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Morphological and clinical analysis of 1177 renal biopsies from nonselected patients with essential hypertension revealed compensated benign nephrosclerosis in 775 cases. Decompensated benign nephrosclerosis was found in 251 cases, and secondary malignant nephrosclerosis was found in 151 cases. This article describes the morphological and clinical features of decompensated benign nephrosclerosis, which has received little recognition until now. The morphological and clinical features of secondary malignant nephrosclerosis, which is induced by hypertension, are also considered. There is also a discussion of the differentiation of the latter from primary malignant nephrosclerosis, in which stenosis of the preglomerular vessels develops in the presence of normal blood pressure and leads secondarily to renal hypertension.

The term "mastocytosis" is used to describe a heterogeneous group of disorders characterized by abnormal growth and accumulation of mast cells (MCs). Cutaneous and systemic variants exist. Systemic mastocytosis may show an indolent or malignant clinical course. In malignant mastocytosis (MM), the diagnosis often is missed because the MCs are morphologically abnormal and lack metachromatic granules or the underlying histologic picture is complex. The cytoplasmic serine protease tryptase is produced by MCs and is thought to be expressed at all stages of MC maturation. To assess the diagnostic value of tryptase staining in mastocytosis, tissue sections from 93 patients with mastocytosis, including MM (n = 37), systemic indolent mastocytosis (n = 47), urticaria pigmentosa (n = 5), MC leukemia (n = 2), and solitary skin mastocytoma (n = 2) were stained with the antitryptase antibody G3. The results were compared with those of Giemsa and chloroacetate esterase (CAE) staining. Using antitryptase antibody G3, MC infiltrates were identified in all patients examined, including those with MM (37 of 37), and virtually all the neoplastic MCs (> 95%) appeared to react with G3. In MM, significantly fewer MCs were positive in Giemsa (54.5%; p < 0.05) and CAE (78.8%; p < 0.05). Moreover, G3 produced clear diagnostic staining in all cases of MM, but the proportion of cases with clear diagnostic results (> 10% of neoplastic cells positive) was considerably lower with Giemsa (48.6%; p < 0.05) and CAE (75.7%; p < 0.05) staining. By contrast, tryptase, Giemsa, and CAE produced diagnostic staining of MCs in virtually all cases of systemic indolent mastocytosis, urticaria pigmentosa, and solitary skin mastocytoma. In systemic mastocytosis, survival was significantly reduced in cases with Giemsa-/tryptase+ or CAE-/tryptase+ tumor cells compared to those cases with Giemsa+ or CAE+ MC infiltrates (p < 0.001).

The rabbit has been a widely accepted animal model for atherosclerosis research since Anitschkow first used this animal in 1913 in identifying dietary-induced hypercholesterolemia as a major risk factor for atherogenesis. Experiments with cholesterol-fed rabbits have demonstrated the beneficial effects of estrogen treatment on the development of atheroma for more than 50 y. Clinical trials have found a reduction in cardiovascular events of up to 50% in postmenopausal women receiving estrogen replacement therapy. However, metabolic conditions in rabbits, as well as physiological estrogen serum levels, differ in some aspects from those in humans. In rabbits, experimentally-induced hormone levels are about 5- to 10-fold higher than those found in untreated animals. Normal physiological estrogen levels in rabbits are not cardioprotective under dietary-induced hypercholesterolemia. We investigated whether replacement induced "hyperestrogenemia" causes adverse effects on organs other than the cardiovascular system. Twenty-nine female rabbits were divided into 4 different groups, 2 without and 2 with estrogen treatment (1 mg estradiol valerate/kg body weight/w over 12 w). Organ weights, transaminases and uterine histology were examined. In rabbits treated with estrogen, we did not see relevant adverse effects on heart, kidney and liver weights, or on liver enzymes. But there was a significant increase in spleen weights, as well as notable changes in the endometrium with moderate inflammation. These findings indicate that the dosage of estrogen commonly used for atherosclerosis research does not cause serious disorders in the major organs of cholesterol-fed rabbits.

Mixed acetylboswellic acids, pentacyclic triterpenes extracted from the gum resin of Boswellia serrata Roxb., significantly inhibited the ionophore-stimulated release of the leukotrienes (LT) B4 and C4 from intact human polymorphonuclear neutrophil leukocytes (PMNLs), with IC50 values of 8.48 micrograms/ml and 8.43 micrograms/ml, respectively. Purified acetyl-11-keto-beta-boswellic acid was about three times more potent as inhibitor of the formation of both LTB4 (IC50 = 2.53 micrograms/ml) and LTC4 (IC50 = 2.26 micrograms/ml) from human PMNLs in the same assay. The comparative agent MK 886 (3-[1-(4-chlorobenzyl)-3-t-butyl-thio-5-isopropylindol-2-yl]- 2,2-dimethylpropanoic acid, L-663,536, CAS 118, 414-82-7) was about 10 to 100-fold more active than the boswellic acids in inhibiting the formation of 5-lipoxygenase products in human PMNLs, with IC50 values of 0.0068 microgram/ml (LTB4) and 0.49 microgram/ml (LTC4). After daily intraperitoneal dosage the extract of mixed acetylboswellic acids (20 mg/kg) significantly reduced the clinical symptoms in guinea pigs with experimental autoimmune encephalomyelitis (EAE) between days 11 and 21. However, the inflammatory infiltrates in the brain and the spinal cord were not significantly less extensive in the treated animals than in the respective control group. The multiple intraperitoneal application of boswellic acids did not inhibit the ionophore-challenged ex vivo release of leukotrienes B4 and C4 from PMNLs separated from the blood of guinea pigs with EAE. The boswellic acids have thus been characterized as selective, non-redox and potent inhibitors of the biosynthesis of leukotrienes in vitro.

Objective: We investigated wether an endothelial lesion, postulated in pathogenesis of preeclampsia (PE) in general, is also pathogenetically relevant in the characteristic renal lesions of PE, presenting as special glomerular alterations, designated as "preeclamptic nephropathy"., Study Design: Renal biopsies of 90 women with PE were analyzed by light microscopy (LM), immunohistology (IH) and electron microscopy (EM). Corresponding with clinical data clinicomorphological correlations were performed., Results: In IH and EM the altered glomeruli demonstrate an endothelial lesion. Consecutive morphological reactions could be revealed by EM, allowing a subdivision in different stages of disease. The late stage indicates the reversibility of these renal lesions. Close correlations were found between clinical and morphological data. Focal glomerulosclerosis presents a hyperperfusion lesion, developing only facultatively in PE as a result of hyperfiltration., Conclusion: In preeclamptic nephropathy the first morphological substrate of renal changes with the key to pathogenesis presents itself as an endothelial lesion. This results in a disturbance of glomerular basement membrane permeability and in an imbalance of different mediator systems, with dominance of vasoconstrictive reactions but also coagulative-, reparation-, and proliferation-processes, leading to the characteristic glomerular alterations of preeclamptic nephropathy.

