Search PubMed⌕ Search

Biomedical subjects

R Walden

Publications and source records attributed to R Walden.

104 records · Page 6Linked to original sources
PubMedDate not supplied

Percutaneous transluminal aortic angioplasty: early and late results.

Percutaneous transluminal angioplasty of the infrarenal abdominal aorta (13 patients) and its bifurcation (15 patients) was performed in 28 patients with a total of 32 dilatation procedures. The group consisted of 16 female and 12 male patients and initial successful dilatation was achieved in all. Recurrence within 1 month requiring bypass surgery occurred in 1 patient. Three patients were lost to follow-up. Long-term follow-up in the remaining 24 patients ranged from 1 to 9 years with a mean of 4.5 years. During the follow-up period, repeat angioplasty of the original stenosis was performed in 3 patients and another patient underwent dilatation of a new lesion which developed in the aorta. According to clinical and noninvasive studies, these 4 patients, as well as the other 20, have maintained patency of the treated lesions and are symptom free. No immediate complications requiring surgery occurred. We conclude that angioplasty is the initial treatment of choice in focal lesions of the distal abdominal aorta and its bifurcation.

Adult↗
PubMedDate not supplied

Identification and role of adenylyl cyclase in auxin signalling in higher plants.

Cyclic AMP is an important signalling molecule in prokaryotes and eukaryotes, but its significance in higher plants has been generally doubted because they have low adenylyl cyclase activity and barely detectable amounts of cAMP. Here we used activation T-DNA tagging to create tobacco cell lines that can proliferate in the absence of the phytohormone auxin in the culture media. The sequence tagged in one line, axi 141, was used to isolate a complementary DNA encoding adenylyl cyclase, the first from a higher plant. Sequence analysis reveals that the tobacco adenylyl cyclase is probably soluble, contains characteristic leucine-rich repeats, and bears similarity with adenylyl cyclase from the yeast Schizosaccharomyces pombe. Expression of the cDNA in Escherichia coli results in an increase in endogenous cAMP levels, and in yeast its expression functionally complements the cry1 mutation. Tobacco protoplasts treated with cAMP, or the adenylyl cyclase activator forskolin, no longer require auxin to divide. This finding, together with the observation that the adenylyl cyclase inhibitor dideoxyadenosine inhibits cell proliferation in the presence of auxin, suggests that cAMP is involved in auxin-triggered cell division in higher plants.

Adenylyl Cyclases↗
PubMedDate not supplied

Processes of transport and absorption in the developing infant intestine.

An understanding of changes in the processes of absorption, detoxification, and intoxication in the intestine of infants, especially during the perinatal period, may aid in reaching an understanding of why the syndrome of infant botulism is restricted to the first six months of life. Some of the important metabolic changes associated with both the perinatal and the postnatal period of development are emphasized in these studies. A more complete understanding of the processes by which substances are absorbed into the intestine and then reexposed via the enterohepatic circulation may provide clues about why infant botulism occurs.

Adenosine Triphosphate↗
PubMedDate not supplied

Qualitative evaluation of antegrade percutaneous transluminal angioplasty by pressure waveform parameters.

When percutaneous transluminal angioplasty (PTA) is performed in an antegrade ("downstream") direction, intraluminal gradient measurements across the stenotic segment are not possible. Pressures recorded proximal to the lesion were evaluated for possible hemodynamic clues of changes in flow in ten consecutive patients before and after PTA. In all patients in whom the procedure was successful, the systolic pressure decreased by an average of 35 mm Hg. This decrease was not evident in the failed procedures. It is concluded that proximally recorded pressure changes can be used as an objective criterion to assess the success of PTA performed in arteries.

Aged↗
PubMedDate not supplied

Randomized placebo-controlled, double-blind trial of ketanserin in treatment of intermittent claudication.

Ketanserin, a selective serotonin (5-HT) antagonist at 5-HT2 receptors, was investigated in a 12-month, double-blind placebo-controlled study in 35 patients with intermittent claudication. Benefit was assessed by repeated treadmill tests, recording claudication distance, and by measurement of Doppler ankle-brachial pressure indices (ABPI) and pulse volume recordings (PVR). Improvement in claudication distance of 42-44% was noted during the 12 months of the double-blind study and this trend continued to 53-67% during an additional 3 month run-out period on placebo. There were no significant differences between the group given Ketanserin and the placebo group. The hemodynamic measurements demonstrated no statistically significant change in either ABPI or PVR throughout the study period, and no significant differences between the two groups. The conclusion of the study indicates that Ketanserin is ineffective in the treatment of intermittent claudication.

Blood Pressure↗
PubMedDate not supplied

Pharmacokinetic activity of nitrites evaluated by digital pulse volume recording.

