Search PubMed⌕ Search

Biomedical subjects

K Alexander

Publications and source records attributed to K Alexander.

At least 55 records · Page 3Linked to original sources
PubMed1996

Untreated arteriovenous fistula after World War II trauma.

A 76-year-old-patient with severe congestive heart failure due to femoral arteriovenous fistula (AVF) after World War II trauma is presented. He was admitted to our clinic because of increasing dyspnea and vertigo during the last years. Moreover he suffered from chronic venous insufficiency on the lower limb distal of the fistula. History revealed a bullet trauma sustained 50 years ago in 1945 while riding on a train that was taken under fire. In 1973 diagnosis of traumatic AVF was first established by arteriography but the patient did not undergo surgical repair. Actual diagnostic procedure included colour Doppler imaging, chest x-ray, and echocardiography. The patient refused invasive treatment, but drug therapy of congestive heart failure was accepted.

Aged↗
PubMed1996

Thrombosis of the terminal aorta, deep vein thrombosis, recurrent fetal loss, and antiphospholipid antibodies. Case report.

The antiphospholipid syndrome (APS) consists clinically of both arterial and venous thrombosis, recurrent fetal loss and thrombocytopenia associated with antiphospholipid antibodies (aPL). Most of these patients were initially found to suffer from systemic lupus erythematosus (SLE). There is an increasing group of patients who exhibit antiphospholipid antibodies and thrombotic complications without clinical features of SLE or related autoimmune disease termed primary antiphospholipid syndrome (PAPS). The case of a 29-year-old woman with thrombosis of the terminal aorta and deep vein thrombosis, recurrent fetal loss, antiphospholipid antibodies and serological support for an underlying connective tissue disease, probably preclinical SLE is reported.

Abortion, Habitual↗
PubMed1995

[How often is thrombolytic therapy of deep pelvic-leg venous thrombosis indicated?].

BACKGROUND: For patients with deep vein thrombosis new thrombolytic regimes are being proposed and demand evaluation in controlled studies. We tested prospectively, how many patients in internal medicine are candidates for thrombolysis. PATIENTS AND METHODS: All available patients with the diagnosis of deep vein thrombosis (DVT) in lower extremities who were admitted to the service of internal medicine in a medium-sized hospital during one year were prospectively evaluated for the indication of fibrinolysis therapy according to the established criteria. RESULTS: A total of 62 patients were enrolled. Fibrinolysis was not proposed in 25 patients aged over 70 years nor in another 9 patients in whom the thrombosis was restricted to calf veins. Nine additional cases had a recurrence of DVT (n = 4) or a history of more than 14 days. Among the remaining 19 patients, fibrinolysis was not performed in 11 because of advanced malignomas (n =4) or other diseases (n = 3) with limited life expectance, enhanced probability of haemorrhage (n = 3) and obvious non-compliance (n = 1). Eight patients were offered thrombolytic therapy, but 5 of them denied consent after being comprehensively informed. CONCLUSION: Obviously by far most of patients admitted to internal medicine for DVT are candidates for standard heparin therapy only.

Adult↗
PubMed1995

Determination of lansoprazole and five metabolites in plasma by high-performance liquid chromatography.

A high-performance liquid chromatographic method for the determination of lansoprazole, a new proton-pump inhibitor, and five of its metabolites in human plasma is described. Lansoprazole, its metabolites, and internal standard (omeprazole) were extracted into diethyl ether-methylene chloride and separation was obtained using a reversed-phase column under isocratic conditions. The method features monochromatic ultraviolet detection at 285 nm, and single extraction, single evaporation sample handling. The lower limit of quantitation, based on standards with acceptable coefficients of variation, was 10 ng/ml for all compounds. No endogenous compounds were found to interfere. This method has been demonstrated to be suitable for pharmacokinetic studies in humans.

2-Pyridinylmethylsulfinylbenzimidazoles↗
PubMed1995

[Traumatically-induced ischemia of the hands].

