starting 2 h after 6-hydroxydopamine (6-OHDA) induced unilateral striatal lesion. In a subsequent experiment either NNZ-2591 (0.2, 1 and 5 mg.day(-1), s.c.) or saline was administered daily for 14 days starting 2 weeks after the lesion. Behavioural and neurochemical outcomes were examined using the adjusting step test and immunohistochemical staining.

KEY RESULTS

Cyclo-L-glycyl-L-2-allylproline given 2 h after the lesion reduced the degree of motor deficit compared with the saline-treated group. Delayed treatment with NNZ-2591, initiated after the onset of motor deficit, significantly improved motor function from week 7 onwards compared with the saline-treated group. Neither treatment regime altered nigrostriatal dopamine depletion. NNZ-2591 significantly enhanced the expression of doublecortin-positive neuroblasts in the sub-ventricular zone.

CONCLUSIONS AND IMPLICATIONS

These studies reveal that early treatment with NNZ-2591 protects against the motor deficit induced by 6-OHDA and that treatment initiated after the establishment of motor impairment significantly improves long-term motor function. These effects of NNZ-2591 on functional recovery were independent of dopamine depletion and also appeared not to be symptomatic as the improved motor function was long-lasting. NNZ-2591 has potential as a therapeutic agent for neurodegenerative disorders.

Screening for major depressive disorders in adolescent psychiatric inpatients with the mood modules from the Primary Care Evaluation of Mental Disorders and the Patient Health Questionnaire

The mood modules from the Primary Care Evaluation of Mental Disorders (PRIME-MD) and the Patient Health Questionnaire (PHQ) were administered to 17 (52%) female and 16 (48%) male adolescent (13-17 years old) psychiatric inpatients. The internal consistencies of both were good (KR-20 for PRIME-MD=.80, Cronbach coefficient alpha for Patient Health Questionnaire=.85). The correlation between the PRIME-MD and Patient Health Questionnaire total scores was .87 (p<.001), and the point-biserial correlation of both questionnaires' total scores with being diagnosed with a Major Depressive Disorder was .54 (p<.001). Both mood modules appeared to be equally effective in screening for a Major Depressive Disorder.

Induction of hepatic 8-oxo-deoxyguanosine adducts by 2,3,7,8-tetrachlorodibenzo-p-dioxin in Sprague-Dawley rats is female-specific and estrogen-dependent

2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) is a hepatocarcinogen that induces sex-specific hepatic neoplastic alterations in female, but not male, rats. It has been hypothesized that TCDD-induced alterations in estrogen metabolism lead to increased generation of reactive oxygen species. The resulting oxidative damage to DNA may contribute to TCDD-induced tumor promotion and hepatocarcinogenesis. This hypothesis is supported by previous observations of increased 8-oxo-deoxyguanosine (8-oxo-dG) adduct formation in the livers of intact, but not ovariectomized (OVX), rats following chronic exposure to TCDD. The aim of the current study was to more clearly define the roles of hormonal regulation, gender, dose-response, and exposure duration in TCDD induction of 8-oxo-dG adducts. Diethylnitrosamine (DEN)-initiated male and female (both intact and OVX) rats were exposed to TCDD in the presence or absence of 17 beta-estradiol. Following 30 weeks of exposure, hepatic 8-oxo-dG adduct levels were significantly higher in TCDD-treated intact female rats, and TCDD-treated OVX female rats receiving supplemental 17 beta-estradiol, when compared to respective corn oil vehicle controls. In DEN-initiated female rats exposed to a range of TCDD concentrations for 30 weeks, TCDD induced 8-oxo-dG adduct levels in a dose-dependent manner. However, 8-oxo-dG adduct levels were not altered in TCDD-treated male or OVX female rats following 30 weeks of exposure. In noninitiated female rats, the level of 8-oxo-dG adducts 4 days following a single dose of TCDD was not significantly different than in control rats. Additionally, 8-oxo-dG adduct formation was not affected by exposure to TCDD for 20 weeks in intact female rats. These data suggest that the induction of 8-oxo-dG adduct levels by TCDD is likely a response to chronic oxidative imbalance. These studies provide strong evidence that the induction of 8-oxo-dG by TCDD occurs via a chronic, sex-specific, estrogen-dependent mechanism.

