KRN5500 induces apoptosis (PCD) of myeloid leukemia cell lines and patient blasts.

The purpose of this study was to determine if KRN5500, a spicamycin derivative with a unique acyl tail, would induce programmed cell death (PCD) of myeloid leukemia cell lines and cryopreserved leukemic blasts from newly diagnosed children with acute leukemia (AL). Cells were incubated with varying concentrations (0-5 ng/ml) of KRN5500 and the percent PCD determined using a modified in situ end labeling (ISEL) technique with Klenow fragment. The percent PCD was calculated using the formula: Percent PCD (% PCD)=[number of apoptotic cells/(viable cells+apoptotic cells)]x100. DMSO (0.30% w/v) was added to the cells in culture as the positive control for PCD; the negative control was media or albumin. KRN5500 increased the amount of PCD significantly in all five of the tested cell lines; U937 41+/-1.8%, KG1a 40+/-0.3%, HEL 14+/-2.2%, HL-60 41+/-0. 9%, K562 36+/-2% (mean PCD+/-SD). Patient blasts exposed to KRN5500 had an increase in PCD when exposed to 2 ng/ml of agent from 2 to 8 h; acute myeloid leukemia patients 7.5+/-0.5% at 2 h to 43.5+/-1.6% at 8 h, and acute lymphocytic leukemia patients rose from 12.4+/-3.8% at 2 h to 29.9+/-11.6% after 8 h (mean+/-SE). Overall the PCD for the patient samples was 3.7 versus 28+/-4% at 2 and 8 h, respectively. PCD was proportional to the dose of KRN5500 and incubation time. Further pre-clinical and clinical studies are required.

Interleukin-12 (IL-12) enhances lysis of non-lymphoid leukemia cell lines in vitro.

IL-2 augments the ability of natural killer (NK) cells to kill myeloid leukemia cells in vitro, and may have a role in the eradication of minimal residual disease (MRD) in AML patients. The ability to enhance lysis of AML cells without the toxicity of IL-2 would be a significant improvement in the use of biologics against AML. Recent interest in IL-12 suggested that this cytokine might meet these criteria. The aim of this study was to evaluate the ability of IL-12 to enhance the in vitro lysis of the non-lymphoid leukemia cell lines in a standard 51Chromium release assay. Effector cells from normal volunteers were incubated with varying concentrations of IL-12 or IL-2 for 18-20 h, then the 51Cr-labeled target cells from five different cell lines of AML origin were added for 4 h. Percent lysis was determined and plotted over four effector:target (E:T) ratios. Our results indicated that IL-12 was able to enhance lysis of all cell lines tested at > or =5 units/ml. When IL-2 was added to the culture at a low dose along with IL-12, there appeared to be a synergistic effect. Although anti-gamma interferon was able to inhibit the cytolytic potential of effectors activated by IL-12, the lysis could not be completely blocked. Thus, it appears that IL-12 has the ability to stimulate NK lysis indirectly through the induction of gamma interferon as well as an alternate mechanism not related to gamma interferon. Thus, IL-12 may have a beneficial role in the treatment of non-lymphoid leukemia.

Calcification of the aortic valve: its progression and grading.

Three hundred and seventy four aortic valves which had been surgically removed over the past five years were studied by routine histology. Most patients were male and over the age of 60 years. There were 3.7% bicuspid valves, 16% valves with evidence of past rheumatic fever and 2.1% with endocarditis. A range of pathological lesions was seen including calcification, chondroid and osseous metaplasia, neovascularization, inflammation and cholesterol deposition. A common lesion was a progressive dystrophic calcification of the valve cusps. This was studied and graded in relationship to the concomitant structural damage. There has been no previously published grading system for this type of pathological change in the aortic valve. Our criteria for the four grades of aortic valve lesion are described. Most patients were found to have lesions of Grades 3 and 4.

Calcified deposit formation in intimal thickenings of the human aorta.