Objective: Our purpose was to determine whether the expression of certain adhesion molecules by endothelium in the human lower uterine segment at term varies with the degree of cervical dilatation., Study Design: Biopsy specimens of the lower uterine segment of 34 women undergoing cesarean section at term at various stages of cervical dilatation were immunostained for endothelial leukocyte adhesion molecule-1, intercellular adhesion molecule-1, vascular cell adhesion molecule-1, and platelet-endothelial cell adhesion molecule., Results: The expression of endothelial leukocyte adhesion molecule-1 was significantly greater at more than 6 cm dilatation than at less than 2 cm (p = 0.00031) as was that of vascular cell adhesion molecule-1 (p = 0.033). Expression of intercellular adhesion molecule-1 and platelet-endothelial cell adhesion molecule did not vary with the degree of cervical dilatation., Conclusion: Cervical dilatation is associated with up-regulation of certain endothelial cell adhesion molecules. The findings support the hypothesis that certain processes associated with cervical dilatation at term resemble those involved in the acute inflammatory reaction.

The long-term prognosis of decompensated benign nephrosclerosis (DBN) was investigated by a retrospective analysis of the fate of 170 patients with this disease, which yielded the following results: 1) DBN carries a particularly poor prognosis. The renal survival rate (RSR) was 35.9% at 5 years and 23.6% at 10 years. The prognosis is therefore worse than that of any other primary glomerulopathy, with the exception of rapidly progressive glomerulonephritis. 2) DBN mainly affects males (sex ratio 5:1) and differs in this respect, among others, from focal sclerosing glomerulonephritis, in which the male:female ratio is 1.2:1. 3) The prognosis for females is no better than for males. 4) The severity of proteinuria at the time of biopsy has no influence on the prognosis. 5) The prognosis is particularly poor in cases in which the serum creatinine concentration is already elevated to more than 2.0 mg% at the time of biopsy. We conclude from these findings that not only the blood pressure, but also the serum creatinine concentration, should be assessed at regular intervals in all hypertensive individuals, so that DBN can be treated at an early stage, when it is still amenable to treatment.

Purpose: Evaluation of the potential of various MR techniques to differentiate bladder wall layers verified by histological findings., Material and Method: 6 bladder specimens of pigs were examined in vitro using T1-weighted spin-echo-sequences, T2-weighted Turbo-SE, fat suppressed T2-weighted SE, and inversion recovery sequences. The MR images were obtained before and after fixating the specimens in formalin. Measurements of the thickness of bladder wall layers were performed on both sets of MR images as well as on histological sections,, Results: T2-weighted SE images showed three layers of different signal intensities: one innermost band of very high signal, one inner band of low and one outer band of intermediate signal corresponding histologically tunica propria and two different muscle layers. Inversion recovery technique provided similar findings but were able to avoid chemical-shift artifacts. After 24 hours in formalin, the signal intensity relation of the two muscle layers was inverted. The thickness of total bladder wall was not reduced significantly. Concerning the thickness of urinary bladder wall, histological measurements and evaluation of MR images correlated well., Conclusion: MR imaging enables the differentiation of three bladder wall layers. Inversion recovery technique achieved the best image quality by avoiding chemical shift artifact.

Background and Objective: Since most clinical laser angioplasties require the use of over-the-wire delivery systems, we studied the effects of pulsed dye laser energy (504 nm, 1.4 microseconds on arterial vessel walls in combination with a multifiber catheter system., Material and Methods: Postmortem arterial segments (n = 368) were exposed under blood or saline. Laser pulses (n = 100-800) were transmitted via 9F-multifiber-catheters, at energy densities of 3-16 J/cm2. Ablation characteristics revealed by histologic examination and morphometry were analyzed by multiple analysis of variance., Results: Ablation occurred more frequently in saline compared to blood. Below an energy density of 10 J/cm2 ablation occurred in saline only. Specimens irradiated under blood showed only thermal changes at 10 J/cm2. In saline, 92% of normal, 88% of fibro-fatty and 60% of calcified tissue showed ablation at 13 J/cm2. The average ablation threshold in saline was about 3-4 J/cm2 per pulse for normal tissue, 5 J/cm2 for fatty plaques, and 8-9 J/cm2 for calcified plaques. In blood, the average ablation thresholds did not differ significantly between the different stages of arteriosclerosis (12 J/cm2 for normal tissue, 11 J/cm2 for fatty plaque, and 10 J/cm2 for calcified tissue). Carbonization and vacuolization were seen regularly at energy levels > or = 13.4 J/cm2., Conclusions: Selective ablation of arteriosclerotic tissue with the pulsed dye laser could not be found. Further investigation is needed before an effective ablation of arteriosclerotic arterial tissue can be expected.

In patients with occult lower gastrointestinal bleeding, locating of the source of hemorrhage can be quite difficult. While multiple diagnostic tests, like arteriography, enteroclysis, nuclear scans, may confirm a small bowel source of bleeding, precise localization allowing a directed, conservative surgical resection may be problematic. We describe a patient presenting with hemorrhage from an angiodysplasia in the small intestine. The preoperative use of highly selective angiographically placed platinum coils into the feeding artery allowed us to precisely locate the angiodysplasia radiographically during operation and to resect a conservative length of small intestine. We believe that preoperative bleeding site localization with platinum coils is a simple, effective tool to aid surgical resection of small bowel angiodysplastic lesions.

The case of an 18-year-old girl is described who 1 year after surgical stabilisation of a spine injury developed a multifocal desmoid tumor in the scar region and another at a distance away from the scar in the area of the left scapula. After nononcological resection of both tumors subsequent diagnosis with magnetic resonance imagins (MRI) showed a questionable recurrence only in the scar; positron emission tomography failed to elucidate the local situation. Because a radical re-resection would mean mutilation, and local radiation may damage the spinal cord, a 'wait-and-see' strategy was chosen for further follow-up.

Correlations between the relative volume of the intertubular capillaries in the renal cortex and the serum creatinine concentration in primary glomerulopathies, renal vasculopathies, and chronic interstitial nephritides are reported. In the mesangioproliferative glomerulonephritides, there are significant negative correlations between the number and area of the intertubular capillaries in the cortex and the serum creatinine concentration. In diabetic glomerulosclerosis, renal glomerular amyloidosis, decompensated benign nephrosclerosis, secondary malignant nephrosclerosis, and chronic interstitial nephritis, there is a significant negative correlation between the relative area of the intertubular capillaries and the serum creatinine concentration. Thus, in these diseases, there is progressive narrowing/ obliteration of the postglomerular capillaries which leads to a progressive decrease in glomerular filtration rate and thus to a rise in serum creatinine concentration.