The uniqueness of being a neurotrophin receptor

Neurotrophins rely on Trk tyrosine kinase and p75 receptors for signal transduction. Recently, other roles for these receptors have been identified. Many questions have been raised about the mechanism by which these receptors mediate diverse cellular functions. Studies indicate a great deal of neurotrophin signaling specificity may stem from ligand-receptor selectivity and intracellular protein recruitment.

Physiological modeling of a proposed mechanism of enzyme induction by TCDD

A physiological model was previously constructed to facilitate extrapolation of surrogates for the effects of 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) in rat liver to doses comparable to human environmental exposures. The model included induction of P450 isozymes and suggested the presence of multiple binding sites with different affinities for the TCDD-liganded Ah receptor at CYP1A1 dioxin responsive elements. The model also indicated that protein synthesis on the mRNA template exhibited saturation kinetics with respect to message levels. In the present work the earlier model was revised to include the increased proteolysis of the Ah receptor on binding TCDD, more realistic representations of gene transcription and mRNA translation, and different stability for each mRNA. The revised model includes multiple TCDD-liganded Ah receptor binding sites for CYP1A1 and CYP1B1 genes, a lag of 0.2 day for production of mRNA and induced proteins, and stabilization of mRNA by a poly(A) tail. The model reproduced the transient depletion of the Ah receptor subsequent to binding ligand and the dose-response of the receptor in rats treated with biweekly oral doses of TCDD in corn oil. The model reproduced tissue TCDD concentrations observed for several dosing scenarios. Such robustness indicates the utility of the model in estimating internal dose. The model also reproduced the observed dose-response patterns for mRNA and protein for CYP1A1, CYP1A2, and CYP1B1 after repeated dosing. Neither of the two dissociation constants for the Ah receptor bound to the CYP1B1 gene is negligible, supporting the assumption of multiple response elements for this gene. The poorer induction of CYP1B1 was predicted to be due to lower affinity of the dioxin responsive elements for binding the liganded Ah receptor, suggesting the involvement of other regulatory factors, and a shorter poly(A) tail on CYP1B1 mRNA, leading to a shorter lifetime. Saturation in the kinetics of protein synthesis was linked to the limited number of ribosomes that could bind to each message molecule, resulting in fewer ribosomes bound per message at higher doses. Predicted induction at low doses was found to vary widely with the assumptions used in the construction of a model. More detailed descriptions of biological processes might provide more reliable predictions of enzyme induction.

Characterization of the mu rhythm during rapid eye movement sleep

OBJECTIVE

The rolandic mu rhythm, a resting activity of somatosensory cortex, is a striking feature of the waking human electroencephalogram. This study will demonstrate that activity with identical features occurs during rapid eye movement (REM) sleep.

METHODS

Eye and chin leads were added during prolonged closed circuit television (video) electroencephalographic (EEG) recording with scalp (12 patients) or subdural electrodes including 64 contract grids over the frontoparietal cortices (5 patients). Sleep staging was performed by reformatting into standard polysomnography montages (using two EEG channels, and eye and chin channels) and applying standard scoring criteria. The recordings were then reviewed using all EEG channels to assess rhythmic EEG activity by a reader blinded to the sleep staging.

RESULTS

During scalp recordings, 7-10 Hz central rhythms were seen during wakefulness in 7 patients, with 6 of these also having similar rhythms during REM sleep. Similar activity was seen over somatosensory cortex during wakefulness and REM in all invasively recorded patients. This activity was blocked by contralateral body movement or contralateral somatosensory stimuli, even during REM sleep. It was absent in other sleep stages.

CONCLUSIONS

This REM sleep activity recapitulates all the characteristics of the waking rolandic mu rhythm. This demonstrates functional similarity between the states of wakefulness and REM sleep.

