The hypodense focus in the petrous apex: a potential pitfall on multidetector CT imaging of the temporal bone

BACKGROUND AND PURPOSE

Hypoattenuated foci in the otic capsule are routinely identified on multidetector CT (MDCT), particularly in pediatric patients. We aimed to describe and characterize the hypoattenuated focus in the anterior otic capsule.

MATERIALS AND METHODS

We first reviewed histologic sections of the temporal bone from 8-month-old fetuses to determine the nature of the hypoattenuated focus in the anterior otic capsule. A cadaver collection of skull bases from fetuses and neonates (n = 19), infants (n = 24), and young children (n = 23) were then studied with MDCT to determine the developmental evolution of this hypoattenuated focus in relation to the petrous apex. We specifically looked for the hypoattenuated focus in the anterior otic capsule, the development of the petrous apex, and the presence of other hypoattenuated foci in the fissula ante fenestram and middle otic layer.

RESULTS

The hypoattenuated focus in the anterior otic capsule corresponded histologically to a cancellous bone trabecula emanating from the middle otic layer and directed toward the petro-occipital fissure. At this level it was covered with a cartilaginous cap. The hypoattenuated focus was observed in all of the fetuses and in all of the postnatal subjects younger than 4 months of age and was always associated with hypoattenuated foci of the middle otic layer and the fissula ante fenestram. This hypoattenuated focus became less obvious as the petrous apex developed.

CONCLUSION

The hypoattenuated focus in the anterior otic capsule should be recognized as a normal variant in pediatrics. It could represent a relic from the development of the petrous apex.

Microvascularisation of the male urethra in neonates and infants

The microvascularisation of the male urethra was studied in neonates and infants by injection of agarised China ink into the circulation. The purpose of this study was to specify the angioarchitecture of each tunic of the urethral wall. The disposition of the microvascularisation networks varies depending on the urethral parts considered: only the mucous membrane networks are uniform throughout the entire urethra. The sub-mucous networks are significantly increased in the spongy part. The muscular networks disappear in the spongy part.

The Role of the Zygomatic Arch in the Statics of the Skull and Its Adaptive Shape

The zygomatic arch of mammals is usually considered a phylogenetic relic of the fenestrations of the skull roof which may be observed in morphological sequences of primitive vertebrate skulls. If this concept is correct, the element is comparable (though not homologous) to the jugal arches of diapsid reptiles. Two major questions then remain unanswered: why different elements are maintained in reptiles and mammals during evolution, and why the arches are maintained as relics of ancestral forms. It is tempting to respond to the latter question with a very simple answer, namely that the elements function in order to sustain mechanical stresses. In this paper, we raise the questions which quality of stresses occurs in a primate skull within the zygomatic arches and what relationship these stresses hold to the morphology of these bony elements. An answer has been sought by means of finite element stress analysis. We found that the zygomatic arch in primate skulls represents a structure which carries, under all biologically relevant conditions, either compressive or tensile stresses. In a very simple model of the human skull under bite forces, a strip of stresses occurs lateral to the orbits, which seems roughly comparable to the zygomatic arch. Once such a structure exists and is used as an insertion of adductor muscles, it will be exposed to bending stress in side view and in frontal view. Morphological details of the zygomatic arch (curvature, profile, suture) are well suited to sustain the evoked stresses by a minimum of material.

Microvascularization of the mucocutaneous junctions of the head in fetuses and neonates

The mucocutaneous junctions of the head (oral, nasal and palpebral) are transitional zones between the integuments and the mucosa. Their microvascularization is studied in the heads of fetuses and neonates by injection of agarized China ink into the vascular system. These zones are situated deep with respect to the free edge of the oral or nasal cavity or relative to the free margin of the eyelid. They present cutaneous-type microvascularization with a papillary network and reticular networks. Long capillary loops connected to the deep reticular network are their main feature. In the lips and eyelids, the morphology of the networks and their relationship with the orbicular muscles are suggestive of a functional structure.

