Evidence that therapy works in clinically representative conditions

This article reports a secondary analysis of past therapy outcome meta-analysis. Fifteen meta-analysis provided effect sizes from 56 studies in previous reviews that met 1 of 3 increasingly stringent levels of criteria for clinical representativeness. The effect sizes were synthesized and compared with results from the original meta-analyses. Effect sizes from more clinically representative studies are the same size at all 3 criteria levels as in past meta-analyses. Almost no studies exist that meet the most stringent level of criteria. Results are interpreted cautiously because of controversy about what criteria best capture the notion of clinical representativeness, because so few experiments have tested therapy in clinical conditions, and because other models for exploring the generalizability of therapy outcome research to clinical conditions might yield different results.

Rise in sexually transmitted diseases during democratization and economic crisis in Mongolia

In 1990, democratic changes and loss of Soviet economic subsidies led to enormous social upheaval in Mongolia. The objective of this study is to map sexually transmitted disease (STD) trends in Mongolia from 1983-1995 and review human immunodeficiency virus (HIV) surveillance data since 1987. Data for syphilis show a decreasing trend from 1983-1993 with a decline in cases from 70 to 18/100,000 population, followed by a rise in cases to 32/100,000 population in 1995. Data suggest a 1.5-3.0 fold higher rate of syphilis for ages 15-24 than for any other group. Data for gonorrhoea show an upward trend in the rate of cases, from 51/100,000 population in 1983 to 142/100,000 in 1995. The majority of cases are aged 15-44. Trichomonas rates also show an upward trend in the number of cases, from 47/100,000 population in 1983 to 155/100,000 cases in 1995. Like gonorrhoea the majority of cases are in the 15-44 year age range. For children aged 0-14, the 1983-1993 rate remained below 4.5/100,000; however, in 1994 and 1995 the rate increased reaching 53 and 48/100,000 respectively. Since 1987, more than 176,000 HIV tests have been done with only one confirmed positive result. Rises in STD rates coincide with deterioration in STD services and reduced active surveillance, suggesting that these data reflect a minimum estimation of the problem. Changes in business and social circumstances may have resulted in increasing HIV and STD risk behaviour.

Cells lacking CIP1/WAF1 genes exhibit preferential sensitivity to cisplatin and nitrogen mustard

We have previously shown that p53 disruption sensitizes certain cancer cell types to cisplatin (CDDP) (Fan et al., 1995). In the present study we investigated the role of the p53 downstream effector, p21CIP1/WAF1 (p21), in this sensitization. Studies were performed in human colon cancer HCT-116 cells and murine embryonic fibroblasts (MEF) with intact versus disrupted p21 genes. For comparison, HCT-116 cells lacking p53 function were also prepared through stable transfection with the human papillomavirus type-16 E6 gene. HCT-116/E6 cells were found to be more sensitive than control transfectants to CDDP and another DNA crosslinking agent, nitrogen mustard (HN2). HCT-116 cells with disrupted p21 genes also exhibited greater CDDP and HN2-sensitivity than parental HCT-116 cells. In contrast, the clonogenic survival of HCT-116 cells exposed to ionizing radiation, adriamycin, taxol or vincristine was not affected by p53 or p21 disruption. Sensitization of HCT-116/p21-/- cells to CDDP and HN2 was not limited to the HCT-116 cell background since MEF from p21 knockout mice were also more sensitive to these DNA crosslinking agents. Investigations into a possible cause of this enhanced sensitivity revealed that HCT-116 cells lacking p53 or p21 function exhibited a reduced ability to repair cisplatin-damaged CAT-reporter plasmids transfected into the cells. In addition, we found that HCT-116/p21-/- cells were much more susceptible to HN2-induced cell cycle delay than parental cells. Our results suggest that p21 disruption preferentially sensitizes at least some cell types to DNA crosslinking agents.

