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H Young

Publications and source records attributed to H Young.

At least 145 records · Page 8Linked to original sources
PubMed1991

An analysis of false positive reactions occurring with the Captia Syph G EIA.

AIM: The Captia Syph G enzyme immuno assay (EAI) offers the potential for the rapid automated detection of syphilis antibodies. This study was designed to assess the role of other sexually transmitted diseases (STDs) in producing false positive reactions in the Captia Syph G EIA. The role of rheumatoid factor (RF) as a potential source of false positives was also analysed. METHODS: Patients who attended a genitourinary medicine (GUM) department and gave a false positive reaction with the EIA between 1988 and 1990 were compared with women undergoing antenatal testing and with the control clinic population (EIA negative) over the same time period. The incidence of sexually transmitted disease (STD) in the clinic population and the false positive reactors was measured in relation to gonorrhoea, chlamydia, genital warts, candidiasis, "other conditions not requiring treatment" and "other conditions requiring treatment." Male: female sex ratios were also compared. Ninety two RF positive sera were analysed with the EIA. RESULTS: The rate of false positive reactions did not differ with respect to the diagnosis within the GUM clinic population. The antenatal group of women, however, had a lower incidence of false positive reactions than the GUM clinic group. No RF positive sera were positive on Captia Syph G EIA testing. CONCLUSIONS: There is no cross reaction between Captia Syph G EIA and any specific STD or with RF positive sera. The lower incidence of false positive reactions in antenatal women is unexplained but may be related to physiological changes associated with pregnancy.

False Positive Reactions↗
PubMed1991

Studies of myocardial protection in the immature heart. V. Safety of prolonged aortic clamping with hypocalcemic glutamate/aspartate blood cardioplegia.

This study tests the hypothesis that multidose, hypocalcemic aspartate/glutamate-enriched blood cardioplegia provides safe and effective protection during prolonged aortic clamping of immature hearts. Of 17 puppies (6 to 8 weeks of age, 3 to 5 kg) placed on vented cardiopulmonary bypass, five were subjected to 60 minutes of 37 degrees C global ischemia without cardioplegic protection and seven underwent 120 minutes of aortic clamping with 4 degrees C multidose aspartate/glutamate-enriched blood cardioplegia ([Ca++] = 0.2 mmol/L), preceded and followed by 37 degrees C blood cardioplegic induction and reperfusion. Five puppies underwent blood cardioplegic perfusion for 10 minutes without intervening ischemia to assess the effect of the cardioplegic solution and the delivery techniques. Left ventricular performance was assessed 30 minutes after bypass was discontinued (Starling function curves). Hearts were studied for high-energy phosphates and tissue amino acids. One hour of normothermic ischemia resulted in profound functional depression, with peak stroke work index only 43% of control (0.7 +/- 0.1 versus 1.7 +/- 0.2 gm x m/kg, p less than 0.05). There was 70% depletion of adenosine triphosphate (7.6 +/- 1 versus control 20.3 +/- 1 mumol/gm dry weight, p less than 0.05) and 75% glutamate loss (6.6 +/- 1 versus control 26.4 +/- 3 mumol/gm, p less than 0.05). In contrast, after 2 hours of aortic clamping with multidose blood cardioplegia preceded and followed by 37 degrees C blood cardioplegia, there was complete recovery of left ventricular function (peak stroke work index 1.6 +/- 0.2 gm x m/kg) and maintenance of adenosine triphosphates, glutamate, and aspartate levels at or above control levels adenosine triphosphate 18 +/- 2 mumol/gm, aspartate 21 +/- 1 versus control 2 mumol/gm, and glutamate 25.4 +/- 2 mumol/gm). Puppy hearts receiving blood cardioplegic perfusion without ischemia had complete recovery of control stroke work index. We conclude that methods of myocardial protection used in adults, with amino acid-enriched, reduced-calcium blood cardioplegia, can be applied safely to the neonatal heart and allow for complete functional and metabolic recovery after prolonged aortic clamping.