Microvascularization of the female urethra in fetuses, neonates and infants

The microvascularization of the female urethra was studied in fetuses, neonates and infants by injection of agarized China ink into the circulation. The purpose of this study was to specify the angioarchitecture of each tunic and their specific drainage. The disposition of the microvascularization of the urethra is superimposed on the orientation of the fibers of the muscular tunic. The orientation of the veins of the sub-mucous tunic is longitudinal and not plexiform.

[Computed tomographic analysis of humeral retrotorsion and glenoid retroversion]

PURPOSE OF THE STUDY

Analysis of the anatomic relations of the humeral head and the glenoid cavity is particularly important for clinical study of shoulder arthroplasty and glenohumeral instability. Analysis of humeral retroversion and glenoid retroversion is quite difficult and data in the literature are scarse. We conducted a computed tomography (CT) analysis of stable shoulders to detail retroversion of the entire height of the glenoid cavity and to measure humeral retrotorsion using two comparative methods. We also compared glenoid retroversion and humeral retrotorsion observed in individual subjects.

MATERIAL AND METHODS

This prospective study used a standardized CT analysis method. Both shoulders of 30 persons free of glenohumeral instability were studied. Two methods, described by Dähnert and Bernageau, were used to analyze humeral retrotorsion. The Benageau method was used to analyze glenoid retroversion.

RESULTS

According to the Dähnert method, humeral retrotorsion was 10 degrees +/- 13 degrees; it was 24 degrees +/- 13 degrees with the Bernageau method; data dispersion was 60 degrees and 65 degrees respectively. According to the Dähnert method, retrotorsion was more pronounced on the dominant side compared with the non-dominant side. There was a significant correlation between retrotorsion values for the two sides. For 95% of the shoulders, glenoid retorversion decreased progressively from the superior part of the glenoid cavity (12.8 degrees +/- 6.4 degrees ) to the lower part (3.1 degrees +/- 4.4 degrees ). Glenoid retroversion was greater on the dominant side. For 21 of the 30 persons (70%), there was a significant correlation between retroversion for the two sides. Correlation coefficients between glenoid retroversion and humeral retrotorsion were negative. Greater humeral retrotorsion was thus related with less pronounced glenoid retroversion and vice versa.

DISCUSSION

This study allowed quantification of glenoid retroversion and humeral retrotorsion. There is a spiral twist in the joint surface of the glenoid cavity with progressive decrease in glenoid retorversion from the upper to the lower part of the cavity for 95% of the shoulders. To our knowledge, this spiral twist in the glenoid cavity is not taken into consideration in any of the currently available implants. The correlation for both parameters between the right and left side is probably determined genetically. The influence of dominance could be explained by adaptation to more or less pronounced stress. The negative correlation between humeral retrotorsion and glenoid retroversion would improve glenohumeral stability. A comparative study with unstable shoulders would be required to verify this hypothesis. The validity of the Dähnert method for assessing humeral retorversion is, in our opinion, insufficiently established. The Bernageau method, which provides a direct measurement, appears to be preferable despite the difficulty in identifying anatomic landmarks.

Microvascularization of the mucocutaneous junction of the eyelid in fetuses and neonates

The aim of this study was to specify the microvascularization of the junctional region between the integuments of the superficial surface of the free margin of the eyelid and the palpebral conjunctival mucosa. The study was carried out using histological or transparified slices of upper and lower eyelids taken from fetuses and neonates, in which the vascular system was injected with agarized China ink. The mucocutaneous junction of the eyelid is located at the posterior border of the free margin and extends to its deep surface. It has vascular similarities to the oral cavity and the nasal pyramid. Under a thickened avascular epithelium, there is a papillary network composed of characteristic loops that are less raised than in the lips but more developed than in the nose. The superficial and deep vascular reticular networks are comparable in fundamental arrangement to those of other junctional zones. Thus, the palpebral mucocutaneous junction shows cutaneous-type microvascularization, just like the other junctional zones of the head.

