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Biomedical subjects

P H Kay

Publications and source records attributed to P H Kay.

At least 91 records · Page 5Linked to original sources
PubMed1985

Sex influences transmission of the supratype associated with the C2 deficiency allele: a possible mechanism for the maintenance of heterozygosity and disease susceptibility.

We have examined the transmission of the supratype associated with C2 deficiency (C2Q0) using our own and many published pedigrees in order to determine whether nonrandom transmission may contribute to the stability of disease-associated supratypes. Unexpectedly, we found that C2Q0 may be preferentially transmitted to the opposite sex and therefore propose that such "zig-zag" transmission may result in the preservation of recessive disease susceptibility genes and in the maintenance of heterozygosity. Further pedigrees are required to verify our findings.

Alleles↗
PubMed1985

Fifteen years' experience with the aortic homograft: the conduit of choice for right ventricular outflow tract reconstruction.

Ninety-seven patients with pulmonary atresia underwent right ventricular outflow tract reconstruction using a homograft conduit. There were 46 hospital deaths (47%). Hospital mortality was significantly related to irreversible pulmonary hypertension (p less than 0.001) and thoracotomy for ligation of bronchial collaterals (p less than 0.01). The actuarial survival was 37 +/- 7% at 10 years. Sixteen patients undergoing recatheterization at a mean of 6 years had a mean transconduit gradient of 24 +/- 15 mm Hg. Obstructed conduits (i.e., with a gradient of greater than 50 mm Hg) were replaced in 3 patients, corresponding to 13 +/- 8% at 10 years. In each instance, the obstruction was due to neointimal hyperplasia in the Dacron tube rather than calcification of the homograft valve. The fresh, antibiotic-sterilized aortic homograft is the conduit of choice for right ventricular outflow tract reconstruction. The valve itself appears more resistant to calcification than its xenograft counterpart, and the absence of Dacron removes the problem of fibrinous peel obstructing the conduit. We now construct a tube of autologous pericardium to increase the length of the conduit and avoid complementary thoracotomy for ligation of bronchial collaterals.

Adolescent↗
PubMed1985

Late results of combined mitral valve replacement and coronary bypass surgery.

The incremental risk of coronary bypass surgery was analyzed in 718 patients undergoing mitral valve replacement between 1971 and 1983. Ninety-eight patients (14%) had significant coronary artery disease requiring coronary bypass surgery. In 70 of these patients, the origin of the mitral valve disease was nonischemic, whereas 28 patients had ischemic mitral regurgitation unsuitable for conservative valve surgery. There were six operative deaths (9%) and four perioperative myocardial infarctions (6%) after mitral valve replacement and coronary bypass surgery for nonischemic mitral valve disease. Operative mortality was related to low output cardiac failure before operation or perioperative myocardial infarction. Actuarial curves predict survival (+/- standard error) of 55 +/- 7% at 5 years and 43 +/- 8% at 10 years. Preoperative functional class was the only significant predictor of long-term survival in this group (p less than 0.05). The actuarial survival of the 620 patients without coronary artery disease who underwent mitral valve replacement alone was 63 +/- 3% at 10 years. This was significantly better than that of the 70 patients who underwent mitral valve replacement and coronary bypass surgery for nonischemic mitral valve disease (p less than 0.001). Conversely, 5 year survival of the 28 patients with ischemic mitral regurgitation was 43 +/- 10%. This confirms the negative detrimental effect of an ischemic origin of mitral valve disease on survival after mitral valve replacement and coronary bypass surgery (p less than 0.0001).

Adult↗
PubMed1985

Secondary Sjögren's syndrome and chromosome six markers.

Patients with Sjögren's syndrome (SS) in association with either Rheumatoid Arthritis (RA), Systemic Lupus Erythematosus (SLE) or Sclerodactyly were tested for HLA-A, B and Dr antigens and the phenotypes of the 4th component of complement (CA). Significant associations were identified between HLA-Bw62, Dr4, C4B2.9, C4A8 and females with SS-RA. The MHC antigen frequencies noted for secondary Sjögren's syndrome differed from those reported for their respective primary diseases and the implications of these observations are discussed.

Adult↗
PubMed1985

Bypass grafting to the right coronary artery with and without endarterectomy: patency at one year.

