Père-Lachaise - Division 8 - Louis-Charles Malassez 08

Louis-Charles Malassez (21 September 1842 – 22 December 1909) was a French

anatomist Anatomy () is the branch of biology concerned with the study of the structure of organisms and their parts. Anatomy is a branch of natural science that deals with the structural organization of living things. It is an old science, having its ...

and

histologist Histology, also known as microscopic anatomy or microanatomy, is the branch of biology which studies the microscopic anatomy of biological tissues. Histology is the microscopic counterpart to gross anatomy, which looks at larger structures vis ...

born in

Nevers Nevers ( , ; la, Noviodunum, later ''Nevirnum'' and ''Nebirnum'') is the prefecture of the Nièvre Departments of France, department in the Bourgogne-Franche-Comté Regions of France, region in central France. It was the principal city of the ...

, department of

Nièvre Nièvre () is a department in the Bourgogne-Franche-Comté region, central-east France. Named after the river Nièvre, it had a population of 204,452 in 2019.Paris Paris () is the capital and most populous city of France, with an estimated population of 2,165,423 residents in 2019 in an area of more than 105 km² (41 sq mi), making it the 30th most densely populated city in the world in 2020. S ...

, where he worked as an ''interne'' from 1867. He served with the 5th Ambulance Corps during the Franco-Prussian War, afterwards returning to Paris, where he worked with distinguished physicians that included

Claude Bernard Claude Bernard (; 12 July 1813 – 10 February 1878) was a French physiologist. Historian I. Bernard Cohen of Harvard University called Bernard "one of the greatest of all men of science". He originated the term '' milieu intérieur'', and the ...

Jean-Martin Charcot Jean-Martin Charcot (; 29 November 1825 – 16 August 1893) was a French neurology, neurologist and professor of anatomical pathology. He worked on hypnosis and hysteria, in particular with his hysteria patient Louise Augustine Gleizes. Charcot ...

and Pierre Potain. In 1875, he attained the chair of anatomy at

Collège de France The Collège de France (), formerly known as the ''Collège Royal'' or as the ''Collège impérial'' founded in 1530 by François I, is a higher education and research establishment ('' grand établissement'') in France. It is located in Paris n ...

, and in 1894 he became a member of the ''

Académie de Médecine An academy ( Attic Greek: Ἀκαδήμεια; Koine Greek Ἀκαδημία) is an institution of secondary or tertiary higher learning (and generally also research or honorary membership). The name traces back to Plato's school of philosophy ...

''. He conducted histological research of the blood, and is credited for design of the

hemocytometer The hemocytometer (or haemocytometer) is a counting-chamber device originally designed and usually used for counting blood cells. The hemocytometer was invented by Louis-Charles Malassez and consists of a thick glass microscope slide with a ...

, a device used to quantitatively measure

blood cells A blood cell, also called a hematopoietic cell, hemocyte, or hematocyte, is a cell produced through hematopoiesis and found mainly in the blood. Major types of blood cells include red blood cells (erythrocytes), white blood cells (leukocytes), a ...

. In the field of

dentistry Dentistry, also known as dental medicine and oral medicine, is the branch of medicine focused on the teeth, gums, and mouth. It consists of the study, diagnosis, prevention, management, and treatment of diseases, disorders, and conditions o ...

, he described residual cells of the

epithelial root sheath The Hertwig epithelial root sheath (HERS) or epithelial root sheath is a proliferation of epithelial cells located at the cervical loop of the enamel organ in a developing tooth. Hertwig epithelial root sheath initiates the formation of denti ...

in the

periodontal ligament The periodontal ligament, commonly abbreviated as the PDL, is a group of specialized connective tissue fibers that essentially attach a tooth to the alveolar bone within which it sits. It inserts into root cementum one side and onto alveolar b ...

. These remaining cells are referred to as

epithelial cell rests of Malassez In dentistry, the epithelial cell rests of Malassez (ERM) or epithelial rests of Malassez (''pax epithelialis pediodontii'') are part of the periodontal ligament cells around a tooth. They are discrete clusters of residual cells from Hertwig's ep ...