Microvascularization of the mucocutaneous junction of the nose

The aim of this study was to describe the microvascularization of the area of junction located between the integuments of the nasal ala and the respiratory mucosa. This study is part of an overall study on the microvascularization of the mucocutaneous junctions of the head. It was undertaken on histological or clarified sections of noses from fetuses, newborns and adults whose vascular system was injected with Indian ink agar. The mucocutaneous junction of the nose shows similarities with the mucocutaneous junction of the oral cavity. Under a well-defined avascular and thick epithelium lies a vascular papillary network with typical loops less high than in the lips. The angioarchitectonics of superficial and deep vascular reticular networks is similar to that of the lips but they are less dense.

[Cellular subcutaneous tissue. Anatomic observations]

INTRODUCTION

We showed in a companion paper that the definition of the French "subcutaneous cellular tissue" considerably varied from the 18th to the end of the 20th centuries and has not yet reached a consensus. To address the anatomic reality of this "subcutaneous cellular tissue", we investigated the anatomic structures underlying the fat tissue in normal human skin.

METHODS

Sixty specimens were excised from the surface to the deep structures (bone, muscle, cartilage) on different body sites of 3 cadavers from the Institut d'Anatomie Normale de Strasbourg. Samples were paraffin-embedded, stained and analysed with a binocular microscope taking x 1 photographs. Specimens were also excised and fixed after subcutaneous injection of Indian ink, after mechanic tissue splitting and after performing artificial skin folds.

RESULTS

The aspects of the deep parts of the skin greatly varied according to their anatomic localisation. Below the adipose tissue, we often found a lamellar fibrous layer which extended from the interlobular septa and contained horizontally distributed fat cells. No specific tissue below the hypodermis was observed. Artificial skin folds concerned either exclusively the dermis, when they were superficial or included the hypodermis, but no specific structure was apparent in the center of the fold. India ink diffused to the adipose tissue, mainly along the septa, but did not localise in a specific subcutaneous compartment.

DISCUSSION

This study shows that the histologic aspects of the deep part of the skin depend mainly on the anatomic localisation. Skin is composed of epidermis, dermis and hypodermis and thus the hypodermis can not be considered as being "subcutaneous". A difficult to individualise, fibrous lamellar structure in continuity with the interlobular septa is often found under the fat lobules. This structure is a cleavage line, as is always the case with loose connective tissues, but belongs to the hypodermis (i.e. fat tissue). No specific tissue nor any virtual space was observed below the skin. Thus, the commonly used term "subcutaneous cellular tissue" is inappropriate.

[Does subcutaneous cellular tissue exist?]

BACKGROUND

The definition of the "subcutaneous cellular tissue" is still debated.

METHODS

In order to establish the localisation and composition of this tissue, or, merely its existence, we interviewed French dermatologists and conducted a bibliographic study on the historical definitions of the so-called "subcutaneous cellular tissue". A questionnaire was sent to French professors of dermatology to assess their definition of the "subcutaneous cellular tissue". They were also asked to make a simple cartoon showing the anatomy of the skin and "subcutaneous cellular tissue".

RESULTS

We obtained 37 answers which could be classified in three main categories: 1) "subcutaneous cellular tissue" and hypodermis are synonymous, 2) "subcutaneous cellular tissue" is an autonomous tissue which separates the hypodermis from the tissues below and 3) "subcutaneous cellular tissue" designates all structures located below the hypodermis. In an historic perspective, the "cellular system" was a macroscopic concept described in the eighteenth century as whitish fibrils delimitating "cells". It was renamed loose connective tissue in the twentieth century and thus "cellular" became obsolete. The definition of skin, and of "subcutaneous cellular tissue" in particular, has greatly changed over time. In the eighteenth century, only epidermis and dermis were considered as belonging to the skin, although some included the tela subcutanea. In the twentieth century, the "subcutaneous cellular tissue" is considered either as a part of the hypodermis, or as the hypodermis itself or as a tissue located between the hypodermis and the fascia.