Background and Objective: Since excimer laser ablation has not shown advantages in comparison to conventional balloon angioplasty, the search for other laser light sources came up with the Er:YAG laser, operating at a wavelength of 2.94 microns., Study Design/materials and Methods: Normal and atherosclerotic human vessel segments were irradiated in vitro, using pulsed Er:YAG laser systems. The laser beam was either focused onto the tissue in air or delivered via a fibre system onto the tissue being immersed in saline. Needle-type hydrophones were used for pressure pulse detection., Results: Er:YAG laser irradiation results in effective tissue ablation of normal and calcified atherosclerotic vessel segments. In comparison to excimer lasers, ablation rates can be increased by a factor of 5 to 10 at least. Er:YAG laser ablation is also associated with a generation of pressure waves. On calcified plaque, the acoustic signals differ significantly from those on normal tissue. Histological tissue analysis reveals small zones of discoloration and tissue fissures that are found 100-200 microns lateral to the crater edge, depending on the energy density used., Conclusion: Er:YAG lasers generate pressure waves that are comparable to excimer laser ablation. Er:YAG lasers, however, show a markedly improved ablation efficiency, which may favour these systems as effectively cutting, less traumatic tools for removal of atherosclerotic plaque.

Different antihypertensive treatment regimes were studied in rats during long-term inhibition of nitric oxide synthesis. Male Munich Wistar rats (weight 150-200 g) were put on oral L-nitro-arginine methyl ester (L-NAME, 50 mg/l drinking water) for 12 weeks. The control group (n = 16) received only tap water. Six weeks after starting L-NAME administration rats were divided into 7 groups (n = 13 in each group: group 1, no treatment; group 2, l-arginine 1 g/l drinking water; group 3, doxazosin 30 mg/kg/day; group 4, felodipine 25-30 mg/kg/day; group 5, losartan 40 mg/kg/day; group 6, metoprolol 300-350 mg/kg/day, and group 7, ramipril 1 mg/kg/day. Systolic blood pressure (sBP) was measured in the conscious rat 1, 6, and 12 weeks after study begin. After a treatment period of 6 weeks albuminuria, glomerular filtration rate (GFR) and renal plasma flow (RPF; inulin and p-aminohippuric acid clearance) were analyzed. All rats showed a significant increase in sBP under 6 weeks of L-NAME administration. Control rats remained normotensive during the whole study period. Rats receiving L-NAME without antihypertensive treatment showed a further increase in sBP after 12 weeks. Blood pressure was lowered in all treated animals, except in rats receiving l-arginine. Values for GFR were lowest in the placebo group, the l-arginine group and in rats receiving felodipine (p < 0.05 compared to the control group). RPF was lowest in the placebo group, the l-arginine group, the felodipine group and the ramipril group (p < 0.05 compared to the control group).(ABSTRACT TRUNCATED AT 250 WORDS)

Aim: The assessment of the value of the antibody QBEND10, which is directed against the haemopoietic stem cell related antigen CD34, in the immunohistochemical diagnosis of myelodysplastic syndrome in routinely processed bone marrow biopsy specimens., Methods: 581 formalin fixed, paraffin embedded trephine biopsy specimens of the iliac crest were immunostained with QBEND10 (avidin-biotin complex/ABC method). The number of CD34+ haemopoietic stem cells/blast cells (referred to hereafter as CD34+ cells) was determined in each case. The Wilcoxon test was used for statistical analysis., Results: The following diagnostic categories were defined: (1) normal or reactive bone marrow (n = 356), (2) lymphoproliferative disorders, usually non-Hodgkin's lymphoma of low grade malignancy or multiple myeloma (n = 118), (3) myelodysplastic syndrome (n = 22), (4) acute leukaemia (n = 44), and (5) myeloproliferative diseases (n = 41). The average number of CD34+ cells was very low (0.2/HPF) in normal and reactive bone marrow, in lymphoproliferative disorders and in the myelodysplastic syndrome subtypes RA and RARS. Myeloproliferative diseases showed an average of three CD34+ cells/HPF. However, the average number of CD34+ cells was significantly higher (p < 0.05) in the myelodysplastic syndrome subtypes RAEB and RAEB-T (8.7/HPF) and in acute leukaemia (including both myeloid and lymphoblastic leukaemia; 111.7/HPF)., Conclusions: QBEND10 is of value for the identification of RAEB and RAEB-T in routinely processed bone marrow biopsy specimens because it enables the detection of even small increases in the number of CD34+ cells.

Unlabelled: To study the ablation effects induced by excimer laser coronary angioplasty (ELCA), we examined 41 segments of nine isolated coronary arteries. An electronic intracoronary ultrasound device (ICUS: 20 MHz, 3.5F, Endosonics) was positioned coaxially within the vessel. Angioplasty was performed using a 1.7 mm ELCA catheter (Spectranetics) which was placed in the lumen and directed vertically onto the intimal surface of the vessel (fluence: 10-50 mJ.mm-2). The laser catheter was removed after each lasing cycle to allow the stepwise evaluation of the morphological effects of ELCA and to avoid reaching the adventitia. Ultrasound images were compared with the corresponding histological specimens. In all cases, the ablation site could be correctly identified by ICUS. No penetration of the adventitia was seen at histology. Ablation depth was 0.31 +/- 0.18 mm as determined by histology and 0.34 +/- 0.18 mm as determined by ultrasound; the diameter of the crater was 0.63 +/- 0.21 mm, and 0.75 +/- 0.16 mm, respectively, and wall thickness was 0.68 +/- 0.18 mm, and 0.83 +/- 0.20 mm, respectively. A statistical relationship between ultrasonic and histology measurements was only found, however, for assessment of wall thickness (r = 0.71)., Conclusions: The identification of small ablation effects by ICUS was possible with great accuracy and ELCA could be performed without penetration of the adventitial layers. However, exact quantification of the crater dimensions was not possible due to limitations of the axial and lateral resolution. Thus, for the guidance of ELCA by ICUS a further improvement in the resolution capabilities of ICUS devices is mandatory.

It is well known that some of the widely used antibodies directed against hemopoietic antigens exhibit cross-reactivity with normal and neoplastic nonhemopoietic cells. By contrast, relatively little is known about the immunoreactivity of hemopoietic cells with antibodies that detect nonhemopoietic antigens. In this study 43 routinely processed bone marrow biopsy specimens containing infiltrates of acute leukemia of different subtypes were stained with a panel of 20 antibodies that detect nonhemopoietic antigens in formalin-fixed and paraffin-embedded tissue. Thirteen of the antibodies applied (KL1; BMA 120; and antibodies against epithelial membrane antigen, alpha-fetoprotein, prostate-specific acid phosphatase, prostate-specific epithelial antigen, placental alkaline phosphatase, alpha-amylase, serotonin, bombesin, beta-human chorionic gonadotrophin, desmin, and S-100 protein) did not stain blast cells in any of the cases. However, anti-vimentin, HMB45, and anti-myoglobin stained blast cells in the majority of the cases; the antibodies against thyroglobulin, actin, and carcinoembryonic antigen stained blast cells in 10% to 25% of the cases; and anti-neuron-specific enolase stained blast cells in less than 10% of the cases. No correlation was found between the leukemia subtype and the pattern of immunoreactivity. The staining specificity, (i.e., the specificity of binding of the primary antibody--immunologic vs. nonimmunologic binding), was tested by increasing the dilution of the primary antibody and comparing the staining intensity in the bone marrow specimens and control tissue. Staining specificity was confirmed only for staining with the antibodies against neuron-specific enolase and vimentin. The findings show that immunoreactivity of tumor cells in bone marrow biopsy specimens for nonhemopoietic antigens does not exclude a diagnosis of acute leukemia.

