A selenopyrylium photosensitizer for photodynamic therapy related in structure to the antitumor agent AA1 with potent in vivo activity and no long-term skin photosensitization

Cationic chalcogenopyrylium dyes 5 were synthesized in six steps from p-aminophenylacetylene (9), have absorption maxima in methanol of 623, 654, and 680 nm for thio-, seleno-, and telluropyrylium dyes, respectively, and generate singlet oxygen with quantum yields [Phi((1)O(2))] of 0.013, 0.029, and 0.030, respectively. Selenopyrylium dye 5-Se was phototoxic to cultured murine Colo-26 and Molt-4 cells. Initial acute toxicity studies in vivo demonstrate that, at 29 mg (62 micromol)/kg, no toxicity was observed with 5-Se in animals followed for 90 days under normal vivarium conditions. In animals given 10 mg/kg of 5-Se via intravenous injection, 2-8 nmol of 5-Se/g of tumor was found at 3, 6, and 24 h postinjection. Animals bearing R3230AC rat mammary adenocarcinomas were treated with 10 mg/kg of 5-Se via tail-vein injection and with 720 J cm(-2) of 570-750-nm light from a filtered tungsten lamp at 200 mW cm(-2) (24 h postinjection of 5-Se). Treated animals gave a tumor-doubling time of 9 +/- 4 days, which is a 300% increase in tumor-doubling time relative to the 3 +/- 2 days for untreated dark controls. Mechanistically, the mitochondria appear to be a target. In cultured R3230AC rat mammary adenocarcinoma cells treated with 0.1 and 1.0 microM 5-Se and light, mitochondrial cytochrome c oxidase activity was inhibited relative to cytochrome c oxidase activity in untreated cells. Irradiation of isolated mitochondrial suspensions treated with 10 microM dye 5-Se inhibited cytochrome c oxidase activity. The degree of enzyme inhibition was abated in a reduced oxygen environment. Superoxide dismutase, at a final concentration of 30 U, did not alter the photosensitized inhibition of mitochondrial cytochrome c oxidase by dye 5-Se. The data suggest that singlet oxygen may play a major role in the photosensitized inhibition of mitochondrial cytochrome c oxidase.

Neuropathologic analysis of postmortal brain samples of HIV-seropositive and -seronegative i.v. drug addicts

Between 1987 and 1992 we performed forensic-pathologic and neuropathologic examinations on 70 cases of i.v. drug addicts who died of an overdose. In almost 25% of the cases HIV-positivity was revealed by serological examinations. In all the cases, irrespective of the result of the serological examination, a diffuse, reactive astrocytosis was the most prominent histologic alteration, accompanied by more or less pronounced regressive changes of this cell type in the deep layers of the white matter. Furthermore, also in all the cases, a slight to moderate, reactive proliferation of microglia could be assessed. In a few cases of the HIV-seropositive group a lymphocytic meningitis, viz. meningoencephalitis was found; these changes may indicate an early invasion of the central nervous system (CNS) by the HIV. In spite of these inflammatory alterations, in the latter cases no HIV-specific antigens (p24 and gp41) could be demonstrated in the brain, most probably because of the small number of infectious particles. In order to reveal the earliest phase of invasion of the CNS by the HIV, we performed a search for HIV-specific nucleic acid sequences by the aid of the polymerase chain reaction (PCR) in 8 HIV-seronegative and 8 normal control cases. Although, most probably due to contamination, also the control cases exhibited some PCR-signals, these were more pronounced and appeared with more primer-pairs within the group of HIV-seronegative drug addicts. It is conceivable that HIV penetrates the CNS and is harboured in it in latent form shortly after the primary infection.(ABSTRACT TRUNCATED AT 250 WORDS)

A randomized, double-blind, placebo-controlled trial of polyethylene glycol effects on fasting and postprandial rectal sensitivity and symptoms in hypersensitive constipation-predominant irritable bowel syndrome

AIM

To assess the effect of polyethylene glycol 3350 (PEG) on fasting and postprandial (PP) perception of rectal distension and symptoms in hypersensitive constipation-predominant irritable bowel syndrome (IBS-C).