Akt phosphorylates and negatively regulates apoptosis signal-regulating kinase 1

The Akt family of serine/threonine-directed kinases promotes cellular survival in part by phosphorylating and inhibiting death-inducing proteins. Here we describe a novel functional interaction between Akt and apoptosis signal-regulating kinase 1 (ASK1), a mitogen-activated protein kinase kinase kinase. Akt decreased ASK1 kinase activity stimulated by both oxidative stress and overexpression in 293 cells by phosphorylating a consensus Akt site at serine 83 of ASK1. Activation of the phosphoinositide 3-kinase (PI3-K)/Akt pathway also inhibited the serum deprivation-induced activity of endogenous ASK1 in L929 cells. An association between Akt and ASK1 was detected in cells by coimmunoprecipitation. Phosphorylation by Akt inhibited ASK1-mediated c-Jun N-terminal kinase and activating transcription factor 2 activities in intact cells. Finally, activation of the PI3-K/Akt pathway reduced apoptosis induced by ASK1 in a manner dependent on phosphorylation of serine 83 of ASK1. These results provide the first direct link between Akt and the family of stress-activated kinases.

L-type Ca(2+) channel-mediated Zn(2+) toxicity and modulation by ZnT-1 in PC12 cells

In view of evidence that Zn(2+) neurotoxicity contributes to some forms of pathological neuronal death, we developed a model of Zn(2+) neurotoxicity in a cell line amenable to genetic manipulations. Exposure to 500 microM ZnCl(2) for 15 min under depolarizing conditions resulted in modest levels of PC12 cell death, that was reduced by the L-type Ca(2+) channel antagonist, nimodipine, and increased by the L-type Ca(2+) channel opener, S(-)-Bay K 8644. At lower insult levels (200 micrometer Zn(2+)+Bay K 8644), Zn(2+)-induced death appeared apoptotic under electron microscopy and was sensitive to the caspase inhibitor benzyloxycarbonyl-Val-Ala-Asp-CH(2)F (Z-VAD); at higher insult levels (1000 microM+Bay K 8644), cells underwent necrosis insensitive to Z-VAD. To test the hypothesis that the plasma membrane transporter, ZnT-1, modulates Zn(2+) neurotoxicity, we generated stable PC12 cell lines overexpressing wild type or dominant negative forms of rat ZnT-1 (rZnT-1). Clones T9 and T23 overexpressing wild type rZnT-1 exhibited enhanced Zn(2+) efflux and reduced vulnerability to Zn(2+)-induced death compared to the parental line, whereas clones D5 and D16 expressing dominant negative rZnT-1 exhibited the opposite characteristics.

A comparison of the cytoplasmic domains of the Fas receptor and the p75 neurotrophin receptor

The p75 neurotrophic receptor (p75) shares structural features with the Fas receptor (FasR). Both receptors contain extracellular cysteine-rich repeats, a single transmembrane domain, and intracellular death domains. However, it has not been clearly established whether their death domains are equivalent in their ability to mediate apoptosis. To understand better the role of p75 during apoptosis, we constructed chimeric receptors that contained the extracellular portion of the FasR and the intracellular portion of p75. These chimeric receptors, one containing the p75 transmembrane domain and the other containing the FasR transmembrane portion, as well as wild-type p75 and Fas receptors, were transiently transfected into human U373 glioma cells and human embryonic kidney 293 cells (293 cells), which are both responsive to Fas-mediated apoptosis. Whereas expression of FasR was sufficient to induce apoptosis in U373 and 293 cells, expression of p75 and the chimeric receptors induced only minimal levels of cell death compared to FasR. The results indicate that the magnitudes of FasR- and p75-induced killing are different and suggest that the death domain of p75 does not function in the same manner as the FasR death domain.

Sonohysterographic screening before in vitro fertilization

OBJECTIVE

To evaluate the use of sonohysterography for uterine screening before IVF.

DESIGN

Prospective screening with sonohysterography and comparison with available hysterosalpingographic and hysteroscopic evaluations.

SETTING

Private practice.

PATIENT(S)

Seventy-two women undergoing IVF-ET using their own or donor eggs.