Role of p21Waf1/Cip1/Sdi1 in cell death and DNA repair as studied using a tetracycline-inducible system in p53-deficient cells

Postulated roles for p21(Waf1/Cip1/Sdi1) (p21) in DNA repair and apoptosis remain controversial. Studies suggest both stimulatory and inhibitory effects of p21 in DNA repair. p21 has also been implicated in induction or protection from apoptosis. Using the tetracycline inducible expression system, we studied the role of p21 in DNA repair and apoptosis in wild-type p53 deficient DLD1 colorectal carcinoma cells. These cells displayed marked heterogeneity in their ability to tolerate higher levels of exogenous p21. The majority of the p21 overexpressing cells grew slower and did not exhibit apoptotic phenotype, some cells underwent apoptotic death within 5-8 days following p21 induction while other became giant cells prior to undergoing cell death. Induction of p21 transgene neither sensitized to nor protected from adriamycin-induced acute cell death. p21 also did not alter the clonogenic survival following adriamycin treatment. Clonogenic survival after u.v.-irradiation was, however, increased when p21 expression was transiently induced a few hours before and after u.v.-irradiation. Consistent with its effect on clonogenic survival, p21 also enhanced the cellular capacity to repair three different exogenously introduced u.v.-damaged reporter plasmids. Taken together our results demonstrate that p21 may modulate the nucleotide excision repair process to facilitate the repair of u.v.-type DNA damage even in the absence of wild-type p53.

Immediate breast reconstruction in patients with locally advanced disease

Immediate breast reconstruction for patients with early-stage disease is well established. This study evaluates a consecutive series of 22 patients with locally advanced disease (stage IIB or III) who underwent mastectomy and immediate breast reconstruction. All patients received several cycles of neoadjuvant chemotherapy (average, 3.5 cycles) followed by completion of chemotherapy beginning approximately 3 weeks following surgery. The perioperative morbidity was 14% and no patient suffered a delay in the resumption of chemotherapy. Patients have been particularly grateful about being offered reconstruction in this setting. Our preliminary results with this technique have been encouraging and further study is warranted.

The value of ventilation-perfusion imaging in pregnancy

Pulmonary embolism (PE) is a major cause of maternal death during pregnancy. The aims of this retrospective study were to review 5 years experience of ventilation-perfusion (V/Q) imaging in pregnancy, to evaluate the effect of the V/Q scan report on the referring clinician's use of anticoagulants and to monitor the course and outcome of pregnancy. 82 patients (aged 17-44 years, gestation 6-40 weeks) underwent V/Q imaging for suspected PE, over a 5 year period. Modified PIOPED criteria were used to assess the probability of PE. 31 patients were shown to have normal scans (38%); 19 (23%) had low probability (LP) scans; 14 (17%) had intermediate probability (IP) scans and 18 (22%) had high probability (HP) scans for PE. Referring clinicians saw the reports and took action within 12 h. Anticoagulation was continued or started in 31 patients (all HP, 12 IP and 1 LP). Anticoagulation was considered unnecessary in 52 patients (all normal, 19 LP and 2 IP). None of the patients with normal or LP scans had documented PE during the follow-up period (median 25 months, range 3-60 months). No complications of anticoagulation were observed and no adverse outcome of pregnancy were reported. V/Q imaging is a valuable technique in the management of pregnant women suspected of having PE.

Neural monitoring of vasovagal syncope

Head-up tilt testing has become a valuable and widely accepted diagnostic tool for evaluation of patients with vasovagal syncope. This test has afforded clinical researchers the opportunity to focus on the hemodynamic, humoral, and neural changes that accompany syncope. We review the animal and clinical studies that provide insight into the possible pathophysiological mechanisms involved in vasovagal syncope. Hemodynamic measurements in patients with vasovagal syncope suggest that a relative decrease in ventricular size and increase in cardiac contractility may be seen in many patients with vasovagal syncope. Patients with vasovagal syncope have also demonstrated numerous "exaggerated" neurohumoral responses to syncope. Differential changes in plasma levels of epinephrine, renin, endothelin, vasopressin, cortisol, prolactin, beta endorphins, and substance P have been reported by some investigators either prior to or during a syncopal episode in patients with vasovagal syncope. The precise pathophysiological significance of these measurements is unknown at the present time. Measurements of autonomic tone may be accomplished indirectly with analysis of heart rate variability or baroreflex slope, or directly by sympathetic neural recordings of the peroneal nerve. We have demonstrated decreased baroreflex slopes in patients with vasovagal syncope. Using microneurography, we and others have demonstrated decreased sympathetic nerve activity occurring 11 +/- 3 seconds prior to syncope during head-up tilt table testing. A variety of other abnormal reflexes, including blunted forearm blood flow responses during exercise, have been demonstrated by others. These observations suggest that pacing instituted after the event may not be as helpful as the use of a hemodynamic sensor that will result in the initiation of pacing prior to sympathetic withdrawal or modify the decrease in sympathetic tone that occurs prior to syncope.