METHODS

Forty-two patients meeting Rome II criteria for IBS-C and with a pain threshold of < 32 mmHg were included in a randomized, double-blind, placebo-controlled trial. Patients received either oral PEG, 3.45 g t.i.d. orally for 30 days or placebo. Rectal sensitivity was assessed before and after treatment with a barostat using the ascending method of limits, during basal and PP periods.

RESULTS

No changes in fasting and PP rectal tone and thresholds for first sensation, gas sensation, urge to defecate, and pain was observed with PEG in relation to placebo. In both groups, pressure at which patients crossed the thresholds for noxious (PEG: from 28 ± 8.8 to 22 ± 6.9 mmHg) and non noxious (PEG: from 16 ± 4.9 to 12 ± 3.6 mmHg) stimuli decreased compared with pretreatment values. PEG improved consistency of faeces and showed a trend to diminish blood in faeces. PEG and placebo increased bowel movements per week (P < 0.001), and relieved symptoms without significant side-effects.

CONCLUSIONS

Both PEG 3350 and placebo were clinically useful in patients with IBS-C, an effect that cannot be explained by changes in rectal tone and sensation. The results support the concept that visceral sensitivity is not stable and has a heterogeneous response to drugs, and suggest the existence of a post healing hypersensitivity state.

Physical and sensory characterizations of oral coatings of oil/water emulsions

The physical and sensory properties of oil coatings on the tongue formed by five oil/water emulsions varying in oil content were investigated. A total of 20 subjects processed orally each emulsion for 30 s in triplicate. In vivo fluorescence measurements at the front and back of the anterior tongue were made to quantify the oil fraction deposited at different time points. Calibration lines relating fluorescence intensity to oil fraction were determined using pig tongues at 37.5 °C to mimic oral conditions. The oil fraction on the tongue increased linearly with an increasing oil content of the emulsions. The oil fraction deposited at the back of the anterior tongue was 1.5-2.0× larger than at the front. The intensity of sensory attributes describing after-feel perception was related to the oil fraction by Weber-Fechner's law. This study uses in vivo fluorescence to study food behavior in the mouth and unravel new insights in after-feel perception of emulsions.

Rectal sensation, pelvic floor function and symptom severity in Hispanic population with irritable bowel syndrome with constipation

OBJECTIVE

In patients with irritable bowel syndrome with constipation (IBS-C, Rome II) we determined if pelvic floor function correlates with rectal sensitivity and tone, and if the pelvic and rectal measurements correlate with symptoms.

PATIENTS AND METHODS

Sensory thresholds and tone in fasting and postprandial states were evaluated with an electronic barostat in 34 patients and 10 normal controls. The pelvic floor was assessed by defaecography.

RESULTS

Pain threshold to rectal distension was lower in IBS-C patients (P = 0.007). Postprandially, IBS-C patients showed lower values for sensation of gas, perception of urge, and pain threshold compared with controls. In IBS-C the anorectal angle widened less and showed less perineal mobility during defecation; the rectal tone in fasting IBS-C patients correlated with the angle at rest (P = 0.04) and with the perineal descent at rest (P = 0.01). The severity of abdominal discomfort or pain, and abdominal fullness correlated with the anorectal angle. The duration of symptoms and frequency of bowel movements correlated with perineal descent. Straining, mucus expulsion, and the feeling of incomplete evacuation correlated with rectal sensitivity variables.

CONCLUSION

Patients with IBS-C have lowered sensory thresholds for noxious and non-noxious stimuli, increased visceral sensitivity after food, less perineal mobility during defecation, and symptoms that correlate with rectal sensitivity and pelvic floor parameters.