Adenosine Triphosphate↗
PubMed1990

First coitus before menarche and risk of sexually transmitted disease.

The prevalence of sexually transmitted disease (STD), pelvic inflammatory disease (PID), and cervical cancer, and the relation between these conditions were studied in 2111 Ethiopian women. Early sexual activity was associated with an increase in prevalence rates of STD and PID; possible aetiological factors include physical and immunological immaturity of the female genital tract and the number of sexual partners.

Adolescent↗
PubMed1990

In vivo measurement of brain water by MRI.

A new method for determining brain tissue water using MRI, developed in the laboratory, has been tested and applied to the clinical setting. To evaluate the accuracy of the technique, samples of human brain tissue were harvested from patients scheduled to undergo surgical removal of tumour and in whom biopsies were required for clinical management. MR determined values from imaging water maps compared favourably with gravimetric measures of samples. From these data, we conclude that accurate non-invasive measures of brain oedema in man are now possible.

Biopsy↗
PubMed1990

Gonococcal infection within Scotland: antigenic heterogeneity and antibiotic susceptibility of infecting strains.

Two panels of monoclonal antibody reagents were used to serotype all strains of Neisseria gonorrhoeae isolated from four separate geographical areas serving two million of the five million Scottish population. Serotype 1B isolates accounted for 60% of the 869 strains examined and were more prevalent than 1A isolates in each geographical area. A total of 11 1A serovars and 47 1B serovars were recognised. Only two of the 11 1A serovars (Aedgkih/Arost and Aedih/Arst) were found in every centre but these accounted for over 90% of the 1A isolates. Although there was a total of 47 different 1B serovars over 80% of the isolates were accounted for by the ten most commonly encountered serovars. There were, however, marked geographical differences within both major and minor serovars. There was a highly significant difference (P less than 0.001) between protein 1A and 1B serovars with respect to their susceptibility to penicillin. Within each protein 1 type there were also differences in antibiotic susceptibility. Penicillinase-producing N. gonorrhoeae (PPNG) were found in all centres and accounted for 24 (2.8%) of the 869 isolates. The majority of the PPNG (71%) were serotype 1A and with one exception were serovar Aedih/Arst. PPNG strains accounted for 37% (16) of the 43 Aedih/Arst isolates. Epidemiological, diagnostic and therapeutic implications arising from the distinct geographical differences in the pool of circulating gonococci are discussed.

Antibodies, Monoclonal↗
PubMed1990

Influence of human immunodeficiency virus infection on treponemal serology, in patients who have been treated for syphilis.

Sera from 20 homosexual men who were infected with the human immunodeficiency virus (HIV) and had been treated previously for syphilis, were examined for cardiolipin and treponemal antibodies by the Venereal Diseases Research Laboratory (VDRL) test, and the Treponema pallidum haemagglutination assay (TPHA) and fluorescent treponemal antibody absorbed test. In only one case was probable reactivation of syphilis, as judged by rising titres in the VDRL test, noted.

Adult↗
PubMed1990

Is coexisting chlamydial infection more common in gonococcal infections with serogroup WI?

Over a 4-year period a total of 8974 women were screened for Neisseria gonorrhoeae and Chlamydia trachomatis. There were 489 cases of cervical gonorrhoea, 261 serogroup WI and 228 serogroup WII/III. A total of 169 (34.6%) cases had a dual infection with C. trachomatis, 92 from the WI serogroup and 77 from the WII/III. Using Fisher's exact test, no statistically significant difference was observed in the rates of chlamydial carriage between the two serogroups (P = 0.39). These findings are at odds with previously reported data, which suggested a biological interaction resulting in a positive correlation between colonization with serogroup WI and C. trachomatis. Possible reasons for the difference between the findings are discussed.

Chlamydia Infections↗
PubMed1989

Improvement of ischemia-reperfusion-induced myocardial dysfunction by modulating calcium-overload using a novel, specific calmodulin antagonist, CGS 9343B.

