Detection of Pseudomonas fluorescens and Related Psychrotrophic Bacteria in Refrigerated Meat by a Sandwich ELISA

A sandwich enzyme-linked immunosorbent assay (ELISA) was developed for detection of Pseudomonas fluorescens and related psychrotrophic bacteria in refrigerated meat. Polyclonal antibodies were raised in rabbits against protein F from the cell envelope of P. fluorescens AH-70. The ELISA involved capturing antigens from the microorganisms present on meat samples with the anti-protein F antibodies immovilized on 96-well plates, and detecting bound antigens with the same anti-PF antibodies conjugated to biotin. Commercial ExtrAvidin-peroxidase conjugate was used to detect the biotinylated antibodies bound to their specific antigens. Subsequent enzymatic conversion of substrate gave distinct absorbance differences when assaying meat samples containing P. fluorescens strains of different origin as well as related psychrotrophic microorganisms. The detection threshold for the ELISA assay developed in this work is 10⁵ CFU/cm².

Evidences for the presence of chymotrypsin-like activity in human spermatozoa with a role in the acrosome reaction

The effect of chymotrypsin inhibitors and substrates on the human sperm acrosome reaction stimulated by the human zonae pellucidae or follicular fluid were evaluated. Motile spermatozoa, selected by a Percoll gradient, were incubated at 1 x 10(7) cells/ml, 37 degrees C, and 5% CO2. After 4.5 hr, the chymotrypsin inhibitor TPCK (N-Tosyl-L-Phenylalanine-Chloromethyl Ketone) or the substrate ATEE (N-Acetyl-L-Tyrosine Ethyl Ester) were added for 30 min. Then, four oocytes were added and the percentage of acrosome-reacted spermatozoa on the zona was determined. TPCK and ATEE inhibited the zona pellucida-induced acrosome reaction. The chymotrypsin inhibitors TPCK and chymostatin and the chymotrypsin substrates ATEE, BTEE (N-Benzoyl-L-Tyrosine Ethyl Ester), Succinyl-Ala-Ala-Phe-7-Amido-4-Methyl-Coumarin (Suc-Ala-Ala-Phe-AMC), and Succinyl-Leu-Leu-Val-Tyr-7-Amido-4-Methyl-Coumarin (Suc-Leu-Leu-Val-Tyr-AMC) inhibited the human follicular fluid-induced acrosome reaction. Sperm extracts exhibited hydrolytic activity toward Suc-Ala-Ala-Phe-AMC and Suc-Leu-Leu-Val-Tyr-AMC. This enzyme activity was abolished by TPCK and chymostatin, was independent of Ca2+, and was not modified by 1,10 phenanthroline. In addition, the activity was present in the supernatant after the acrosome reaction was induced with calcium ionophore and in epididymal spermatozoa recovered from the cauda region. Electron microscopic observations indicated that the inhibitors prevented the membrane events of the acrosome reaction. These data suggest an association between human spermatozoa and chymotrypsin-like activity with a possible role in the acrosome reaction.

Sperm-oocyte interaction: studies on the kinetics of zona pellucida binding and acrosome reaction of human spermatozoa

Successful sperm-oocyte interaction depends, among other things, on sperm capacitation, which is defined by acrosomal and motility alterations. In the study described here the authors evaluated different aspects of this gamete interaction in humans. Specifically, the authors studied (1) the relationship between the number of spermatozoa bound to the zona pellucida and sperm concentration and incubation period, (2) the capacitation status and kinetics of acrosome reaction among the zona-bound spermatozoa, and (3) the effect of human follicular fluid on the zona-binding potential and acrosome status of spermatozoa from different men. The results indicated a concentration of 10(7) cells ml-1 after 15 min of coincubation to be the optimum for zona binding. The number of sperm bound after 0, 3 and 5 h of incubation was the same. In addition, spermatozoa incubated for 3 or 5 h underwent the acrosome reaction (range 9-43%) on the zona surface within 15 min of binding. The maximum percentage of acrosome-reacted spermatozoa was reached after 60 min of binding. Follicular fluid affected the sperm populations selectively, since it did not influence zona binding capacity in all cases. The data enhances the authors' understanding of critical events occurring before fertilization.