BACKGROUND: The widely unknown hypothenar hammer syndrome (HHS) is caused by chronic mechanical trauma; in these cases the hypothenar is used as a tool. This may cause intimal lesions of the ulnar artery usually near the hamate bone resulting in thrombosis or aneurysms. PATIENTS: Six patients with HHS are presented. In four cases occupational activities were most probable cause for HHS, in two patients sport activities. DIAGNOSIS: Clinical examination already indicates insufficient blood supply in the supply area of the ulnar artery. Non invasive methods of examination are doppler measurements of hand arteries and occlusion plethysmography of finger arteries. For differential diagnosis capillaroscopy, laboratory tests and hand arteriography can be necessary. THERAPY: Avoiding the releasing cause is main part in therapy of HHS. Only in few patients special medical treatment is indicated. CONCLUSION: Positive evidence of causal relationship between occupational exposure and appearance of HHS has to be acknowledged as occupational disease.

Adult↗
PubMed1995

[A nomogram of duplex ultrasound quantification of peripheral arterial stenoses. Studies of the cardiovascular model and in angiography patients].

BACKGROUND AND METHODS: Blood flow velocity measurements were performed with duplex ultrasound in vitro (flow phantom) and in 62 patients who underwent angiography due to peripheral vascular disease. RESULTS: Intrastenotic peak systolic velocity (PSV) divided by proximally recorded PSV (peak velocity ratio, PVR) exhibited a strong correlation with percent diameter reduction: r2 = 0.86; N = 106 stenoses. A PVR value > or = 2.4 indicated a more than 50% stenosis with a sensitivity of 87% and a specificity of 94%. Calculation of PVR may normalize for patient variation and allow noninvasive quantification of lumen narrowing with high sensitivity and specificity. The intraobserver variability (95% CI) of stenosis quantification using PVR values was 10%. A nomogram simplifies estimation of lumen narrowing after measurement of intrastenotic and proximal PSV values. CONCLUSION: Quantification of peripheral artery stenoses can be performed easily and noninvasively with duplex ultrasound using the peak velocity ratio (PVR).

Aged↗
PubMed1995

Three genes and two isozymes: gene conversion and the compartmentalization and expression of the phosphoglycerate kinases of Trypanosoma (Nannomonas) congolense.

The glycosome, a microbody organelle found only in kinetoplastid protozoa, compartmentalizes the first six enzymes of glycolysis. In order to better understand the regulation and targeting of glycolytic enzymes in trypanosomes, we have cloned and analyzed the three genes of the phosphoglycerate kinase (PGK) complex of Trypanosoma (Nannomonas) congolense. The organization of the genes within the complex is similar to that of Trypanosoma brucei brucei. The nucleotide and amino-acid sequences, including those of the novel high-molecular-weight 56PGK, show substantial cross-species similarity. However, the two downstream genes, c1PGK and c2PGK, encode identical isozymes in T. congolense, while they encode distinct glycosomal and cytoplasmic isozymes in T. brucei. Western analysis also indicated that there are only two isozymes in T. congolense and that these are constitutively expressed. Differential digitonin solubilization of the trypanosomes indicated that 56PGK is primarily localized to the glycosome, as expected, and that c1/c2PGK is cytoplasmic. Northern analysis demonstrates that while 56PGK is constitutively expressed, c1PGK and c2PGK mRNAs are differentially expressed in the T. congolense developmental stages. This work demonstrates that T. congolense has only one PGK isozyme, 56PGK, that is predominantly localized in glycosomes.

Amino Acid Sequence↗
PubMed1995

Skin oxygen pressure histograms in patients with peripheral arterial occlusive disease during intraarterial and intravenous prostaglandin E1 infusions of different dosages and their prognostic value.

