Marked Constriction Research Articles

AN UNEXPECTED SHORT TOOTH REPLACEMENT CYCLE PERIOD IN <em>MARESAURUS COCCAI</em> (PLESIOSAURIA; RHOMALEOSAURIDAE) FROM THE BAJOCIAN OF ARGENTINEAN PATAGONIA

The Rhomaleosauridae were a clade of Jurassic plesiosaurians, characterized by triangular skulls, elongated preorbital region, marked premaxillary-maxillary constriction, and intermediate body proportions between pliosauromorphs and plesiosauromorphs. Despite recent progress in the study of dental replacement in plesiosaurians, the replacement features in rhomaleosaurids have not been studied. Here, the dental features of the rhomaleosaurid Maresaurus coccai are described and analyzed based on the holotype specimen. Regarding symmetry, it was determined that M. coccai shows symmetrical replacement in the maxillary-premaxillary and asymmetrical replacement in the dentary. Additionally, the tooth replacement cycle period (TRCP) of two alveoli was determined for the dental series, with the exception of the anterior part of the left mandibular ramus, which presents an TRCP of three, an asymmetry considered here as teratology. This result indicates that the replacement cycle period (TRCP) of the two alveoli would correspond to a primitive character for Plesiosauria, observing an increase of TRCP from two to three alveoli in taxa comparatively more derived within Pliosauridae.

Epinephrine-induced Effects on Cerebral Microcirculation and Oxygenation Dynamics Using Multimodal Monitoring and Functional Photoacoustic Microscopy.

The administration of epinephrine after severe refractory hypotension, shock, or cardiac arrest restores systemic blood flow and major vessel perfusion but may worsen cerebral microvascular perfusion and oxygen delivery through vasoconstriction. The authors hypothesized that epinephrine induces significant microvascular constriction in the brain, with increased severity after repetitive dosing and in the aged brain, eventually leading to tissue hypoxia. The authors investigated the effects of intravenous epinephrine administration in healthy young and aged C57Bl/6 mice on cerebral microvascular blood flow and oxygen delivery using multimodal in vivo imaging, including functional photoacoustic microscopy, brain tissue oxygen sensing, and follow-up histologic assessment. The authors report three main findings. First, after epinephrine administration, microvessels exhibited severe immediate vasoconstriction (57 ± 6% of baseline at 6 min, P < 0.0001, n = 6) that outlasted the concurrent increase in arterial blood pressure, while larger vessels demonstrated an initial increase in flow (108 ± 6% of baseline at 6 min, P = 0.02, n = 6). Second, oxyhemoglobin decreased significantly within cerebral vessels with a more pronounced effect in smaller vessels (microvessels to 69 ± 8% of baseline at 6 min, P < 0.0001, n = 6). Third, oxyhemoglobin desaturation did not indicate brain hypoxia; on the contrary, brain tissue oxygen increased after epinephrine application (from 31 ± 11 mmHg at baseline to 56 ± 12 mmHg, 80% increase, P = 0.01, n = 12). In the aged brains, microvascular constriction was less prominent yet slower to recover compared to young brains, but tissue oxygenation was increased, confirming relative hyperoxia. Intravenous application of epinephrine induced marked cerebral microvascular constriction, intravascular hemoglobin desaturation, and paradoxically, an increase in brain tissue oxygen levels, likely due to reduced transit time heterogeneity.