Today, local therapy is an established alternative to radical resection for the treatment of rectal tumours. Selection of the operative technique requires an exact perioperative estimation of risks, with both clinical and histopathological examination. Of crucial importance in making a decision to perform a local resection is exact and meticulous histopathological preparation of the tissue. The most important criterion is the estimation of risk of lymph node metastases. This risk is assessed on the basis of the depth of invasion of the tumour, the histological grade of differentiation and the presence or absence of invasion of lymphatic vessels.

The value of immunohistochemical staining in the subtyping of acute leukemia was investigated on 36 routinely processed (formalin-fixed and paraffin-embedded) trephine biopsy specimens from the iliac crest containing diffuse infiltrates of acute myelogenous leukemia (AML; n = 23) and acute lymphoblastic leukemia (ALL; n = 13). These were stained with a broad panel of antibodies (n = 23) against various leukocyte antigens, among them 11 macrophage-associated antibodies (MAAs): Ki-M1p, MAC387, HAM56, LN5, KP1 (CD68), PG-M1 (CD68), Ki-M4p, DAKO-DRC (CD35), and antibodies against lysozyme, alpha 1-antichymotrypsin, and S100 protein. The French-American-British (FAB) classification subtypes of the AML cases, as determined by enzyme-cytochemical and/or immunocytological investigation of bone marrow smears, were as follows: M1 = 6, M2 = 5, M4 = 7, M5 = 3, and AML (not classified) = 2. The 13 cases of ALL were classified as follows: c-ALL (pre-B-ALL) = 7, B-ALL = 3, T-ALL = 2, and ALL (not classified) = 1. All the MAAs except LN5, Ki-M4p, and DAKO-DRC stained blast cells in AML. However, the number of stained blast cells varied considerably within and between the individual subtypes (M4/5 > M2/1). Using Fisher's exact test a significant difference in frequency of blast cell staining between AML and ALL was found for four MAAs (anti-lysozyme, MAC387, Ki-M1p, and KP1) and two of the three myeloid cell markers applied (Ki-My2p and anti-neutrophil elastase). Of these six antibodies, the combination of anti-lysozyme and KP1 can be recommended for use in routine diagnostics for the differentiation of AML from ALL on the basis of immunohistochemical staining because both of these antibodies were found to stain a relatively large percentage of cases of AML but none of ALL. However, none of the MAAs were found to discriminate reliably between the FAB M4/5 and M1/2 subtypes of AML.

To define the accuracy of electronic and mechanical ultrasound (US) devices for determining the thickness of intima and media, 32 fresh normal and atherosclerotic human femoral arteries were obtained at necropsy. The samples were imaged with a 64-element array and a mechanically rotating US transducer at 20 MHz. The mean thickness of the intimal and medial layer was measured with electronic calipers followed by histopathologic and micromorphometric analysis. Morphometric correlation for intima showed r = 0.64 for the electronic and r = 0.58 for the mechanical US device. The correlation between ultrasonic and histologic measurement of medial thickness in normal and diseased specimens was r = 0.79 for the multielement and r = 0.76 for the mechanical transducer. In conclusion, multielement array transducers are equivalent to mechanically driven probes in the quantitative assessment of peripheral arterial wall layers. Both systems lack sufficient accuracy in the determination of mild to moderate intimal thickening.

Precise cutting combined with reliable coagulation of the margins of the lesion is an important requirement for dissection techniques in endoscopic surgery. These requirements are met by the two most common ancillary energy sources applied for endoscopic dissection today, electrosurgery and "thermal lasers", mostly the Nd:YAG. For the comparison of the histological effects of monopolar and bipolar high frequency with the Nd:YAG laser an experimental in vitro and in vivo study has been performed. In order to evaluate the advantages of non thermal dissection for endoscopic procedures, a water jet cutting system was included in the in vitro study. In parenchymatous tissue the water jet was found to be the least traumatic technique, followed by bipolar high frequency, laser and monopolar high frequency. The water jet was not applicable for intestinal dissection since uncontrolled bloating of the rectal wall with uncontrolled disruption of the tissue layers occurred. A general disadvantage is that secure haemostasis in the line of incision is hard to achieve. In the microscopic comparison of the shape of the incision, the Nd:YAG laser produced the smoothest lesions with well-defined margins. The monopolar technique was more often associated with irregular and sometimes fissured margins. These results were confirmed in the in vivo part of the study (Transanal Endoscopic Microsurgery).

We present the case of an adrenal incidentaloma of considerable size which turned out to be a stomach-like diverticular mass, probably a malformation arising from the embryonic foregut. We discuss whether results possibly obtained by extensive and costly investigative techniques would have changed the management.

Comparative clinical and morphological investigations on the pathogenesis of chronic renal insufficiency in various types of renal vasculopathy revealed the following: 1) Compensated benign nephrosclerosis, with hyalinosis of the walls of the afferent vessels, does not lead to renal insufficiency, since relatively few glomeruli, mostly subcapsular, become obliterated in this disease. 2) In decompensated benign nephrosclerosis, in which not only the afferent vessels but also the glomeruli and the cortical interstitium are involved, there is a significant positive correlation between the relative width of the renal cortical interstitium and the serum creatinine concentration and a significant negative correlation between the relative volume of the postglomerular capillaries and the serum creatinine concentration, as in the primary glomerulopathies. 3) In primary malignant nephrosclerosis, which is always accompanied by haemolytic-uraemic syndrome, the relative width of the cortical interstitium is not related to the serum creatinine concentration. Chronic renal insufficiency develops in this disease as a result of a fall in glomerular filtration rate to inadequate levels due to impairment of renal perfusion by stenotic changes in the preglomerular vessels. 4) In secondary malignant nephrosclerosis, which is never accompanied by haemolytic-uraemic syndrome, there is, as in the primary glomerulopathies, a significant positive correlation between the relative width of the renal cortical interstitium and the serum creatinine concentration and a significant negative correlation between the relative capillary volume and the serum creatinine concentration. 5) In decompensated benign nephrosclerosis the severity of the renal insufficiency depends largely on the degree of obliteration of the postglomerular capillaries.(ABSTRACT TRUNCATED AT 250 WORDS)

