Multicentric reticulohistiocytosis: a report of a case and a review of the pathology

A case of multicentric reticulohistiocytosis (MR) in a 24-yr-old woman is presented. MR is a rare disorder characterized by progressive polyarthropathy and a papulo-nodular skin rash. The diagnosis was established by histological examination of biopsies of erythematous nodules on the fingers which showed circumscribed collections of large mononuclear cells and multinucleate giant cells in the reticular dermis. These were embedded in a fine network of mature fibrous tissue with a scanty lymphocytic infiltrate. Histochemical, immunopathological and ultrastructural investigations confirmed that the large mononuclear cells had the properties of macrophages. The histopathological features of MR are reviewed in the light of current knowledge of macrophage physiology, and evidence for lymphocyte-histiocyte interactions in the pathogenesis of this bizarre granulomatous disorder is presented.     

Once in a lifetime: a case of a pineal tumour

This paper describes the case of a 14-year-old boy who presented to his general practitioner with a history of headaches and visual problems. Investigations subsequently revealed that he had a pineal tumour. The management of the patient is described and this rare condition discussed.     

Experimental investigation of the flow of a blood analogue fluid in a replica of a bifurcated small artery

The scope of this work is to study the pulsatile flow of a blood mimicking fluid in a micro channel that simulates a bifurcated small artery, in which the Fahraeus-Lindqvist effect is insignificant. An aqueous glycerol solution with small amounts of xanthan gum was used for simulating viscoelastic properties of blood and in vivo flow conditions were reproduced. Local flow velocities were measured using micro Particle Image Velocimetry (μ-PIV). From the measured velocity distributions, the wall shear stress (WSS) and its variation during a pulse were estimated. The Reynolds numbers employed are relatively low, i.e. similar to those prevailing during blood flow in small arteries. Experiments both with a Newtonian and a non-Newtonian fluid (having asymptotic viscosity equal to the viscosity of the Newtonian one) proved that the common assumption that blood behaves as a Newtonian fluid is not valid for blood flow in small arteries. It was also shown that the outer wall of the bifurcation, which is exposed to a lower WSS, is more predisposed to atherosclerotic plaque formation. Moreover, this region in small vessels is shorter than the one in large arteries, as the developed secondary flow decays faster. Finally, the WSS values in small arteries were found to be lower than those in large ones.     

Multiple myeloma presenting as a sellar plasmacytoma and mimicking a pituitary tumor: Report of a case and a review of the literature

A case of multiple myeloma presenting as a plasmacytoma and mimicking a pituitary tumor is reported. The importance of recognizing the existence of plasmacytoma in the differential diagnosis of sellar and parasellar tumors is stressed, as it leads to important differences in management. The literature is reviewed. Patients presenting with plasmacytoma with symptoms of a pituitary adenoma have an average age of 58 years; the male to female ratio is 3:1; diplopia, headache, and progressive visual loss are the most important symptoms; third, sixth, and fourth cranial nerve palsies are the most common signs; and pituitary function is usually normal. CT scan of the sellar region is the imaging modality of choice; pathologically, light and electron microscopy are invaluable in making the correct diagnosis. Making the correct diagnosis allows further appropriate investigation for systemic disease and consequent management.     

Lay understanding of genetics: a test of a hypothesis.

There have been growing calls for more education in genetics for the public and in schools. However, studies of the public, school children, and those who have received genetic counselling show that understanding of scientific genetics is very limited. A hypothesis to explain this limited understanding is proposed and tested. It is argued that there is a widespread lay knowledge of inheritance which conflicts in a number of aspects with scientific explanations and which impedes the assimilation of the latter. It is suggested that this lay knowledge is derived from concepts of the social relationships of kinship. Concepts of kinship ties are sustained by everyday social activities and relationships which may make them resistant to change. A prediction which follows from the hypothesis that the lay understanding of genetics is derived from concepts of family and kinship relationships is that closeness in genetic terms will be determined by the closeness of the family ties of social relationship and social obligation. While the proportion of genes shared with parents, children, and sibs is, on average, the same, kin relationships and obligations are much stronger between parents and children than between sibs. The hypothesis was tested in a questionnaire study of two samples of adult women (n = 64 and n = 113) and one of social science students (n = 73). In all three groups a higher proportion of subjects gave the correct response for the proportion of shared genes with a father and child than with a sister, uncle, or grandmother. In the cases of sisters and uncle (and grandmother), there was a consistent tendency to underestimate the degree of genetic connection as predicted by the hypothesis. Answers to other questions are consistent with the hypothesis. The fundamental implications of the hypothesis for genetic education in the clinic and classroom are outlined.     

Cytogenetic analysis of a mature teratoma and a yolk sac tumor component of a late relapse of a disseminated testicular nonseminoma.

We report on the cytogenetics of a primary testicular nonseminoma, a residual mature teratoma after remission-induction chemotherapy, and a late relapse after 9 years of follow-up, in one patient. The late relapse was composed of a mature teratoma and a yolk sac tumor component. Cytogenetic comparison of the different tumors shows that progression of primary testicular nonseminoma to residual mature teratoma and to a late-relapse lesion is accompanied by net loss of chromosomes. In addition, our findings may suggest that transformation to viable cancer in a late-relapse lesion is accompanied by further chromosomal losses.     