Changes in the bioenergetic state of rat hippocampus during 2.5 min of ischemia, and prevention of cell damage by cyclosporin A in hyperglycemic subjects

A recent study from this laboratory has shown that brief transient ischemia (2 min 30 s) in normo- and hyperglycemic rats leads to moderate neuronal necrosis in CA1 cells of the hippocampus, of equal density in the two groups. However, hyperglycemic animals failed to depolarize during the ischemia, nor did they show a decrease in extracellular calcium concentration. The present study was undertaken to study the metabolic correlates to these unexpected findings. Normoglycemic (plasma glucose approximately 6 mM) and hyperglycemic (approximately 20 mM) rats were subjected to ischemic periods of 1 min and 2 min 15 s (2 min 30 s with freezing delay considered), and their brains were frozen in situ. Samples of dorsal hippocampus were dissected at -22 degrees C and extracted for the measurement of phosphocreatine (PCr), creatine, ATP, ADP, AMP, glucose, glycogen, and lactate. Normoglycemic animals showed rapid depletion of PCr, ATP, glucose, and glycogen, and a rise in lactate content to 10-12 mM x kg(-1) during the ischemia. Hyperglycemic animals displayed a more moderate rate of fall of PCr and ATP, with ATP values exceeding 50% of control after 2 min 30 s. Glycogen stores were largely maintained, but degradation of glucose somewhat enhanced the lactic acidosis. The results demonstrate that hyperglycemic rats maintained ATP at levels sufficient to prevent cell depolarization and calcium influx during the ischemic period. However, the metabolic perturbation observed must have been responsible for the delayed neuronal damage. We speculate that lowered ATP, increased inorganic P, and oxidative stress triggered a delayed mitochondrial permeability transition (MPT), which led to delayed neuronal necrosis. This assumption was supported by a second series of experiments in which CA1 damage in hyperglycemic rats was prevented by cyclosporin A, a virtually specific inhibitor of the MPT.

Evaluation of the role of routine serial cranial computed tomography in the management of children with human immunodeficiency virus infection

OBJECTIVE

To review the impact of routine follow-up cranial computed tomography (CT) scans on the management of children with human immunodeficiency virus (HIV) infection.

DESIGN

Longitudinal data collected from 58 HIV-infected children followed in one center for mean of 3.8 +/- 1.8 years.

SETTING

HIV/AIDS pediatric program following over 90% of the identified HIV-infected children in one region in Canada.

RESULTS

The baseline CT scans showed intracranial abnormalities in 35 of 58 children (60%). In five children with basal ganglia calcifications (BGC) without cerebral atrophy, there has not been progressive encephalopathy. For the 43 children who had serial CT scans for routine follow-up, 34 (79%) had changes in the scans that were concordant with the clinical assessment. In all but five children with progressive ventricular and sulcal dilatation on CT scan, there was simultaneous clinical evidence of encephalopathy. Those five children were already on antiretroviral therapy, and therapy was not changed in response to the CT scan findings.

CONCLUSION

Baseline CT scans provide useful diagnostic and prognostic information. Further research is needed to evaluate the role of cranial CT imaging in the management of pediatric HIV encephalopathy.

New protein and PCR markers RAK for diagnosis, prognosis and surgery guidance for breast cancer

Breast cancer antigens RAK-p120, -p42, -p25 were detected in 100% of breast cancer cases tested (71 cases). Only 10% of adjacent tissue cases tested positive for all three cancer antigens, and 17.5% of the cases tested positive for two antigens only. Eighty-five percent of histologically normal breast tissue samples, isolated either from breast cancer patients or patients with advanced fibrocystic disease, tested RAK-negative, with the exception of low expression of p25, observed in some patients. Polymerase chain reaction (PCR) with HIV-1 gp 41-derived primers revealed cancer-associated DNA fragments of similar size (140 bp) as in HIV-1 genome. Fifty-four percent of cancer adjacent tissues, and 50% of malignancy-free breast tissue samples, tested PCR-negative. It is suggested that genetic predisposition to cancer may be associated with the presence of RAK genes, while expression of RAK antigens marks an already ongoing process of malignant changes.