Assessment of sperm function in fertile and infertile men

The sperm function of fertile men (control), infertility patients (experimental), and men with varicocele were compared. The bioassays used were the follicular fluid-induced acrosome reaction, the binding to the zona pellucida, and the penetration of zona-free hamster oocytes. The percentage (mean +/- SEM) of reacted spermatozoa was 35 +/- 3 in the control, 22 +/- 1 in the experimental, and 22 +/- 3 in the varicocele. The minimum value of acrosome reaction in control men was 20%. The mean number of zona-bound spermatozoa was 250 +/- 30 in the control, 160 +/- 28 in the experimental, and 196 +/- 44 in the varicocele. The minimum number of zona bound spermatozoa in control men was 50. The mean number of hamster oocytes penetrated was 50 +/- 8 in the control, 19 +/- 3% in the experimental, and 10 +/- 3 in the varicocele. The minimum number of oocytes penetrated in control men was 6%. In the experimental group, 22 men had a normal sperm function, 58 had 1 or 2 bioassays below the minimum (relative dysfunction), and 10 had all bioassay below the minimum (abnormal sperm function). The results of these bioassays could help to reclassify the infertile men in several subgroups.

Monoclonal Antibody Detection of Porcine Meat

A stable hybridoma cell line (DD9) has been produced secreting a monoclonal antibody specific for porcine muscle proteins. The DD9 monoclonal antibody (mAb) failed to show a significant cross-reactivity when tested against beef, horse, chicken, and soya proteins, as well as bovine caseins, gelatin, and bovine serum albumin. The DD9 mAb was further used in an indirect ELISA format for detection of defined amounts of porcine meat (1-100%) in beef and chicken meat mixtures immobilized on 96-well plates. Immunorecognition of monoclonal antibodies adsorbed to porcine meat was made with rabbit anti-mouse immunoglobulins conjugated to the enzyme horseradish peroxidase.

Dialysis membranes and PTH changes during hemodialysis in patients with secondary hyperparathyroidism

Changes in parathyroid hormone (PTH) during hemodialysis have been explained by the influence of ionized calcium changes on PTH secretion. In this study we have investigated the influence of dialysis membranes of different permeability on PTH changes during hemodialysis. Five chronic renal failure patients underwent three consecutive hemodialysis sessions with cuprophane (CUP) polysulfone (PS) and polyacrylonitrile (PAN). Two hours of isolated ultrafiltration were followed by 3 h dialysis. A significant decrease in carboxy terminal PTH (COOH PTH) was observed with PAN (p < 0.05) but not with CUP or PS. Intact PTH decreased (p < 0.001) with all three membranes, following a significant increase in ionized calcium (p < 0.001). Sieving coefficients for COOH PTH were significantly lower with CUP than with PS (p < 0.05) or PAN (p < 0.001). Intact PTH sieving coefficients were near zero for all three membranes. COOH PTH and intact PTH clearance rates were significantly higher with PAN (p < 0.001) than with PS or CUP, either in isolated ultrafiltration or with dialysis fluid. Thus PTH changes during hemodialysis do not only depend on the increase in calcium but also on the nature of the dialysis membrane. Adsorption of PTH to the PAN membrane surface explain the high PTH clearance rates achieved with this filter.

Clinical follow-up in 24 nonfamilial renal tumors cytogenetically characterized in tissue culture

OBJECTIVE

This study investigates the relationship between clonal chromosomal abnormalities detected in nonfamilial renal cell carcinoma and the clinical outcome, specifically, whether or not patients whose tumors had karyotypic changes have a different prognosis than those whose tumors did not.

METHOD

Fresh tumor tissue obtained from 32 cases was grown in tissue culture. Twenty four grew successfully and were harvested and multiple cells of each karyotyped. Clinical follow-up was obtained for at least five years or until the time of death.

RESULTS

Fourteen of 24 cases demonstrated karyotypic abnormalities including loss of Y chromosome (64%), trisomy 7 (50%), trisomy 12 (14%), trisomy 9, 10, 14, 15, 16, and 17, monosomy 9 and 20, and long-arm deletion of chromosome 16 (1 case each). Tumors were well-differentiated in 16 cases, moderately differentiated in 5 cases, and poorly differentiated in 1 case; 13 cases were pathologic Stage I, 5 Stage II, and 6 Stage III. Thirty-three percent of the patients demonstrated clinical progression.

CONCLUSIONS

No significant difference in prognosis could be found between patients with and without karyotypic abnormalities. The only clinical or pathologic difference which could be established was sex distribution. Significantly greater numbers of males had karyotypic abnormalities than females, but this could be explained by the high number of Y chromosome deletions that were detected. The lack of correlation between karyotypic abnormalities and clinical outcome may reflect a confounding factor in genetic evolution such that clinically determining chromosomal changes present early in a tumor's growth in vivo may no longer be present when the tumor is diagnosed, treated, or after it is grown in culture. This may make demonstration of such clinically significant chromosomal changes very difficult.