INTERVENTION(S)

Sonohysterography was performed by instilling saline into the uterine cavity through an intracervical balloon catheter; there was concurrent vaginal sonographic visualization in all cases.

MAIN OUTCOME MEASURE(S)

Sonohysterographic findings and pregnancy rates.

RESULT(S)

Cavitary lesions were detected in 8 (11.1%) of 72 sonohysterographic examinations. Six of 8 cases were confirmed and treated by hysteroscopy. After sonohysterographic evaluation, 35 (48.6%) of 72 patients conceived, resulting in 25 ongoing or delivered pregnancies, 5 chemical pregnancies, and 5 spontaneous abortions. No statistically significant difference was observed in the pregnancy outcome for patients undergoing IVF who had sonohysterography compared with that for patients undergoing IVF during the same period who previously had a uterine evaluation by a different method. The estimated cost savings per patient undergoing sonohysterography instead of in-office hysteroscopy was $275.

CONCLUSION(S)

Sonohysterography offers advantages over in-office hysteroscopy and hysterosalpingography for evaluation of the uterus before IVF.

Sonohysterography for screening in recurrent pregnancy loss

OBJECTIVE

To evaluate the role of sonohysterography for screening of the uterine cavity in patients with recurrent pregnancy loss.

DESIGN

Prospective evaluation of sonohysterography, including comparison with available hysterosalpingography and hysteroscopy.

SETTING

University referral center.

PATIENT(S)

Thirty-four reproductive-aged women with at least two consecutive pregnancy losses.

INTERVENTION(S)

Sonohysterography was performed on all patients, using saline instilled through an endocervically placed balloon catheter with concurrent vaginal sonography.

RESULT(S)

Seventeen of 34 sonohysterograms (50.0%) demonstrated intrauterine abnormalities. Eighteen of 34 cases have undergone hysteroscopy or, in 1 case, laparoscopy. All confirmed the positive or negative sonohysterographic finding, resulting in a sensitivity and specificity of 100%. Additionally, 100% (12/12) of the defects were diagnosed accurately at sonohysterography when confirmed by surgery. Twenty-seven of 34 patients also had a hysterosalpingogram that demonstrated a 90.0% sensitivity and 20.0% specificity based on hysteroscopic findings, yet only 5 of 11 (45.5%) defects were diagnosed accurately at hysterosalpingography when compared with surgery.

CONCLUSION(S)

Sonohysterography is a highly sensitive, specific, and accurate screening tool for the evaluation of uterine cavitary defects associated with recurrent pregnancy loss and offers several advantages over hysterosalpingography.

Surgical management of endometriosis in relation to infertility and assisted reproductive technologies

Endometriosis is one of the most enigmatic and common diseases encountered by the gynecologist in the reproductive-age female. An estimated 10% of reproductive-age women and 25-35% of infertile women have this progressive disease which may result in significant morbidity.

Polymerase chain reaction-based diagnosis of del (5q) in acute myeloid leukemia and myelodysplastic syndrome identifies a minimal deletion interval

Loss of all or part of the long arm of human chromosome 5 is a recurrent abnormality in patients with acute myeloid leukemia (AML) and myelodysplastic syndrome (MDS), especially after chemotherapy for a prior malignancy. It is one of the worst prognostic indicators in AML, associated with chemotherapy resistance and short survival. These deletions center at band 5q31, which has thus been proposed as the location of a tumor suppressor gene; this site is to be distinguished from that observed in 5q- syndrome, centering at 5q32. To define the molecular extent and the clinical prevalence of 5q31 deletions, we collected a series of AML and MDS cases of mixed karyotype, taking care to exclude MDS cases with 5q- syndrome. The samples were analyzed for loss of heterozygosity (LOH) using a panel polymerase chain reaction (PCR)-based microsatellite markers from 5q, comparing malignant cells with normal tissue derived from lymphoblastoid cell lines or buccal mucosa scrapings. Losses were detected in seven of 29 matched samples, including four of 17 with MDS, and three of 12 with AML; six of these seven also had a cytogenetically-visible del(5q) or -5. The one case without a cytogenetic deletion showed molecular loss of three contiguous markers, with retention of flanking markers interleukin-9 (IL-9) and D5S414, and thus contained a small deletion that is below cytogenetic resolution. PCR failed to detect 5q loss in two cases with large cytogenetic deletions, but both had been treated and contained low percentages of malignant cells in the samples. This study thus led to the identification of a case with a minimal deletion for the 5q31 tumor suppressor gene, specified by IL-9-D5S414, that is approximately 1 Mb (2 cM) in extent. Additionally, we demonstrate that PCR-based allelotyping is a reliable method for the detection of chromosomal deletion in myeloid malignancy, providing the specimens contain a high proportion of malignant cells. These studies will help to identify the tumor-suppressor gene at 5q31, and will help to develop molecular methods for diagnosis and monitoring of these disorders.