The p53-regulated cyclin G gene promotes cell growth: p53 downstream effectors cyclin G and Gadd45 exert different effects on cisplatin chemosensitivity

Among the p53-regulated genes that have been identified thus far, cyclin G is a relatively recent one. We conducted a series of experiments aimed at elucidating cyclin G function. Ectopic overexpression of cyclin G in human RKO colon carcinoma cells accelerated cell growth. Transfection of normal human fibroblasts with the cyclin G expression vector promoted clonal expansion. Cyclin G immune complexes isolated from the transfected cells exhibited appreciable levels of cyclin-dependent kinase activity, as evidenced using histone H1 as a substrate. The retinoblastoma protein, pRb, was detectable in cyclin G immune complexes, raising the possibility that Rb may be one mediator of cyclin G action. Cyclin G-overexpressing cells were more sensitive to cisplatin cytotoxicity than the parent cells, probably because cyclin G overexpression overrides cell cycle checkpoint(s). Overexpression of another p53-regulated gene, GADD45, by contrast, protected cells from cisplatin killing. These findings suggest that different downstream effectors of the p53 pathway may exert different effects on cellular survival after treatment with cancer chemotherapy drugs such as cisplatin.

Necrosis of the substantia nigra, pars reticulate, in flurothyl-induced status epilepticus is ameliorated by the spin trap alpha phenyl-N-tert-butyl nitrone

The objective of the present study was to explore whether a diffusible free radical scavenger can ameliorate the pan-neurotic lesions of the substantia nigra, pars reticulate (SNPR), which are incurred in rats subjected to status epilepticus of more than 30 min duration. Vehicle-injected animals had flurothyl seizures induced for 45 min. The seizures were then terminated and the animals were recovered for 7 d to allow histopathological evaluation of the SNPR lesions. Drug-treated animals, which were otherwise treated identically, were given either 100-800 mg/ kg of dimethylthiourea (DMTU), a diffusible hydroxyl ion scavenger, or the diffusible spin trap alpha-phenyl N-tert-butyl nitrone (PBN) in a dose of 100 mg/kg i.p.. All animals given DMTU died 2 to 8 h after status epilepticus, but PBN was tolerated well by the animals. The amount of flurothyl required to sustain the electrographic seizures was identical in the vehicle- and drug-injected groups, demonstrating that PBN did not suppress seizure activity. Vehicle-injected animals had large bilateral infarcts localized to the SNPR. Of the six animals treated with PBN, one had a small, unilateral lesions, and in all other animals the SNPR had a normal histological appearance. The results strongly suggest that the pan-necrotic lesions of the SNPR incurred during ongoing seizure activity represent a free radical-mediated lesion.

Gas chromatographic/mass spectrometric detection of narcotine, papaverine, and thebaine in seeds of Papaver somniferum

In addition to codeine and morphine, three more compounds: narcotine (noscapine), papaverine, and thebaine were found in Indian and Netherlands poppy seeds (Papaver somniferum L). The compounds were detected by a GC/MS technique and the identities were confirmed by comparing retention times and ion ratios with the known references. The concentrations of codeine, morphine, thebaine, papaverine, and narcotine were 44, 167, 41, 67, and 230 micrograms/g in Indian poppy seeds, and were 1.8, 39, 1.0, 0.17, 0.84 micrograms/g in Netherlands poppy seeds, respectively. Because these compounds may be urinary products after poppy seed consumption, the lowest detectable concentrations of codeine, morphine, thebaine, papaverine, and narcotine in urine are of interest and were found to be 4, 4, 5, 0.4, and 4 ng/ml, respectively. The detection of urinary narcotine, papaverine, or thebaine may be utilized to differentiate poppy seed consumption from illicit codeine, morphine, or heroin use.

