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Biomedical subjects

H Walters

Publications and source records attributed to H Walters.

17 recordsLinked to original sources
PubMed1992

Arteriovenous fistulas in renal transplants: color Doppler ultrasound observations.

One hundred twenty-six new renal transplants were scanned regularly with color Doppler ultrasound (CDU). In 22 (17.5%) of the grafts there was evidence of postbiopsy arteriovenous (AV) fistula during the first 6 months postoperatively. In 14 cases the fistula closed spontaneously. In the remaining eight, the fistula was still present up to 24 months later (four cases) or until the graft failed (four cases). Additionally, 163 established grafts were scanned for evidence of vascular abnormality. AV fistulas were observed in 15 grafts (8%). Circulatory complications of fistulas observed include vascular steal and a possible association with graft vein and artery stenosis.

Arteriovenous Fistula↗
PubMed1991

Renal transplant vein stenosis: demonstration and percutaneous venoplasty of a new vascular complication in the transplant kidney.

Stenosis of the renal transplant vein has been demonstrated in eight patients undergoing investigation for renal dysfunction arising 3 weeks to 3 years after transplantation. The stenoses were diagnosed by duplex Doppler ultrasound in three cases and by angiography in the presence of arterio-venous fistula in five cases. In four patients percutaneous venous dilatation was performed with technical success in three. In two patients this was repeated for recurrent stenosis but sustained improvement in renal function was not observed. Progression of the venous stenoses was documented with one patient suffering graft loss due to complete venous occlusion.

Adult↗
PubMed1990

Aortic dissection presenting as acute leg ischaemia.

Lower limb ischaemia as the only or main clinical manifestation of aortic dissection is a rare event. Two cases are presented where this occurred resulting in attempted embolectomy before the correct diagnosis was made. The diagnosis should be considered when embolectomy fails to retrieve thrombus and when angiography demonstrates spiral lucencies within the lumen of large vessels or non-filling of major vascular branches. The value of pre-operative angiography is emphasized.

Aged↗
PubMed1990

Superselective embolization using a coaxial catheter technique.

A method of superselective embolization of 0.64 mm or 0.89 mm coils using a coaxial catheter system is described. The normally functioning parts of an organ can be easily preserved. A number of clinical cases are briefly described which illustrate the application of this method. It is particularly suited to the control of bleeding points in diseased organs or precious organs such as transplants where embolization of a larger volume of tissue would have serious consequences.

Arteriovenous Fistula↗
PubMed1989

The effect of filtration on absolute and differential cell counts in fluid obtained at bronchoalveolar lavage.

We have studied the effects of filtering mucus from bronchoalveolar lavage (BAL) fluid on its cellular contents. We examined BAL fluid from 18 patients without excessive endobronchial mucus, and from three patients with bronchiectasis. In the non-bronchiectatic subjects there was a fall of 18% in mean absolute cell count from 2.66 +/- SD 1.9 x 10(9) l-1 to 2.18 +/- 1.4 x 10(9) l-1 (P less than 0.05) as a result of filtration. This was due to a selective loss of macrophages and there were no significant changes in the absolute numbers of either lymphocytes or neutrophils. The differential macrophage count fell from a mean of 82 +/- 14% to 76 +/- 16%, while the mean differential lymphocyte count rose from 14 +/- 7% to 19 +/- 9% and the mean differential neutrophil count increased slightly from 4 +/- 4% to 5 +/- 4%. In the three patients with bronchiectasis the absolute cell counts were grossly raised, due almost entirely to an excess of neutrophils. In these patients, filtration reduced the absolute macrophage count by 61% and the absolute neutrophil count by 27%. Overall, change in absolute cell count correlated significantly with mucus volume (r = 0.76, P less than 0.05). Removal of mucus by filtration affects absolute cell count and may have a selective effect on cell numbers. If filtration of BAL fluid is unavoidable, its effect on cell counts should be clearly established if data from different centres are to be meaningfully compared.

Adult↗
PubMed1988

The effect of bronchoalveolar lavage on bronchial responsiveness in patients with airflow obstruction.

This study assessed the effect of bronchoalveolar lavage (BAL) on nonspecific bronchial responsiveness in 31 patients. Of these, 20 had airflow obstruction; 11 control subjects had normal pulmonary function. Bronchial responsiveness to methacholine, expressed as the dose of inhaled methacholine required to provoke a 20 percent fall in forced expiratory volume in one second (PD20 FEV1), was measured before and after BAL. We found no evidence for the induction of responsiveness by BAL in 11 control subjects with negative methacholine tests prior to the procedure. There were small but significant falls in FEV1 following BAL in both the control group and in patients with airflow obstruction. Thus, BAL does not appear to induce nonspecific bronchial hyperresponsiveness in subjects without airflow obstruction, nor does it affect airway responsiveness in emphysema patients. Among asthmatics, bronchial responsiveness can be increased as a result of BAL; this increase was greatest in patients who were most responsive initially.

Adolescent↗
PubMed1986

Computerised planning of maxillo-facial osteotomies: the program and its clinical applications.

A totally computerised program has been developed which undertakes the 2-dimensional planning of a complete maxillo-facial reconstruction using Le Fort I, II & III, Wassmund, Schuchardt, Küfner, Köle, Dingman, Obwegeser and VSS osteotomies with augmentation or reduction genioplasty and rhinoplasty. The program incorporates the calibration of the equipment, initialization of new discs, a filing system for osteotomy patients, unlimited expansion facilities for storage of files and an automatic cephalometric analysis which is updated at each stage. A suggested operation, which may be altered for aesthetics, is generated spontaneously by the computer. The surgeon or the patient is free to accept or reject the computer's suggestion in part or whole.

Cephalometry↗
PubMed1975

On the dissociation and association of Escherichia coli ribosomes.

The dissociation and association behaviour of 70-S ribosomes of Escherichia coli has been studied. It has been shown that the dissociation-association reaction can be both a real dynamic equilibrium and a non-equilibrium reaction, dependent upon the ionic conditions of the solvent. At relatively high ionic strength (I = 0.15 M or more) the dissociation-association reaction is an equilibrium reaction, whereas at lower ionic strength (I = 0.1 M or less) there is no dynamic equilibrium between 70-S ribosomes and its subunits. In the latter case a hysteresis in the dissociation-association reaction is observed. Whether there is a dynamic equilibrium or not can be demonstrated by a single centrifugation experiment, using the analytical ultracentrifuge.

Escherichia coli↗
PubMedDate not supplied

Vascular calcification, autonomic neuropathy, and peripheral blood flow in patients with diabetic nephropathy.

The possibility that digital gangrene in patients with diabetic nephropathy might be due to abnormalities of peripheral blood flow secondary to vascular calcification has been investigated. Twenty patients with renal failure due to diabetic nephropathy were studied. Peripheral blood flow was measured using venous occlusion plethysmography, together with an assessment of medial arterial calcification on plain radiographs of the hands and feet, and transcutaneous oxygen tension (TcPO2). Hallux blood flow was markedly raised (median 22.5, range 11.5-56.5, ml min-1 100-ml-1) compared with non-diabetic control subjects (4.7, 1.1-10.5, ml min-1 100-ml-1; p less than 0.01) and similar to that in diabetic patients with autonomic neuropathy (29.5, 16.7-49.6, ml min-1 100-ml-1). Although vascular calcification was common and extensive in the patients with diabetic nephropathy, TcPO2 measurements in the supine foot were normal and did not indicate tissue ischaemia. We conclude that despite extensive vascular calcification high peripheral blood flow occurs in the feet of these patients at rest together with normal transcutaneous oxygen tension.

Adult↗