Case Report of a Term Newborn with Prenatally Diagnosed Alobar Holoprosencephaly

Holoprosencephaly is a congenital structural abnormality of brain resulting from incomplete cleavage of prosencephalon into two cerebral hemispheres. It is classified as a disorder of organogenesis and brain histogenesis and is typically associated with facial anomalies.Holoprosencephaly is relatively rare – the incidence in live births varies between 1:10,000 – 1:15,000 but is described in 1 out of 250 spontaneously aborted embryos.There are four major varieties of holoprosencephaly according to the degree of separation of the brain hemispheres; this division is crucial for the patient’s prognosis. Three classic subtypes are alobar, semilobar, and lobar holoprosencephaly and there is also a fourth subtype called middle interhemispheric variant.We present a case study of a term newborn with prenatally diagnosed holoprosencephaly with severe facial dys-morphism and associated health complications.

Heteropagus Twins with Hepatobiliary and Gastrointestinal Connectedness and Complex Cardiac Malformation in Autosite

Introduction: Heteropagus twins are a set of conjoined twins with one being grossly abnormal, the ‘parasite’, and the other being relatively normal, the ‘autosite’. Case Report: A pair of heteropagus twins were initially identified on prenatal ultrasound and subsequently confirmed using prenatal MRI at 25 weeks gestational age. Prenatal imaging identified supernumerary limbs, accessory small bowel loops in the parasitic twin, a hypoplastic left heart in the right hemithorax of the autosite, and a shared liver and bowel between the two. Delivery occurred at 38 + 5 weeks gestation via C-section with an APGAR score of 9/9 for the autosite at both 1 and 5 minutes. MRI confirmed an interconnected autosite-parasite liver that was herniating into the left hemithorax as well as continuous autosite-parasite bowel loops. The patient underwent surgical management including resection of the parasitic twin and repair of the congenital heart defect and is now thriving. Discussion: Heteropagus twins include a spectrum of clinical entities from nonconjoined twins to intact conjoined twins. The predominant theory regarding etiology is an incomplete cleavage of a monozygotic embryo at approximately 2 weeks gestation. Following differentiation, ischemia-induced atrophy leads to the embryonic death of the parasite and hemodynamic changes in the autosite to support parasite tissues. The use of antenatal and postnatal imaging is crucial in establishing the diagnosis, management plan, and longterm prognosis secondary to the congenital cardiac malformations and degree of interconnectedness. Conclusion: This is the first reported case of heteropagus twins with co-existing hepatobiliary and gastrointestinal continuity.

Cyclopia: A Rare Congenital Malformation

Cyclopia is a rare and lethal congenital anomaly of the forebrain system, resulting from incomplete cleavage of prosencephalon into right and left hemispheres occurring between the 18th and the 28th day of gestation. Approximately 1.05 in 100,000 births are identified as infants with cyclopia, including stillbirths. Many teratogenic factors are identified as the causative factors for this anomaly which include irregular cholesterol biosynthesis, radiation exposure, viruses, alcohol intake and maternal diabetes. Many authors also suggest genetic etiology of this illness. We report a case of 35 year old lady G7P6L5 with previous history of normal vaginal delivery who presented to us in second stage of labor. She delivered a male baby with a large head, a median single eye and absent nose with intact mouth. The baby died soon after the birth. This case is presented because of its rarity. Early ultrasound diagnostics and proper management of this anomaly must be emphasized most strongly to prevent complication associated with this condition.

Influence of pr-M Cleavage on the Heterogeneity of Extracellular Dengue Virus Particles

ABSTRACT During dengue virus replication, an incomplete cleavage of the envelope glycoprotein prM, generates a mixture of mature (prM-less) and prM-containing, immature extracellular particles. In this study, sequential immunoprecipitation and cryoelectron microscopy revealed a third type of extracellular particles, the partially mature particles, as the major prM-containing particles in a dengue serotype 2 virus. Changes in the proportion of viral particles in the pr-M junction mutants exhibiting altered levels of prM cleavage suggest that the partially mature particles may represent an intermediate subpopulation in the virus maturation pathway. These findings are consistent with a model suggesting the progressive mode of prM cleavage.

Embryo development, megagametophyte storage product accumulation, and seed efficiency in Taxus brevifolia

Taxus brevifolia Nutt. has a reduced ovulate structure that consists of a single ovule in a leaf axil instead of a compound ovulate strobilus. Taxus brevifolia on southern Vancouver Island, British Columbia, were studied over three seasons. Proembryos occurred from mid-May to mid-June. They underwent four free nuclear divisions forming 16 nuclei before cellularization. Early embryos were present from mid-May to mid-August. Simple polyembryony was observed up to the massive embryo stage, and differential growth of the embryonal cells was interpreted as incomplete cleavage polyembryony. Mid-embryos were present from mid-June to late August and had a distinct protoderm and focal zone. Late embryos were visible from mid-July onwards. Carbohydrates began accumulating at the early embryo stage, whereas proteins and lipids accumulated in the late embryo stage. The presence of a red aril corresponded to increased amounts of lipid in the megagametophyte cells. Individual seeds matured from July until November. The seed efficiency ranged from 0 to 16% and averaged 5%. Prezygotic loss was the most common fate of ovules, followed by postzygotic loss. Possible causes of this poor seed efficiency are poor pollination success, insect damage, or light limitation.

Thrombin-stimulated Human Platelets Express Molecular Forms of α-Granule Factor V (FV), which Differ from FVa

SummaryBinding of 125I-Fab fragments of chain-specific antibodies indicate that both heavy and light chains of a-granule factor Va (FVa) were externalized on the platelet membrane after stimulation with thrombin. Using a Mab against the activation peptide of factor V (FV), the epitope appears on the stimulated platelet surface. Half as much light chain and heavy chain (FVa) was expressed compared to the activation peptide, suggesting that expression of α-granule FV occurs after thrombin stimulation. Using an ELISA, we find that 32% of a-granule FV was released and 68% is retained in the platelet pellet. Immunoblots of platelets indicate that FV exists in 200 kDa und 150 kDa forms, representing incomplete cleavage, while the releasate demonstrates a more complete cleavage by proteases. We conclude that expression of α-granule FV is quantitatively greater than that released and exists in molecular forms which cannot be completely explained by the binding of FVa.

A clinical and pathological study of inherited glaucoma in New Zealand white rabbits

The eyes of 7 rabbits with clinical megaloglobus, selected from a large colony, were studied with slit-lamp microscopy, gonioscopy, indirect ophthalmoscopy and tonometry. Selected light and scanning electron microscopy was also performed. There were 11 glaucomatous eyes among the 7 rabbits: gonioscopy demonstrated open iridocorneal angles with absence of pectinate fibres. Incomplete cleavage of the iridocorneal angles in glaucomatous eyes was noted histologically. Because of the similarity of the iridocorneal angles of glaucomatous rabbit eyes with those of human eyes with congenital glaucoma, these rabbits may serve as an experimental model in the understanding and management of certain types of human glaucoma.