Search PubMed⌕ Search

Biomedical subjects

R Higgins

Publications and source records attributed to R Higgins.

At least 73 records · Page 4Linked to original sources
PubMed1996

Toward quality assurance for metaphase FISH: a multicenter experience.

Although fluorescent in situ hybridization (FISH) is rapidly becoming a part of clinical cytogenetics, no organization sponsors multicenter determinations of the efficacy of probes. We report on 23 laboratories that volunteered to provide slides and to use a probe for small nuclear ribonucleoprotein polypeptide N (SNRPN) and a control locus. Experiences with FISH for these laboratories during 1994 ranged from 0 to 645 utilizations (median = 84) involving blood, amniotic fluid, and bone marrow. In an initial study of hybridization efficiency, the median percentage of metaphases from normal individuals showing two SNRPN and two control signals for slides prepared at each site was 97.0 (range = 74-100); for slides prepared by a central laboratory, it was 97.8 (range = 81.6-100). In a subsequent blind study, each laboratory attempted to score 5 metaphases from each of 23 specimens [8 with del(15)(q11.2-->q12) and 15 with normal #15 chromosomes]. Of 529 challenges, the correct SNRPN pattern was found in 5 of 5 metaphases in 457 (86%) and in 4 of 5 in 33 (6%). Ambiguous, incomplete, or no results were reported for 32 (6%) challenges. Seven (1%) diagnostic errors were made, including 6 false positives and 1 false negative: 1 laboratory made 3 errors, 1 made 2, and 2 made 1 each. Most errors and inconsistencies seemed due to inexperience with FISH. The working time to process and analyze slides singly averaged 49.5 min; slides processed in batches of 4 and analyzed singly required 36.9 min. We conclude that proficiency testing for FISH by using an extensive array of challenges is possible and that multiple centers can collaborate to test probes and to evaluate costs.

Autoantigens↗
PubMed1996

Toward quality assurance for metaphase FISH: a multi-center experience.

Although fluorescent in situ hybridization (FISH) is rapidly becoming a part of clinical cytogenetics, no organization sponsors multi-center determinations of the efficacy of probes. We report on 23 laboratories that volunteered to provide slides and to use a probe for SNRPN and a control locus. Experiences with FISH for these laboratories during 1994 ranged from 0 to 645 utilizations (median = 84) involving blood, amniotic fluid and bone marrow. In an initial study of hybridization efficiency, the median percentage of metaphases from normal individuals showing two SNRPN and 2 control signals for slides prepared at each site was 97.0 (range = 74-100); for slides prepared by a central laboratory, it was 97.8 (range = 81.6-100). In a subsequent blind study, each laboratory attempted to score 5 metaphases from each of 23 specimens [8 with del(15) (q11.2-->q12) and 15 with normal 15 chromosomes]. Of 529 challenges, the correct SNRPN pattern was found in 5 of 5 metaphases in 457 (86%) and in 4 of 5 in 33 (6%). Ambiguous, incomplete or no results were reported for 32 (6%) challenges. Seven (1%) diagnostic errors were made including 6 false positives and 1 false negative: 1 laboratory made 3 errors, 1 made 2, and 2 made 1 each. Most errors and inconsistencies seemed due to inexperience with FISH. The working time to process and analyze slides singly averaged 49.5 minutes; slides processed in batches of 4 and analyzed singly required 36.9 minutes. We conclude that proficiency testing for FISH using an extensive array of challenges is possible and that multiple centers can collaborate to test probes and to evaluate costs.

Humans↗
PubMed1996

Lymph node metastases and prognosis in patients with stage IA2 cervical cancer.

Ninety-four patients with squamous cell carcinoma invading the cervical stroma to a depth of >3.0-5.0 mm with 7 mm or less in horizontal spread (FIGO Stage IA2) were evaluated. Depth and lateral extent of stromal invasion were verified using an ocular micrometer. Cell type and lymph vascular space invasion (LVSI) were recorded in each case. Patients were treated primarily by radical hysterectomy with pelvic lymphadenectomy, and those with lymph node metastases were offered postoperative radiation. Following treatment, patients were seen at 3-month intervals for 2 years, and every 6 months thereafter. The mean duration of follow-up was 6.9 years (range 0.4-23.5 years). Seven of 94 patients (7.4%) had lymph node metastases. Five patients had 1 positive node, 1 patient had 2 positive nodes, and 1 patient had 3 positive nodes. Five patients developed recurrent cancer and 4 died of disease. LVSI was present in 31 cases (33%). Tumor recurrence was significantly increased in patients with positive LVSI (9.7% vs 3.2%). The 5-year survival rate of patients with LVSI was 89% vs 98% in patients without this finding (P = 0.058). The 5-year survival rate of all Stage IA2 cervical cancer patients was 95%. Patients with Stage IA2 cervical cancer have a significant risk of lymph node metastases and should be treated by radical hysterectomy with pelvic lymphadenectomy. LVSI is an important prognostic variable in these patients and should be recorded in all cases.

