Physiological and clinical outcome of anterior sphincteroplasty

A total of 55 women underwent sphincteroplasty for the treatment of faecal incontinence related to anterior defects. Patients were followed prospectively for a mean of 29 months to evaluate the outcome overall and according to age. All patients were evaluated clinically by means of a questionnaire and graded using an incontinence scoring system ranging from 0 (perfect continence) to 20 (complete incontinence). Some 52 patients (95 per cent) had had a previous vaginal delivery and 30 (55 per cent) had a history of previous anal sphincter repair. Physiological and functional parameters in patients with a successful outcome (n = 39) were compared with those in patients with a poor outcome (n = 16). The results were also compared in patients under (n = 39) and over (n = 16) 60 years of age. Overall, patients with a successful outcome had a significant change in mean and maximal resting and squeeze pressures. These changes correlated well with the increase in the high-pressure zone (HPZ) length from 1.0-2.2 cm (P = 0.0002) and with functional outcome (change in incontinence score from 15.3 to 5.8; P < 0.0001). In patients over 60 years of age, a significant change in mean squeeze pressure (P = 0.03) and HPZ length (P = 0.01) was noted and correlated with functional outcome (change in incontinence score from 14.3 to 6.4; P < 0.0001). A successful outcome after anterior sphincteroplasty is related to improvement in sphincter function even in an older population. These results demonstrate that age itself does not seem to be a predictor of poor outcome. Patients should not be denied a repair exclusively on grounds of age.

Role of monocytes in the up-regulation of the early activation marker CD69 on B and T murine lymphocytes induced by microbial mitogens

CD69 is an early marker of lymphoid cell activation. The authors report on an up-regulation of CD69 in splenic B and T cells of C57Bl/6 mice after administration of lipopolysaccharide (LPS) or microbial immunosuppressive/mitogenic (ISM) proteins produced by C. albicans (p43) and African Swine Fever Virus (p36). This up-regulation of CD69 was observed 6 and 24 h after mitogenic treatments. The same pattern of increased CD69 expression was observed in the lymph nodes of mice treated with p43 or LPS, whereas p36 treatment failed to induce increased CD69 expression in this organ. Intracellular calcium mobilization was induced in splenic B and T lymphocytes after incubation of total spleen cells with LPS, p43 or p36. This increase was higher in B than in T cells. Increased calcium mobilization was also seen in lymph node B cells after incubation with p43 or p36 and in lymph node T cells after p43 stimulation. Up-regulation of CD69 expression on B and T cells was also observed after in vitro stimulation of spleen cells with the three mitogens used. Similar results were obtained with culture supernatants of macrophage/monocyte (M phi) cells activated with LPS (LPS/M phi CS). Stimulation of M phi cells with LPS or with the ISM proteins is demonstrated by the increased production of nitrites by these cells. The increased in vitro expression of CD69 was, however, not abolished by monoclonal antibodies to M phi cytokines such as IL-6, IL-10 or TNF alpha. No increased expression of CD69 was found in vitro on purified B or T cells, even when mixed upon stimulation with p43, p36, LPS or with LPS/M phi CS. However, an increase in the expression of CD69 was observed on B cells co-cultured with M phi cells after treatment with LPS or p36. All three mitogens failed to induce increased CD69 expression on cultured T cells mixed with M phi cells.

Autosomal recessive retinitis pigmentosa caused by mutations in the alpha subunit of rod cGMP phosphodiesterase

Retinitis pigmentosa (RP) constitutes a group of genetically heterogeneous progressive photoreceptor degenerations leading to blindness and affecting 50,000-100,000 people in the U.S. alone. Over 20 different RP loci have been mapped, of which six have been identified. Three of these encode members of the rod photoreceptor visual transduction cascade: rhodopsin, the rod cGMP-gated cation channel alpha subunit, and the beta subunit of cGMP-phosphodiesterase (PDEB). As null mutations in PDEB cause some cases of RP and since both alpha and beta subunits are required for full phosphodiesterase activity, we examined the gene encoding the alpha subunit of cGMP phosphodiesterase (PDEA) in 340 unrelated patients with RP. We found three point mutations in PDEA in affected members of two pedigrees with recessive RP. Each mutation alters an essential functional domain of the encoded protein and likely disrupts its catalytic function. PDEA is the seventh RP gene identified, highlighting the extensive genetic heterogeneity of the disorder and encouraging further investigation into the role of other members of the phototransduction cascade in RP.

cDNA, gene structure, and chromosomal localization of human GAR1 (CNCG3L), a homolog of the third subunit of bovine photoreceptor cGMP-gated channel

