When size matters: the first comprehensive anatomical study of a species of “Condylocardiidae”, an extremely miniaturized bivalve

‘Miniaturization’ is a widespread phenomenon among the Metazoa. In the molluscan class Bivalvia, records of miniaturization are numerous. Among the Archiheterodonta, Warrana besnardi (Klappenbach, 1963) has attracted attention for its tiny size, which does not exceed 1.5 mm in shell length, and because it belongs to a group with limited anatomical information and often-debated status, the “Condylocardiidae” (which recent molecular studies place deeply nested within the family Carditidae). All species of Warrana Laseron, 1953 are small-bodied, and so miniaturization presumably occurred from a large-bodied ancestor within the Carditidae sensu lato. South American W. besnardi is here studied in detail. Its small size and the enlargement of the anterodorsal region during growth, reflects (and likely led) to infaunal habit, living as a burrowing bivalve that passively feeds on deposit particles entering the pallial cavity anteriorly. Mantle glands, previously reported as a common feature of other archiheterodonts, are missing in W. besnardi, but spongiform tissue in the antero-ventral portion of the mantle lobes presumably represents a blood sinus that might compensate for the great reduction of the ctenidia. Lecithotrophy is reported, with yolky oocytes bearing a thick non-cellular capsule layer; brooding was not observed, and it is here hypothesized that the extreme miniaturization, with the great reduction of ctenidia, is responsible for a shift in the reproductive mode of condylocardiids, contrasting with the commonly reported ovoviviparity of the carditids.

Angiographic Features and Transarterial Embolization of Retained Placenta With Abnormal Vaginal Bleeding

Objectives: To clarify characteristic angiographic features and clinical efficacy of selective transarterial embolization (TAE) of retained placenta with abnormal vaginal bleeding.Methods: The study cohort comprised 22 patients (mean age, 33.5 years; range, 22–24 years) who underwent selective TAE for retained placenta with abnormal bleeding between January 2018 and December 2020 at our institution. Angiographic images were reviewed by two certified radiologists with consensus. Medical records were reviewed to evaluate the efficacy of TAE. Angiographic features of retained placenta, technical success (disappearance of abnormal findings on angiography), complications, clinical outcomes (hemostatic effects and recurrent bleeding) were evaluated. Results: Pelvic angiography showed a dilated vascular channel mimicking arteriovenous fistulas or an aneurysm contiguous with dilated uterine arteries in the mid-arterial–capillary phase (tentatively named “serpiginous blood sinus”) in 20 patients; it showed contrast brush in the remaining two patients. TAE technical success was achieved in all patients. No major complications were observed in any patients. Fifteen patients were followed up with expectant management after TAE; all but one patient showed no re-bleeding during the follow-up period (mean follow-up interval, 3.4 months; range, 1–17 months). One patient showed minor rebleeding, which resolved spontaneously. Seven patients underwent scheduled hysteroscopic resection within 1 week after TAE, and no excessive bleeding was observed during or after the surgical procedure in all seven patients.Conclusions: The characteristic angiographic feature of retained placenta is “serpiginous blood sinus.” TAE is a safe and effective treatment to manage retained placenta with abnormal bleeding.

On the ‘Visceral Nervous System’ of Ciona

Ciona intestinalis has a well developed nerve plexus associated with the dorsal strand, as first described by Marco Fedele. The dorsal strand plexus is immunoreactive with antisera against gonadotropin-releasing hormone. Immunoreactivity is seen in the cell bodies, which lie peripherally, and in processes which run throughout the dorsal blood sinus, enter the branchial sac and penetrate the brain via the visceral nerve. The plexus provides a rich innervation of the gonoducts, and processes have been seen in the gonads. The pericardium is not innervated by processes from the plexus and the rectum is poorly innervated, but the full extent of the plexus in the viscera remains uncertain. While this study confirms many of Fedele's observations, it does not support the view that the dorsal strand plexus is equivalent to the vertebrate visceral nervous system.