Adult↗
PubMed1996

Biochemical and antigenic relationships between porcine and equine isolates of Actinobacillus suis.

A total of 50 Actinobacillus suis isolates were studied for their biochemical and antigenic characteristics. Of them, 40 isolates originated from different tissues of diseased pigs, and the other ten isolates were from horses with respiratory problems. There was no major biochemical difference among equine and porcine A. suis isolates. Results of tube agglutination tests showed that porcines isolates were antigenically homogeneous while equine isolates were heterogeneous.

Actinobacillus↗
PubMed1996

Helicobacter canis isolated from a dog liver with multifocal necrotizing hepatitis.

On the basis of biochemical, phenotypic, and 16S rRNA analysis, a novel gram-negative bacterium, isolated from normal and diarrheic dogs as well as humans with gastroenteritis, has been recently named Helicobacter canis. A 2-month-old female crossbred puppy was submitted to necropsy with a history of weakness and vomiting for several hours prior to death. The liver had multiple and slightly irregular yellowish foci up to 1.5 cm in diameter. Histologically, the liver parenchyma contained randomly distributed, occasionally coalescing hepatocellular necrosis, often accompanied by large numbers of mononuclear cells and neutrophils. Sections of liver stained by the Warthin-Starry silver impregnation technique revealed spiral- to curve-shaped bacteria predominantly located in bile canaliculi and occasionally in bile ducts. Aerobic culture of liver was negative, whereas small colonies were noted on Campylobacter selective media after 5 days of microaerobic incubation. The bacteria were gram negative and oxidase positive but catalase, urease, and indoxyl acetate negative; nitrate was not reduced to nitrite, and the organism did not hydrolyze hippurate. The bacteria were also resistant to 1.5% bile. Electron microscopy revealed spiral-shaped bacteria with bipolar sheathed flagella. By 16S rRNA analysis, the organism was determined to be H. canis. This is the first observation of H. canis in active hepatitis in a dog and correlates with recent findings of Helicobacter hepaticus- and Helicobacter bilis-related hepatic disease in mice. Further studies are clearly warranted to ascertain whether H. canis-associated hepatitis is more widespread in canines as well as a cause of previously classified idiopathic liver disease in humans.

Animals↗
PubMed1996

Myeloencephalitis associated with a viridans group Streptococcus in a colony of Japanese macaques (Macaca fuscata).

Five weaned immature Japanese macaques (Macaca fuscata), bred in captivity, showed nervous signs over a 12-month period. Hemorrhagic cerebral infarcts with vasculitis were detected in four necropsied animals. The distribution and nature of the lesions were consistent with bacterial embolism, and a Streptococcus isolate, biochemically similar to S. salivarius, was recovered from the cerebral lesions from three of the four necropsied macaques. Treatment with antibacterial agents (enrofloxacin) improved the clinical condition of the surviving affected animal. These observations strongly suggest that this Streptococcus spp., member of the viridans group, is responsible for this outbreak. Dental pulpitis, present in two of the four macaques, probably served as the entry for this bacterium.

Animals↗
PubMed1996

Detection of cervical bacterial contamination in swine by two methods of swabbing in relation to artificial insemination.