A unique glutamic acid-rich protein was previously identified in bovine rod photoreceptors (Sugimoto et al., 1991, Proc. Natl. Acad. Sci. USA 88: 3116-3119) and later suggested to be a third subunit (gamma) of the rod cGMP-gated cation channel (Chen et al., 1994, Proc. Natl. Acad. Sci. USA 91: 11757-11761). Here, we report on the characterization of the GAR1 gene encoding a human homolog of bovine gamma. Sequence analysis of cDNA clones encoding human gamma revealed an open reading frame predicting a protein of 299 amino acids (approximately 32 kDa), half the size of the bovine gamma subunit. Comparison of the N-terminal half of bovine gamma with the predicted human gamma sequence revealed 90% identity within the first 31 amino acids, and only 60% homology was found throughout the remainder of the protein sequence. As in bovine gamma, the predicted isoelectric point of the human protein is very acidic despite the absence of the bovine C-terminal glutamic acid-rich domain. The integrity of the cDNA sequence was confirmed by analysis of several overlapping genomic clones that span the GAR1 gene. The protein coding region of the gene consists of 12 exons spanning approximately 11 kb with exon sequence identical to that of the cDNA clones. PCR of somatic cell hybrid DNA with primer pairs that amplify a portion of the GAR1 gene (locus designation CNCG3L) demonstrate localization to chromosome 16. The location of the gene was further delimited by fluorescence in situ hybridization placing the gene at 16q13.(ABSTRACT TRUNCATED AT 250 WORDS)

Fate in humans of dietary intake of cyanogenic glycosides from roots of sweet cassava consumed in Cuba

We studied if consumption of boiled fresh roots from sweet cassava varieties grown in Cuba resulted in exposure to cyanogenic glycosides and their final breakdown product, cyanide. When adult, nonsmoking subjects consumed 1-4 kg cassava over 2 days, their urinary levels of the main cyanide metabolite, thiocyanate, only increased from a mean +/- SEM of 12 +/- 2 to 22 +/- 2 mumol/l, indicating a negligible cyanide exposure. Their mean urinary linamarin, the main cyanogenic glucoside in cassava, increased from 2 +/- 1 to 68 +/- 16 mumol/l. In a second experiment 5 subjects consumed one meal of 0.5 kg boiled cassava that contained 105 mumol linamarin and 8 mumol hydrogen cyanide (HCN). Quantitative urine collections prior to and after intake showed that 28% of linamarin was excreted during the following 24 hours, whereas a modest increase of urinary thiocyanate (SCN) only corresponded to the small amount of free HCN ingested. These results indicate that the dominant cyanogen in boiled cassava is glycosides that pass through the human body without causing cyanide exposure. It remains to be studied whether humans occasionally possess intestinal or tissue beta-glucosidases that can hydrolyse cyanogenic glycosides from cassava.

Human retinal guanylate cyclase (GUC2D) maps to chromosome 17p13.1

3',5'-Cyclic guanosine monophosphate is the intracellular second messenger regulating phototransduction in mammals. The level of cGMP in photoreceptor cells is controlled by the cGMP-hydrolyzing enzyme cGMP phosphodiesterase and the cGMP-producing enzyme guanylate cyclase. Identification of a photoreceptor-specific guanylate cyclase (retGC) that may function in visual transduction was recently reported. As an initial step in assessing the potential for defects in the retGC (GUC2D) gene to be causal of hereditary retinal disease, we have determined its chromosome location. A 720-bp region of the human GUC2D locus was amplified with exon-specific primers. The amplified product contains three introns, two intact exons, and part of two additional exons, suggesting a high degree of structural complexity. PCR analysis of human-rodent somatic cell hybrids was used to map the GUC2D locus to chromosome 17. This assignment was confirmed and a more precise localization to 17p13.1 was obtained by fluorescence in situ hybridization.

[Treatment of colonic atresia. Report of 3 cases]

Atresia of the colon (AC) is an uncommon cause of neonatal intestinal obstruction requiring prompt surgery. However, its optimal operative management is matter of discussion. We report the surgical therapy and evolution of three cases successfully treated at our department. A type I case was submitted to a coloplasty plus resection of the diaphragm; two cases of type III underwent a two-staged procedure, i.e., colostomy with subsequent anastomosis without resection. After analysing the different operative procedures we suggest that a colostomy with later establishment of intestinal continuity may be an advantageous procedure even in the healthy patients with proximal lesions. A coloplasty is a safe alternative to type I atresias.