The present paper explores the mechanism of calcium-overloaded cardiac cell exocytosis during reperfusion of ischemic myocardium. A novel specific inhibitor of calmodulin, CGS 9343B, was used to pretreat an ischemic heart in an effort to enhance myocardial preservation. The experimental model employed an isolated in situ pig heart subjected to 120 min of ischemic insult by reversibly occluding the left anterior descending coronary artery, the last 60 min being superimposed with global hypothermic cardioplegic arrest. This ischemic episode was followed by 60 min of revascularization. CGS 9343B enhanced post-ischemic myocardial recovery, as judged by improved regional as well as global myocardial functions, better preservation of high-energy phosphate compounds, and reduced release of creatine kinase. Since this compound blocks calmodulin without inhibiting protein kinase C, the results of this study suggest that calmodulin-dependent kinase, rather than protein kinase C, is primarily involved in expressing calcium-overloaded cell exocytosis, and a specific calmodulin antagonist such as CGS 9343B can be used to salvage an ischemic heart from reperfusion injury.

Animals↗
PubMed1989

Analysis of the blocking activity of charybdotoxin homologs and iodinated derivatives against Ca2+-activated K+ channels.

Two charybdotoxin peptides were purified from venom of the Israeli scorpion, Leiurus quinquestriatus hebraeus. Microsequencing of the most abundant toxin, ChTX-Lq1, revealed identity with the 37-residue peptide previously sequenced by Gimenez-Gallego et al. [Gimenez-Gallego, G., et al., Proc. Natl. Acad. Sci. USA 85:3329-3333 (1988)]. Sequence data on the minor peptide, ChTX-Lq2, showed substantial homology to ChTX-Lq1 with differences observed at eight positions. These two charybdotoxin sequences, along with that of noxiustoxin, define a distinct family of scorpion peptide toxins with activity against K+ channels. Both charybdotoxin homologs inhibited Ca2+-dependent K+ efflux from human erythrocytes with similar potency, K0.5 approximately 40 nM. In planar bilayer assays of single K(Ca) channels from rat muscle, ChTX-Lq1 and ChTX-Lq2 blocked with intrinsic Kd's of 1.3 and 43 nM, respectively, in the presence of 50 mM external KCl. A new application of dwell-time histogram analysis of single-channel blocking events was used to characterize the kinetic homogeneity of toxin samples and the blocking kinetics of ChTX derivatives. The lower blocking affinity of ChTX-Lq2 was the combined result of a faster dissociation rate and a slower association rate as compared to ChTX-Lq1. The blocking activity of two mono-iodinated derivatives of ChTX-Lq1 was also analyzed. Blocked dwell-time histograms of the iodinated peptides were characterized by predominately brief (0.2-2 sec) blocking events in comparison to the native toxin (20 sec). Histogram analysis revealed that mono-iodination of ChTX-Lq1 impairs blocking activity by adverse effects on both dissociation and association rate constants. Frequency density histograms of single channel blocking events provide a sensitive assay of toxin purity suitable for quantitating structure-activity relationships of charybdotoxin derivatives.

Amino Acid Sequence↗
PubMed1989

Genital gonorrhoea in women: a serovar correlation with concomitant rectal infection.