The formation of calcified deposits in intimal thickenings of human aorta was studied by electron microscopy. Microzones of calcification were detected in about 20% of fatty streaks and were located predominantly in the deep musculoelastic layer of the intima. Calcified deposits formed only on previously existing structures including extracellular vesicles and unesterified cholesterol. Calcified deposits in the musculoelastic layer of the intima localised inside altered elastin fibres, but initiating the calcification of of elastin required the prior accumulation of cholesterol esters inside elastin fibres. Co-localization of calcified deposits and elastin fibres was followed by destruction of elastin. The present study suggests that at an early stage of development is atherosclerotic lesions, calcified deposits are formed by a physicochemical process which is not strongly controlled by the intimal cells. The recognition of calcified deposits in intimal thickenings support the hypothesis that a subset of fatty streaks might progress to fibrous plaques in human atherosclerosis.

The scanning electron microscopy of scolices in a case of hydatid cyst from human liver.

The scanning electron microscopic (SEM) features of hydatid scolices from a case of hydatid disease of the liver are described. The scolex when fully everted has a double circle of hooklets which occupy a large area of the parasite. The hooklets are inserted into the rostellum with one row of hooklets overlapping the other. Each hooklet is about 20 to 40 um long, has a basic round structure sharp at the distal end and broadens as it curves towards the point of insertion at the rostellum, where 2 blunt projections correspond to the 2 annular bundles of muscle fibres at the orifice of the scolex. The function of the hooklets is not fully understood but they are possibly used for anchorage and/or for the purpose of propulsion in a fluid medium by the act of invagination and evagination of the hooklets.

A practical approach to the diagnosis of renal disease by biopsy.

The pathologist has an important role in the diagnosis and monitoring of renal disease. However, for optimal useful information to be derived from renal biopsy specimens, certain guidelines must be adhered to and these are enunciated here. The 3 avenues of observation of renal biopsies viz. light microscopy, immunofluorescence and electron microscopy, all have important roles to play and give differing data which informs the diagnosis for the renal biopsy report. The relative emphasis on each of these modalities of investigation will vary depending upon the situation in which the renal biopsy is performed. The methods used here have been shown to be effective in practice over a period of 20 yrs. Although there may be variations in methodology from centre to centre, the general background aims and principles remain the same. The emphasis in this paper has been on common practical aspects of renal biopsies. Much of the practical information concerning renal biopsies, which is brought together here, is otherwise scattered and not readily available. The aim of this article is to allow the reader to understand the rationale for the steps that are involved in renal biopsy diagnosis.

Neurocysticercosis: a report of four cases.

Cysticercosis is an uncommon disease in Australia. Only 4 cases of neurocysticercosis were found in our hospital with an active neurosurgical service over a 10 yr period. All 4 cases were migrants, 3 from South America and one from Cyprus. Epilepsy, aseptic meningitis and raised intracranial pressure were the common symptoms. Although the cerebral lesions were seen on CT scans, misinterpretation of the X-ray appearances readily occurs and the diagnosis can only be confirmed by histopathological examination of tissues. The pathological features are described including electron microscopy of one case. The cysticercus has a unique ultrastructure which is most helpful in establishing the diagnosis in cases were tissue sample is small and light microscopy is difficult. Neurocysticercosis can masquerade as a glioma or other space occupying lesion or aseptic meningitis. This condition should be considered in obscure neurological syndromes in migrants from affected regions of the world.

A study of parathyroid hyperplasia in chronic renal failure.

Specimens removed at parathyroidectomy from 41 patients with chronic renal failure, 12 patients with parathyroid adenomas and parathyroid glands from 24 autopsies were studied by light microscopy, immunohistochemistry and electron microscopy. The morphological abnormalities were correlated with clinical data obtained from patients' medical records. Glandular enlargement in chronic renal failure, primarily due to parenchymal cell hyperplasia, was as much as 20 times the normal in contrast to 40 times the normal cases of adenomas. Glandular hyperplasia was mostly due to an increase in the number of chief cells and to a lesser extent increase in the number of oxyphil cells, transitional oxyphil cells and water-clear cells. There was a corresponding reduction in fat and intracellular lipid content. There were differences in the overall morphology of normal, hyperplastic and adenomatous glands. The clear histological distinction between hyperplastic and adenomatous glands was at times difficult. There was no correlation between the extent of hyperplasia, the cause of renal failure, duration of chronic renal failure, levels of serum calcium, phosphate or parathyroid hormone. Immunohistochemical studies showed that all 3 types of cells contained parathyroid hormone but in hyperplastic and adenomatous glands there was a reduction in parathyroid hormone and chromogranin A staining. There were no specific ultrastructural abnormalities which would distinguish between hyperplastic and adenomatous glands.