Between January 1979 and December 1981, 142 patients undergoing surgery to the right coronary artery agreed to have repeat coronary arteriography one year later. Thirty patients underwent combined endarterectomy and bypass grafting to the right coronary artery. The patency of these grafts was compared with that of grafts in 69 patients undergoing direct grafting to the right coronary artery and in 43 with grafting to the posterior descending coronary artery. There were two hospital deaths and one late death. No patients developed new inferior Q waves on the electrocardiogram. Repeat coronary arteriography at one year showed that 21 (72%) of the 29 grafts were patent after combined endarterectomy and bypass grafting to the right coronary artery. Sixty three (94%) grafts to the right coronary artery and 40 (93%) grafts to the posterior descending coronary artery were patent at one year. Direct grafts to the right coronary artery or its posterior descending branch had a significantly higher patency rate at one year than grafts to the endarterectomised right coronary artery. Graft patency after the combined procedure correlated with the extent of atherosclerosis in the posterior descending coronary artery. It was not influenced by treatment with platelet antagonists. Endarterectomy of the right coronary artery was most successful when it allowed a single graft to perfuse both the large posterior descending and left ventricular branches.

Adult↗
PubMed1985

Open lung biopsy in patients with diffuse pulmonary shadowing.

The radiological appearances of diffuse pulmonary shadowing are not specific and frequently histological examination is necessary to provide a diagnosis or assess the activity of the disease. From July 1979 to May 1983 open lung biopsy was performed in 101 patients through a limited submammary incision. Twenty seven patients had undergone prior invasive investigations and 27 were taking corticosteroids at the time of biopsy. In 92 patients the histological appearances after open lung biopsy were sufficiently specific to permit diagnosis. Respiratory tract infection occurred in six patients and in eight there was some superficial infection of the wound. These complications were more frequent in patients taking corticosteroids but the difference was not statistically significant. The chest drain was removed usually on the first postoperative day. In three critically ill patients an air leak occurred after removal of the drain, requiring formal surgical re-exploration and drainage in two cases and a brief period of intercostal drainage in the third. Four patients in the series died. All had severe pre-existing lung disease; in three open lung biopsy was performed in the late stages of severe, rapidly progressive lung disease eluding diagnosis; the fourth patient, who had massive pulmonary fibrosis from asbestos lung disease, developed a respiratory tract infection and died from progressive respiratory failure. Open lung biopsy can be performed with minimal morbidity and a high diagnostic yield. The approach used in this series provides a safe and reliable operation with good cosmetic results.

Adult↗
PubMed1984

Thyrogastric autoimmunity and MHC associated alleles at the C4 locus in patients with type 1 (insulin-dependent) diabetes.

HLA antigens, complement allotypes, insulin antibodies and thyrogastric autoantibodies were determined in 69 patients with Type 1 (insulin-dependent) diabetes defined by a tendency to ketosis, non-obesity and insulin requirement within 2 years of diagnosis. Analysis of HLA and C4 allotypes suggested that Type 1 diabetes was associated with only certain DR3- and DR4-containing supratypes. Low antibody response to insulin was associated with all HLA-DR3, being present in 89% of those with DR3 compared with 48% of those without. Thyrogastric autoantibodies were associated with a null allele at the C4A locus, usually with HLA-B8-C4AQO-C4B1-BfS-DR3. These results indicate that, unlike Type 1 diabetes, low insulin antibody response was associated with all HLA-DR3. Thyrogastric autoantibodies, on the other hand, were associated with a null allele at the C4A locus. It is probable that while interaction between certain HLA-DR3 and DR4-containing supratypes is important in conferring susceptibility to Type 1 diabetes, other manifestations of autoimmunity are associated with supratypes containing C4AQ0, and in particular the diabetogenic supratype HLA-B8-C4AQ0-C4B1-BfS-DR3.

Alleles↗
PubMed1984

Autoimmunity in spontaneous myasthenia gravis in dogs.

Spontaneous canine myasthenia gravis (MG) mimics the human disease in almost every respect. Both dogs reported here exhibited the autoantibodies characteristic of MG, i.e., anti-acetylcholine receptor (anti-AChR) and antistriational (AStr). Fluctuations in the anti-AChR titer during spontaneous remission and recurrence of MG in one dog provide support for the concept of a symptomatic threshold titer above which anti-AChR must rise before disease signs develop. The increase in the anti-AChR titer and recurrence of disease signs followed vaccination and an infection. Interestingly AStr also reappeared in this dog and serum IgG concentration increased. AStr in the second dog was associated with the presence of a thymoma and had a staining pattern characteristic of human MG.

Animals↗
PubMed1984

Genetic polymorphism of complement C4 in the dog.