Antisense GADD45 expression results in decreased DNA repair and sensitizes cells to u.v.-irradiation or cisplatin

Loss of p53 function in cancer cells commonly results in a condition of genomic instability. This is believed to emanate from a loss of the G1 checkpoint response to DNA damage. While the role of p53 in the induction of a G1 arrest is well-accepted, additional p53 functions are being discovered. Cell cycle checkpoints presumably function to allow additional time for DNA repair after damage is incurred, however, genetic studies in yeast suggest that components of the checkpoint pathway may also be involved in DNA lesion processing (Lydall and Weinert, 1995). Recent evidence suggests that this may also be the case for p53, as suggested by numerous reports linking p53 function to DNA repair. Thus, loss of p53 function might contribute to genomic instability independent of G1-arrest. In the present study, we explored the effect of p53 disruption and consequences of antisense GADD45 expression on the DNA repair capacity of human colon carcinoma RKO cells. DNA repair was assayed using host-cell reactivation of u.v.-damaged reporter plasmids and unscheduled DNA synthesis experiments in transiently-transfected cells. We show that a number of transfected genes that suppress p53 function reduce the ability of cells to repair u.v.-induced DNA damage. Moreover, cells in which expression of the p53-regulated gene GADD45 was blocked by antisense vectors, also showed altered levels of DNA repair. Blocking Gadd45 expression by constitutive antisense expression sensitized cells to killing by u.v.-radiation or by cis-platinum (II) diamine-dichloride (CDDP, or cisplatin), a cancer chemotherapy drug which produces DNA cross-links. These findings suggest the involvement of downstream effectors of the p53 pathway in the coordination of cell cycle arrest and DNA repair.

MDA-MDMA concentrations in urine specimens

Urine specimens collected from active-duty U.S. Army personnel were submitted for analysis to the Tripler Army Medical Center, Forensic Toxicology Drug Testing Laboratory as part of the random drug testing program. During an 18-month drug-screening period, 34 specimens tested positive for amphetamines with the Roche Abuscreen Radioimmunoassay for Methamphetamine (High Specificity); based on gas chromatographic-mass spectrometric (GC-MS) analysis, the presence of 3,4-methylenedioxymethamphetamine (MDMA) was suspected. These samples were subsequently submitted to the Division of Forensic Toxicology, Office of the Armed Forces Medical Examiner, Armed Forces Institute of Pathology for further testing. All 34 samples screened positive using both the Abbott TDx Amphetamine/ Methamphetamine II assay and the Amphetamine class assay. Confirmation and quantitation by GC-MS revealed the presence of both MDMA and 3,4-methylenedioxyamphetamine (MDA) in all samples. The MDMA concentrations ranged from 0.38 to 96.2 mg/L (mean, 13.4 mg/L) and the MDA concentrations ranged from 0.15 to 8.6 mg/L (mean, 1.6 mg/L). The mean ratio of MDA, the N-demethylation metabolite of MDMA, to MDMA was 0.15, similar to the ratio of amphetamine, the N-demethylation metabolite of methamphetamine, to methamphetamine of 0.10. The presence of MDA in urine specimens at a concentration approximately 10-15% that of the MDMA present is consistent with MDMA metabolism, which may be indicative of the use of MDMA only, as compared with the combined use of both drugs.

One-step esterification of benzoylecgonine with dimethylformamide-dipropylacetal or dimethylformamide-diisopropylacetal in the presence of pyridine

A simple procedure was developed to derivatize benzoylecgonine extracted from urine for subsequent confirmation by gas chromatography-mass spectrometry. The compound was esterified with dimethylformamide-dipropylacetal (DMF-DPA) or dimethylformamide-diisopropylacetal (DMF-DIPA) to the corresponding propyl and isopropyl esters. The optimum reaction condition was found to be heating the reaction mixture in the presence of pyridine at 100 degrees C for 30 min. The procedure is a one-step esterification followed by evaporation of excess reagents. When benzoylecgonine was extracted from urine using a solid-phase extraction technique and derivatized with this procedure, the compound was detected at a level as low as 10 ng/mL. Quantitation was linear over the concentration range 10-8000 ng/mL.

Abrogation of p53 function affects gadd gene responses to DNA base-damaging agents and starvation