Cytokine induction of heat shock protein in human granulosa-luteal cells

The infiltration of leukocytes is a characteristic feature of luteolysis in humans. Leukocytes are known to generate physiological inducers of cell stress such as cytokines which have been implicated as mediators of functional luteal regression. In cells exposed to stress, a response characterized by an increase in heat shock protein (HSP) synthesis occurs. Recently, the induction of HSP-70 in rat luteal cells has been shown to inhibit luteinizing hormone (LH) and cAMP-sensitive progesterone production, possibly by interfering with the translocation of cholesterol to the mitochondrial cytochrome P450scc. We therefore investigated whether HSP-70 is induced in human granulosa-luteal cells and its relationship to steroidogenesis. [35S]Methionine labelling showed an increase in a 70 kDa protein after heat treatment which was demonstrated to be HSP-70 by Western analysis using monoclonal antibodies against the constitutive and inducible forms of HSP-70. Induction of HSP-70 in human granulosa-luteal cells was also seen with interferon (IFN) gamma (10 ng/ml), tumour necrosis factor (TNF)-alpha (100 ng/ml) and a combination of IFN gamma/TNF-alpha (10/50 ng/ml). Interleukin-1 beta (IL-1 beta) (30 ng/ml) showed minimal induction of HSP-70 above control values. An increase in activated heat shock factor, which binds to the heat shock transcriptional control element, was detected after heat shock, IFN/TNF, and IFN treatment. Coincident with the induction of HSP-70 by heat shock was the inhibition of progesterone production compared with non-shocked granulosa-luteal cells. Heat shock inhibition of progesterone synthesis was partially reversed by the cell- and mitochondria-permeant cholesterol analogue, 22R-hydroxycholesterol. Cell viability was unaffected by heat treatment. White blood cell-depleted granulosa-luteal cell cultures treated with IFN demonstrated a significant reduction in progesterone production. Treatment with IFN/TNF, TNF, and IL-1 also decreased progesterone secretion, although statistical significance was not achieved. These findings provide evidence that a stress response occurs in human granulosa-luteal cells in response to heat and cytokines. The inhibition of gonadotrophin-sensitive steroidogenesis coincident with the induction of HSP-70 synthesis by physiological agents which are present in the corpus luteum implicates HSP-70 as a potential mediator of luteolysis in the human.

Reproductive outcome after tubal reversal in women 40 years of age or older

OBJECTIVE

To determine the reproductive outcome of women who received a microsurgical tubal anastomosis operation at age 40 years or older.

DESIGN

Multicenter retrospective cohort study.

SETTING

Four university teaching hospitals.

PATIENTS

Fifty-two women having undergone tubal sterilization reversal at age > or = 40 years.

MAIN OUTCOME MEASURES

Pregnancy and live birth rate.

RESULTS

Of the 52 women, 10 were lost to follow-up. Of those traced, 18 of 42 (42.8 percent) conceived. Of those 18, 6 patients had a live birth, 10 patients had a first trimester spontaneous abortion, 1 patient had an ectopic pregnancy, and 1 patient had an elective termination. Overall, the live birth rate was 14.3 percent, spontaneous abortion rate was 23.8 percent, and ectopic pregnancy rate was 2.4 percent.

CONCLUSIONS

Microsurgical tubal anastomosis is a justifiable alternative to IVF-ET in women age 40 years or older.