Comparative analysis of renal biopsy findings and clinical status in patients with different types of glomerulopathy (primary glomerulonephritis, 1747; diabetic glomerulosclerosis, 488; renal AA and AL amyloidosis, 225) was undertaken to investigate the pathogenesis of chronic renal failure in these diseases. Morphometric, cytological and electron-microscopic investigations were undertaken and yielded the following results: 1. Disease of the renal corpuscles alone, even if it is very severe, does not lead to renal insufficiency or even elevation of the serum creatinine concentration. 2. Chronic renal insufficiency develops only in those cases of glomerulopathy in which the postglomerular capillaries in the renal cortex exhibit chronic inflammation that causes such severe narrowing of these vessels as to impair glomerular perfusion. 3. The passage of basement membrane material from the glomerular capillaries into the primary urine may play a critical role in the pathogenesis of some forms of chronic renal failure, since this material can be reabsorbed by the tubules and is probably presented as an autoantigen to intraepithelial T lymphocytes by proximal tubular epithelial cells that express distinct HLA class II antigens and ICAM-1. 4. The presentation of these autoantigens to intraepithelial T lymphocytes leads in genetically predisposed individuals to an autoimmune response with a consequent marked increase in numbers of T lymphocytes and an increase in macrophages/monocytes, fibroblasts/fibrocytes and plasma cells, and increased production of extracellular matrix by fibroblasts/fibrocytes. 5. The increase in extracellular matrix leads to obliteration of the postglomerular capillaries.(ABSTRACT TRUNCATED AT 250 WORDS)

To evaluate the impact and limitations of intracoronary ultrasound in the assessment of lumen, we examined 80 segments of 20 isolated coronary arteries with a mechanical ultrasound device (CVIS) comparing the results of ultrasound with the corresponding histological specimens. Ultrasound was performed with and without echogenic contrast dye (Laevovist, Schering AG, FRG). After application of contrast dye, correlation of luminal area between histology and ultrasound was improved from r = 0.85 to r = 0.89 (p = ns). Accuracy of lumen measurements was low in segments < 2.5 mm; only after application of contrast dye a relationship between ultrasound and histological measurements was found. In all cases in which a deviation of more than 20% between ultrasound and histology was observed, this deviation could be reduced by the application of contrast dye. There are considerable limitations in the accuracy of ultrasound measurements in the near field. Thus, further improvement of intracoronary ultrasound devices is mandatory. However, with the use of the currently available systems, additional application of echogenic contrast dye can improve accuracy of luminal measurements, especially in smaller size vessels.

Thorough studies of kidney specimens obtained at autopsy or by renal biopsy revealed, that in noninflammatory acute renal failure oliguria/anuria is caused by increased activation o the renal renin-angiotensin system and increased generation of adenosine. At the polyuric phase moderately increased adenosine in kidney tissue seems to be the main factor responsible for decreased glomerular filtration.

A combination of laparoscopic and rectoscopic procedures has enabled complete resection of the sigmoid colon and eliminated the need for minilaparotomy when constructing the anastomosis or withdrawing the specimen. This combined procedure was performed in different ways in a series of animal models until the definitive technique had been standardized. These techniques were then successfully used in 15 consecutive medium-sized pigs. Histological evaluation of the specimens, including the anastomosis (examined 2-3 weeks after operation) confirmed the efficacy and safety of the method.

Studies on the proliferative compartment of human tissue mast cells (MCs) and their tumours (mastocytosis) have not been performed. We have used the monoclonal antibody PC10 to study MCs in reactive or hyperplastic states (chronic non-specific lymphadenitis, n = 10; benign and malignant solid tumours, n = 5) and in the various subtypes of mastocytosis (urticaria pigmentosa, n = 22; solitary mastocytoma of the skin, n = 7; systemic mastocytosis; n = 8; malignant mastocytosis, n = 4). The identification of PC10-positive MC nuclei was achieved by double staining. We found no PC10-positive MCs in reactive or hyperplastic states, or in 14 of 22 cases of urticaria pigmentosa. PC10-positive MCs could be identified in all other mastocytosis but mostly in very low numbers. The mean percentages of PC10-positive MCs amounted to 0.5 in eight positive cases of urticaria pigmentosa, 1.2 in mastocytoma, 0.7 in systemic mastocytosis, and 4.0 in malignant mastocytosis. The difference between the latter form of mastocytosis and each of the other subtypes proved to be significant (P < 0.05). The very small proliferative compartment in the cutaneous and systemic variants of mastocytosis is in accord with their favourable prognosis. Most of the patients with systemic mastocytosis in the present study are all alive and well up to 12 years after diagnosis. In contrast, most of the patients with malignant mastocytosis died within 1 year of diagnosis.

Cyclosporine A (15, 30 or 50 mg/kg.day) or olive oil (30 mg/kg.day) were administered orally to 32 male Sprague-Dawley rats for 12 or 24 days, or withdrawn for 24 days following 24 days of treatment. The specific activity of a lysosomal marker enzyme, N-acetyl-beta-D-glucosaminidase, was determined fluorometrically in single nephron segments microdissected from lyophilized kidney sections of these animals and of an additional 2 normal rats. The segments were classified according to their normal or reduced succinate dehydrogenase activity as detected in stained adjacent sections. In addition, urine specimens collected after 12, 24, 36, and 48 days of the experiment were tested for N-acetyl-beta-D-glucosaminidase activity. After treatment with cyclosporine A, changes in the activities of N-acetyl-beta-D-glucosaminidase were found only in the proximal tubules. In the convoluted segments with normal succinate dehydrogenase activity, the activity of N-acetyl-beta-D-glucosaminidase was 138-163%, and in those with reduced succinate dehydrogenase activity, it was unchanged or 66-83% of the control values. In the straight segments with reduced succinate dehydrogenase activity, the activity of N-acetyl-beta-D-glucosaminidase increased gradually along the medullary rays (122-214%) to the outer stripe of the outer medulla (178-263%) in comparison to the control values. In the urine specimens, the activity of N-acetyl-beta-D-glucosaminidase was increased to 148-152%. These tubular and urinary changes were similar for each dosage and treatment period. After withdrawal of cyclosporine A they were not present. The variety of alterations occurring within the lysosomes along the proximal tubules of cyclosporine-A-treated rats implies the convoluted part as the site of increased release of N-acetyl-beta-D-glucosaminidase into the urine.