The tumor suppressor p53 is required for induction of its downstream effector genes such as GADD45 and CIP1/WAF1 by ionizing radiation (IR). This response is probably mediated through defined p53 binding sites located in the promoter of CIP1/WAF1 and in the third intron of GADD45. In contrast, the gadd gene stress response to base-damaging agents, such as methylmethane sulfonate (MMS) or UV radiation, or medium depletion (starvation) occurs in all mammalian cells examined to date regardless of p53 status for both GADD45 and also GADD153, which is not IR-responsive in many lines with functional p53. These agents strongly induce the p53 protein and raise the possibility that, although p53 is not required for the typical "gadd" response to these agents, p53 may contribute to these non-IR stress responses. This possibility was confirmed by the finding that disruption of p53 function by transfection with dominant-negative vectors expressing HPV E6, mutant p53, or SV40 T Ag reduced the induction of GADD45 and GADD153 as measured by increases in mRNA and protein levels in human lines with wild-type p53. Similarly, induction of these genes by MMS or UV radiation was consistently stronger in the parental mouse embryo fibroblasts compared to cells derived from mice where both p53 alleles had been deleted. Similar qualitative responses were also seen for CIP1/WAF1. In agreement with reduced induction of p53-regulated genes, the G1 checkpoint activated by MMS or UV radiation was markedly abrogated in p53-wt human MCF-7 breast carcinoma cells by E6 expression. Interestingly, induction of reporter constructs driven by the GADD45 or GADD153 promoters was substantially reduced in human cells transfected with mutant p53 or E6 expression vectors or in cells lacking p53 following treatment with MMS, UV radiation, or starvation. Because neither promoter is inducible by IR, and neither contains a strong p53 binding site, these results indicate that p53 has a synergistic or cooperative role in these non-IR stress responses for both GADD45 and GADD153, and that this role is not mediated through identifiable p53-binding sites.

Escape from het-6 incompatibility in Neurospora crassa partial diploids involves preferential deletion within the ectopic segment

Self-incompatible het-6OR/het-6PA partial diploids of Neurospora crassa were selected from a cross involving the translocation strain, T(IIL-->IIIR)AR18, and a normal sequence strain. About 25% of the partial diploids exhibited a marked increase in growth rate after 2 weeks, indicating that "escape" from het-6 incompatibility had occurred. Near isogenic tester strains with different alleles (het-6OR and het-6PA) were constructed and used to determine that 80 of 96 escape strains tested were het-6PA, retaining the het-6 allele found in the normal-sequence LGII position; 16 were het-6OR, retaining the allele in the translocated position. Restriction fragment length polymorphisms in 45 escape strains were examined with probes made from cosmids that spanned the translocated region. Along with electrophoretic analysis of chromosomes from three escape strains, RFLPs showed that escape is associated with deletion of part of one or the other of the duplicated DNA segments. Deletions ranged in size from approximately 70 kbp up to putatively the entire 270-kbp translocated region but always included a 35-kbp region wherein we hypothesize het-6 is located. The deletion spectrum at het-6 thus resembles other cases where mitotic deletions occur such as of tumor suppressor genes and of the hprt gene (coding for hypoxanthine-guanine phosphoribosyl-transferase) in humans.

PDGF AA as mediator in nicotine-dependent carcinogenesis

Effect of nicotine on PDGF AA and PDGF BB interaction with cervical cancer SiHa cells was tested. [125I]PDGF AA was internalized by cells and accumulated in the cytoplasm and nucleus (chromatin). In the absence of nicotine, maximal accumulation of [125I]PDGF AA inside the cells occurred after 1 day of incubation, which was followed by a progressive degradation of the growth factor during the next 2, 3 and 5 days of cell exposure. In the presence or 0.001 or 0.01% nicotine, accumulation of [125I]PDGF AA was slightly higher than in the absence of nicotine, and maximal accumulation occurred after 2 days or incubation. In the presence of 0.1 % nicotine, maximal accumulation occurred after 5 days of incubation and was 20 and 14 times higher in the cytoplasm and chromatin, respectively. Nicotine-postponed degradation and increased nuclear accumulation of PDGF AA resulted in activation of RNA synthesis and cell proliferation. PDGF BB, which was not internalized by cells did not respond to nicotine treatment. The proposed mechanism of nicotine-PDGF AA co-carcinogenesis may involve inhibition of growth factor degradation at the lysosomal level and an increased chromatin accumulation of the non-degraded PDGF.