Multiple cholesterol emboli syndrome complicating angiographic techniques.

Three cases of widespread microembolisation of cholesterol crystals following angiography are described. The multiple cholesterol emboli syndrome has been well described as a spontaneous phenomenon and it is surprising that its occurrence during angiography appears rare. Only 19 cases could be found in the literature and these are reviewed. Dissemination of particulate cholesterol material produces irreversible organ ischaemia when a threshold 'dose' is reached. Males and patients with clinical evidence of widespread atherosclerosis are at increased risk. Prognosis is poor and available therapy unsatisfactory.

Renal granulomatous angiitis--a case report.

A case of non-necrotizing granulomatous angiitis without significant glomerular pathology is described in a 61 yr-old female. The characteristic lesion consists of periarterial inflammation comprising a mixed population of mononuclear cells with prominent giant cell formation. There is no evidence of immunoglobulin, complement or fibrin deposition. It is concluded that this represents an unusual variant of polyarteritis nodosa which is apparently controlled by steroid therapy.

Primary (spontaneous) chordal rupture: relation to myxomatous valve disease and mitral valve prolapse.

The excised valves of 152 consecutive patients who underwent isolated primary mitral valve replacement between May 1979 and July 1983 were studied to determine the cause of primary (spontaneous) rupture of the chordae tendineae and estimate the prevalence of floppy mitral valve with underlying myxomatous disease. Of these 152 patients, 72 had nonrheumatic disease; 42 (28% of the total group) had a floppy valve, and 39 of these valves had microscopic changes of myxomatous disease. Primary chordal rupture had occurred in 31 patients, including 29 with myxomatous disease. Seven of these patients had prior documentation of mitral valve prolapse and an additional 20 patients had a long-standing murmur. Ischemic mitral regurgitation (22 patients) accounted for the majority of the remaining 30 patients with nonrheumatic disease. Therefore, approximately half of all isolated mitral valve replacements in this institution are now performed for nonrheumatic disease, the majority for a floppy valve in which myxomatous disease was the underlying abnormality. Primary chordal rupture almost invariably occurs as a complication of myxomatous disease, and mitral valve prolapse may be a common precursor.

A case of Lhermitte-Duclos disease.

A 34-year-old patient has an 18-year history of cerebellar disturbance. She has histology typical of Lhermitte-Duclos disease. Her father and son have large heads, and it is possible that they may be asymptomatic cases of the disease, as first described by Ambler et al. (1969).

Cerebral atheroembolism. An animal model.

Human atheromatous material was injected into the cerebral vasculature of anaesthetized rabbits via the left common carotid artery. The lethality of varying dosages was determined and the distribution and general character of occlusive vascular lesions which developed were analyzed by light and transmission electron microscopy. It was found that a dose exceeding 55 mg of the atheromatous material (125 mg/ml saline) was lethal in New Zealand white male rabbits weighing between 3 and 5 kg. In nonsurviving animals, parts of the Circle of Willis and usually one or more of its major tributaries were occluded. Some surviving animals exhibited signs of neurologic deficit evidenced by motor dysfunction. Occlusive vascular lesions found in surviving animals were predominantly localized in ipsilateral cortical and subcortical vessels within the distribution territory of the middle cerebral artery. The character of occlusive lesions showed strong evidence of thrombosis. These results demonstrated that this experimental system may be useful as a model for the study of blood-atheroembolic vascular reactions, cerebral infarction development and the testing of agents potentially prophylactic against the development or stabilization of occlusive lesions.

Thrombogenicity of components of atheromatous material. An animal and in vitro model of cerebral atheroembolism.

Human atheromatous material was separated into lipid and nonlipid fractions by ether and chloroform-methyl alcohol procedures. The maximum nonlethal doses of nonlipid, lipid, and whole (unseparated) atheromatous material were 8 mg, between 15 and 30 mg, and between 50 and 60 mg when injected into the left common carotid arteries of rabbits. In vitro production of thrombi showed that the nonlipid material produced thrombi that were larger in volume, weight, and length than those produced by whole material.