In order to save time for changing instruments and minimize thermal damage in underlying tissue caused by monopolar high frequency in transanal endoscopic microsurgery (TEM), we have developed a new electrosurgical instrument, in which four functions are integrated: bipolar cutting, monopolar coagulation, suction and irrigation. The new device and the conventional monopolar knife were tested during both in vitro and in vivo experiments to compare the thermal alterations and effects on operating time. In vitro experiments demonstrated that the extent of thermal alterations created by bipolar cutting was less than in the case of monopolar cutting in the fresh porcine liver and bovine rectum. The mean severity scores for carbonization, coagulation and vacuolization in the resected mucosae obtained during in vivo animal operations by the bipolar procedure were 2.09, 2.27 and 1.36, respectively, whereas those obtained using the monopolar technique were 2.64, 2.82 and 2.36, respectively. The new device required an average operation time of 673.5 seconds, whereas the conventional setup required 701.9 seconds to resect the same diameter of rectal mucosa. Reduced operation time with the new device was mainly attributable to the reduced time needed for changing the instruments for hemostasis. The decreased thermal damage to the underlying bowel wall produced by the bipolar procedure should reduce the incidence of such operative complications in TEM (Transanal Endoscopic Microsurgery, developed in 1983 by Buess, Theis and Hutterer) as perforation, dehiscence in the suture line or post-polypectomy coagulation syndrome. By quickly switching between the multiple functions of this new device a clear operative field can always be achieved, thus decreasing operation time and bleeding.(ABSTRACT TRUNCATED AT 250 WORDS)

Investigation of the long-term prognosis and pathogenesis of chronic renal failure in 225 cases of AA and AL renal amyloidosis (perireticular and perireticular + pericollagenous amyloidosis) yielded the following results: 1) The prognosis of both AA and AL amyloidosis is poor, and is worse than all other types of glomerulopathy with the exception of rapidly progressive glomerulonephritis. 2) The probability of maintaining renal function in AL amyloidosis is no lower than that in AA amyloidosis. 3) The prognosis of both AA and AL amyloidosis is significantly worse in cases in which the renal cortical interstitium exhibits fibrosis at the time of the biopsy than in those in which it is normal. 4) In AA and AL amyloidosis, as in various types of inflammatory glomerulopathy, the relative area of the renal cortical interstitium shows a significant positive correlation with the serum creatinine concentration and a significant negative correlation with the creatinine clearance. However, the extent of interstitial amyloid deposition does not correlate with the serum creatinine concentration. Deposition of amyloid in the renal cortical interstitium has no effect on renal excretory function. 5) The long-term prognosis of renal amyloidosis is related to the severity of the glomerular amyloidosis in as much as it is generally worse in Grades III to V than in Grades I and II. However, it must be borne in mind that the incidence of interstitial fibrosis, which is decisive for the long-term prognosis, increases with the severity of glomerular changes. 6) The long-term prognosis of renal amyloidosis is worse if acute renal failure or interstitial fibrosis is present at the time of the biopsy. Patients with both acute renal failure and interstitial fibrosis have the worst prognosis. 7) Isolated glomerular amyloidosis, even if there is severe vascular amyloidosis (vas afferns), does not lead to renal insufficiency or even to a rise in serum creatinine concentration. 8) The number of T lymphocytes in the tubular epithelium in AA and AL amyloidosis is significantly greater than normal, and the number of T lymphocytes, macrophages/monocytes, and fibroblasts/fibrocytes per unit area of interstitium is also significantly increased. 9) As far as the pathogenesis of renal cortical interstitial fibrosis in renal amyloidosis is concerned, it is proposed that, in some cases, this develops from the interstitial edema that is seen in biopsy specimens of patients with renal amyloidosis and acute renal failure.(ABSTRACT TRUNCATED AT 400 WORDS)

Bone marrow lymphocyte subsets in normal and reactive states and in neoplastic diseases involving the marrow were investigated with a select panel of monoclonal antibodies reactive on routinely processed, paraffin-embedded trephine biopsy material. In all cases, the antibodies beta F1 and UCHL1 (CD45RO) stained virtually equal numbers of T cells (reactive and neoplastic), whereas antibody OPD4 stained only about one half of this number of T cells. Antibody L26 (CD20) stained B cells (reactive and neoplastic) in all specimens. The T-cell to B-cell ratio in the normal marrow was between 4:1 and 5:1, and a significant increase in T-cell numbers was observed in reactive and myelodysplastic states. A significant increase in B-cell numbers, however, was seen only in marrow infiltrated by B-cell lymphoma. Bone marrow exhibiting infiltrates of B-cell lymphoma, acute leukemia, or myeloproliferative disorders showed normal or decreased numbers of T cells. These findings show that antibodies UCHL1, beta F1, and L26 can be used to determine the numbers of B and T lymphocytes in paraffin-embedded, formalin-fixed bone marrow specimens and thus may help to distinguish reactive T lymphocytosis from B-cell lymphoma.

Ablation of atherosclerotic plaque and normal arterial wall was performed using a xenon-chloride-excimer laser with a wavelength of 308 nm and a pulse duration of 115 ns. The light was transmitted via a 600 micron fiber and adjusted to an energy density of 3.5 J/cm2. The acoustic signals generated by the laser pulse were measured with hydrophones consisting of polyvinylidenefluoride with active diameters of 0.3 mm and recorded on a dual-channel digital storage oscilloscope using either a 0.5 m coaxial cable or a broadband transmission system. From 19 cadavers human aortic tissue segments were excised and macroscopically classified as either normal or calcified atherosclerotic plaque. Approximately 500 measurements were performed in saline and blood each. Histological analysis was carried out after the experiments to verify the macroscopic diagnosis and to correlate the acoustic responses with the tissue characteristics. For "normal" arterial segments, maximum peak pressure was 1.25 MPa +/- 0.85 MPa, rise time 163 ns +/- 43 ns, and pressure increase 8.2 kPa +/- 5.4 kPa/ns in saline. For calcified, atheromatous segments a significantly higher maximum pressure (2.20 MPa +/- 1.16 MPa), a significantly shorter rise time (69.9 ns +/- 25.8 ns), and a significantly higher pressure increase (32.3 kPa +/- 21.3 kPa/ns) was found in saline (p < or = 0.0001). In blood, maximum peak pressure was 1.29 MPa +/- 0.43 MPa, rise time 93.3 ns +/- 27.7 ns, and pressure increase 14.6 kPa +/- 5.2 kPa/ns for "normal" arterial segments. Maximum peak pressure (2.28 MPa +/- 0.63 MPa) and pressure increase (32.8 kPa +/- Pa/ns) were significantly higher for calcified tissue segments.(ABSTRACT TRUNCATED AT 250 WORDS)

To evaluate the impact and limitations of intracoronary ultrasound, 64 segments of 13 isolated coronary arteries were examined and 2 mechanical devices (device A, 30 MHz 5Fr [CVIS] and device B, 20 MHz 4.8Fr [Diasonics/Boston Scientific] were compared with the corresponding histologic specimens. Luminal dimensions were assessed with and without echogenic contrast dye (Laevovist, Schering AG, Germany). After application of contrast dye, correlation of luminal area between histology and ultrasound was improved from r = 0.62 to r = 0.77 (device B; p < 0.05) and from r = 0.82 to r = 0.88 (device A; p = NS). Low accuracy of lumen measurements in segments < 2.5 mm could be improved by application of contrast dye. The number of quadrants in which wall thickness measurements were impossible was significantly higher for device B (n = 56; 22%) than for device A (n = 28; 11%); p < 0.01. This may be due to the different ringdown diameters of both systems (B, 2.6 mm; A, 2.0 mm; p < 0.0001). In assessing wall thickness only in segments of > 2.5 mm, a reliable correlation between ultrasound and histology was found (A, r = 0.80; B, r = 0.60). Sensitivity of plaque (n = 51) detection was lower for device B (63%) than for device A (82%, p < 0.05), and measurements correlated with histology only for device A. There are considerable differences in the accuracy of ultrasound measurements between mechanical systems. Nevertheless, additional application of contrast dye can improve accuracy of luminal measurements, especially in smaller vessels.