Improved Basic Cytogenetics Challenges Holocentricity of Butterfly Chromosomes

Mitotic chromosomes of butterflies, which look like dots or short filaments in most published data, are generally considered to lack localised centromeres and thus to be holokinetic. This particularity, observed in a number of other invertebrates, is associated with meiotic particularities known as “inverted meiosis,” in which the first division is equational, i.e., centromere splitting-up and segregation of sister chromatids instead of homologous chromosomes. However, the accurate analysis of butterfly chromosomes is difficult because (1) their size is very small, equivalent to 2 bands of a mammalian metaphase chromosome, and (2) they lack satellite DNA/heterochromatin in putative centromere regions and therefore marked primary constrictions. Our improved conditions for basic chromosome preparations, here applied to 6 butterfly species belonging to families Nymphalidae and Pieridae challenges the holocentricity of their chromosomes: in spite of the absence of primary constrictions, sister chromatids are recurrently held together at definite positions during mitotic metaphase, which makes possible to establish karyotypes composed of acrocentric and submetacentric chromosomes. The total number of chromosomes per karyotype is roughly inversely proportional to that of non-acrocentric chromosomes, which suggests the occurrence of frequent robertsonian-like fusions or fissions during evolution. Furthermore, the behaviour and morphological changes of chromosomes along the various phases of meiosis do not seem to differ much from those of canonical meiosis. In particular, at metaphase II chromosomes clearly have 2 sister chromatids, which refutes that anaphase I was equational. Thus, we propose an alternative mechanism to holocentricity for explaining the large variations in chromosome numbers in butterflies: (1) in the ancestral karyotype, composed of about 62 mostly acrocentric chromosomes, the centromeres, devoid of centromeric heterochromatin/satellite DNA, were located at contact with telomeric heterochromatin; (2) the instability of telomeric heterochromatin largely contributed to drive the multiple rearrangements, principally chromosome fusions, which occurred during butterfly evolution.

Myosin light chain phosphorylation exhibits a gradient across the wall of cerebellar arteries under sustained ex vivo vascular tone

Small blood vessel diseases are often associated with impaired regulation of vascular tone. The current understanding of resistance arteries often focuses on how a level of vascular tone is achieved in the acute phase, while less emphasis is placed on mechanisms that maintain vascular tone. In this study, cannulated rat superior cerebellar arteries (SCA) developed spontaneous myogenic tone and showed a marked and sustained constriction in the presence of diluted serum (10%), a stimulus relevant to cerebrovascular disease. Both phosphorylated myosin light chain (MLC-p) and smooth muscle alpha actin (SM-α-actin) aligned with phalloidin-stained actin filaments in the vessel wall, while exhibiting a ‘high to low’ gradient across the layers of vascular smooth muscle cells (VSMC), peaking in the outer layer. The MLC-p distribution profile shifted towards the adventitia in serum treated vessels, while removal of the serum reversed it. Furthermore, a positive correlation between the MLC-p signal and vessel wall tension was also evident. The gradients of phosphorylated MLC and SM-α-actin are consistent with a spatial regulation of the myosin-actin apparatus in the vessel wall during the maintenance of vascular tone. Further, the changing profiles of MLC-p and SM-α-actin are consistent with SCA vasoconstriction being accompanied by VSMC cytoskeletal reorganization.

Description of Paravulvus zhongshanensis sp. nov. (Dorylaimida: Nygolaimidae) from Nanjing, China.

Paravulvus zhongshanensis sp. nov., isolated from soil in a location at Jiangsu Province, China, is described and illustrated based on morphological, morphometric and molecular characterizations. The new species is characterized by its body 1.17-1.53 mm long, lip region offset by marked constriction and 12.1-13.8 μm broad, mural tooth deltoid and 9.6-11.7 μm long, neck 278-360 μm long, pharyngeal expansion 164-208 μm long or occupying more than one-half (54-62%) of total neck length, uterus 32.5-35.3 μm long or 1.0-1.1 times the corresponding body diameter, V = 47.8-53.4, paravulvae absent, female tail subcylindrical conoid (30.5-39.5 μm, c = 36.0-45.5, c' = 1.7-2.2) with widely rounded end, and male unknown. The new species was compared with six known species of the genus including Paravulvus acuticaudatus, Paravulvus confusus, Paravulvus hartingii, Paravulvus iranicus, Paravulvus loofi and Paravulvus microdontus mainly by similarities in having conical tail and c' value larger than 1.3. The rRNA and mitochondrial cytochrome oxidase subunit 1 genes of the new species were obtained and were used for reconstructing the phylogenetic relationships of the new species.