Defaecography in patients with irritable bowel syndrome and healthy volunteers

BACKGROUND

In patients with IBS, many symptoms have their origin in the recto-anal segment, with motility changes in the rectum and in the internal anal sphincter, and alterations in rectal sensitivity. However, up to now, it is not known if these clinical and physiological changes are equated with morphological changes in the recto-anal segment.

METHODS

Sixteen consecutive patients with IBS (mean age 22, range 18-33 years; 13 females) and 10 healthy volunteers (mean age 34.5, range 19-50 yr.; 6 males) were evaluated prospectively with defaecography.

RESULTS

1) Anorectal angle: No significant differences were observed in the anorectal angle during rest (91.6 +/- 3.5 degrees vs 92.6 +/- 2.5 degrees) and during defaecation (92 +/- 5.5 degrees vs 98.7 +/- 2.6 degrees) between patients with IBS and healthy volunteers. However, patients with IBS were unable to widen the angle during defaecation, remaining the same at rest (91.6 +/- 3.5 degrees) as during defaecation (92 +/- 5.5 degrees). IBS patients with constipation (n = 2) compared to those with normal frequency defaecation (n = 13) showed no significant differences at rest (95 +/- 6 vs 89.8 +/- 4.1 degrees) and during defaecation (100 +/- vs 88.9 +/- 6.4 degrees). Healthy volunteers widened the angle by more than 5 degrees during defaecation. 2) Perineometry: although not significant, patients with IBS had less perineal descent during the simulated defaecation (1.98 +/- 0.37 cm) than healthy subjects (2.1 +/- 0.3 cm). Nevertheless, during squeeze there was significantly less mobility or perineal descent in patients with IBS than in control subjects (0.21 +/- 0.17 vs 0.95 +/- 0.21 cm; P = 0.01).

CONCLUSIONS

The findings of this study suggest that patients with IBS as a whole, whether constipation predominant or not, showed changes in pelvic-floor mobility.

A measure of the within-chromosome synergistic epistasis for Drosophila viability

In order to detect possible synergistic epistasis for viability in Drosophila melanogaster we assayed the relative viability of chromosomes II in: (i) panmixia, (ii) forced total homozygosity, and (iii) homozygosity for, on the average, half of their loci. As these genotypes were constructed using exactly the same set of chromosomes in the three cases, the design allows us to estimate the inbreeding depression rate at two different inbreeding levels in the absence of purging natural selection. Overall, no consistent synergistic epistasis was found. However, there was a small fraction of chromosomes whose severely deleterious effect when homozygous was almost significantly larger than expected from their viability when homozygous for half of their loci. This suggests occasional but important synergistic epistasis, which might confer evolutionary advantage to recombination in tightly linked genomes. Nevertheless, such epistasis is unlikely to be an evolutionary advantage driving the evolution of sexual anisogamous reproduction, as its contribution to overall viability is small when compared with the two-fold cost of anisogamy.

Transrectal ultrasonography: relationship with anorectal manometry, electromyography and sensitivity tests in irritable bowel syndrome

Irritable bowel syndrome is the most frequently diagnosed disorder in gastroenterology. It has been demonstrated with specialized motility studies that these patients compared to healthy subjects show changes in rectoanal electrical and mechanical activity and in rectoanal sensitivity. However, until now no report has been published on morphological alterations in the rectum or the internal anal sphincter. Twenty-five consecutive patients with irritable bowel syndrome (mean age 32, range 17-47 years; 24 females) were evaluated prospectively by transrectal ultrasonography, rectal sensitivity studies, and recordings of both electrical and mechanical activity of the distal rectum and internal anal sphincter during a 2-h inter-digestive period. Ten healthy volunteers (mean age 34.5, range 19-50 years) served as a control group. Paired and non-paired Student's two-tailed t test and linear regression analysis were used. It was shown that muscle thickness of the rectum during rest (4.7 +/- 0.1 mm) was correlated neither with its rectal spike amplitude (0.73 +/- 0.1 mV) nor with rectal spike frequency (17.06 +/- 3.6 spike/2 h). In addition, the diameter of the internal anal sphincter (1.2 +/- 0.1 mm) was correlated neither with its resting pressure, nor with frequency (17.1 +/- 3.2/2 h), duration (14.9 +/- 1.5 s), or amplitude (14.1 +/- 1.9 mmHg), of inhibition of the spontaneous rectoanal inhibitory reflex. No correlation was found between ultrasonographic parameters and rectal distension variables (r = 0.03). This study demonstrates for the first time morphological anorectal changes in patients with irritable bowel syndrome compared to healthy subjects, in addition to showing that morphological changes are independent of physiological ones. Therefore both transrectal ultrasonography to determine anorectal morphology and electromanometry to assess anorectal function are important measures in the evaluation of patients with irritable bowel syndrome.

