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Biomedical subjects

H M Windsor

Publications and source records attributed to H M Windsor.

At least 19 recordsLinked to original sources
PubMed2001

Helicobacter pylori is not the cause of sudden infant death syndrome (SIDS).

OBJECTIVES: The cause of sudden infant death syndrome (SIDS) is unknown, but our previous hypothesis proposed that Helicobacter pylori could be a causative organism. In this study, we aimed to test this hypothesis by examining gastric and tracheal tissues from a prospective cohort of SIDS infants and re-examining previously studied paraffin-fixed tissues for H. pylori. METHODS: Fresh gastric antral and trachea specimens obtained at postmortem from nine consecutive new cases of SIDS in Perth, Western Australia were studied prospectively. Tissues were evaluated for H. pylori by rapid urease test (CLOtest), bacterial culture, histology (hematoxylin and eosin, Warthin-Starry Silver, and immmunoperoxidase staining), and polymerase chain reaction (PCR). The latter two tests were also used for the re-examination of paraffin-embedded specimens from infants who died from SIDS (n = 17) and other non-SIDS causes (n = 7) in Kansas City, Missouri. RESULTS: Specimens from nine consecutive SIDS infants in Western Australia showed no evidence of H. pylori by any analyses. In the paraffin-embedded gastric and trachea specimens from Missouri, rod and coccoid-shaped bacteria were seen histologically in 33.3% of the specimens, but these were not typical H. pylori. Upon analysis by PCR, "H. pylori DNA" was detected in 53% (9/17) of SIDS samples versus 57% (4/7) in non-SIDS samples. In all cases the immunoperoxidase stain was negative, suggesting that PCR either 1) gave false positive results in this type of potentially contaminated postmortem specimen or 2) H. pylori DNA was indeed present but not increased in prevalence in SIDS infants. CONCLUSIONS: H. pylori is unlikely to be an etiological agent in SIDS.

Child, Preschool↗
PubMed2000

Bacteriology and taxonomy of Helicobacter pylori.

As the scientific community approaches the twentieth anniversary of the first isolation of H. pylori, it appears that despite the wealth of articles published in journals throughout the world every month, there are still many unanswered questions about the microbiology of this bacterium and others in the genus Helicobacter.

Bacterial Typing Techniques↗
PubMed2000

Accurate diagnosis of Helicobacter pylori. Polymerase chain reaction tests.

Although PCR has improved considerably the sensitivity of the diagnosis of H. pylori infection, many studies have not shown conclusively the full potential of PCR in clinical diagnosis. In daily clinical practice, PCR does not have to be performed to establish H. pylori infection. PCR is still classified primarily as a research technique in the Helicobacter field. PCR or similar technology will expand in the future when automation and commercialized kits are available to most laboratories. The development of a noninvasive PCR test may prove useful because it may lead ultimately to the determination of the source and route of transmission of this important pathogen.

DNA, Bacterial↗
PubMed1999

Successful recovery of H. pylori from rapid urease tests (CLO tests).

OBJECTIVE: Culture of Helicobacter pylori (H. pylori) and the determination of its antibiotic susceptibility is of increasing importance with the rise in numbers of antibiotic-resistant strains. The aim of this study was to determine whether H. pylori could be successfully isolated from antral biopsies used in Rapid Urease Tests (CLOtests) in clinical practice. METHODS: Antral biopsies from patients undergoing endoscopy were inserted into the gel of CLOtests to determine the H. pylori status of the patients. If the CLOtest was positive at the end of the endoscopy session, it was kept at ambient temperature until processed. In the laboratory, biopsies were removed from the gel and cultured on selective and nonselective media. In an attempt to enhance the recovery rate of H. pylori, a subset of positive CLOtests were kept at 4 degrees C from the time that the color change was noted until the removal of the biopsy. RESULTS: One hundred and forty-one positive CLOtests were studied at times between 1 h and 6 h postendoscopy. Culture success was 93% in the 1st hour but fell off sharply after 2 h (p < 0.001). Isolation was also improved if positive CLOtests were stored at 4 degrees C and plated out within 4 h (p < 0.001). CONCLUSIONS: H. pylori can be successfully cultured from biopsies in CLOtests kept at room temperature within 2 h or within 4 h if kept at 4 degrees C. Thus the antral biopsy in the CLOtest can be usefully retrieved when, in the light of the CLOtest result, the physician wishes to obtain both culture and antibiotic sensitivity results.