Highlights from the International Twins Congress 2021

Highlights from the International Twins Congress 2021

Dentinogénesis imperfecta: reporte de un caso

Introducción: La dentinogénesis imperfecta (DI) es una alteración hereditaria que se origina en la etapa de histodiferenciación durante la odontogénesis, constituyendo una forma de displasia mesodérmica localizada, caracterizada por una expresa alteración de las proteínas dentinarias. Se clasifica en dentinogénesis tipo I (relacionada con osteogénesis imperfecta), DI tipo II (no relacionada con OI) y DI tipo III (de Brandynwine). Objetivo: Determinar el tipo de dentinogénesis, tendencia familiar y características clínicas del paciente, para establecer un diagnóstico temprano y el patrón hereditario que presenta. Presentación del caso: Paciente masculino de 3 años de edad, acudió a consulta por hipersensibilidad dental y molestia durante la masticación; presentó una alteración de estructura y color de los órganos dentales presentes, abscesos, atricción y pérdida de la dimensión vertical, radiográficamente se observa obliteración pulpar, marcada constricción cervical y raíces cortas. Después de los análisis clínico y radiográfico, historia familiar e interconsulta con genética se descartó OI y se estableció el diagnóstico de dentinogénesis imperfecta tipo II, de carácter autosómico dominante, sin predilección de sexo. Se restauró con coronas de acero cromo y se realizaron las extracciones necesarias, continuando con la colocación de mantenedores de espacio y prótesis parciales removibles. Conclusión: Debido a que en los pacientes con DI, la primera dentición se ve más afectada, es de suma importancia realizar un diagnóstico temprano para iniciar cuanto antes un tratamiento adecuado. En este tipo de pacientes es imprescindible llevar a cabo interconsulta con genética para descartar su asociación con otras entidades.

Cretaceous Blind Snake from Brazil Fills Major Gap in Snake Evolution

SummaryBlind snakes (Scolecophidia) are minute cryptic snakes that diverged at the base of the evolutionary radiation of modern snakes. They have a scant fossil record, which dates back to the Upper Paleocene-Lower Eocene (∼56 Ma); this late appearance conflicts with molecular evidence, which suggests a much older origin for the group (during the Mesozoic: 160–125 Ma). Here we report a typhlopoid blind snake from the Late Cretaceous of Brazil, Boipeba tayasuensis gen. et sp. nov, which extends the scolecophidian fossil record into the Mesozoic and reduces the fossil gap predicted by molecular data. The new species is estimated to have been over 1 m long, much larger than typical modern scolecophidians (<30 cm). This finding sheds light on the early evolution of blind snakes, supports the hypothesis of a Gondwanan origin for the Typhlopoidea, and indicates that early scolecophidians had large body size, and only later underwent miniaturization.

New cynodonts (Therapsida, Eucynodontia) from the Late Triassic of India and their significances

AbstractThe Upper Triassic Tiki Formation of India has yielded several new cynodont taxa, which are described on the basis of multiple isolated teeth and a jaw fragment. A new species of dromatheriid,Rewaconodon indicus, is defined by a tri- and tetracuspid asymmetric crown, long anterior edge of the major cuspa, cingular cuspsdandf, and marked constriction at the crown-root junction. Another new dromatheriid,Inditherium florisn. gen. n. sp., is characterized by a broad, flower-shaped pentacuspid crown, multiple cingular cusps, and a weak lingual cingulum is also described from the same horizon. In addition, a new mammaliamorph taxon,Tikiodon cromptonin. gen. n. sp., is established on a tooth specimen, which has a shovel-shaped crown, three closely spaced main cusps, a pronounced lingual cingulum with multiple cingular cusps, and a root of incomplete root bifurcation. Such a tooth morphology occupies an intermediate position between the non-mammalian cynodonts and the early mammals, as is evident from the co-occurrence of various cynodont dental morphotypes in the Tiki Formation. Moreover, Late Triassic cynodonts occurred along narrow belts demarcated by paleolatitudes, though the Indian fauna shows both Laurasian and Gondwanan affinities.UUID:http://zoobank.org/c2c575ad-ee23-4f33-8a30-661c548a5b17

Valve morphology of Didymosphenia geminata (Bacillariophyceae) from Santa Cruz and Tierra del Fuego provinces, Patagonia, Argentina.