Rectal hyposensitivity for non-noxious stimuli, postprandial hypersensitivity and its correlation with symptoms in complete spinal cord injury with neurogenic bowel dysfunction

STUDY DESIGN

Prospective clinical study.

OBJECTIVES

To assess fasting and postprandial (PP) perception of rectal distension and its correlation with symptoms in patients with spinal cord injury (SCI) and neurogenic bowel dysfunction compared to ten healthy subjects (HS).

SETTING

Experimental Medicine and Motility Unit, Mexico General Hospital and National Institute of Rehabilitation.

METHODS

Twenty patients with complete SCI at cervical, thoracic and lumbar levels [American Spinal Injury Association (ASIA) A] were studied. Rectal sensitivity was evaluated with a barostat.

RESULTS

In SCI patients, while lower the rectal tone more time was used for defecate (R=0.50, P=0.048) and more PP episodes of fecal incontinence occur (R=0.54, P=0.030). The thresholds for non-noxious stimuli of first (23.6 mmHg, CI 19.5-27.7) vs 14.0 (CI 10.9-17.1), P=0.004; gas (27.9 mmHg, CI 19.9-35.8) vs 17.9 mmHg (CI 14.25-21.69), P=0.02 and urge-to-defecate sensation (33.2 mmHg, CI 27.5-38.8) vs 22.4 mmHg (CI 17.9-26.9), P=0.01 were reported by SCI patients at higher pressure than HS, respectively. SCI patients reported PP pain sensation at a lower pressure than controls (27.8 mmHg, CI 21.5-34.2 vs 36.5 mmHg, CI 31.8-41.2), P=0.04.

CONCLUSION

SCI patients preserve rectal sensation, present rectal hyposensitivity for non-noxious stimuli and PP hypersensitivity. Lower rectal tone was related to the time used for defecate and with fecal incontinence. The results suggest that an intact neural transmission between the spinal cord and higher centres is indispensable for noxious stimulus, but not for non-noxious stimuli. Also, barostat sensitivity studies can complement ASIA criteria to verify a complete injury.

Reduction of post-prandial motility by pinaverium bromide a calcium channel blocker acting selectively on the gastrointestinal tract in patients with irritable bowel syndrome

BACKGROUND

Growing evidence points to irritable bowel syndrome physiologically as a disease of the enteric nervous system characterised by hypermotility. The aim of this study was to investigate the action of pinaverium bromide a calcium channel blocker acting selectively on the gastrointestinal tract on basal and post-prandial recto-anal motility of 40 irritable bowel syndrome patients in a random, double blind and placebo controlled trial.

METHODS

Pinaverium bromide (50 mg) or placebo was taken orally t.i.d. with food. Myoelectrical and mechanical activities of the rectum and the internal anal sphincter were recorded before treatment for 2 h in the fasting state and for an additional 2 h post-prandial.

RESULTS

Post-prandial rectal spike amplitude and frequency as well as the spontaneous recto-anal inhibitory reflex frequency decreased after pinaverium bromide (P < 0.01) but not after placebo.

CONCLUSIONS

These results suggest that the calcium channel blockers acting selectively on the gastrointestinal tract may have a therapeutic role in patients with irritable bowel syndrome.