Coexistence of a Meckel's diverticulum and a urachal remnant

Meckel's diverticulum, which is a remnant of the omphalomesenteric or vitelline duct, is the most common congenital abnormality of the gastrointestinal system. Urachal abnormalities, resulting from anomalous urogenital development, are not observed frequently and case reports are mainly represented in literature. The presence of these two congenital anomalies together is a very rare pathology. Complications arising from a Meckel's diverticulum or urachal remnant may clinically mimic acute appendicitis and other surgical pathologies. We report on a patient who underwent surgery for acute appendicitis when it was discovered that the symptoms were produced by a perforated Meckel's diverticulitis. In the course of the surgery, a urachal remnant was found to coexist with the diverticulum.     

Early diagnosis of a newborn with a mediastinal mass

Neuroblastoma is an embryonal tumour that evolves from the neural crest cell. This neoplasm may arise at any site in the sympathetic nervous system, including the brain, the cervical region, the posterior mediastinum, the para-aortic sympathetic ganglia, the pelvis, and the adrenal medulla. The clinical presentation in neonatal age is rare and the differential diagnosis includes congenital lung malformations, pneumoniae, atelectasia, etc. The case of a newborn with a mediastinal neuroblastoma is presented. This case illustrates how a patient with an X-ray image compatible with a thoracic tumor should be studied.     

Elucidation of a pericentric inversion of a D-group chromosome in the mother of a child with Patau''s syndrome

The mother of a child with Patau's syndrome has an inversion of chromosome 13. The karyotype is designated 46, XX, inv (13) (p13q21). It is deduced that the deceased child had the karyotpye 46, XY, rec(13), dup q, inv(13) (p13q21).     

Shear Augmented Dispersion of a Solute in a Casson Fluid Flowing in a Conduit

The unsteady dispersion of a solute in a Casson fluid flowing in a conduit (pipe/channel) is studied using the generalized dispersion model of Gill and Sankarasubramanian. With this approach, the entire dispersion process is described appropriately in terms of a simple diffusion process with the effective diffusion coefficient as a function of time, in addition to its dependence on the yield stress of the fluid. The results are accurate up to a first approximation for small times, but verified with Sharp to be exact for large times. The model brings out mainly the effect of yield stress, or equivalently, the plug flow region on the overall dispersion process. It is found that the rate of dispersion is reduced (i.e., the effective diffusivity decreases) due to the yield stress of the fluid, or equivalently, the plug flow region in the conduit. Also, the effective diffusivity increases with time, but eventually attains its steady state value below a critical time [0.48(a²/D_m) for dispersion in a pipe and 0.55(a²/D_m) for dispersion in a channel—the critical transient time for a Newtonian fluid—where a is the radius of the pipe and D_m is the molecular diffusivity]. At steady state, for dispersion in a pipe with the plug flow radius one tenth of the radius of the pipe, the effective diffusivity is reduced to about 0.78 times of the corresponding value for a Newtonian fluid at equivalent flow rates; for dispersion in a channel, the reduction factor is about 0.73 confirming the earlier result of Sharp. Further, the location of the center of mass of a passive species over a cross section is found to remain unperturbed during the course of dispersion and for different values of the plug flow parameter (i.e., the yield stress of the fluid). The study can be used as a starting first approximate solution for studying the dispersion in the cardiovascular system or blood oxygenators. © 2000 Biomedical Engineering Society. PAC00: 8719Uv, 4760+i, 8350Nj, 8370Hq, 8715Vv, 8710+e, 4755Kf     

Fragile X syndrome a case report of a family

Fragile X syndrome is the most common of the inherited disorders causing mental retardation. This disorder results from an abnormal expansion in (CGG)n in repeat found in the coding sequence of the FMRI gene, located at Xq 27.3. Previously it was detected by Karyotyping. With the advent of Molecular Biology PCR, has become the best method in the diagnosis of this disorder. This is a case report of a family with this disorder detected by PCR.     

Induction of a menadione-dependent respiratory shunt by a platinum complex

On treatment of submitochondrial particles (SMP) from bovine heart with the platinum complex K[C₂H₄PtCl₃] (Zeize's salt) a menadione-dependent shunt is formed in them, and is manifested as stimulation of the oxygen uptake by menadione when electron transport is blocked by rotenone. The effect is observed only when NADH and not succinate is used as substrate. Menadione-dependent respiration induced by Zeize's salt is sensitive to dicoumarin but is not inhibited by antimycin or cyanide, which distinguishes it from the menadione-reductase shunt in intact mitochondria.Laboratory of Physicochemical Methods, Research Institute for Biological Trials of Chemical Compounds, Kupavna, Moscow Region. (Presented by Academician of the Academy of Medical Sciences of the USSR S. E. Severin.) Translated from Byulleten' Éksperimental'noi Biologii i Meditsiny, Vol. 86, No. 8, pp. 164–167, August, 1978.     