DISCUSSION

The difficulty in defining "subcutaneous cellular tissue" is the result of a French semantic problem. The "cellular tissue" became loose connective tissue. For French dermatologists, the skin is composed of epidermis, dermis and hypodermis and the hypodermis can therefore not be subcutaneous. In order to check whether an autonomous tissue could be evidenced under the skin, we conducted an histologic study, which is presented in a second article.

Microvascularisation of lips in ageing edentulous subjects

Macroscopic changes of the lips in the edentulous elderly subject are accompanied by variations in their microvascularisation. This study was undertaken on histological or clarified sections from totally edentulous subjects whose vascular system was injected with Indian ink agar. A reduction in density and size of the superficial (papillary or mucosal) and deep (reticular or submucosal) networks is observed with age. These changes are to be seen in relation to imaging and to the reduction in occlusal potential of the lips.

Microvascularisation of the lips in the fetus and neonate

The differences observed in the microvascularisation of the lips in the perinatal period correspond to the differences in the histological structures of the cutaneous, glabra, intermediate cutaneous, villous, intermediate mucosal and mucosal parts. A basic pattern is found in each part: on the surface, a papillary or mucosal network, at a deeper level, reticular or submucosal networks and their pedicles. The vascular changes correspond to the transition of tissue (mucocutaneous junction) and are indicative of the functional aspect. The same histological and microcirculatory structures were found in all the preparations, irrespective of the subject's age. Knowledge of the microvascularisation makes it possible to interpret magnetic resonance imaging of the lip better and finds its application in the surgery of the lips.

Microvascularisation of the raphe buccalis in edentulous subjects, fetus, new-born and adult

The aim of this study is to describe the microvascularisation of the raphe buccalis located at the inner surface of the cheek. The raphe buccalis is the zone where the maxillary and mandibulary prominences fuse in the embryo during the second month of life. This study was conducted using heads from edentulous subjects, fetuses, newborns and adults, injected with Indian ink in agar, then dissected or sectioned in the three basic planes. The vascular networks of the raphe buccalis are as followed: a deep reticular network, a superficial reticular network and a papillary network. The microvascularisation of the raphe buccalis classifies it as a continuation of the commissure of the mouth and of the mucosa of the cheek.

Ex vivo high resolution MR imaging of the human lip with a dedicated low field system

Histological correlations of the human lip with corresponding magnetic resonance (MR) images obtained ex vivo are presented. MR images were acquired with a dedicated low-field (0.1 T) MR system, with a resolution of 100 x 100 micron2 and a slice thickness of 1 mm using 3D-FLASH sequences. The outermost tissues visible on images are of high signal intensity, while the innermost connective tissues are of low signal intensity, both for skin and oral mucosa. It is possible to use a low-field system to obtain high resolution images of small biological samples.

Amino acid utilization and isotope discrimination of amino nitrogen in nitrogen metabolism of rat liver in vivo

Urea and plasma protein differ in natural 15N abundance up to 10%. The origin of this difference is the branched nitrogen metabolism in the liver. One main branch is the protein synthesis pathway, the other the urea synthesis pathway. By this branching 15N of precursor amino acids is depleted in urea while it is enriched in protein. With the 15N abundance of precursor amino acids, which may be taken from jejunum tissue, utilization of amino acids in liver metabolism can be calculated from isotope discrimination in either pathway. This was investigated by feeding different proteins to rats. When feeding high quality protein (whey protein) utilization of amino acids in liver metabolism at requirement intake was better than at zero protein intake (> 85% vs. 70%). From this we conclude that the pattern of amino acids available from the metabolic pool at zero protein intake is characterized by an imbalance. This endogenous imbalance can be complemented by exogenous dietary amino acids so that nitrogen excretion may even be smaller than the so-called "obligatory" losses of intakes not exceeding requirement. Thus, the quality of dietary protein is reflected not only by N balance. It also may be quantified by analysis of isotope discrimination in nitrogen metabolism of the liver. In addition, the quality of amino acid pattern available from the metabolic pool is indicated by this method.

