A case of acardiac anomaly in the cynomolgus monkey (Macaca fascicularis): a complication of monozygotic monochorial twinning

A case of acardius acephalus in a Macaca fascicularis is reported. This congenital anomaly occurs only in multiple-birth gestations (most commonly monozygotic twins). Artery-to-artery and vein-to-vein anastomoses appear to be a constant feature. This condition is very rare in man and probably even more so in monkeys. Classification and theories on etiology are discussed.     

The free-convective anomaly.

Persons exposed to high temperature, or to equivalent environmental factors, have quantifiable reactions, such as reducing the resistance to both heat and moisture flow in skin tissues and clothing needed to maintain thermal equilibrium. The one-to-one relationship between this resistance in the walking person and temperature, with the other factors neutral, is the basis for the apparent temperature scale and the derived heat index. When this approach is taken to assess the thermal environment for a still person exposed to heat in still air, there is a zone of ambient conditions in which there are three solutions to the heat-balance equation. Extraordinary thermal stress occurs, depending slightly on other conditions, at ambient temperatures near 41 degrees C, especially at high humidity, because of the difficulty in carrying sweat vapor from the person when free convection is minimal. This anomaly is examined for a range of ambient vapor pressures and extra radiation. The rapid rise in heat stress when ambient temperature just exceeds body temperature in still conditions may explain the severity of some observed distress.     

The ultrastructure of megathrombocytes in May-Hegglin's anomaly

A clinical and extensive electron microscopic study was made of the circulating granulocytes and thrombocytes from three female patients of a family with May-Hegglin anomaly. There have been observed inclusion bodies (D?hle-bodies) in a high proportion of polymorphonuclear leukocytes as well as a thrombocytopenia and giant platelets (so-called megathrombocytes). Other family members did not show hematologic abnormalities. The investigated giant platelets show ultrastructurally a different electron density of the alpha-granules, however, these structures present no typical formation of "bull's eye granules" which has been observed in other cases of May-Hegglin anomaly. Peripheral or central situated net-like structures of the endoplasmic reticulum have been found frequently. There were seen no microtubuli whereas glycogen particles were scattered within the peripheral cytoplasm.     

A coronary anomaly

Coronary anomalies occur in up to 1.5% of the population who undergo coronary angiography because of symptoms. 1,2 Numbers concerning coronary anomalies in the general population are less clear.     

The anomaly of oxygen diffusion in aqueous xanthan solutions

A membrane-covered polarographic oxygen electrode was used to measure oxygen diffusion coefficients in aqueous polyelectrolyte solutions of xanthan gum, sodium alginate, and sodium carboxymethylcellulose (CMC). In sodium alginate solutions, dilute xanthan solutions, and solutions containing more than 0.3 wt % CMC, oxygen diffusion coefficients decrease with increasing polymer concentrations. Interestingly, in dilute CMC solutions and concentrate xanthan solutions containing more than 0.5 wt % xanthan gum, oxygen diffusion coefficients increase with increasing polymer concentrations, and values exceeding that in pure water are generally observed.     

Acardiac anomaly spectrum

BACKGROUND: Acardiac anomaly spectrum is a rare congenital malformation found in monozygotic twin pregnancy. Besides the absence of heart, the condition is associated with variable grades of developmental disruption. Thus, no two cases are similar. METHODS: This case report is based on physical examination and autopsy findings. RESULTS: The twin had acardia and partial development of head and face. There was complete absence of upper extremities. CONCLUSIONS: The twin reversed arterial perfusion (TRAP) theory is the most accepted etiology of the disorder. Normally, the cephalic pole is the most severely affected, being most distal to the retrograde perfusion. In acardia, partial development of head, face, and brain is usually associated with the development of the upper extremities. However, in the present case, there was extensive cephalic development in the absence of upper extremity development.     

The prion hypothesis: from biological anomaly to basic regulatory mechanism

Prions are unusual proteinaceous infectious agents that are typically associated with a class of fatal degenerative diseases of the mammalian brain. However, the discovery of fungal prions, which are not associated with disease, suggests that we must now consider the effect of these factors on basic cellular physiology in a different light. Fungal prions are epigenetic determinants that can alter a range of cellular processes, including metabolism and gene expression pathways, and these changes can lead to a range of prion-associated phenotypes. The mechanistic similarities between prion propagation in mammals and fungi suggest that prions are not a biological anomaly but instead could be a newly appreciated and perhaps ubiquitous regulatory mechanism.     

Polydactyly in the Pelger-Huet anomaly

The present paper is concerned with a report on a kin affected with Pelger-Huet's anomaly (PHA). 17 living heterozygous carriers of the anomaly are covered by the pedigree. Three further dead carriers of anomaly could be detected by genealogical studies. Polydactylia was found in three members of the kin, viz. in two sisters and a niece of second degree. Polydactylia could be found to have occurred at the same place in all these three persons concerned, with only one of them being a carrier of PHA: in all cases it was the doubling of the fifth toe of the right leg. This localisation of the same kind favours the assumption that this malformation is caused by genetics, however, without its having any genetical connection with PHA. The hypothesis was put forth that an enzyme defect is responsible for this hyposegmentation which simultaneously could have an impact on further elements of the mesenchymal tissue playing an important part in the histogenetic differentiation of organs.     

The question mark ear: an unappreciated major anomaly of the auricle

Eight and possibly nine cases of a major congenital ear anomaly that has been termed the question mark ear have been presented in the course of the last two decades. The consistency of the appearance of the anomaly and the demonstration that it has in several instances been familial makes it clear that a chance event is not involved, but rather that a consistent anomaly is being described. Appropriate repair requires reduction in size and prominence of the upper ear as well as correction of the waist between the upper ear and the lobule. This anomaly should take its place with the other major congenital defects of the external ear.