Ablation of atherosclerotic plaque and normal arterial wall was performed using a Xenon-Chloride Excimer laser with a wave-length of 308 nm and a pulse duration of 115 ns. The light was transmitted via a 600 microns bare fibre and adjusted to an energy density of 3.5J/cm2. The acoustic signals generated by the laser pulse were measured with two types of hydrophones consisting of polyvinylidenefluoride with active diameters of 0.3 mm and 0.5 mm and recorded on a dual channel digital storage oscilloscope using either a 0.5 m coaxial cable or a broadband fibre-optic transmission system. Tissue was retrieved from nine cadaver human aortas and macroscopically classified as either normal or calcified atherosclerotic plaque. Histological analysis (Haematoxylin eosin, elastica van Gieson, and immunohistochemical staining) was carried out after the experiments to verify the macroscopic diagnosis and to correlate the acoustic responses with the tissue characteristics. For normal arterial wall, maximum peak pressure was 1.28 MPa +/- 0.85 MPa, rise time 163 ns +/- 43 ns, and pressure increase 8.2k Pa +/- 5.4k Pa/ns. For calcified, atheromatous segments, a maximum peak pressure of 2.02 MPa +/- 1.16 MPa, a rise time of 69.9 ns +/- 25.8 ns, and a pressure increase of 32.3 kPa +/- 21.3 kPa/ns was found. Statistical analysis showed a significant shorter rise time (P < 0.0001) and a higher pressure increase (P < 0.0001) for calcified tissue in comparison to normal arterial wall, whereas maximum pressures alone did not allow a differentiation of tissue characteristics. Several hundred kPa are generated during Excimer laser ablation.(ABSTRACT TRUNCATED AT 250 WORDS)

This experimental study was designed to define the potential value of a mid-infrared holmium laser in the free running mode for angioplasty. Immediately after removal, fresh normal and diseased human cadaveric arteries were irradiated under saline with a Ho:YAG laser (wavelength 2.13 microns). The laser was pulsed at 3 Hz, 250 microseconds pulse width and fluences of 10 to 40 J/cm2. The laser beam was coupled to ring catheters with multiple low-OH quartz fibers. The tip of the delivery device was held in direct contact with the vessel surface with the laser beam oriented perpendicularly. Ablation of atherosclerotic plaque was accomplished at an ablation threshold of 10 J/cm2. The ablation rate was 2.1 to 8.3 microns/pulse. Removal of calcified plaque was only partially effective. There were marked thermal effects with vacuolizations extending up to 1505 +/- 178 microns into the adjacent tissue. Laser light at the mid-infrared wavelength of 2.13 microns is supposed to be attractive as it is readily absorbed in water and can easily be transmitted through optical fibers. However, Q-switching seems to be essential to minimize thermal side effects and to make effective ablation of calcium possible.

Long-term studies of all types of primary glomerulonephritis (GN) taking into consideration the major morphological and clinical findings revealed the following: 1) Endocapillary GN, post-streptococcal type has a very good prognosis when only glomerulitis is present. The prognosis is significantly worse if either interstitial inflammation with fibrosis or nephrotic syndrome (NS) is present at the time of the biopsy. 2) The prognosis of the various types of mesangioproliferative GN (IgA nephritis, non-IgA nephritis, and immunohistologically negative GN) is very good if there is only glomerulitis. The prognosis is worse for all three types when the renal cortical interstitium exhibits inflammation with fibrosis at the time of the biopsy, and is worst of all when both interstitial fibrosis (IF) and the signs of acute renal failure (ARF) are present. Of this group, the type in which there are negative immunohistological findings exhibits the best prognosis. No difference in prognosis is found between IgA nephritis and non-IgA nephritis. 3) Minimal changes GN with NS has a very good prognosis when the interstitium is not involved. The presence of interstitial inflammation and fibrosis worsens the prognosis significantly. 4) Focal sclerosing GN has a much poorer prognosis than minimal changes GN with NS, even when there is glomerulitis only (5- and 10-year renal survival rates (RSRs) of 90% and 67%, respectively). If interstitial inflammation and fibrosis are present, the prognosis is significantly worse (5- and 10-year RSRs of 84% and 55%, respectively). The prognosis is worst when both ARF and IF are present at the time of the biopsy (5- and 10-year RSRs of 56% and 46%, respectively). From the clinical side, the prognosis is significantly worse if, at the time of the biopsy, NS is present or the serum creatinine concentration is elevated to more than 1.3 mg%. 5) Chronic membranous GN has a better prognosis than focal sclerosing GN if glomerulitis only is present (5-year RSR, 88%; 10-year RSR, 77%). If the renal cortical interstitium is also involved (in the form of IF), the prognosis is significantly worse (5-year RSR, 65%; 10-year RSR, 38%). The prognosis in this disease, too, is worst when both ARF and IF are present at the time of the biopsy (5-year RSR, 38%; 10-year RSR, 25%). 6) Membranoproliferative GN has a worse prognosis than any of the types of GN so far mentioned (5-year RSR, 51%; 10-year RSR, 32%).(ABSTRACT TRUNCATED AT 400 WORDS)

The suitability of a pulsed dye laser (504 nm) in experimental and clinical angioplasty was investigated. In an experimental study, the ablation thresholds were 3 J/cm2 +/- 8 (mean +/- standard deviation) for fibrofatty plaque and 25 J/cm2 for calcified tissues under saline. At a radiant exposure of 10 J/cm2 the etch rates were 1.7 microns per pulse +/- 0.3 for media, 2.8 microns/pulse +/- 0.4 for normal intima, and 3.9 microns/pulse +/- 1.1 for fibrofatty plaque (P less than .05). Pressure wave effects with a separation of tissue layers were predominantly localized at the internal elastic lamina. Thermal injury with vacuolations extended 15 microns +/- 6 into adjacent tissue. For clinical study, laser-assisted balloon angioplasty was performed in 10 patients (64 years +/- 14) with occlusions of peripheral arteries using a 9-F multifiber ring catheter. Lesion length ranged from 2 to 12 cm (mean, 7 cm). Laser angioplasty with an 80 mJ/pulse decreased the mean stenosis from 100% to 58% +/- 12% (P less than .005). The ankle-brachial index rose from a median of 0.48 to 0.88 (P less than .001). In 33% of patients, there were subintimal dissections after laser angioplasty. After a mean follow-up of 10.2 months, the overall clinical success was 70% with a primary patency of 78%. The over-the-wire approach with a pulsed dye laser may constitute a safe and feasible tool in laser angioplasty.