Large bowel-to-pelvic sidewall adhesions associated with chronic pelvic pain

STUDY OBJECTIVES

To assess retrospectively the prevalence of colon-to-pelvic sidewall adhesions associated with pelvic pain or pelvic endometriosis, and to evaluate prospectively their prevalence compared with controls.

DESIGN

A retrospective review of all patients undergoing laparoscopy for chronic pelvic pain between August 1992 and September 1993; and abased on a power analysis, a prospective comparison of women undergoing laparoscopy for chronic pelvic pain with those undergoing laparoscopy for tubal sterilization between October 1994 and December 1995.

SETTING

A university-associated teaching hospital.

PATIENTS

Fifty women in the retrospective portion, and 30 women (15 in each group) in the prospective portion.

MEASUREMENTS AND MAIN RESULTS

Of the 50 women undergoing laparoscopy for pelvic pain, 47 (94%) had either right- or left-sided colon-to-sidewall adhesions, and these adhesions were more common than any other type of intraabdominal adhesion, 94% versus 58%. Thirty-eight (76%) of these women had visual and 25 (50%) histologic evidence of endometriosis. The prospective study revealed that women with pelvic pain had a higher rate of colon-to-sidewall adhesions than controls (93.3% vs 13.3%) and a correspondingly higher rate of visualized endometriosis (73.3% vs 6. 7%). Right-sided paracolic adhesions were both more common than left-sided adhesions (87.7% vs. 46.7%) and were more often extensive than minimal (46.7% vs 6.7%).

CONCLUSIONS

Colon-to-sidewall adhesions occur in the majority of patients with chronic pain, whereas they are an uncommon finding in the general population. The lateral gutters are dependent regions of the abdominal cavity that are susceptible to the spread of peritoneal endometriosis or other inflammatory processes, and should be evaluated at diagnostic laparoscopy for chronic pelvic pain.

Origin of estradiol fatty acid esters in human ovarian follicular fluid

The estradiol fatty acid esters are the most potent of the naturally occurring steroidal estrogens. These esters are present predominantly in fat, where they are sequestered until they are hydrolyzed by esterases. Thus they act as a preformed reservoir of estradiol. We have previously shown that ovarian follicular fluid from patients undergoing gonadotropin stimulation contains very high amounts of estradiol fatty acid esters (approximately 10(-7) M). The source of these esters is unknown. They can be formed by esterification of estradiol in the follicular fluid by lecithin:cholesterol acyltransferase (LCAT), or in the ovary by an acyl coenzyme A:acyltransferase. In order to determine which of these enzymatic processes is the source of the estradiol esters in the follicular fluid, we incubated [3H]estradiol with follicular fluid and cells isolated from human ovarian follicular fluid and characterized the fatty acid composition of the [3H]estradiol esters biosynthesized in each. In addition, we characterized the endogenous estradiol fatty acid esters in the follicular fluid and compared them to the biosynthetic esters. The fatty acid composition of the endogenous esters was different than those synthesized by the cellular acyl coenzyme A:acyltransferase, and the same as the esters synthesized by LCAT, demonstrating that the esters are produced in situ in the follicular fluid. Although the role of these estradiol esters in the ovary is not known, given their remarkable estrogenic potency it is highly probable that they have an important physiological role.

Dilutional hyponatremia during hysteroscopic myomectomy with sorbitol-mannitol distention medium

To determine the frequency of hyponatremic complications during hysteroscopic myoma resections using sorbitol-mannitol distending medium and its relationship to operative time, fluid balance, and myoma size, we reviewed all operative hysteroscopic procedures performed by the Section of Reproductive Endocrinology and Fertility at Yale-New Haven Hospital over a 1-year period during which that medium was used. Twenty-six cases were identified of which seven involved hysteroscopic myoma resections. Hyponatremia occurred in four of the seven patients, and in one it was associated with severe posttransurethral prostatic resection (post-TURP) syndrome. The degree of hyponatremia varied roughly in direct proportion to fibroid volume and fibroid volume as a percentage of uterine volume. No relationship was found between the degree of hyponatremia and operating time, estimated submucosal volume, and uterine volume. We conclude that dilutional hyponatremia and the post-TURP syndrome may occur with the use of sorbitol-mannitol distension medium during hysteroscopy. They occur more frequently during operative hysteroscopy to resect myomata, with myoma size and myoma volume expressed as a percentage of uterine volume possibly influencing the degree of hyponatremia.