Factors associated with uterine contamination during artificial insemination (AI) are not well defined. A frequently imputed risk factor is vulvar hygiene, although its role has never been assessed objectively. The aim of this study was to identify an objective marker of hygiene during AI and to assess the impact of vulvar hygiene on cervical contamination. In a herd in a depopulation-repopulation process, 68 paired sows of each parity were divided into 2 treatment groups. Before 2 sham AIs, with a 24 hour interval, control sows (CTR) had their vulva cleaned and treatment sows (TRT) had theirs soiled with feces. After the 2nd sham AI, swabbings were taken from the spirette and from the cervix. Bacterial growth was assessed by a semiquantitative method, and aerobic bacterial species identified. The discordance between the paired data was assessed by a McNemar chi-square test. No difference in gram-positive bacterial counts between the 2 groups was found using the cervical swab (P > 0.05). The presence of trace colonies of Escherichia coli were, however, more frequent in TRT (P < 0.05). The spirette showed a greater contamination for mixed flora of bacterial species such as E. coli (P < 0.001) and non-S. suis streptococci (P < 0.05) in TRT sows. A light cervical E. coli growth was more frequent when the vulva had been soiled. Bacterial flora on the spirette following AI may be used as an objective and practical indicator of vulvar hygiene during AI in sows.

Animals↗
PubMed1995

Non-neoplastic lesions in beluga whales (Delphinapterus leucas) and other marine mammals from the St Lawrence Estuary.

In a 3-year (1988-1990) pathological study, 24 carcasses of beluga whales from the St Lawrence Estuary, Québec, Canada, showed numerous severe lesions, many of which had never been reported in cetaceans. The most common lesions were found in the digestive tract (21 animals) and consisted mainly of periodontitis and of erosions and ulcers in the oesophagus and the first two gastric compartments. Pneumonia, usually of parasitic origin, was also a common finding (12 animals). The adrenal glands often contained nodules (five animals) or cysts (seven animals), and mastitis was observed in five females. Overall, the incidence of degenerative, infectious, hyperplastic or necrotic lesions, in addition to numerous neoplasms described in another paper, was considerably higher than that found in marine mammals elsewhere or in other species of marine mammal from the same waters.

Animal Diseases↗
PubMed1995

A needs-led approach to hospital resettlement.

Reports on an inter-agency initiative in Wakefield that used a needs-led case management approach for the resettlement of 32 former users of long-term hospital mental health services. Reviews the programme using headings provided by the values which underpinned local mental health services, namely, that services should endeavour to be appropriate, acceptable, accessible, effective/efficient and equitable for service users. The main objective of the programme was achieved--32 former users of hospital mental health services were resettled. Issues were, however, raised concerning the extent to which the programme could be described as needs-led. Concludes that there is still much to learn about the application of case management within the British health context.

Community Mental Health Services↗
PubMed1995

Seroepidemiologic study of three zoonoses (leptospirosis, Q fever, and tularemia) among trappers in Québec, Canada.

This study was undertaken to evaluate the prevalence of antibodies against Francisella tularensis, Coxiella burnetii, and certain serovars of Leptospira interrogans among trappers in Québec, Canada. Muskrat trapping was identified as a risk factor for F. tularensis infection, whereas having a cat at home apparently protected trappers against infection by L. interrogans. High percentages of control sera were positive for antibodies against C. burnetii (15%) and L. interrogans (5%), most frequently serovar bratislava. This is the first report of human infection by serovar bratislava in North America.

Adult↗
PubMed1995

Discrimination of virulent and avirulent Streptococcus suis capsular type 2 isolates from different geographical origins.

In an effort to relate the protein profile to virulence, proteins from the cellular fractions and from culture supernatants of Streptococcus suis capsular type 2 strains from different geographical origins were compared by using Western blots (immunoblots). The protein profiles of the cellular fractions were similar for the majority of virulent and avirulent isolates studied, with the exception of three virulent Canadian strains for which a 135-kDa protein was not detected. Examination of the culture supernatants revealed the presence of a 135-kDa protein in all strains except the same three virulent Canadian isolates. In addition, a 110-kDa protein was present in 14 of 16 virulent strains and not in avirulent isolates. When injected into mice, the 110-kDa protein induced an immunoglobulin G response and protected against infection with homologous and heterologous virulent strains. Four strains (1330, 0891, TD10, and R75/S2) that were avirulent in the mouse model of infection and four other strains (1591, 999, JL590, and AAH4) that were virulent in the mouse model were injected into pigs. All virulent strains reproduced the disease, and all avirulent strains failed to reproduce the disease (with the exception of transient lameness in one case and fever in another case). The 110-kDa protein therefore appears to be a reliable virulence marker and a good candidate for a subunit vaccine.

Animals↗
PubMed1995

Purification and characterization of a 52-kilodalton immunoglobulin G-binding protein from Streptococcus suis capsular type 2.