Plasma samples from 129 dogs have been typed using an immunofixation technique to define the polymorphism of canine C4. The mode of inheritance was inferred by study of four large pedigrees. In contrast to the situation in man, canine C4 may be encoded by a single locus. At least five different co-dominant structural alleles have been detected. A deficiency allele has not been found as yet. Because there are associations between C4 allotypes and spontaneous autoimmune disease in man, the well defined polymorphism of canine C4 may provide an excellent model for understanding of the pathogenetic mechanisms of autoimmune disease.

Alleles↗
PubMed1984

Late surgical results for ischemic mitral regurgitation. Role of wall motion score and severity of regurgitation.

The indication for concomitant valve operations for ischemic mitral regurgitation is examined in 120 consecutive patients with regurgitation who had coronary bypass. Ischemic mitral regurgitation was mild in 56%, moderate in 18%, and severe in 27%. Compared with patients without mitral regurgitation who underwent coronary bypass, significantly more patients with regurgitation had cardiomegaly (31% versus 5%), left heart failure (42% versus 6%), and abnormal wall motion scores (71% versus 42%). Eighty-three patients (69%) with ischemic mitral regurgitation had coronary bypass alone and 37 (31%) also had a valve operation. All patients with mild ischemic mitral regurgitation were treated by coronary bypass alone, as compared to 67% with moderate and 6% with severe regurgitation. Operative mortalities for mild, moderate, and severe ischemic mitral regurgitation were 4%, 10%, and 38%, respectively; 5 year survival rates were 82%, 60%, and 48%, respectively. Other significant determinants of survival were wall motion score, shock, cardiomegaly, left heart failure, and acute and multiple myocardial infarctions. Patients with mild ischemic mitral regurgitation and a low wall motion score (n = 40) had a 5 year survival rate of 94%. For patients with either moderate/severe regurgitation (n = 27) or a high wall motion score (n = 25), but not both, the 5 year survival rate was 70%. In 20 patients with both a high wall motion score and moderate/severe regurgitation, it was 33%. An additive detrimental effect is apparent. The change from mild to moderate/severe ischemic mitral regurgitation was equivalent to an increase of about 8 wall motion score units in terms of effect on survival. Ischemic mitral regurgitation is a powerful additive risk factor to wall motion score in coronary bypass. Mild regurgitation is best managed by coronary bypass alone. If regurgitation is moderate, it may still be possible to avoid a valve operation and have acceptable results. Severe ischemic mitral regurgitation usually necessitates coronary bypass and a mitral valve operation.

Adult↗
PubMed1983

HLA and complement allotypes in Type 1 (insulin-dependent) diabetes.

A group of patients with Type 1 (insulin-dependent) diabetes mellitus was investigated for HLA-A, B and DR antigens as well as C4 and factor B polymorphism. A significant excess of DR3/DR4 heterozygotes was observed (27% versus 17% by Hardy-Weinberg expectation). The factor B allele BfF1 was present in 13% of patients with Type 1 diabetes (gene frequency of 0.08 versus 0.01 in control subjects). A rare C4 B allele, C4 B2.9, was found in 18% of patients with Type 1 diabetes (n = 63) compared with 1.1% of control subjects (n = 176). Total C4 deficiency at the C4 A locus (C4 AQ0,0) was present in 10% of patients with Type 1 diabetes compared with 0% of control subjects. Examination of HLA, C4 and Bf phenotypes in patients with Type 1 diabetes suggested that three high risk supratypes, HLA-A1 B8 BfS C4 AQ0 C4 B1 DR3; HLA-B18 BfF1 C4 A3 C4 BQ0 DR3; HLA-A2 CW3 BW62 BfS C4 A3 C4 B2.9 DR4 are markers for susceptibility alleles.

Adult↗
PubMed1983

Complement allotyping in SLE: association with C4A null.

Immunogenetic factors are important in systemic lupus erythematosus (SLE) and deficiency of a number of complement components is often associated with a lupus-like illness. The complement components Bf, C2 and C4 are encoded within the human major histocompatibility complex (MHC) and are polymorphic. A study of HLA and Bf and C4 polymorphism in 43 patients with SLE was undertaken firstly, to determine whether partial deficiency of C2 and C4 may predispose to disease and secondly, because it may allow the better definition of important supratypes associated with the disease and which may include the relevant disease gene(s). An increased frequency of C4A null alleles has been shown in SLE, with a minimal estimated C4A null gene frequency of 0.32 versus 0.20, but no case of partial C2 deficiency was identified. These results may indicate a direct role for partial C4 deficiency or that C4A null may be a marker for an important supratype which includes the relevant disease gene(s).

Complement C2↗