Skin surface oxygen pressure fields (tcPO2 [37 degrees C]) reproducibly characterize skin microcirculation in patients with peripheral arterial occlusive disease. These appear suited for investigation of short- and long-term effects of vasoactive drug treatment. The authors studied whether skin surface oxygen pressure histograms change depending on dosage and route of administration of prostaglandin E1 (PGE1), whether they are of predictive value for patients' clinical outcome, and whether they normalize after therapy with PGE1. The authors investigated 15 patients with various degrees of disease and measured forefoot oxygen histograms consisting of at least 80 single tcPO2 (37 degrees C) values before and during intraarterial infusion (1.5, 3, or 6 ng/kg/minute) and intravenous infusion (4.5, or 9 ng/kg/minute). The measurements were repeated two and six hours after the end of intraarterial application of 1.5 ng/kg/minute. Furthermore, the orthostatic vasoconstrictor response was tested. Skin oxygen pressure histograms were controlled after a period of twenty-two (mean) days of intraarterial PGE1 therapy. Resting histograms were left shifted with median tcPO2 (37 degrees C) between 1 and 7 mm Hg. During intraarterial application, histograms were shifted to lower tcPO2 (37 degrees C) values in most patients. Only in 3 diabetic subjects with proximal or acral obliterations was a marked increase observed. The alterations were detectable at least two hours after the end of the infusion. During intravenous infusion, histograms did not change in most cases. After long-term therapy, histograms were substantially unchanged. A pathologic vasoconstrictor response, which was present in 10 patients, could not be restored. Despite a marked deterioration of the histograms the clinical outcome was favorable in 7 patients. Patients with a high resting tcPO2 (37 degrees C) (median 4 mm Hg and more) and those with a vasoconstriction on orthostasis are likely to respond to PGE1 therapy.

Adult↗
PubMed1995

[Left internal thoracic artery as a collateral vessel in chronic occlusion of the pelvic artery].

Four years after implantation of an aorto-bi-iliac artery graft, a 53-year-old man suffered from intermittent claudication with a walking distance of 50 meters. By transaxillary aortography the left femoral artery could not be visualized. Selective angiography of the internal thoracic artery revealed a collateral circulation from the subclavian artery via the left internal thoracic artery, the superior epigastric artery and the inferior epigastric artery into the left external iliac artery (Winslow's pathway). Prior to using the internal thoracic artery for coronary bypass surgery, a function of this vessel as a collateral to the lower extremities should be excluded.

Aorta, Abdominal↗
PubMed1995

Influence of diabetic neuropathy on skin microcirculation assessed by transcutaneous oxymetry.

Skin microcirculation was investigated in 45 patients with long term diabetes and with severe, moderate or no neuropathy, and in 15 controls. Transcutaneous oxygen pressure (tcPO2) measurements on the forefoot were performed at 37 degrees C to assess local capillary flow at rest, during leg dependency and reactive hyperaemia, and also at 44 degrees C, including the response to oxygen inhalation. TcPO2 (37 degrees C) at rest was significantly elevated with an increasing degree of neuropathy (Controls: 4.8 +/- 3.7; patients without neuropathy: 4.2 +/- 2.9; with moderate neuropathy: 6.0 +/- 2.9 (p < 0.01); with severe neuropathy: 7.2 +/- 4.2 mmHg (p < 0.001)). Leg dependency resulted in a decrease of tcPO2 in the controls, while an increase was observed in 18.6% of the measurements in patients, reflecting a disturbed vasoconstrictor response. Regardless of neuropathy, absolute tcPO2 values during reactive hyperaemia were reduced in all patient groups as well as tcPO2 (44 degrees C) and its increase during oxygen breathing. Diabetic neuropathy is likely to increase local capillary flow, while the other differences to healthy controls may be contributed to a microcirculation disorder independent of neuropathy.

Adult↗
PubMed1994

L-arginine infusion decreases peripheral arterial resistance and inhibits platelet aggregation in healthy subjects.

1. L-Arginine is the physiological precursor of nitric oxide which induces vasodilatation and inhibits platelet aggregation by the formation of cyclic GMP. 2. In the present study we investigated the effects of an intravenous infusion of L-arginine (30 g, 30 min) compared with placebo on blood pressure, heart rate and peripheral haemodynamics in ten healthy male subjects. Cyclic GMP, NO2- and NO3- were determined in plasma and urine to assess NO production in vivo by a new, highly specific and sensitive gas chromatography-mass spectrometry method. 3. L-Arginine significantly decreased mean arterial blood pressure and increased heart rate. The effect was more pronounced on diastolic than on systolic blood pressure. This was due to a decreased peripheral arteriolar resistance, as in femoral artery Doppler sonography the arterial diameter was unchanged but blood flow was increased. These haemodynamic effects were not observed after placebo administration. 4. Urinary excretion of cyclic GMP increased by 65.4% after L-arginine and by 25.1 after placebo. Urinary NO2- excretion was near the threshold of detection. Urinary NO3- excretion increased by 79.7% after L-arginine. Plasma arginine levels increased nearly ten-fold after the L-arginine infusion, and plasma cyclic GMP increased by a similar rate as in urine. However, plasma NO2- and NO3- remained unchanged after both treatments, as did plasma alpha-atrial natriuretic peptide levels. 5. Platelet aggregation was inhibited by 32.7% after L-arginine (P < 0.05), but was unchanged after placebo. Platelet intracellular cyclic GMP was increased by 43.0% after L-arginine, but not after placebo (P < 0.05).(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1994

Intestinal type of thromboangiitis obliterans (Buerger's disease).

