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Biomedical subjects

S Lundstam

Publications and source records attributed to S Lundstam.

At least 19 recordsLinked to original sources
PubMed1992

Effect of substance P on detrusor muscle in rats with diabetic cystopathy.

Diabetic cystopathy (DCP) is a well known complication in diabetes mellitus (DM). In the present experimental study, DM was induced in rats by streptozotocin and DCP was confirmed on cystometry. In vitro studies on detrusor strips from diabetic rats showed an increased contractile response to substance P (SP) compared with controls, indicating denervation supersensitivity. A decreased response to capsaicin in diabetic detrusor strips indicated a decreased neuronal content of SP or a diminished number of SP-containing sensory nerves. This suggests that DM induces alterations in nerves containing SP which may be at least partly responsible for sensory loss and the development of DCP.

Animals↗
PubMed1990

Renal function during reperfusion after warm ischaemia in rabbits: an experimental study on the possible protective effects of pretreatment with oxygen radical scavengers or lidoflazine.

Survival and renal function were studied after 60 min of renal ischaemia and contralateral nephrectomy in four groups of French loop rabbits. One group served as untreated control animals. The other groups were pretreated with superoxide dismutase (SOD) and catalase, lidoflazine or a buffered albumin solution containing mannitol, L-methionine and MgCl2. Six out of nine rabbits died during the 14-day follow-up period in the untreated control group, while the corresponding figure in each of the three treatment groups was one out of nine. Five of the rabbits that died exhibited azotaemia or hyperpotassaemia that could explain the death, while four died of non-renal related causes. In the surviving animals, no differences in serum creatinine, potassium and sodium concentration or urinary output of osmoles was observed between the four groups. The increase in serum creatinine of the French loop rabbits observed after 60 min of ischaemia was considerably less pronounced than the corresponding increase observed in New Zealand White rabbits, indicating that the kidneys of the former strain are more tolerant to ischaemia. A cardiomyodepressant factor could be demonstrated in the venous effluent from previously ischaemic kidneys. This release could not be prevented by pretreatment with SOD and catalase.

Animals↗
PubMed1988

Effects of oxygen free radical scavengers, xanthine oxidase inhibition and calcium entry-blockers on leakage of albumin after ischaemia. An experimental study in rabbit kidneys.

The effect of pretreatment with various substances protecting against oxygen free radicals on the leakage of proteins across the vessel walls of rabbit kidneys induced by ischaemia has been studied. The leakage of proteins was estimated from the difference between the 120-min distribution space of [131I]albumin and the 5-min distribution space of [125I]albumin, the latter mainly measuring the intravascular volume. Neither SOD (superoxide dismutase), catalase, allopurinol or two different Ca2+ channel blockers (nifedipine, felodipine) could alone reduce the leakage induced by ischaemia. A combined pretreatment with SOD, catalase and nifedipine reduced the leakage in the cortex, and pretreatment with mannitol alone reduced the leakage in the cortex and outer stripe of the medulla. The results indicate that oxygen free radicals are involved in the leakage of proteins across the vessel walls induced by ischaemia, but that other mechanisms are involved as well.

Allopurinol↗
PubMed1987

Perfusion characteristics and norepinephrine reactivity of human renal carcinoma.

Kidneys, surgically removed due to carcinoma, were subjected to perfusion in vitro. The perfusion distribution was studied by means of labeled microspheres injected during maximal vascular dilation and during two different norepinephrine concentrations. The perfusion concluded with injection of barium sulfate. Two-mm-thick slices of tissue were autoradiographed and microangiographed for visualization of perfusion and distribution of vascular density, respectively. Multiple specimens from tumor and cortical tissues were subjected to quantitative perfusate flow analysis. In spite of regionally high vascular density, perfusion through "normal-sized" capillaries was very low in tumor tissue as compared to cortex (during maximal dilation, one-tenth of the cortical flow). During moderate norepinephrine infusion, the perfusate flow decreased, and the resistance of the cortex increased. The flow to tumor tissue increased while the vascular resistance remained constant. During higher norepinephrine concentrations, the flow was redistributed; i.e., the cortical flow increased while that of the tumor decreased, due to a marked increase in tumor vascular resistance while the cortical tissue showed a very moderate rise in resistance. The thin-walled tumor vessels might be collapsed under a high tissue pressure at low perfusion pressures. At higher perfusion pressure, the vessels might open up, and contractile activity may not be expressed until then. The tumor vascular resistance increased 3 to 4 times, while that of cortex showed a 7-fold increase. Indications that a considerable fraction of the perfusate passes arteriovenous passages larger than 15 micron were obtained in individual experiments, this fraction increasing upon norepinephrine infusion.

Carcinoma↗
PubMed1987

Effects of ischaemia on leakage of albumin in rabbit kidneys.

The effect of ischaemia on the leakage of proteins across the vessel walls in rabbit kidneys was studied. The leakage of proteins was estimated from the distribution space of labelled albumin. Various methods to calculate the vascular volume yielding the true extravascular leakage were tested. The most reliable method appeared to be to use the same tracer (131I-albumin, 125I-albumin) for both estimating the leakage and the intravascular volume. One hour of ischaemia induced a drastic increase in the extravasation of proteins in the cortex and outer zone of the medulla but not in the inner zone.

Animals↗
PubMed1987

Prognostic value of consecutive peripheral pressure registration after reconstructive peripheral arterial surgery.