The following parameters were measured in 63 renal biopsy specimens, most of which exhibited mesangioproliferative glomerulonephritis: the relative area of the interstitium and the area of the capillaries in the cortex and outer stripe of the outer medulla, and the area of the epithelium of the proximal tubules and of the ascending limbs of Henle's loop. The percentage of hyalinized glomeruli was also determined. Investigation of correlations between these values and parameters of renal function revealed the following: 1) The serum creatinine concentration increases and the endogenous creatinine clearance decreases significantly as the interstitium of both the cortex and the outer stripe of the outer medulla increases in width. 2) The urine osmolality decreases significantly as the epithelial areas of the proximal tubules and ascending limbs of Henle's loop decrease, and as the serum creatinine concentration rises and the areas of the interstitium increase. 3) No significant correlation exists between the percentage of hyalinized glomeruli and the urine osmolality. 4) The total area of the intertubular capillaries in the cortex decreases significantly as the interstitium in this area increases in width and as the serum creatinine concentration increases. 5) Compensatory hypertrophy of individual nephrons, as proposed by Bricker's hypothesis, was found only where more than 90% of the glomeruli were hyalinized.(ABSTRACT TRUNCATED AT 250 WORDS)

To determine the temporal evolution of laser induced tissue ablation, arterial wall specimens with either hard calcified or fatty plaques and normal tissue were irradiated in a 0.9% saline solution using a XeCl excimer laser (wavelength 308 nm, energy fluence 7 J/cm2, pulse width 30 ns) through a 600 microns fused silica fiber pointing perpendicular either at a 0.5 mm distance or in direct contact to the vascular surface. Radiation of a pulsed dye laser (wavelength 580 nm) was used to illuminate the tissue surface. The ablation process and the arising bubble above the tissue surface were recorded with a CCD camera attached to a computer based image-processing system. Spherical cavitation bubbles and small tissue particles emerging from the irradiated area have been recorded. The volume of this bubble increased faster for calcified plaques than for normal tissue.

To investigate the effect of radiofrequency energy (600 kHz) on atherosclerotic tissue, high frequency current was applied on 160 specimens of human abdominal and iliac artery autopsies with various duration and energy density. All experiments were performed in air, saline, and blood. Application of 5 to 30 joule resulted in coagulation of the intima and the media. Time dependent a shrinking of the vessel wall did occur at energy rates above 30 joule. At higher energies vaporization was found. In blood coagulation at the catheter tip became evident at 30 joule and higher energies. Histologic cross sections showed distending of intimal layers at 25 joule, additional shrinking of medial layers at 50 joule, vacuoles at 75 joule and separation of intima layers from underlying layers at 200 joule. In vitro application of high frequency current on atherosclerotic tissue results in thermal effects only. The extent of these effects seems to be unpredictable because of the ever changing composition of the tissue, resulting in changes of energy delivery at the tip tissue interface. On calcified plaques an energy dependent contraction mainly of adjacent vessel wall could be seen. Because of the non-predictable effects and adverse side effects on adjacent normal vessel wall the method seems not to be useful for clinical application.

It has been shown that coronary excimer laser angioplasty can remove atherosclerotic intracoronary tissue. Stand alone coronary excimer laser angioplasty was successfully performed in a 53 year old white man with 90% stenosis of the left anterior descending coronary artery and exertional angina (Canadian Cardiovascular Society class III). The lesion was reduced to a 30% residual stenosis with use of a 1.2 mm and subsequently a 1.8 mm diameter laser catheter. Early follow-up angiography 24 h later revealed persistent patency and unchanged lesion diameter of the target vessel. The patient was free of symptoms during the 2 month follow-up period, but died suddenly while playing in a tennis tournament 63 days after the procedure. Postmortem histologic examination revealed 80% restenosis at the lesion site without plaque disruption or thrombosis. Specific staining of the histologic specimen for smooth muscle cells using alpha-actin revealed significant smooth muscle cell proliferation at the site of coronary excimer laser angioplasty. However, most of the vessel narrowing appeared to be due to underlying fibrotic plaque as a result of insufficient tissue ablation. This was probably related to the size of the currently available catheters, which are too small to create a large channel.

Investigation of renal biopsy specimens from 488 patients with diabetic glomerulosclerosis (DGS) of varying severity revealed the following: 1) The severity of DGS increases with the duration of the diabetes. 2) As the severity of DGS increases, it is complicated with increasing frequency by exudative changes, which correspond in detail to hyperperfusion lesions described in the literature. 3) As the severity of DGS increases, the severity of arteriolosclerosis and the incidence of nephrotic syndrome increase significantly. 4) The 5- and 10-year renal survival rates are highest for those diabetic patients in whom the tubules and renal cortical interstitium are of normal appearance. These survival rates are diminished if any of the following are present at the time of biopsy: a) interstitial fibrosis; b) hyperperfusion lesions; c) nephrotic syndrome; d) elevation of the serum creatinine concentration to more than 1.3 mg%. 5) No significant correlation was found between renal survival rate and age, sex, or type of diabetes. 6) The inflammation of the renal interstitium seen in diabetes does not differ from that seen in chronic glomerulonephritis. Monocytes, macrophages, T lymphocytes, fibroblasts and fibrocytes play the major role in this inflammation. This inflammatory process is considered to represent not pyelonephritis, but rather an auto-immune process. In other words, it is proposed that the diabetic kidney fails not only as a result of non-specific glomerular lesions (hyperperfusion lesions) but also because of non-specific tubulointerstitial changes, whereas diabetic glomerulosclerosis alone does not lead to chronic renal failure.

Tissue effects of the mid-IR Holmium laser (emitting at a wave-length of 2130 nm) were evaluated. This wavelength is attractive because it combines high water absorption and easy transmission through standard optical fibres. The laser was pulsed with pulse durations in the range of 100 microseconds and repetition rates between 2 and 6 Hertz. For all experiments a repetition rate of 2 Hertz was used. The laser beam was coupled into waterfree quartz fibers with core diameters of 200 and 800 microns with an efficiency of 70 and 80%, respectively. Ablation of atherosclerotic plaque has been performed at an ablation threshold of 10J/cm2 for the 800 microns and 40J/cm2 for the 200 microns fibre. Removal of calcified plaque was possible. Ablation efficiency increased in a non-linear fashion with increasing pulse energies. The ablation rate per pulse was approximately 2 mm at energy fluences of 1000J/cm2 for the 200 microns fibre and 1.25 mm at energy fluences of 70J/cm2 for the 800 microns fibre; a further increase in energy densities did not result in higher ablation rates. On macroscopic examination only very limited thermal injury was found in crater adjacent tissue structures. Crater edges were even and did not reveal signs of crater charring or debris in the crater lumen. However, the histologic specimens revealed zones of thermal damage extending 100 up to 1000 microns lateral into adjacent tissue. Thermal damage increased with increasing radiant exposures and depended on the medium used.