Valsalva's maneuver revisited: a quantitative method yielding insights into human autonomic control

Seventeen healthy supine subjects performed graded Valsalva maneuvers. In four subjects, transesophageal echographic aortic cross-sectional areas decreased during and increased after straining. During the first seconds of straining, when aortic cross-sectional area was declining and peripheral arterial pressure was rising, peroneal sympathetic muscle neurons were nearly silent. Then, as aortic cross-sectional area and peripheral pressure both declined, sympathetic muscle nerve activity increased, in proportion to the intensity of straining. Poststraining arterial pressure elevations were proportional to preceding increases of sympathetic activity. Sympathetic inhibition after straining persisted much longer than arterial and right atrial pressure elevations. Similarly, R-R intervals changed in parallel with peripheral arterial pressure, until approximately 45 s after the onset of straining, when R-R intervals were greater and arterial pressures were smaller than prestraining levels. Our conclusions are as follows: opposing changes of carotid and aortic baroreceptor inputs reduce sympathetic muscle and increase vagal cardiac motor neuronal firing; parallel changes of barorsensory inputs provoke reciprocal changes of sympathetic and direct changes of vagal firing; and pressure transients lasting only seconds reset arterial pressure-sympathetic and -vagal response relations.

The product of the het-C heterokaryon incompatibility gene of Neurospora crassa has characteristics of a glycine-rich cell wall protein

Filamentous fungi are capable of hyphal fusion, but heterokaryon formation between different isolates is controlled by specific loci termed het loci. Heterokaryotic cells formed between strains of different het genotype are rapidly destroyed or strongly inhibited in their growth. In Neurospora crassa, at least 11 loci, including the mating type locus, affect the capacity to form a heterokaryon between different isolates. In this report, we describe the molecular characterization of the vegetative incompatibility locus, het-C. The het-COR allele was cloned by genetically identifying the het-C locus in a chromosome walk, and the activity of clones containing the het-COR allele was tested in a functional transformation assay. The het-COR allele encodes a 966-amino acid polypeptide with a putative signal peptide, a coiled-coil motif and a C-terminal glycine-rich domain, similar to glycine-rich domains detected in various extracellular and structural cell envelope proteins. Both the coiled-coil and one-third of the glycine-rich carboxyl terminal domains were required for full het-COR activity. Mutants of het-COR were obtained by repeat-induced point mutation (RIP); these mutants were indistinguishable from wild type during vegetative growth and sexual reproduction but displayed dual compatibility with both of two mutually incompatible het-COR and het-cPA strains.

Factor structure of mental health measures

This study investigated the factor structure of 18 scales that measure personal growth, subjective well-being, stress-resistant personality, self-deceptive positivity, and demographics. The sample of 338 persons was drawn from university students and community residents. A principal-components analysis with oblique rotation found a large factor for measures of subjective well-being as well as smaller factors for measures of personal growth, gender and age, and personality integration and education. Results provided support for the hypothesis that subjective well-being and personal growth are related, but not identical, constructs. Implications are discussed.

Characteristics of postischemic seizures in hyperglycemic rats

Normoglycemic animals subjected to 10-20 min of transient ischemia survive without major neurological symptoms, but incur delayed neuronal damage selectively affecting vulnerable neuronal populations. If the animals are hyperglycemic before ischemia is induced, cell damage develops more rapidly, and postischemic seizures appear after a delay of 18-24 h. This study was designed to assess whether the primary insult, i.e., transient ischemia in hyperglycemic animals, triggers early epileptogenic activity which 'matures' into clinical seizures, or if the seizures arise as a result of secondary events occurring after many hours of recirculation. EEG activity during 20-24 h of postischemic recirculation was recorded from electrodes implanted in the neocortex and hippocampus of freely moving rats which had been subjected to 10 min of ischemia under normoglycemic or hyperglycemic conditions. Normoglycemic animals showed a transient postischemic reduction of EEG amplitude and frequency, and sparse and temporary epileptiform activity. In contrast, hyperglycemic animals showed a more pronounced reduction of EEG amplitude and frequency, and early appearing epileptiform activity which was sustained, and ultimately transformed into overt electrographic seizures. The EEG changes were more pronounced in the neocortex than in the hippocampus. The results thus demonstrate that the initial ischemic insult, and not the secondary damage appearing many hours after the initiation of recirculation, triggers epileptiform activity that 'matures' into status epilepticus.

Religious insistence on medical treatment. Christian theology and re-imagination

Families and surrogates sometimes use religious themes to justify their insistence on aggressive end-of-life care. Their hope that "God will work a miracle" can halt negotiations with health care professionals and lead to litigation. The possibility of "re-imagining" religious themes, to broaden their scope and present a wider vision of the Christian tradition, may offer a solution.