A reliable predictive test as a guide in selection for arterial reconstruction vs. primary amputation would be of great value. An ideal test should also be simple and noninvasive. We evaluated prediction based on preoperative and early postoperative (repeatedly in the first week) measurements of ankle and toe pressure in relation to patency 6 months after reconstructive peripheral vascular surgery in 39 patients. Occlusion occurred within 6 months in ten patients. In eight of them the preoperative ankle-brachial pressure index (ABI) was less than 0.4, but seven other patients with ABI less than 0.4 had maintained patency. In six of the ten with occlusion the toe-brachial pressure index (TBI) was less than 0.1, but in three others with TBI less than 0.1 the grafts were patent. During the first postoperative week there was progressive rise in pressure indices, reaching statistical significance on day 6, though with greatest rise on day 1. Although preoperative ABI less than 0.4 and TBI less than 0.1 were associated with high occlusion risk, the specificity of these indices was too low for predictive value. The repeated measurements during postoperative week 1 added no useful information to that obtained on day 1.

Aged↗
PubMed1985

Prostaglandin synthetase inhibition of renal pelvic smooth muscle in the rabbit.

The prostaglandin synthetase inhibitors diclofenac and indomethacin relieve pain in renal colic probably by decreasing renal pelvic pressure. Decreased diuresis and effects on the oedema around the obstructing stone are plausible explanations. In the present study on rabbit renal pelvic tissue strips it was found that both indomethacin and diclofenac decreased the spontaneous phasic activity of the strips. ED50 was 5.4 +/- 0.7 X 10(-5) M for indomethacin and 2.4 +/- 0.5 X 10(-5) M for diclofenac (P less than 0.001). With the prostaglandin synthetase inhibitors still in the tissue bath the activity was regained when either prostaglandin E2 or F2 alpha was added, prostaglandin E2 being more potent in this respect. It was concluded that prostaglandin synthetase inhibitors seem to reduce smooth muscle activity in the renal pelvis, a mechanism which might contribute to the pain-relieving ability of these drugs in renal colic.

Animals↗
PubMed1984

Acute gastric hemorrhage secondary to wandering spleen.

A patient presenting with acute life-threatening upper gastrointestinal hemorrhage caused by a wandering spleen is reported. Emergency laparotomy revealed profuse gastric bleeding, large engorged varicose veins in the gastric wall, and a normal liver parenchyma. Gastroscopy after arrest of the hemorrhage showed varicose veins in the fundus without esophageal varices. Angiography revealed an ectopic spleen, occlusion of the splenic vein, and large venous collaterals in the gastric fundus. Elective splenectomy was performed. Wandering spleen as a cause of left-sided portal hypertension, also referred to as segmental splenic hypertension, is discussed.

Acute Disease↗
PubMed1984

Evaluation of kidney viability during hypothermic perfusion or cold storage.

The effect of up to 6 days of hypothermic perfusion and up to 72 h of cold storage on tissue viability were studied from measurements of sodium potassium pump activity and adenosine nucleotide content. For the hypothermic perfusion two different albumin-based perfusates were used, one with, the other without addition of caprylic acid and amino acids. No difference could be found in the parameters studied between perfusion with these two perfusates. For both perfusates total adenine nucleotide content (TAN) decreased by approximately 60% during perfusion while energy charge potential (ECP) and the ATP/ADP ratio remained constant. During cold storage a decrease of both TAN and ECP and the ratio ATP/ADP was seen, the main decrease occurring within the 1st h. The transmembrane potassium influx as deduced from potassium content in incubated cortical slices during steady state conditions decreased during 6 days of hypothermic storage to 24.5 +/- 2.4 mumol/kg which was a significantly higher level than after 24 h of cold storage. Thus, addition of extra substrate to the perfusate does not seem to improve kidney cortex viability during hypothermic perfusion. Parenchymal viability is better preserved with continuous hypothermic perfusion, compared to simple cold storage in a solution of the same ionic composition as that used for perfusion.

Adenine Nucleotides↗
PubMed1983

Hypothermic perfusion of human kidney carcinoma: effects on viability and perfusate distribution.

A more deteriorating effect on tumour tissue than on normal renal parenchyma by hypothermic perfusion has previously been observed. The purpose of this study was to further evaluate changes in the perfusate distribution and the viability of normal cortical tissue and of kidney carcinoma during hypothermic perfusion. Tumour-involved kidneys obtained by nephrectomy from 12 patients were studied either with regard to viability, as measured with the Na+-K+ pump function in incubated tissue slices, or with regard to perfusate flow, as analysed with an isotope labelled microsphere technique. Six days of hypothermic perfusion decreased the potassium content in the tumour tissue, while it was mainly unchanged in the cortical tissue. The steady-state level of potassium in incubated slices reflected that the transmembrane K+ influx was unchanged after 6 days of perfusion in normal cortical tissue, whereas a significant reduction was observed in the tumour tissue. The relative perfusate flow in the tumour, when compared to the normal kidney cortex flow, was reduced from 60% after 1 hr of perfusion to 30% after 6 days of perfusion.

Adult↗
PubMed1983

Acute radiorenography during attacks of renal colic.

Acute radiorenography was compared to emergency excretory urography to evaluate its diagnostic accuracy in 22 patients with clinical signs of renal colic, including erythrocytes in the urinalysis. All 16 patients with delayed excretion and/or dilated renal pelves on excretory urography had delayed excretion of radioactivity on renography. Furthermore, 6 patients with reduced renal function judged by renography had marked or slight delay in excretion on excretory urography. Small stones not causing stasis were found on excretory urography in 2 patients with normal renograms. It is concluded that acute radiorenography is simple, rapid and safe, and identifies accurately patients with abnormal renal function during attacks of colic, with less risks than excretory urography of causing renal damage or aggravating the pain of renal colic.

Adult↗