Strains of gonococci isolated from 383 episodes of infection in women were classified serologically by means of two independently developed panels (Pharmacia (Ph) and Genetic Systems (GS] of monoclonal coagglutination reagents. Strains isolated from two groups of patients-those with concomitant genital and rectal infection (Group R) and those with genital infection in the absence of rectal infection (Group G)-were compared in order to determine whether certain strains of gonococci are isolated more often from women with concomitant rectal infection. Group R patients accounted for 126 (33%) episodes and Group G patients accounted for 223 (58%) episodes. Strains belonging to serogroup WII/III accounted for 61 (48%) Group R infections and 86 (39%) Group G infections. The difference was not statistically significant (0.1 greater than P greater than 0.05). Strains of serogroup WI could be resolved into 7 Ph- and 10 GS-serovars while strains of serogroup WII/III could be resolved into 19 Ph- and 14 GS-serovars. One GS-serovar, Bajk, was isolated from 34 (27%) Group R patients compared with 39 (17%) Group G patients. This difference was statistically significant (P = 0.05). Compared with non-Bajk isolates, Bajk strongly correlated with reduced susceptibility to penicillin: 60 (92%) Bajk isolates had minimum inhibitory concentrations (MIC) greater than or equal to 0.06 mg/l penicillin compared with 81 (33%) non-Bajk isolates (P less than 0.001). The GS-serovar Bacejk, however, was significantly less susceptible to penicillin than was serovar Bajk: 26 (90%) Bacejk isolates had MICs greater than or equal to 0.12 mg/l penicillin compared with 29 (44%) Bajk isolates (P less than 0.001). Therefore decreased susceptibility to penicillin does not lead in itself to rectal colonisation. It was concluded that certain gonococcal strains are more likely to cause concomitant rectal infection than others and that their reduced susceptibility to penicillin suggests that rectal test-of-cure cultures are essential in those women treated for anogenital infection.

Female↗
PubMed1989

Cardiogenic shock after acute coronary occlusion. Pathogenesis, early diagnosis, and treatment.

The early natural history of left anterior descending coronary artery (LAD) occlusion and the development of cardiogenic shock was studied in 35 open chest anesthetized dogs observed for 6 hours. Six control dogs underwent LAD isolation without occlusion, 13 underwent isolated LAD occlusion to simulate single vessel disease, and 14 underwent LAD occlusion and a 50% left circumflex coronary artery (LCA) stenosis to stimulate multi-vessel disease. Control dogs undergoing anesthesia showed no significant changes in hemodynamics after 6 hours. All dogs with single vessel disease survived and developed immediate and persistent dyskinesis of the anterior wall, a compensatory hypercontractility of remote muscle (131% of control)*, slight energy and substrate depletion and anaerobic metabolism (increased G6P)* despite maintenance of "normal" blood flow through the LCA. In contrast, early mortality was 57% in simulated multi-vessel disease as intractable ventricular fibrillation and/or cardiogenic shock caused the deaths of 7 of 13 dogs (57%)*. Remote muscle became progressively hypocontractile (61% of control)* and caused progressive reduction in stroke work index (less than or equal to 0.5 g x m/kg)*. Remote muscle showed moderate substrate and energy depletion (greater than or equal to 60% fall of ATP and CP, 37% fall of glutamate)* and more pronounced evidence of anaerobic metabolism (G6P rose 373%)* despite "normal" blood flow. These findings suggest that remote muscle is the principle determinant of mortality after an otherwise non-lethal cardiac event.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1989

An assessment of the value of Ag NOR staining in the identification of dysplastic and other borderline melanocytic naevi.

One hundred and six melanocytic lesions were studied to determine the value of the so called Ag NOR technique in differentiating dysplastic naevi, Spitz naevi and spindle cell naevi of Reed from malignant melanoma and from 'banal' compound or intradermal naevi. In 79 cases Ag NOR counts were possible. The banal naevi (36) had a mean count of 1.54, (SD 0.3), and the unequivocally malignant superficial spreading melanomas (13), lentigo maligna melanomas (4) and secondary melanomas (4) had a mean count overall of 3.9 (SD 1.59). For dysplastic naevi (16) the mean Ag NOR count was 1.63 (SD 0.36) and for Spitz and spindle cell naevi (in toto 6) the figure was 1.72 (SD 0.55). The difference in Ag NOR counts between all types of naevi and all types of melanoma was highly statistically significant, but there was no difference between banal naevi and dysplastic, Spitz, and spindle cell naevi. Correlation of Ag NOR counts between three independent observers was good. This technique may, therefore, be a useful adjunct in separating true melanoma from borderline melanocytic naevi.