Regulation of aplanospore germination in Vaucheria : Time-dependent responses to calcium modulators

Germination of aplanospores in Vaucheria longicaulis Hoppaugh var. macounii Blum proceeds through three stages of development. Stage I begins with the initiation of germination and lasts approx. 2 h. During this stage germinating filaments grow at an accelerated rate (266 ± 12 μm · h(-1)). Stage II is characterized by a sharp decline in the growth rate of germinating filaments (96 ± 4 μm · h(-1)) and lasts 4 h. This is followed, during the next 4 h, by a recovery in the growth rate (168 ± 8 μm · h(-1)) of germinating filaments, stage III. Growth rates stabilize and remain unchanged during subsequent development (Oliveira and Fitch, 1988, J. Submicrosc. Cytol. Pathol. 20, 397-406). The Ca(2+)-influx modulators LaCl3, nifedipine and methyl 1,4-dihydro-2,6-dimethyl-3-nitro-4 (2-trifluoromethylphenyl)-pyridine-5-carboxylate (Bay K-8644), the ionophore calcimycin (A23187), the intracellular Ca(2+)-release antagonist 8-N-N'-(diethylamino)-octyl-3,4, 5-trimethoxybenzoate (TMB-8), the Ca(2+)-uptake inhibitor ruthenium red and the phosphoinositide-cycle modulators LiCl and myo-inositol show that the events required for the initiation are distinct from those required for the completion of each stage of germination. These studies in conjunction with microinjection of germinating filaments with inositol 1,4,5-trisphosphate, the natural ligand for Ca(2+) release from Ca-storing organelles (endoplasmic reticulum, vacuole), and treatment with chlorotetracycline (CTC), to visualize the distribution of membrane-bound Ca(2+) reveal that both the initiation and completion of each stage of germination are controlled by Ca(2+) signals which are restricted to well-defined time intervals and are modulated by the origin (source) of Ca(2+).

Horse urinary kallikrein, I. Complete purification and characterization

The isolation procedure for horse urinary kallikrein was considerably improved by the introduction of two new purification steps: a) removal of mucoproteins and concentration of the urine by ultrafiltration and b) affinity chromatography on benzamidine-Sepharose conjugate. The homogeneity of the enzyme preparations, regarding their protein moiety, was demonstrated by: 1) a single symmetric peak on DEAE-Sephadex chromatography, with constant values for A280/A260 ratios, esterolytic and amidolytic specific activities; 2) a single band, although dispersed, on gel-electrophoresis at pH 8.3, also in the presence of sodium dodecyl sulfate, and 3) a unique sequence for the six amino-terminal residues. The isolated enzyme was shown to be a single chain glycoprotein (alpha-kallikrein), similar to human urinary and porcine-pancreatic kallikreins regarding the protein moiety molecular mass, amino-acid composition, and partial amino-terminal sequence; differences were found in their total sugar content and even more conspicuously in their carbohydrate composition. In contrast to porcine pancreatic beta-kallikrein, horse urinary kallikrein was not substrate-activated and unlike other alpha-kallikreins, did not present the biphasic time-course in benzoyl-L-arginine ethyl ester hydrolysis. The specificity constants (kcat/Km) for ester and 4-nitroanilide substrates were lower for horse urinary than for pancreatic beta-kallikrein and as observed with the latter enzyme, were affected by NaCl.

Horse urinary kallikrein, II. Effect of subsite interactions on its catalytic activity

The effect of secondary-subsite interactions on the catalytic efficiency of horse urinary kallikrein was studied using as substrates oligopeptides and peptidyl-4-nitroanilides with L-Arg at P1. The known secondary specificity of tissue kallikreins for hydrophobic residues at P2 was also demonstrated for horse urinary kallikrein and a higher preference of this enzyme for L-Phe over L-Leu at P2 was evident. Interaction of subsites S3 with D-Pro and D-Phe enhanced the catalytic efficiency but tripeptidyl-4-nitroanilides with acetyl-D-Pro, L-Pro and acetyl-L-Pro at P3 were no better substrates than acetyl-dipeptidyl-4-nitroanilides. The importance of the leaving group for the catalysis was proved by higher kcat/Km values for the peptides in relation to peptidyl-4-nitroanilides containing a common acyl-chain. The low kcat value for the peptide with L-Pro at P'2 stresses the importance of a hydrogen bond between P'2 amide and the carbonyl group at S'2. One L-arginine residue at the leaving group, specially at the P'2 position, decreases the value of the apparent Km. This effect resulting of side-chain interactions with S'2, is impaired by a second L-Arg at P'1.