Biopsy↗
PubMed1997

An outbreak of respiratory disease in horses associated with Mycoplasma felis infection.

Lower respiratory tract disease developed in a group of racehorses in training between two and six years of age. Disease was observed in 22 of 25 horses for which full records were available. Seroconversion to Mycoplasma felis was demonstrated by indirect haemagglutination assay in 19 of 22 paired sera and high titres (> or = 64) were found in convalescent sera from the three remaining horses. Evidence of respiratory viral infection was confined to seroconversions to equine herpesvirus-4 in two of the horses. Tracheal wash samples, taken from four horses with visibly increased tracheal mucopus, contained more than 10(4) colony forming units/ml M felis and high proportions of neutrophils. This is the first description of an outbreak of lower respiratory tract disease in horses in training associated with M felis infection.

Animals↗
PubMed1993

Growth characteristics of V factor-independent transformants of Haemophilus influenzae.

Haemophilus influenzae is a V factor-dependent species. A plasmid conferring V factor independence in Haemophilus parainfluenzae and Haemophilus ducreyi was transferred to plasmid-free H. influenzae Rd by DNA transformation. The growth characteristics of the transformants in a complex and a chemically defined medium were compared, and the ability of several exogenous pyridine nucleotides and precursors to support growth was examined. Although the transformants appeared to be V factor independent in a complex medium, in a chemically defined medium they exhibited both V factor-dependent and nicotinamide-dependent growth. Because of the inability of the plasmid-free H. influenzae Rd to utilize nicotinamide for growth, it was concluded that the genes conferring this function were plasmid linked. Our results indicate that the V factor requirement, as it is presently defined, is not suitable to serve as a definitive taxonomic criterion for species determination in the family Pasteurellaceae.

Cell Division↗
PubMed1991

Plasmid-mediated NAD independence in Haemophilus parainfluenzae.

The location of the genes coding for NAD independence in four unusual clinical isolates of Haemophilus parainfluenzae was determined by transferring these genes to plasmid-free Haemophilus influenzae Rd by transformation and analysing transformants for the presence of plasmids by agarose gel electrophoresis. All NAD-independent transformants were found to carry a single plasmid species. The plasmids, originally harboured by the four H. parainfluenzae isolates recovered from unrelated sources, were of the same size (5.25 kb). Spontaneous reversion to NAD dependence occurred with a low frequency (0.1 to 0.2% of the progeny of a single clone) in both H. parainfluenzae and H. influenzae Rd. The revertants had lost this small plasmid. Mitomycin C exhibited a plasmid 'curing' effect with a frequency of 'curing' of between 1 and 6% of the surviving clones. It was concluded that the genes conferring NAD independence were located on the small 5.25 kb plasmid.

Child↗
PubMed1984

Subacute heart rupture and hemopericardium following acute myocardial infarction: report of successful treatment and ten year follow-up.

Hemopericardium complicating acute myocardial infarction generally has a poor prognosis. Two cases of this complication, one due to subacute rupture of the free left ventricular wall, are reported. Both patients are still alive and well ten years after urgent surgical intervention. Good long-term results are possible in this condition if diagnosis and surgical intervention are not delayed.

Assisted Circulation↗
PubMed1982

Postinfarction cardiac rupture.