Loss of heterozygosity in 8p is associated with microinvasion in colorectal carcinoma

Loss of heterozygosity (LOH) from the short arm of chromosome 8 is frequent in a variety of malignancies, suggesting the presence of a tumor suppressor gene in this region. Previous studies suggested that this deletion may correlate with higher clinicopathologic stages in colorectal cancer, but others did not support this finding; in part, this difficulty is due to the low heterozygosity of the RFLP markers that were used. Here we report on a preliminary investigation in which we used highly informative microsatellite markers to determine whether deletions of 8p are correlated with poor prognostic features. Paraffin-embedded tumor tissue from 15 patients was analyzed with a panel of three microsatellite markers that are known to be sites of frequent LOH. Fourteen of the 15 cases were informative with at least one marker, and 7 showed LOH. Analysis of clinical features showed that there was no relation of 8p LOH with patient age or tumor stage, grade, location, or pattern of growth. However, a statistically significant correlation was seen between LOH and lymphatic, vascular, or perineural microinvasion (Fisher exact test, P = 0.01). This histologic feature is known to be a stage-independent indicator of prognosis. Our data suggest that 8p LOH may be associated with poor outcome and demonstrate the utility of these microsatellite markers for its detection.

Cardiorespiratory and stress hormone responses during first dose surfactant administration in neonates with RDS

Our hypothesis was that surfactant instilled into the trachea, followed by body positioning maneuvers utilized to enhance drug distribution, could alter hemodynamic function and stimulate the release of catecholamines. We conducted a prospective randomized study designed to compare the immediate physiologic effects of the first dose of Exosurf Neonatal (5 mL/kg; n = 16) or Survanta (4 mL/kg; n = 18), when surfactant administration was standardized with strict adherence to drug company protocol. Physiologic variables were monitored continuously. Arterial blood gases (ABG) and plasma catecholamine concentrations were measured before, and 5 minutes after, surfactant administration. Both surfactants had an immediate effect on arterial oxygen saturation (SaO2), partial pressure of oxygen in arterial blood (PaO2), and oxygen index (OI). The improvement in oxygenation after surfactant therapy was similar in both groups. There was no significant difference in the mean umbilical arterial blood pressure (ABP) following surfactant therapy in both groups. High concentrations of plasma norepinephrine (reflecting activity of the sympathetic nerves) and epinephrine (a measure of secretion from the adrenal medulla) indicate that preterm infants with respiratory distress syndrome (RDS) prior to treatment mount a substantial stress response. The currently recommended techniques for instillation of surfactant appear not to trigger a significant further surge of plasma catecholamines or to acutely change mean ABP. Alternatively, it may be possible that the lack of response was because catecholamine release was already maximal.

Quantitative EEG correlates of crack cocaine dependence

Evidence for a distinctive syndrome of neuroadaptation in cocaine dependence has accumulated from behavioral, neurophysiological, and preclinical and clinical pharmacological studies. The authors report on the results of a preliminary investigation of the quantitative electroencephalographic (QEEG) correlates of severe DSM-III-R crack cocaine dependence in seven patients abstinent from cocaine for 1 to 68 days. The major QEEG finding was increased absolute and relative alpha power. Increased alpha power has also been reported in multiple previous studies of depressed patients. This series of crack-dependent patients showed significant depressive morbidity; four patients attempted suicide subsequent to initiating their use of crack and the group mean (+/- SD) Beck Depression Scale score was 18.9 (+/- 6.5). These results complement other studies that support the concept of neuroadaptation to chronic cocaine exposure. Prospective studies correlating QEEG measures with subsequent response to pharmacological interventions for cocaine dependence should be considered.