Background and aims: In 2013, blooms similar to those produced by Didymosphenia geminata (Lyngbye) M. Schmidt around the world, were detected in the Grande River basin, Tierra del Fuego province, and in 2014 in de las Vueltas River in Santa Cruz province. The aim of this paper is to analyze the valve morphology and morphometry of these materials to establish if they correspond to D. geminata or to other species of the genus that is producing the massive growth in southern Patagonia. M&amp;M: Samples were collected at Grande River in 2013 and 2015 and, in de las Vueltas River in 2015 and 2016. Samples were analyzed with light and electron microscopy. For morphometric analyses 100 specimens from each sample were measured and statistical analyses were carried out using the R statistical package. Results: The studied populations have the same fine morphology described for other populations collected in Patagonia. Nevertheless, in some sampling sites from Santa Cruz province, we found a morphotype with a markedly smaller size, subcapitated poles, little marked constrictions of the poles, a broad central area (relative to cell size) and 1 to 3 stigmata, that was never reported in South America. Conclusions: The studied populations correspond to D. geminata ssp. geminata Metzeltin &amp; Lange-Bertalot. From a morphological point of view the smaller morphotype present in Santa Cruz belongs to the same subspecies but can be easily misidentified during the routine monitoring programs carried out with light microscope due its size and valve outline.

Restorative Management of Dentinogenesis Imperfecta in an adult - A case report

Dentinogenesis Imperfecta is a localized mesodermal dysplasia affecting both the primary and permanent dentition. First described in the late 19th century, it is characterized by discolored and translucent teeth ranging from grey to brownish-blue or amber. Dentinogenesis Imperfecta, type II (DGI-2) is rare and it is a severe form of the condition. Radiographically, the crowns of the teeth are bulbous with marked cervical constrictions, and the pulp chambers become obliterated over a period of time. Sensori-neural hearing loss has also been reported in some patients. This case report presents the restorative management of DGI-2 in a 44year old clergy woman whose primary complaints were poor aesthetics and lack of social acceptance. The case was managed with consideration of the patient's limited financial resources at the Lagos State University Teaching Hospital, Ikeja (LASUTH). The objective of the management of this condition was to open the bite of the patient using maxillary posterior bite plane followed by intermediate restoration of worn teeth using composite resin for the newly established occlusion. The patient used the restorations for a while before definitive restorations, using ceramo-metal crowns as well as over dentures, were carried out. The restorative treatments corrected the patient´s vertical dimension of occlusion with resultant acceptable aesthetics and function. The patient was satisfied with maxillary anterior ceramo-metal crowns and a posterior removable over denture as well as a complete mandibular over denture.&#x0D;

Meningeal Carcinomatosis Presenting with Isolated Pseudotumor Cerebri

A 46-year-old man presented with a progressive headache lasting for 2 weeks. Initial lumbar puncture revealed a pressure of 31 cm H&lt;sub&gt;2&lt;/sub&gt;0 and 30 white cells. His symptoms had worsened despite the treatment of intracranial hypertension. Visual field exam showed marked peripheral constriction and the fundus showed marked papilledema. Cytological analysis of cerebrospinal fluid demonstrated positive for metastatic carcinoma. We report a case of a patient with meningeal carcinomatosis who developed isolated intracranial hypertension with papilledema.

Bronchodilator Dose Responsiveness in Children and Adolescents: Clinical Features and Association with Future Asthma Exacerbations

Bronchodilator reversibility measures are often associated with poor asthma outcomes in children. Whether bronchodilator dose responsiveness is similarly useful in children is unclear. We hypothesized that children and adolescents requiring higher doses of bronchodilator to achieve maximal bronchodilation would have unique risk factors and increased risk of future exacerbation. Children (6-11 years, N= 299) and adolescents (12-21 years, N= 331) with confirmed asthma underwent clinical phenotyping procedures and a test of maximal bronchodilation with escalating doses of albuterol sulfate up to 720 mcg. Outcome measures were assessed at 12 months and included exacerbations treated with systemic corticosteroids, emergency department (ED) visits, and hospitalizations for asthma. A total of 6.7% of children and 9.3% of adolescents had poor bronchodilator dose responsiveness, defined as attainment of maximal forced expiratory volume in 1 second with 720 mcg albuterol. Risk factors included type 2 inflammation, prior exacerbations, and greater asthma severity; historical pneumonia and tobacco exposure were also risk factors in children. Children and adolescents with poor bronchodilator dose responsiveness did not have increased current symptoms or impaired quality of life, but had approximately 2-fold increased odds of exacerbation or ED visit and approximately 3-fold increased odds of hospitalization by 12 months, independent of airflow obstruction. Bronchodilator dose responsiveness may be useful for phenotyping and may be of utility in practice and future studies focused on asthma outcomes or quantification of treatment responses. In children and adolescents, this phenotype of poor bronchodilator responsiveness may be associated with periods of relatively stable disease yet marked airway constriction in response to triggers, including tobacco smoke, respiratory infections/pneumonia, and aeroallergens.