Effect of multidose intracorporeal injection and audiovisual sexual stimulation in vasculogenic impotence

Erections are inhibited by sympathetic stimulation. Anxiety or psychologic inhibition may produce abnormal response during impotence workup. The use of intracorporeal alpha blockers (phentolamine) and audiovisual sexual stimulation (AVSS) has been used to decrease sympathetic outflow and enhance erectile response. Thirty-three patients with suspected vasculogenic impotence were studied. They underwent pulsed Doppler ultrasound (PDUS) with multiple doses of tri-mix (mix of papaverine, phentolamine, and prostaglandin E1). AVSS was applied after maximal response to tri-mix. Seventeen patients (51.5%) responded to multidose with grade IV or V erection. When AVSS was started, 5 more patients responded, and 7 upgraded to grade V with overall response of 40 percent. AVSS can augment the in-office response to pharmacologic testing above that obtained by "maximal" pharmacologic dosing, thereby increasing the sensitivity and specificity of the test.

Pentoxifylline increases sperm penetration into zona-free hamster oocytes without increasing the acrosome reaction

Several drugs have been used to stimulate human sperm motility, including 3-deoxy-adenosine, caffeine, and pentoxifylline. Pentoxifylline is an inhibitor of the phosphodiesterase and may stimulate sperm motility by increasing the intracellular levels of cAMP. In this study we have evaluated the effect of pentoxifylline in the outcome of the sperm penetration assay into zona-free hamster oocytes. Twenty-seven semen samples, obtained for diagnostic purposes, were used. After the motile sperm were selected by the swim-up technique, the samples were divided into two aliquots. One aliquot was incubated with 1 mg ml-1 of pentoxifylline at 37 degrees C, 5% CO2 for 30 min. The control aliquot was incubated with culture medium. The samples were then washed and resuspended in fresh, pentoxifylline-free medium, at a sperm concentration of 10 x 10(6) cells ml-1. One hundred microlitres of each sperm suspension was then deposited under oil and 30-40 zona-free hamster oocytes were added. After 6 h of gamete coincubation, the percentage of penetrated oocytes and the number of decondensed sperm heads were evaluated. The percentage of acrosome-reacted sperm was evaluated using the Pisum sativum lectin. The percentage of zona-free hamster oocytes penetrated was increased after pentoxifylline-treatment. The percentage of acrosome reacted sperm and the number of decondensed sperm heads per egg were not different between the control and the pentoxifylline-treated groups. The results suggest that the beneficial effect of pentoxifylline upon the sperm cells is not mediated by stimulation of the acrosome reaction.

Studies of lysophospholipids related to the hamster sperm acrosome reaction in vitro

Phospholipase A2 and lysophospholipids have been implicated in the mammalian sperm acrosome reaction. In this study we further investigated the role of this enzyme and lysophospholipids on the acrosome reaction of hamster spermatozoa. Hamster epididymal spermatozoa were incubated under capacitation and acrosome reaction-inducing conditions. After 3.0 and 3.5 h, the spermatozoa were treated with different doses of lysophosphatidylcholine for 12 min. Then the percentage of motility, hyperactivation, and acrosome reaction was evaluated by light microscopy. Lysophosphatidylcholine, 10 micrograms/ml, was the highest acrosome reaction-inducing dose without an effect on sperm motility. Lysophosphatidylcholine induced the acrosome reaction only when added to spermatozoa capacitated for a minimum of 2 h. This effect was apparent after 1 min of its addition and reached a plateau after 5 min. Lysophosphatidylethanolamine and lysophosphatidylinositol were also effective in inducing the acrosome reaction. Lysophosphatidylserine did not have any effect on the reaction, but caused an increase in sperm hyperactivation. Sperm treated with the phospholipase A2 inhibitors quinacrine dihydrochloride and p-bromophenacyl-bromide showed an inhibition of the spontaneous occurrence of the acrosome reaction. These inhibitors, however, did not block the acrosome reaction induced by lysophosphatidylcholine. The time course of the lysophosphatidylcholine-induced acrosome reaction was the same whether control or inhibitor treated spermatozoa were used. These results suggest that the membrane events of the acrosome reaction initiate with the activation of the phospholipase A2, thus producing the fusogen agents necessary for this exocytotic event.