Allergy to the heat-labile proteins alpha-lactalbumin and beta-lactoglobulin in mare's milk

BACKGROUND

Allergy to mare's milk is rare. Recently, however, mare's milk has been recommended for treatment of various ailments by practitioners of "alternative medicine," and it is available in health food stores.

OBJECTIVE

We report a case of allergic reaction to mare's milk in a 51-year-old woman who was able to tolerate cow's milk.

METHODS

The protein composition of mare's milk was determined by methods based on measurement of nitrogen content. The patient underwent prick and intracutaneous tests with commercially available bovine milk proteins and several mare's milk preparations, including mare's milk granulate and boiled mare's milk. RAST and immunoblotting were also performed.

RESULTS

Results of skin testing and RAST with cow's milk were negative but demonstrated an IgE-mediated allergy to mare's milk. Immunoblotting revealed two allergen bands with molecular weights of 16 and 18 kd, most likely representing the whey proteins alpha-lactalbumin and beta-lactoglobulin. The bands disappeared after the mare's milk was boiled, indicating that the proteins are heat-labile.

CONCLUSION

The results of this study demonstrate the existence of an IgE-mediated mare's milk allergy caused by low molecular weight heat-labile proteins, most likely alpha-lactalbumin and beta-lactoglobulin, which do not cross-react with the corresponding whey proteins in cow's milk.

The lunula: a magnetic resonance imagining approach to the subnail matrix area

High-resolution sagittal magnetic resonance images depict an oval area in the dermis beneath the nail matrix that gives a particular signal. This study defines the magnetic resonance imaging characteristics of this area and examines its correlation with the lunula. A high-resolution surface gradient coil specially designed for skin imagining was used on a 1.5 T magnetic resonance unit. The subnail matrix (SNM) areas of 12 subjects had a significantly longer T2 relaxation time and a higher enhancement ratio after injection of gadolinium than did the nail bed dermis. The length of the SNM area distal to the free edge of the proximal nail fold was highly correlated with the length of the lunula (R = 0.98) in 30 fingers and 10 toes. The total length of the SNM area was somewhat correlated with the nail thickness (R = 0.86) in 30 fingers. The histology and microvascularization of the subungual tissue in 21 fingers showed that this SNM area had specific features: The area was composed of loose connective tissue without bundles, and the reticular and subdermal vascular networks had large regular meshes in this oval area. The lunula is shown to be linked to a well-defined area in the underlying dermis with a specific histology and microvascularization.

Exogenous and endogenous nitrogen flow rates and level of protein hydrolysis in the human jejunum after [15N]milk and [15N]yoghurt ingestion

Milk and yoghurt proteins were 15N-labelled in order to measure the flow rate of exogenous N during digestion in the human intestine. After fasting overnight, sixteen healthy volunteers, each with a naso-jejunal tube, ingested either [15N]milk (n 7) or [15N]yoghurt (n 9). Jejunal samples were collected every 20 min for 4 h. A significant stimulation of endogenous N secretion was observed during the 20-60 min period after yoghurt ingestion and the 20-40 min period after milk ingestion. The endogenous N flows over a 4 h period did not differ between the groups (44.3(SEM 6.5) mmol for milk and 63.5(SEM 5.9) mmol for yoghurt). The flow rates of exogenous N indicated a delayed gastric emptying of the yoghurt N compared with N from milk. The jejunal non-protein N (NPN) flow rate increased significantly after milk and yoghurt ingestion due to an increase in the exogenous NPN flow rate. The NPN fraction of exogenous N ranged between 40 and 80%. The net gastro-jejunal absorption of exogenous N did not differ significantly between milk (56.7(SEM 8.5)%) and yoghurt (50.9(SEM 7)%). The high level of exogenous N hydrolysis is in accordance with the good digestibility of milk products. Fermentation modifies only the gastric emptying rate of N and does not affect the level of diet hydrolysis, the endogenous N stimulation or the digestibility rate.