This paper records an experience of 42 cases of cardiac rupture or syndromes simulating rupture. These include free wall rupture, hemopericardium without rupture, septal rupture associated with free wall rupture, pseudoaneurysm, and septal rupture. These groups constitute a series of syndromes with many features in common in terms of clinical presentation, difficulty in assessment, timing of operative intervention, and operative management. Free wall rupture, which can be simulated by hemopericardium without rupture, is not always rapidly fatal. Successful intervention was achieved in six of the 13 cases in the free wall group. Ventricular septal defect occurs less frequently than free wall rupture, is more easily diagnosed, and less frequently requires urgent medical intervention. In 12 of the 14 cases of acute rupture, stabilization of the patient by conservative measures could not be achieved and operation was undertaken within 1 week of infarction. There were seven survivors, in four of whom the defect reopened, with successful reoperation in three. In the remaining 15 cases, stabilization by conservative measures was achieved and operation was delayed until at least 2 weeks after infarction. There were 14 survivors and only one instance of reopening of the defect.

Aged↗
PubMed1981

Infected ventricular septal defect.

This paper reports a case of recurrent septic pulmonary emboli resulting from bacterial endocarditis on a ventricular septal defect. This was managed by the removal of vegetations, resection of the septal leaflet of the tricuspid valve, closure of the ventricular septal defect, and pulmonary embolectomy. The literature regarding the incidence and mortality of bacterial endocarditis on ventricular septal defects, and the management of the infected tricuspid valve, is reviewed. The patient remains well two and a half years after surgery.

Adult↗
PubMed1979

Cardiac valve replacement (1963-1979).

A 15-year experience (from 1963-1978) in cardiac valve replacements with mechanical prosthetic valves (caged ball or tilting disc types) and with bioprostheses (porcine xenografts) is reported. The actuarial survival rates for patients who received the caged ball type prostheses (Starr-Edwards) were 42% and 36% respectively for mitral valve-replacements at 12 and 14 years. The actuarial survival rate for patients who received the tilting disc type prostheses (Björk-Shiley type and later the Lillehei-Kaster type) was 74% at six to seven years. The actuarial survival rate for patients who had aortic valve replacement with a caged ball valve was 43% at 14 years, and for those who had a tilting disc valve it was 80% at six to seven years. Multiple valve replacements were carried out with combinations of prostheses. The actuarial survival rate for patients was 65% for triple valves, and 57% for double valves at 13 years. Bioprostheses are now our first choice as cardiac valve replacements. In 121 implants performed since 1977, there have been two operative deaths, but no late deaths. Bioprostheses, although less thrombogenic than mechanical valve prostheses, are less durable and some risk of thromboembolism remains.

Adolescent↗
PubMed1978

Perforation of the interventricular septum complicating myocardial infarction.

The presentation and management of 21 patients with postinfarction ventricular septal defect (VSD) in whom surgical treatment was considered or performed since 1970 have been analysed and reviewed. An acute group of 11 patients, each of whom developed cardiogenic shock, 9 of whom came to surgery within one week from the onset of their VSD, had a poor outlook, only 27% becoming long-term survivors. Six patients were classified as subacute because their surgery was precipitated by worsening congestive cardiac failure in all, and by pulmonary oedema at the time of surgery in three patients. Four chronic patients were operated upon electively. The results in the subacute and chronic groups were excellent, and all are long-term survivors. Operative closure of the defect is best achieved by the use of a patch. Infarctectomy and aneurysmectomy are necessary in more than half of the cases. Left ventricular assistance by the intra-aortic balloon counterpulsation catheter has been disappointing and did not contribute to long-term survival. The major factor determining survival is the integrity of the closure, and the function of the remaining viable myocardium. Reoperation for reopening of the defect should always be considered.

Acute Disease↗
PubMed1978

Calcification of the mitral annulus.

Successful valve replacement has been achieved within the first three years in two patients who had extensive calcification of the mitral valve annulus. This condition, although commonly reported in pathology and autopsy studies, has been rare in our clinical experience. Surgical management does not appear to us to have been reported previously. It was regarded in our earlier experience as a deterrent to mitral valve surgery. Certain technical factors which contributed to success are emphasized in the two cases described in this report.

Calcinosis↗