Spatiotemporal dynamics of red blood cells in capillaries in layer I of the cerebral cortex and changes in arterial diameter during cortical spreading depression and response to hypercapnia in anesthetized mice.

Control of red blood cell velocity in capillaries is essential to meet local neuronal metabolic requirements, although changes of capillary diameter are limited. To further understand the microcirculatory response during cortical spreading depression, we analyzed the spatiotemporal changes of red blood cell velocity in intraparenchymal capillaries. In urethane-anesthetized Tie2-green fluorescent protein transgenic mice, the velocity of fluorescence-labeled red blood cells flowing in capillaries in layer I of the cerebral cortex was automatically measured with our Matlab domain software (KEIO-IS2) in sequential images obtained with a high-speed camera laser-scanning confocal fluorescence microscope system. Cortical spreading depression repeatedly increased the red blood cell velocity prior to arterial constriction/dilation. During the first cortical spreading depression, red blood cell velocity significantly decreased, and sluggishly moving or retrograde-moving red blood cells were observed, concomitantly with marked arterial constriction. The velocity subsequently returned to around the basal level, whileoligemia aftercortical spreading depression with slight vasoconstriction remained. After several passages ofcortical spreading depression, hypercapnia-induced increase of red blood cell velocity, regional cerebral blood flow and arterial diameter were all significantly reduced, and the correlations among them became extremely weak. Taken together with our previous findings, these simultaneous measurements of red blood cell velocity in multiple capillaries, arterial diameter and regional cerebral blood flow support the idea that red blood cell flow might be altered independently, at least in part, from arterial regulation, that neuro-capillary coupling plays a role in rapidly meeting local neural demand.

Traditional Chinese medicine treatment of solid-pseudopapillary tumor of the pancreas: a case report

To assess the feasibility of acoustic rhinometry for the evaluation of velopharyngeal function in preschool children by detecting changes in nasal cavity volume (NV) and minimal cross-sectional area (MCSA) after palatoplasty.Sixty-one preschool children with incomplete cleft palate who underwent Sommerlad palatoplasty were examined by acoustic rhinometry. MCSA, distance of the MCSA from the nostril (DMCA), NV, and nasopharyngeal volume (NPV) were measured. Patients were grouped according to velopharyngeal state and lateral cephalographic findings.MCSA, NV, and NPV showed a meaningful difference between the experimental and control groups. DMCA in the experimental group (7.09 ± 1.33 mm) was not markedly different between the 2 sides. NV, NPV, and MCSA in the velopharyngeal insufficiency (VPI) subgroup were obviously larger than those in the velopharyngeal competence (VPC) and marginal VPI subgroups. NV in the VPC group showed no relevant difference from that in the control group. No relevant difference in MCSA, DMCA, and NPV was observed among the 3 subgroups at radiographic evaluation. NV in the noncontact group was markedly larger than in the control group. The curve showed marked constriction in the anterior part but an elevation in the posterior part, especially at a distance of 7.09 cm.Acoustic rhinometry is a rapid, noninvasive, and reproducible method that can be used in lieu of lateral cephalography for quantitative evaluation of the NV and MCSA. It can be used to assess postoperative velopharyngeal function in children and has good adaptability.

Morphological and molecular characterization of two new species of the genus Aporcelinus Andrássy, 2009 (Nematoda, Dorylaimida, Aporcelaimidae) from the USA, with new insights on the phylogeny of the genus.