We previously reported that group D streptococci exhibited immunoglobulin G (IgG)-binding activity and that a 52-kDa IgG-binding protein was present in all Streptococcus suis strains examined (B. Serhir, R. Higgins, B. Foiry, and M. Jacques, J. Gen. Microbiol. 139:2953-2958, 1993). The objective of the present study was to purify and characterize this protein. Pig IgG were immobilized through their Fab fragments to ECH-Sepharose 4B, and the protein was purified by affinity chromatography. Electron microscopy observations of the purified material showed filamentous structures with a diameter of approximately 4 nm; these structures were not observed when the material was treated with either urea or ethanolamine. Electrophoretic and Western immunoblot analyses showed that the 52-kDa protein constituted the bulk of the recovered material. This protein was stained with either Coomassie brilliant blue or silver nitrate; it reacted with a large variety of mammalian IgG, human IgG (Fc) fragments, human IgA, and other human plasma proteins. The 52-kDa protein exhibited lower IgG-binding affinities than protein A and protein G. However, it was able to compete with protein A and protein G for binding to human IgG. In addition, it bound chicken IgG with high affinity. This last property differentiated the 52-kDa protein of S. suis from the six IgG-binding proteins described to date. The 52-kDa protein displayed similar affinities for untreated and deglycosylated pig IgG. The N-terminal amino acid sequence (SIITDVYAXEVLDSXGNPTLEV) revealed no homology with any bacterial proteins in the Swiss-Prot database. Its isoelectric point of approximately 4.6 and its amino acid composition, rich in aspartic and glutamic acids, showed that it had some similarities with other IgG-binding proteins. In this report, we have purified and characterized a 52-kDa IgG-binding protein from S. suis capsular type 2. Although this protein shares some similarities with other IgG- and/or IgA-binding proteins, it is unique in reacting with chicken IgG.

Amino Acid Sequence↗
PubMed1995

Need for vaccination of sewer workers against leptospirosis and hepatitis A.

OBJECTIVES: This study compared the prevalence of Leptospira interrogans and hepatitis A virus (HAV) antibodies in serum samples from sewer workers and controls. METHODS: A blood sample was obtained from 76 of the 101 municipal sewer workers (75%) of Quebec City and from two controls matched to each for age and sex. Testing was done for antibodies against serovars of Leptospira icterohaemorragiae, bratislava, hardjo, grippotyphosa, and kennewicki (pomona) and hepatitis A. RESULTS: Sewer workers had a greater prevalence of antibodies against leptospirosis than controls (12% v 2%, P = 0.003). In contrast, antibodies to HAV were not significantly more prevalent among workers than among controls (54% v 49%, P = 0.51). Prevalence of HAV antibodies increased significantly with age both among workers and controls (chi 2 for trend, P < 0.001). In contrast with younger workers, prevalence of HAV antibodies was greater among workers > or = 40 years than among their controls (81% v 65%, P = 0.04). CONCLUSION: Leptospirosis continues to be a problem to sewer workers but hepatitis A is apparently no longer a risk. The likely explanation is that leptospira are still abundant in the sewage system in contrast with HAV, which is only rarely to be found in sewage as a result of the generalised decrease in incidence of hepatitis A in the past three decades. The decision to vaccinate sewer workers against hepatitis A should take into account that it is impossible to avoid all contact with sewage fluid and, despite the fact that the actual incidence of hepatitis A is low, there is a real possibility of sporadic exposure during a future outbreak.

Adult↗
PubMed1995

Porcine colonic spirochetosis: a retrospective study of eleven cases.

This retrospective study of porcine colonic spirochetosis was done in order to characterize the clinical signs, the macroscopical and microscopical changes, and the bacteriological results of cases observed in Quebec. Necropsy records of all cases of colitis were reviewed. Eleven cases with filamentous bacteria colonizing the colonic epithelium were selected. This condition was only observed in weaned piglets, and was associated with mild persistent diarrhea and growth retardation. Macroscopic changes were generally limited to the presence of soft to liquid colonic contents. Adherence of filamentous helicoidal bacteria to the apical surface of the colonic epithelium and mild diffuse infiltration of the colonic lamina propria by mononuclear cells were the main histological findings. Weakly beta-hemolytic spirochetes were isolated in 6 cases. This condition seems to be underestimated for various reasons, and it is possible that some cases diagnosed as nonspecific colitis or superficial colitis, in fact, represent later stages of porcine colonic spirochetosis.

Animals↗