Antigens, Nuclear↗
PubMed1989

Infection with Chlamydia trachomatis and Neisseria gonorrhoeae in women with lower abdominal pain admitted to a gynaecology unit.

One hundred and sixty-five women admitted to a gynaecology unit with lower abdominal pain were screened for infection with Neisseria gonorrhoeae and Chlamydia trachomatis by members of a department of genitourinary medicine. C. trachomatis alone was detected in 21 patients. N. gonorrhoeae alone was isolated from five patients, and dual infection was present in six patients, giving a total of 32 (19%) patients in whom a sexually transmitted disease (STD) was diagnosed. The combination of an endocervical swab placed in Amies transport medium for gonococcal isolation and an endocervical slide for immunofluorescent detection of chlamydiae proved to be a simple and accurate method of screening for STD. As a result of contact tracing, 16 sexual partners of women in whom STD was detected were examined. Three cases of gonococcal and nine cases of non-gonococcal urethritis were diagnosed. None of the sexual partners had symptoms suggestive of genitourinary infection.

Abdomen↗
PubMed1989

Utility of monoclonal antibody coagglutination to identify Neisseria gonorrhoeae.

The Phadebact monoclonal gonococcus coagglutination test was evaluated with 1367 (996 anogenital and 371 pharyngeal) neisserial isolates from patients who gave positive diagnostic test results for Neisseria gonorrhoeae. The overall correlation with carbohydrate utilisation was 99.7%. The Phadebact test had a specificity of 100% (286/286) and a sensitivity of 99.7% (1077/1080). The three non-reactive strains were epidemiologically linked and were of a very unusual serovar. Unlike polyclonal antibody based tests, the monoclonal antibody test provides reliable identification of gonococci from anogenital and pharyngeal sites. Because non-reactive strains are rare, however, negative anogenital isolates from heterosexual patients should be tested biochemically. The use of two reagents comprising separate pools of monoclonal antibodies against gonococcal protein IA and IB permitted the identification of an appreciable number of double infections, which would otherwise have been missed. Genital, rectal, and pharyngeal isolates from the same patient should be identified individually.

Agglutination Tests↗
PubMed1989

Screening for treponemal infection by a new enzyme immunoassay.

A new enzyme immunoassay (EIA, Captia Syphilis-G) for detecting IgG antibodies against Treponema pallidum was evaluated as a screening test for syphilis. When serum samples were tested at a dilution of 1 in 20 (EIA20), the overall agreement between the IgG EIA and serological status based on the T pallidum haemagglutination assay (TPHA) and the fluorescent treponemal antibody absorption (FTA-ABS) test was 99.2% (1310/1321). The sensitivity of the EIA20 was 98.4% (60/61) and the specificity 99.3% (1251/1260). Discrimination between patients with and without treponemal infection was good: the mean EIA20 absorbance ratios (patient/mean low titre positive control results) were 0.49 for antibody negative patients, 3.30 for patients with positive Venereal Diseases Research Laboratory (VDRL) test and TPHA results, and 1.77 for patients with negative VDRL but positive TPHA results. The cut off point for excluding treponemal infection was taken as 0.9. Specimens with ratios of more than 0.9 should be confirmed by the FTA-ABS test and evaluated for specific IgM antibodies to treponemes. When serum samples were tested at a 1 in 50 dilution (EIA50) the sensitivity was lower (80.3%) but the specificity was absolute. The reduction in sensitivity correlated with low absorbance ratios in the patients who were VDRL negative and TPHA positive. The screening performance of the IgG EIA20 is thus comparable with that provided by a combination of the VDRL test and TPHA. The potential for automation makes the EIA an attractive alternative, particularly in larger centres. Alternatively, the test can be performed at a 1 in 50 dilution (EIA50), at which level it is ideally suited for confirming the treponemal status of antibodies in serum samples preselected by positive cardiolipin antigen screening test results.

Antibodies, Bacterial↗