Two new species of the genus Aporcelinus from the USA are described and illustrated. Aporcelinus floridensis sp. n. is characterized by its 1.12-1.52 mm long body, lip region offset by marked constriction and 14.5-17.0 μm broad with perioral liplets, odontostyle 16.5-20.0 μm at its ventral side and 1.1-1.2 times the lip region diameter, neck 316-395 μm long, pharyngeal expansion occupying 43-48% of total neck length, uterus simple and 33-56 μm long or 0.8-1.2 times the corresponding body diameter, V = 48-54, female tail conical (36-49 μm long, c = 27-41, c' = 1.2-2.0) with finely rounded terminus and no hyaline portion, and male absent. Aporcelinus paolae sp. n. is characterized by its 1.29-1.80 mm long body, lip region offset by marked constriction and 14-16 μm broad, odontostyle 15-17 μm at its ventral side and 1.0-1.1 times the lip region diameter, neck 314-397 μm long, pharyngeal expansion occupying 43-53% of total neck length, uterus tripartite and 128-164 μm long or 2.6-3.6 times the corresponding body diameter, V = 53-57, female tail conical (30-39 μm long, c = 40-51, c' = 1.1-1.3) with finely rounded terminus and variably re-curved dorsad, male tail conical (27-36 μm, c = 39-59, c' = 0.9-1.2), ventrally straight and dorsally convex, spicules 48-54 μm long, and 7-9 irregularly spaced ventromedian supplements lacking hiatus. The analyses of the D2-D3 expansion segments of 28S rRNA (LSU) gene sequences of the two new species confirmed the monophyly of the genus, based upon currently available data, showing a close relationship between the genera Aporcelinus and Makatinus, and justified the placement of Aporcelaimellus, Makatinus and Aporcelinus under the subfamily Aporcelaimellinae.

Combined CNV, haplotyping and whole exome sequencing enable identification of two distinct novel EYS mutations causing RP in a single inbred tribe.

Whole exome sequencing (WES) has become routine in clinical practice, especially in studies of recessive hereditary diseases in inbred consanguineous families, where homozygosity of a founder mutation is assumed. Multiple members of two consanguineous families of a single Bedouin tribe were diagnosed with apparently autosomal recessive/pseudo-dominant retinitis pigmentosa (RP). Affected individuals exhibited severe visual impairment with nyctalopia, marked constriction of visual fields, markedly reduced and delayed responses on electro-retinography (ERG) and eventual loss of central vision. Combined copy-number variant (CNV) analysis, haplotype reconstruction and WES of the kindred identified two distinct novel mutations in EYS (RP25): a p.(W1817*) nonsense mutation (identified through WES) and a large deletion encompassing 9 of the 43 exons, that was missed by WES and was identified through microarray CNV analysis. Segregation analysis of both mutations demonstrated that all affected individuals were either homozygous for one of the mutations, or compound heterozygous for both. The two mutations are predicted to cause loss of function of the encoded protein and were not present in screening of 200 ethnically-matched controls. Our findings of two distinct mutations in the same gene in a single inbred kindred, identified only through combined WES and microarray CNV analysis, highlight the limitations of either CNV or WES alone, as the heterozygous deletion had normal WES read-depth values. Moreover, they demonstrate pitfalls in homozygosity mapping for disease-causing variant identification in inbred communities.

Reversal of cerebrovascular constriction in experimental cerebral malaria by L-arginine

Vascular dysfunction associated with low nitric oxide (NO) biavailability and low plasma L-arginine levels is observed in both human and experimental cerebral malaria (ECM). In ECM, cerebrovascular constriction results in decreased pial blood flow and hypoxia, and administration of NO donors reverses constriction and increases survival. Supplementation of L-arginine, the substrate for NO synthesis by NO synthases, has been considered as a strategy to improve vascular health and act as adjunctive therapy in human severe malaria. We investigated the effect of L-arginine supplementation on pial vascular tonus of mice with ECM after direct superfusion on the brain surface or systemic delivery. Pial arteriolar diameters of Plasmodium berghei-infected mice with implanted cranial windows were measured using intravital microscopy methods, before and after L-arginine administration. Systemic delivery of L-arginine was performed intravenously, at 10, 50, 100 and 200 mg/kg, as bolus injection or slowly through osmotic pumps, combined or not with artesunate. Direct superfusion of L-arginine (10−7M, 10−5M and 10−3M) on the brain surface of mice with ECM resulted in immediate, consistent and dose-dependent dilation of pial arterioles. ECM mice showed marked cerebrovascular constriction that progressively worsened over a 24 h-period after subcutaneous saline bolus administration. L-arginine administration prevented the worsening in pial constriction at all the doses tested, and at 50 mg/kg and 100 mg/kg it induced temporary reversal of vasoconstriction. Slow, continuous delivery of L-arginine by osmotic pumps, or combined bolus administration of artesunate with L-arginine, also prevented worsening of pial constriction and resulted in improved survival of mice with ECM. L-arginine ameliorates pial vasoconstriction in mice with ECM.