Thromboangiitis obliterans (TAO) is a recurrent, inflammatory, segmental occlusive disease of distal limb arteries which may involve veins as well. Young smokers are predisposed to TAO. The intestinal vessels are rarely affected. We report the clinical, angiographic and histologic findings of a 23-year-old smoker with extended thrombophlebitis who developed severe abdominal angina and liver hypoxia due to occlusion of the coeliac artery and subtotal occlusion of the superior mesenteric artery. Two surgical bypassing procedures were followed by early graft occlusion. Subsequently, a plastic patch of the superior mesenteric artery and an aortohepatic bypass were performed. The literature since 1945 pertinent to intestinal TAO is reviewed.

Adult↗
PubMed1994

Effects of resistance exercise on glucose tolerance in normal and glucose-intolerant subjects.

This study was conducted to determine whether improvements in glucose tolerance could be observed after a single bout of resistance exercise in young (27.1 +/- 1.24 yr) control subjects, older (53.3 +/- 1.7 yr) patients with non-insulin-dependent diabetes mellitus (NIDDM), and older (50.7 +/- 1.9 yr) age-matched control subjects. Each subject was screened for fitness level and any contraindications to exercise before inclusion in the study. A 75-g oral glucose tolerance test was administered 2 wk after the subjects were screened, and the subjects were familiarized with the exercise equipment. The maximum weight that could be lifted with one repetition was determined on seven Nautilus machines that utilized the upper and lower body. After a 48-h rest period, a 3-set x 10-repetition protocol based on the subject's one repetition maximum was completed by each participant on each machine. Eighteen hours after the lifting protocol, a second oral glucose tolerance test was administered. There was no change in the pre- to post-exercise glucose levels in any of the treatment groups, but the total insulin responses (area under the curve) of the young control and NIDDM groups were significantly lower after exercise: from 6.93 +/- 0.8 x 10(3) to 5.38 +/- 0.65 x 10(3) pM in the young control group and from 9.83 +/- 1.95 x 10(3) to 7.77 +/- 1.50 x 10(3) pM in the NIDDM group. The postexercise C-peptide levels were unchanged in all groups.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1993

In vivo inhibition of acute platelet-dependent thrombosis in a baboon model by Bay U3405, a thromboxane A2-receptor antagonist.

Bay U3405 is a thromboxane A2 (TxA2)-receptor antagonist that inhibits the binding of TxA2 to its target cells. The aim of this study was to determine if Bay U3405 could be used to inhibit arterial thrombosis. A thrombogenic device, consisting of uncrimped Dacron vascular graft material (0.5 cm2) built into the wall of silicone rubber tubing with 4 mm inside diameter, was exposed to native flowing blood under arterial blood flow conditions (100-140 ml/min) by interposing the devices as extension segments into permanent femoral arteriovenous shunts implanted in baboons. Thrombus formation was quantified in vivo by measuring the deposition of 111In-labelled platelets onto the graft material with a scintillation camera. In six baboons, a bolus injection of Bay U3405, calculated to attain an initial plasma concentration of 300 ng/ml, reduced the maximum thrombus formation measured over a 2 h study period. Platelet deposition was reduced by 33 +/- 14% (SD) at 2 h as compared to control studies done in the same baboons. The accumulation of additional platelets onto a thrombus that was allowed to form for 1 h, was reduced by 58 +/- 28% at 2 h. Ex vivo platelet aggregation in response to ADP, activated partial thromboplastin time (APTT), prothrombin time (PT), and thrombin time (TT) were not affected by the treatment. Ex vivo platelet aggregation in response to collagen was markedly inhibited for 2 h after treatment. The results demonstrated that selective blocking of the TxA2-receptor on platelets reduced platelet-dependent thrombus formation and the accumulation of additional platelets in a freshly formed thrombus.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