A study of the neurosecretory centres of the eyestalk in Siriella armata M. Edw. (Crustacea: Mysidacea): their involvement in molting and reproduction

Neurosecretory cells and centres arc described in the eyestalk of the mysid Siriela armata. The sinus gland is situated on the neuropilar regions along the main blood sinus. The medulla interna and medulla externa X organ is formed of G1 cells; the medulla terminalis X organ consists of G3 and G4 cells. Other neurons, the G2 cells, and a "giant cell" may also be neurosecretory. Destruction of the medulla interna – medulla externa X organ results in an inhibition of the preparation for molt and ecdysis in both sexes. Reproducing females also show inhibition of secondary vitellogenesis and of marsupial development. The role of the medulla interna – medulla externa X organ in the control of premolt, secondary vitellogenesis, and marsupial development is discussed.

Canine Angiosarcoma (Lymphangiosarcoma): A Case Report

After injury to the left foreleg, a 2 1/2-year-old Great Dane bitch developed severe oedema of the limb, which did not respond to pressure bandaging or a proteolytic agent. Skin breakdown occurred over the metacarpal region and lymph could be expressed from this lesion. The oedema spread, anaemia and dyspnoea developed and the animal died of respiratory insufficiency 55 days after the initial injury. Autopsy showed widespread infiltration of subcutis, fascial planes and some muscles of the leg by invasive cords and sheets of small endothelial-type cells which formed channels sometimes filled with blood. There was widespread diffuse metastatic neoplasm throughout the lung but no cavernous blood sinus formation. There were small metastases in local lymph nodes, kidney, bone marrow and spleen. It was concluded that the injury made obvious an oedema caused by pre-existing angiosarcoma.

Fine Structure of the Crayfish Sinus Gland

The sinus gland of the crayfish, Procambarus clarkii, is located on the dorsum of the eyestalk, just beneath the exoskeleton and adjacent to the medullae interna and externa optic ganglia. It functions to secrete a variety of proteinaceous hormones, including the erythrophore concentrating hormone, melanophore dispersing hormone, molt inhibiting hormone, diabetogenic hormone, distal retinal pigment hormone, and ovary inhibiting hormone.The gland is composed of numerous neurosecretory axon terminals clustered about a branching blood sinus. The neurosecretory axons arise from cells lying some distance away from the sinus gland, in the medulla terminal is X-organ, the brain, and possibly the thoracic ganglion. The hormones are manufactured in the perikarya of these cells and transported through the axons to their terminals in the sinus gland for storage and release into the blood sinus.Small, electron dense spherules within the axons contain the hormone secretory product. These neurosecretory granules are very similar in morphology to those reported in the sinus glands of the dwarf crayfish, Cambarellus shufeldti, the land crab, Gecarcinus lateralis, and the Mediterranean isopod, Sguilla mantis. The sinus glands of each of these crustaceans contain two size ranges of neurosecretory granules: 1500-2000A and 500-900A.

ENCAPSULATION OF RHABDITOID NEMATODES IN MOSQUITOES

In third and fourth instar larvae of Aedes aegypti (L.), juveniles of the rhabditoid, DD136, penetrate the blood sinus and cardial epithelium of the proventriculus to enter the body cavity of the host, where they complete their development. By 5 hours, a thick capsule developed about many of the ensheathed immature adults of DD136 within the body cavity of A. aegypti larvae. This rapid defence reaction of the mosquito to DD136, which has both a melanin and a cellular manifestation, occurs both in the exotic mosquito A. aegypti and in the two endemic species tested, Aedes stimulans (Walker) and Aedes trichurus (Dyar). The resistance of A. stimulans to an endemic rhabditoid, possibly of the Diplogasteridae, is also similar. The histological structure of the capsule is not affected during metamorphosis in A. aegypti; however, during histogenesis of adult tissue displacement and (or) distortion of some tissues and organs may be caused by the presence of the capsule within the host's body cavity. The activity of the adult A. aegypti is normal when this distortion or displacement is minor. Though usually encapsulated DD136 are retained within the body cavity of A. aegypti during metamorphosis, sometimes they are partially or completely expelled from the host's body cavity at the time of molting.