(ERM). A

genus Genus ( plural genera ) is a taxonomic rank used in the biological classification of extant taxon, living and fossil organisms as well as Virus classification#ICTV classification, viruses. In the hierarchy of biological classification, genus com ...

fungi A fungus ( : fungi or funguses) is any member of the group of eukaryotic organisms that includes microorganisms such as yeasts and molds, as well as the more familiar mushrooms. These organisms are classified as a kingdom, separately from ...

called ''

Malassezia ''Malassezia'' (formerly known as ''Pityrosporum'') is a genus of fungi. It is the sole genus in family Malasseziaceae, which is the only family in order Malasseziales, itself the single member of class Malasseziomycetes. ''Malassezia'' species a ...

'' bears his name. The species in the genus include: ''

Malassezia furfur ''Malassezia furfur'' (formerly known as ''Pityrosporum ovale'' in its hyphal form) is a species of yeast (a type of fungus) that is naturally found on the skin surfaces of humans and some other mammals. It is associated with a variety of dermat ...

'', '' Malassezia ovalis'', '' Malassezia pachydermatis'', ''

Malassezia sympodialis ''Malassezia sympodialis'' is a species in the genus '' Malassezia''. It is characterized by a pronounced lipophily, unilateral, percurrent or sympodial budding and an irregular, corrugated cell wall ultrastructure. It is one of the most comm ...

'' and ''Malassezia orbiculare''. ''Malassezia furfur'' is a

lipophilic Lipophilicity (from Greek λίπος "fat" and φίλος "friendly"), refers to the ability of a chemical compound to dissolve in fats, oils, lipids, and non-polar solvents such as hexane or toluene. Such non-polar solvents are themselves lipop ...

species that forms on human skin and can cause seborrheic

dermatitis Dermatitis is inflammation of the skin, typically characterized by itchiness, redness and a rash. In cases of short duration, there may be small blisters, while in long-term cases the skin may become thickened. The area of skin involved can v ...

and

tinea versicolor Tinea versicolor (also pityriasis versicolor) is a condition characterized by a skin eruption on the trunk and proximal extremities. The majority of tinea versicolor is caused by the fungus '' Malassezia globosa'', although ''Malassezia furfur'' i ...

, ''Malassezia pachydermatis'' is a species that is associated with

otitis externa Otitis externa, also called swimmer's ear, is inflammation of the ear canal. It often presents with ear pain, swelling of the ear canal, and occasionally decreased hearing. Typically there is pain with movement of the outer ear. A high fever is ...

in dogs.

Selected publications

* 'De la numération des globules rouges du sang. I. Des méthodes de numération. II. De la richesse du sang en globules rouges dans les différentes parties de l'arbre circulatoire. Paris 1873 * Sur les lésions histologiques de la syphilis testiculaire. Paris, 1881 - (with

Paul Reclus Paul Reclus may refer to: *Paul Reclus (anarchist) (1858–1941), French anarchist. *Paul Reclus (surgeon) (1847–1914), French physician specializing in surgery. {{hndis, Reclus, Paul ...

1847-1914). * Sur l’existence d’amas épithéliaux autour de la racine des dents chez l’homme adulte et a l’état normal (débris épithéliaux paradentaires. Paris, 1885 * Sur les role des débris épithéliaux paradentaires. In: Archives de physiologie normale et pathologique. Paris, S. 309–340, 1885

References

Dorlands's Medical Dictionary, Definition of Malassezia species & Cell rests
*

Malassezia Infections of the Skin, D. R. Thomas, MD, FRCPC * "List of publications copied from the equivalent article at the

German Wikipedia The German Wikipedia (german: Deutschsprachige Wikipedia) is the German-language edition of Wikipedia, a free and publicly editable online encyclopedia. Founded on March 16, 2001, it is the second-oldest Wikipedia (after the English Wikipedia), ...

.'' French histologists French anatomists Collège de France faculty 1842 births 1909 deaths People from Nevers Burials at Père Lachaise Cemetery {{France-scientist-stub