Interaction of narcotic antagonist naltrexone with nicotinic acetylcholine receptor

The interactions of naltrexone with the nicotinic acetylcholine receptor were studied electrophysiologically using the frog sciatic nerve-sartorius muscle and biochemically using membranes from the electric organ of Torpedo ocellata. At nanomolar concentrations naltrexone increased the peak amplitude of endplate currents with little change in the decay time constant. At micromolar concentrations there was a concentration-dependent depression of endplate current and miniature endplate current amplitudes and decay time constants. Decay time constant depression was enhanced with hyperpolarization. Only marginal curvature was induced in peak endplate current amplitude versus membrane voltage plots by naltrexone. Naltrexone had no effect on single channel conductance but decreased open channel lifetime, according to fluctuation analysis. Naltrexone alone (less than or equal to 3 microM) did not impair binding of [125I]alpha-bungarotoxin to the receptor in a fast pre-equilibration assay, but increased the ability of acetylcholine to displace [125I]alpha-bungarotoxin. The drug displaced the agonist-stimulated binding of [3H]perhydrohistrionicotoxin to the channel site. Biphasic functional changes in neuromuscular transmission can be attributed to an allosteric mechanism with increased agonist binding to the nicotinic receptor at nanomolar concentrations and caused a non-competitive blockade of the ionic channel at micromolar concentrations.

Substrate activation of porcine pancreatic kallikrein by N alpha derivatives of arginine 4-nitroanilides

Hydrolysis of several N alpha-substituted L-arginine 4-nitroanilides with porcine pancreatic kallikrein was studied under different conditions of pH, temperature, and salt concentration. At high substrate concentrations a deviation from Michaelis-Menten kinetics was observed with a significant increase in the hydrolysis rates of almost all substrates. Kinetic data were analyzed on the assumption that porcine pancreatic kallikrein presents an additional binding site with lower affinity for the substrate. Binding to this auxiliary site gives rise to a modulated enzyme species which can hydrolyze an additional molecule of the substrate through a second catalytic pathway. The values of both Michaelis-Menten and catalytic rate constants were higher for the modulated species than for the free enzyme, suggesting a mechanism of enzyme activation by substrate. Kinetic data indicated similar substrate requirements for binding at the primary and auxiliary sites of the enzyme. Tris(hydroxymethyl)aminomethane hydrochloride and NaCl were shown to alter the kinetic parameters of the hydrolysis of N alpha-acetyl-L-Phe-L-Arg 4-nitroanilide by porcine pancreatic kallikrein but not the enzyme activation pattern (ratio of the catalytic constants for the activated and the free enzyme forms). Similar observations were made when the hydrolysis of D-Val-L-Leu-L-Arg 4-nitroanilide was studied under different pH and temperature conditions.

Computation of ventilation-perfusion ratio with Kr-81m in pulmonary embolism

Diagnostic difficulties occur in pulmonary embolism (PE) during visual analysis of ventilation-perfusion images in matched defects or in chronic obstructive lung disease (COPD). In 44 patients with angiographically confirmed PE and in 40 patients with COPD, the regional ventilation-perfusion ratios (V/Q) were therefore computed using krypton-81m for each perfusion defect, and were displayed in a functional image. In patients with PE and mismatched defects, a high V/Q (1.96) was observed. A V/Q greater than 1.25 was also found in nine of 11 patients having PE and indeterminate studies (studies with perfusion abnormalities matched by radiographic abnormalities). COPD was characterized by matched defects and low V/Q. The percentage of patients correctly classified as having PE or COPD increased from 56% when considering the match or mismatched character to 88% when based on a V/Q of 1.25 in the region of the perfusion defect. This quantitative analysis, therefore, seems useful in classifying patients with scintigraphic suspicion of PE.

Culture Studies on the Effects from Fluoride Pollution on the Growth of Marine Phytoplankters

The autotrophic growth of 12 species of marine phytoplankters, from eight classes of algae, was tested on axenic cultures with NaF additions of 0–100 mgF/L. All species showed good growth without indication of toxicity or adaptation lag. The highest fluoride concentration caused 25–30% growth-rate inhibition of a diatom, a dinoflagellate, and a haptophyte; other diatoms and species from other classes of algae were virtually unaffected. It is hypothesized that the unexpected lack of toxicity from F− ion may be due to the formation of innocuous complexes with one or more ions of seawater. The ecological inference is drawn that fluoride pollution may be readily tolerated by some marine phytoplankton under nutrient-sufficient conditions. Key words: marine phytoplankton, growth in culture, fluoride-pollution effects

Studies in the brown alga Ectocarpus in culture: ultrastructural localization of enzymic activities

The localization of enzymic activities (catalase. peroxidase, adenosinetriphosphatase) in vegetative cells of Ectocarpus sporophytes was carried out at the ultrastructural level.Catalase (EC 1.11.1.6) was only found in organelles recognizable as microbodies. Peroxidase (EC 1.11.1.7) was present in the cell wall, but the deposition of reaction product was also observed in the perinuclear space, endoplasmic reticulum, dictyosomes, and paramural space. Adenosinetriphosphatase (ATPase) (EC 3.6.1.3) was found associated with mitochondria, thylakoids, and the plasma membrane.