Clinical gallbladder disease in NIDDM subjects. Relationship to duration of diabetes and severity of glycemia

OBJECTIVE

To examine the relationship between the prevalence of gallbladder disease and severity of glycemia among diabetic individuals and to provide insight into whether the diabetes-gallstone association is a causal one, because NIDDM patients have an increased prevalence of clinical gallbladder disease.

RESEARCH DESIGN AND METHODS

We examined 462 diabetic individuals identified during the San Antonio Heart Study, a population-based survey of diabetes and cardiovascular disease in Mexican Americans and non-Hispanic whites. Diabetes was diagnosed according to National Diabetes Data Group criteria.

RESULTS

The prevalence of self-reported gallbladder disease was 34.2% in diabetic women and 7.2% in diabetic men. Although duration of diabetes was positively related to the prevalence of gallbladder disease (P < 0.01), type of therapy was not associated, and fasting glucose concentration was inversely associated with gallbladder disease.

CONCLUSIONS

Factors other than hyperglycemia may account for the increased prevalence of gallbladder disease in diabetic subjects.

Three new HLA-G alleles and their linkage disequilibria with HLA-A

Three new allelic forms of the HLA-G DNA sequence (HLA-G*II, HLA-G*III, and HLA-G*IV) have been identified. With the HLA-G*I sequence (previously designated HLA 6.0) as a reference, HLA-G*II shows a silent (G-->A) mutation at the third base of codon 57, HLA-G*III bears a non-synonymous (A-->T), but conservative, (Thr-->Ser) substitution at the first base of codon 31, and HLA-G*IV shows two silent substitutions: (A-->T) at the third base of codon 107 and (G-->A) at the third base of codon 57. A rapid method of singling out each allele on genomic DNA has been developed by using polymerase chain reaction amplification followed by restriction endonuclease treatment. Also, more or less strong linkage disequilibria has been found between most HLA-A alleles and either HLA-G*I or *II, both being the most prevalent alleles in the population, with a genotypic frequency of 0.55 and 0.38, respectively; HLA-G*III is very rare and HLA-G*IV has a genotypic frequency of 0.07. An evolutive classification of HLA-A alleles results according to their association with either HLA-G*I or HLA-G*II, which does not correlate with the classical serological cross-reacting groups classification. The finding of a strong and selective A/G linkage disequilibria with most HLA-A alleles, together with the existence of less frequent random A/G associations, may suggest that there exist in different haplotypes true and varied A/G genetic distances (and not a recombinational hotspot). It may be inferred from preliminary data that in primates HLA-A/G haplotypes bearing G*II may have appeared later than those bearing G*I.

The cultural construction of childhood diarrhoea in rural Nicaragua: relevance for epidemiology and health promotion

As a component of a series of studies of childhood diarrhoea in rural Nicaragua, lay knowledge regarding the condition and its appropriate management has been investigated through semistructured interviews with 70 mothers. These data have been combined with information from focus group discussions and observations from investigators who have been resident in the study area for many years. For any episode of childhood diarrhoea, the lay nosology influences the treatment path followed. Thus for some types of diarrhoea, treatment at a health centre or health post and the use of rehydration fluids is seen to be appropriate, while for other types the use of traditional healers or home-based treatment, often explicitly without the use of rehydration fluids, is applicable. The implications of lay nosological systems for the interpretation of epidemiological studies and for the implementation of health promotion programmes are discussed.

Bellevue pouch: ileocolonic continent urinary reservoir

The technique for the Bellevue Pouch, another continent intestinal reservoir, is described. A large-capacity low-pressure reservoir is created from detubularized ascending colon, cecum, and terminal ileum. Continence is achieved by means of an intussuscepted segment of ileum and a modulating colonic pressure cuff wrapped around it. The operation has been performed on 19 patients, all of whom achieved satisfactory continence. Two patients were converted to free drainage systems at a later date. Average follow-up was twenty-five months.