Running a weight control group: experiences of a psychologist and a general practitioner

A weight control group is described, led jointly by a general practitioner and a clinical psychologist. Approaches employed included dietary advice, behavioural advice, and group support. Of the original 16 members (including one group leader), seven dropped out at an early stage and the reasons for this are discussed. All members were re-weighed at intervals up to 18 months after the beginning of the six-month intensive period. They were also interviewed by a psychological research worker a year after the start of the group. The results suggest that a combined dietetic and psychological approach to weight control is of value.     

Toward a theory of sexual aggression: a quadripartite model

Sexually aggressive behavior against adult females is an increasingly serious societal problem. The need for a unified theoretical model is addressed by integrating the elements of existing models into a quadripartite model in which the heterogeneity of sexual aggressors is accounted for by the prominence of potential etiological factors. The components of the model--physiological sexual arousal, cognitions that justify sexual aggression, affective dyscontrol, and personality problems--function as motivational precursors that increase the probability of sexually aggressive behavior. The relative prominence of these precursors within different sexually aggressive populations is used to define major subtypes.     

Noninactivation of a portion of Xq28 in a balanced X-autosome translocation

We present a balanced translocation (X;9) (q28;q21) in which the normal X chromosome is preferentially active. The derivative X chromosome is inactive in 93% of fibroblasts, but the X portion translocated onto chromosome 9 is not inactivated, as apparent from DNA methylation and chromosome replication patterns. Consequently, the patient is functionally disomic for the part of Xq28 distal to the locus LICAM.     

Study of quality of a branch laboratory--an opinion of a laboratory manager

At the stage of establishing a branch laboratory, quality evaluation is extremely difficult. Even the results of a control survey by the headquarters of the branch laboratory are unhelpful. For a clinical laboratory, the most important function is to provide reliable data all the time, and to maintain the reliability of clinical doctors with informed responses. We mostly refer to control surveys and daily quality control data to evaluate a clinical laboratory, but we rarely check its fundamental abilities, such as planning events, preserving statistical data about the standard range, using the right method for quality control and others. This is generally disregarded and it is taken for granted that they will be correct the first time. From my six years of experience working with X's branch laboratory, I realized that there might be some relation between the quality of a branch laboratory and the fundamental abilities of the company itself. I would never argue that all branch laboratories are ineffective, but they should be conscious of fundamental activities. The referring laboratory, not the referral laboratory, should be responsible for ensuring that the referral laboratory's examination results and findings are correct.     

The potential utility of a staging model as a course specifier: a bipolar disorder perspective

Staging models are widely used in clinical medicine, and offer an insight into the progressive nature of many disorders. In general, the earlier stages of illness may be associated with a better prognosis and a higher treatment response. Once chronicity is reached, more complex and invasive treatments may be required, and the utility of treatments may decline. There is evidence that treatment response is greatest in the early phases of the disorder. There is also a progressive social and psychological burden of ongoing illness. This is paralleled by the twin notions of neuroprotection, which is supported by increasing evidence that structural changes in the disorder may be progressive and reversible with algorithm appropriate treatment, and that of early intervention, which posits that the optimal window for intervention is early in the illness course. A staging model compliments existing and proposed classifications of bipolar disorder, adding a temporal dimension to a cross sectional view. It may inform treatment choice and prognosis, and could have utility as a course specifier.     

Palatal epithelium of a monotreme and a marsupial.

The palatal epithelium of a monotreme, Tachyglossus aculeatus and a marsupial, Tarsipes spenserae were examined histologically and with the scanning electron microscope. Each animal possess keratinized palatal spines which although histologically similar, show significant differences in their external morphology. It is suggested that the spines in each case are highly differentiated filiform papillae which have developed as a compensatory mechanism of mastication, since both animals are in effect, edentulous. In the light of these findings and observations on the tongue of both animals, it is suggested that a degree of parallel evolution of the palate (as part of the masticatory apparatus) has occurred.     

Ultrastructure of a polysome-lamellae complex in a human paraganglioma.

Study of a human abdominal paraganglioma under electron microscopy revealed an unusual cytoplasmic inclusion appearing as a hollow cylinder made up of one or several concentric lamellae surrounded by single or aggregated granules. Cross sections of the lamellar element show a discontinuous juxtaposition of particles. It is moderately dense and is bordered by 140--to 250-A granules of sure ribosomal nature. The inclusion is closely connected to the rough endoplasmic reticulum. The origin and significance of this complex are discussed.     

Isolation of a Nodulisporium Species from a Case of Cerebral Phaeohyphomycosis

A fungal infection of the brain of a 55-year-old male patient is reported. The lesion and involved fungus were located exclusively in the right medial temporo-parietal region. The patient was successfully treated with surgical resection of the lesion and antifungal chemotherapy. Few pathogenic dematiaceous fungi exhibit neurotropism and can cause primary infection in the central nervous system (CNS). The etiological agent is described as a Nodulisporium species. To date Nodulisporium has never been reported as an agent of CNS infection in humans.