Evaluation of the pharmacological properties of vasoactive drugs using routine pharmaco-chemical methods is often complex, time consuming and expensive. We used finger plethysmography for the evaluation of the bioactivity of two long-acting nitrite preparations. Eight healthy male volunteers were exposed to four different drugs: (1) Nitroglycerin; (2) Placebo; (3) Isosorbide dinitrate as Isotard Forte; (4) Isosorbide dinitrate as Cordil-40 SR. Digital pulse volume recording (PVR) was monitored for twelve hour periods. The shape of the PVR curve was used to calculate the diastolic amplitude response intensity, an indication of the vasoactive effect of the drug. There was no measurable response to the administration of placebo. The effect of nitroglycerin was maximal one hour after administration and disappeared after three hours. The long term effect of the two long-acting nitrite preparations was clearly demonstrated as compared to nitroglycerin. Noninvasive measurements of peripheral blood flow can serve as a convenient and accurate tool for pharmacokinetic studies of vasoactive drugs.

Adult↗
PubMedDate not supplied

Scoring of vascular disease in the lower extremities.

Lack of standardisation in reporting the vascular status of patients leads to difficulties in comparing different series. A method of vascular scoring is presented, integrating symptoms, physical examination, vascular laboratory studies and arteriography. The score is expressed in a concise form by several letters and numbers supplying the relevant information as to the main segment involved, the severity of the ischaemia and the completeness of the examination. The files of 100 candidates for vascular surgery were recorded with the scoring method. Vascular indices were calculated by dividing the sum of points assigned to each item by the maximal available score. The internal consistency of the method was evaluated by computing separate indices for the three components of the scoring--clinical examination (CE), vascular laboratory (VL) and arteriography (AR)--and comparing them with the overall index and with each other. Correlation coefficients with the overall index were for CE 0.90, for VL 0.92 and for AR 0.75. The data on the 200 limbs were reviewed independently by three experienced vascular surgeons and ranked in order of increasing severity of ischaemia; the correlation coefficient between this ranking and one based solely on the scoring method was 0.91. A vascular scoring method may help create a mutual language among practitioners, enabling them to compare results and benefit from accumulating worldwide experience.

Adult↗
PubMedDate not supplied

Tube graft replacement of abdominal aortic aneurysm: is concomitant iliac disease a contraindication?

One hundred and fifty nine patients underwent surgery for abdominal aortic aneurysm (AAA) from 1975 to 1985. Of these, a tube graft was inserted in 86 patients (55.1%). Immediate and late results of these 86 patients were evaluated retrospectively as to the effect of concomitant common iliac artery (CIA) disease on early and late results. There were 77 males and nine females aged 35-91 (average 70.7) years. Surgery was elective in 44 patients (51.2%), and as an emergency due to expanding, ruptured or thrombosed AAA in 42 patients (48.8%). The CIAs showed unilateral or bilateral aneurysmal dilatation or atherosclerotic changes in 47 patients (54.7%). At the time of surgery additional bypass grafting from the tube graft to one femoral artery was performed in four patients, and patch angioplasty to the CIA in one. Operative mortality was 4.6% (two patients) in the elective group, and 45.2% (19 patients) in the emergency operations. Follow-up was 94% complete for a mean of 4.1 (range 0.5-10) years). Late mortality for the whole series was 20.0% (12 patients). Only one patient died of a cause related to the AAA operation. All but one of the 48 late survivors are free of any peripheral vascular problems. We conclude that tube graft replacement of AAA is a good choice even in the presence of some degree of CIA atherosclerosis or aneurysmal dilatation.

Aged↗
PubMedDate not supplied

Pulmonary embolism in post-mortem material with clinical correlations in 425 cases.

425 patients with pulmonary emboli at post mortem were studied retrospectively with the main focus on the clinical diagnosis. The diagnosis of pulmonary embolus was made or suspected while the patient was still alive in 59 patients (14%) and was first written in the post mortem request form in 130 patients (30%). In 236 patients (56%) the diagnosis was made only at post mortem. Even in fatal emboli the diagnosis was missed in 43% of cases. A multiplicity of non specific symptoms and signs was observed with a minority of patients showing signs and symptoms considered as typical. Of 231 thrombophlebitis processes found in locations which could give rise to clinical symptoms in the lower extremities the diagnosis was noted only in 25 cases. Chest x-ray and ECG were negative in two thirds of the cases. The high rate of misdiagnosis derived from two reasons: (a) subjective factors: lack of awareness; (b) objective difficulties: lack of specificity of clinical symptoms and signs as well as of results of the routine tests (chest x-ray and ECG). Since sophisticated confirmative tests for pulmonary emboli will be performed only on the basis of clinical suspicion, clinical awareness based on the observations detailed in this survey is still the cornerstone of diagnosis.

Aged↗