Purification and Characterization of Alkaline Xylanases from Bacillus polymyxa

By applying different classical and fast protein liquid chromatographic techniques, three xylanases (β-1,4- d -xylan xylanhydrolase) were purified to homogeneity from the extracellular enzymatic complex of Bacillus polymyxa . The three enzymes (X 34 C, X 34 E, and X 22 ) were small proteins of 34, 34, and 22 kDa and basic pIs 9.3, >9.3, and 9.0, respectively. X 34 C and X 34 E are closely related and seem to be isoforms of the same enzyme. However, they differ in some characteristics. The three enzymes had different pH and temperature optima. One of them, X 34 E, showed a high thermal stability. The V max values determined for X 34 C, X 34 E, and X 22 enzymes on oat spelts xylan were 14.9, 85.5, and 64.0 U mg -1 , respectively, and 16.1, 62.0, and 150.6 U mg -1 on birchwood xylan. When oat spelts xylan was the substrate used, K m values of 3.4, 2.4, and 1.9 mg ml -1 were obtained for X 34 C, X 34 E, and X 22 enzymes, respectively, and 0.65, 6.3, and 0.32 mg ml -1 were the respective K m values determined with birchwood xylan as the substrate. The enzymes were nondebranching endo-β-xylanases. Xylose was one of the products of xylan hydrolysis by xylanases X 34 C and X 34 E, but this monosaccharide was not released by X 22 enzyme. However, neither of the enzymes was able to degrade xylobiose.

Potentiation of drug-induced erection with audiovisual sexual stimulation

Twenty-five patients underwent audiovisual sexual stimulation (AVSS) after pharmacologically-induced erection. Grade of erection and cavernosal blood flow were assessed after intracorporeal (IC) injection of TRI-MIX or prostaglandin E1, and then after AVSS, using pulsed Doppler ultrasonography (PDUS). After IC injection, 5 patients had a Grade II erection, 8 had Grade III, 10 had Grade IV, and 2 had Grade V. There was an increase in peak arterial flow and arterial diameter which corresponded with the grade of erection obtained. After addition of AVSS, 56.5 percent of patients experienced improved erection. The improvement from Grade III to IV in 13 percent is especially significant because it showed the attainment of adequate erection when IC injection alone failed. Penile blood flow improved among AVSS responders but not in nonresponders. AVSS may enhance pharmacologically-induced erection and may improve the diagnostic accuracy of PDUS.

A sandwich enzyme-linked immunosorbent assay (ELISA) for detection of Pseudomonas fluorescens and related psychrotrophic bacteria in refrigerated milk

A sandwich ELISA (enzyme-linked immunosorbent assay) was developed for detection of Pseudomonas fluorescens and related psychrotrophic bacteria in refrigerated milk. Polyclonal antibodies were raised in rabbits against protein F from the cell envelope of Pseudomonas fluorescens AH-70. The anti-protein F antibodies (anti-PF) bound to the wells of a microtitre plate were used to capture this protein from the micro-organisms on milk samples. Further immunorecognition of the captured antigen was attained with the same anti-PF antibodies conjugated to biotin. ExtrAvidin-peroxidase was used to detect the biotinylated antibodies bound to their specific antigens. Subsequent enzymic conversion of substrate gave clear absorbance differences when assaying milk samples containing Ps. fluorescens strains of different origin as well as related psychrotropic micro-organisms.

Evolutionary relationships of HLA-DR8 alleles and description of a new subtype (DRB1*0806) in the Algerian population

A new HLA-DR8 allele (HLA-DRB1*0806) found in the Algerian population is described here. This allele has an exon-2 nucleotide sequence identical to that of the HLA-DRB1*0801 allele, except for a GGT to GTG change in codon 86, yielding an amino acid substitution (glycine to valine). This change is also found in other HLA-DRB1 and HLA-DRB3 evolutionary-related allele pairs. HLA-DRB1*0806 is the most frequent HLA-DR8 allele found in this population (three of eight HLA-DR8-positive individuals) and is included within the HLA-DQA1*0102-DQB1*0602 haplotype (HLA-DQ6 serotype). This combination of HLA-DQ alleles is sporadically found associated with other HLA-DR8 alleles in other ethnic groups, i.e., HLA-DRB1*0804 in Bushmen and in North American blacks and HLA-DRB1*0803 in African blacks. Also, the HLA-DRB1*0806-DQ6 haplotype only bears one HLA-DRB gene copy, a common characteristic of the HLA-DR8 haplotype family. An exon-2 HLA-DR8 dendrogram has also been constructed with the available sequence data, indicating that this new allele does not seem to be placed at a distance significantly different from the origin to that of HLA-DRB1*0804 (proposed to be the eldest in the HLA-DR8 allele diversification pathway). A possible HLA-DR8 evolutive pathway is postulated according to the available exon-2 HLA-DR8 allele sequences.