A new humicolous Parhydraena d'Orchymont, 1937 from South Africa (Coleoptera, Hydraenidae).

Parhydraena d'Orchymont, 1937 currently includes 19 species, 17 of which are endemic to South Africa (Perkins 2009; Bilton 2014). Most species of the genus are fully aquatic, but a few, together with members of other genera of Parhydraenini, occupy moist habitats rich in organic debris (Perkins 2009). These so-called humicolous habitats (Perkins Balfour-Browne 1994) occur both beside water and elsewhere, and have been colonised a number of times by primarily aquatic hydraenid lineages, particularly in Africa and Australasia (e.g. Perkins Balfour-Browne 1994; Perkins 2004a, 2004b; Perkins 2009; Hernando Ribera 2017). Within Parhydraena the toro group (sensu Perkins 2009) comprises four (sub)humicolous species which share a broad habitus, a marked constriction between the pronotum and elytral shoulders, and short legs and maxillary palpi. Whilst phylogenetic relationships within Parhydraena remain unclear in the absence of molecular data, the toro group as currently defined may not be monophyletic, given the differences in aedeagal anatomy observed amongst its members (see Perkins 2009). The most morphologically divergent species described to date is P. toro Perkins, 2009, whose simplified aedeagal anatomy differs considerably from all other known members of the genus. P. toro appears to be narrowly endemic to the inselberg of Table Mountain and surroundings, occurring in damp litter in Afromontane forests and beside seepages and streams (Perkins 2009; DTB pers. obs.). Here I describe a new species from a cool, high-altitude gully in the western end of Hex River Mountains, which closely resembles P. toro in external and aedeagal morphology and shares its humicolous microhabitat.

Imperfecta Dentinogenesis: a case report

Summary: Introduction: Dentinogenesis imperfecta (DI) is an inherited dental diaseasein which dental crowns are affected. DI originates by defects on the histo-differenciation stage ofodontogenesis, constituting a localized mesodermal dysplasia characterized by an expressedalteration of dentin proteins. There are three types of dentinogenesis imperfecta: Type I(associated with osteogenesis imperfecta OI), type II (no associated with OI), and type III(Brandywine’s). Objectives: To determine the type of dentinogenesis imprefecta, the family historyand clinical characteristics of a patient within extensive coronal destruction, to establish aprecise diagnosis and a treatment to recover masticatory function. Case Report: A 3-year-old malechild was referred to the clinic with dental hypersensitivity and pain during mastication. Hepresented generalized and extensive crown destructions and discoloration of erupted teeth,abscesses, attrition and loss of vertical dimension. Radiographs showed obliterated pulp chambers,marked cervical constriction and short roots. After clinical and radiographic analysis, familyhistory and consultation with a Geneticist, a relation with OI was not established. In contrast, adiagnosis of dentinogenesis imperfecta type II was confirmed. DE type II is an autosomyc dominanttrait, without gender predilection. Restorative treatment involved stainless steel crowns, requiredextractions, space maintainers and removable partial dentures placement. Conclusion: Early diagnosisand treatment of DI is recommended because the severe destruction of primary dentition that mayaffect child chewing and nutrition. Consultation wit a Geneticist in DI cases is reccomended todiscard any association with OI or other genetic syndromes. Key words: Dentinogenesis imperfecta.Odontogenesis imperfecta. Opalescent dentin. Hereditary opalescent dentin.