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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
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↗
PubMed1977

Coronary artery surgery.

This paper assesses the results in 543 patients undergoing coronary artery surgery between 1969 and March, 1976. Indications included angina, acute infarction and ventricular arrhythmia, and there were some angina-free patients. Surgical techniques were constantly reviewed and frequently changed. The mortality in all groups was 4.2%. The mortality in chronic stable angina (424 cases) was 3%, but as from January, 1975, it has been 2%. The perioperative infarction rate in all groups was 10.7%, and this condition was the most significant cause of perioperative mortality. Modern principles of myocardial protection during surgery have helped to lower mortality and morbidity rates.

Coronary Artery Bypass↗
PubMed1977

Right coronary endarterectomy: a procedure with increased risk of perioperative infarction.

Although right coronary endarterectomy extends operability on this vessel, the procedure is associated with increased risk of perioperative infarction. Forty-nine patients at St Vincent's Hospital underwent endarterectomy and saphenous vein grafting to the distal right coronary artery, with a hospital mortality of 6.1% and a perioperative infarction rate of 20.4%, compared with rates of 4.2% and 10.9% respectively in a group of patients who did not require endarterectomy. These figures show a trend toward statistical significance which suggests that careful patient selection for endarterectomy is required to obviate an increased risk of complications with this procedure.

Coronary Artery Bypass↗
PubMed1977

Left main coronary artery obstruction: early surgical experience with forty-two patients.

Direct coronary artery surgery was performed on 42 patients with high grade obstruction of the left main coronary artery (LMCA), with a perioperative infarction rate of 7% and a hospital mortality of 9-6%. There was no significant difference in presentation of patients with LMCA lesions and no prediction of this lesion could be made by preangiographic assessment. Significant obstructive lesions in other coronary vessels were noted in most patients, triple vessel disease occurring in 27 patients (64-3%), double vessel in 14 patients (33-3%) and the LMCA lesion was an isolated lesion in only one patient (2-4%). Right coronary lesions occurred in 35 patients (83%), left anterior descending artery artery lesions in 38 patients (90%) and left circumflex system lesions in 34 patients (81%). The surgical procedures are discussed.

Acute Disease↗
PubMed1976

Post-infarction cardiac rupture.

Three allied conditions are described in this paper: (i) haemopericardium with cardiac rupture (5 cases); (ii) haemopericardium without rupture (2 cases); (iii) pseudoaneurysm (1 case). In the first 2 of these, the significant features were clinical deterioration with shock 3 or more days after infarction, recurrent cardiac pain, cardiac tamponade, and immediate or later ineffectiveness of counterpulsation. An additional feature in the second group was the development of haemopericardium after heparin therapy. In the third group, infarction followed by left ventricular failure and progressive cardiac enlargement was the significant feature. An apical systolic murmur was not present, as a false sac had not been formed. Ante-mortem diagnosis depends upon an appreciation of these features. Without it successful surgery is impossible. There were 4 survivors in this group of 8 patients.

Aged↗
PubMed1976

Tracheal injury following prolonged intubation.

Prolonged respiratory assistance by positive pressure ventilation via cuffed tracheostomy or endotracheal tube can be complicated by mucosal erosions, tracheal stenosis, tracheomalacia, excavation of the tracheal wall with loss of tissue and tracheoesophageal fistula. Stenosis can occur at the subglottic region, at the stoma, or at the cuff site, whereas the other complications occur most often at the cuff site. This paper is concerned with complications occurring below the first tracheal ring.

Adolescent↗