Vascular networks of the periphery of the fingernail

The vascular networks of the periphery of the fingernail have been studied on fingers of adults, foetuses and neonates, by injecting the vascular system with gelatinous Indian ink. The nail is an avascular structure, partially covered by the nail wall. It is lying on the nail bed which is prolonged forwards with the hyponychium. Each part of the nail apparatus presents a characteristic vascular network derived from dorsal collaterals arising from the palmar digital vessels and from their arcades. These networks are papillary, pseudopapillary, reticular and subdermal. Their morphology and density vary according to their localization and correspond with histological variations of the different parts of the nail apparatus. Thus, the germinal part of the nail bed shows poor vascularization. It is responsible for the colour of the lunula. The sterile part and the hyponychium have dense vascular networks with glomus bodies.

15N-labeled immunoglobulins from bovine colostrum are partially resistant to digestion in human intestine

To evaluate true ileal digestibility of bovine immunoglobulins, seven healthy human adults ingested a 15N-labeled preparation of an immunoglobulin concentrate. After fasting overnight, subjects drank 400 mL of immunoglobulin concentrate (77 mmol), and ileal effluents were collected for 8 h at 20-min intervals using a naso-intestinal intubation technique. In addition to osmolality and pH, the concentrations of exogenous and endogenous nitrogen and ions (Na+, K+, Cl-, Ca2+, Mg2+) in the effluents were measured. Bovine immunoglobulin concentrations (IgG, IgM, IgA) were estimated by a radial immunodiffusion technique. The mean flow rate of the liquid phase was 22.3 +/- 6.1 mL/20 min and did not vary significantly during the collection period. No change was observed for osmolality, pH or Na+, K+ and Cl- concentrations. Two hours after meal ingestion, Ca2+ and Mg2+ concentrations increased significantly (P < 0.05). The recoveries of nitrogen of ingested IgG and IgM still immunologically active were 19 +/- 3% and 19 +/- 4%, respectively. No IgA was detected in the ileum. Mean digestibility of the exogenous nitrogen fraction was 79 +/- 3%. In comparison to literature data, which show that other milk proteins have ileal digestibilities of > 90%, our results demonstrate a lower ileal digestibility of bovine immunoglobulins in humans.

[Imaging of connective tissue formations of the sub-umbilical anterior abdominal wall]

New high resolution imaging modalities (CT and MRI) can distinguish between bladder and anterior abdominal wall pelvic connective tissue. The main structure is the umbilicovesical fascia located anterior to the peritoneum and posterior to the transversalis fascia. This layer divides the space between an anterior prevesical space and a posterior perivesical space. An understanding of these spaces facilitates the clinical identification and topography of pelvic the fluid collections.

[A cephalometric study of the pterygoid process during growth]

This study consists in a three dimensional cephalometric approach of the pterygoid process and its relationships with the neighbouring cranio-facial structures, using biostatistical analysis. The authors present the results of this method comparing the variations of the pterygoid process in relation to the variations of the basi-cranium and the face.

Ammonia production from hippurate by the rat kidney in vitro

Hippurate is known to be synthesized from benzoate and glycine in the liver and kidney. It takes part in renal ammoniagenesis by modulating the activity of gamma-glutamyl transpeptidase (gamma GT). Due to its chemical structure, however, hippurate might also serve as a substrate of renal ammoniagenesis. Hippurate may yield ammonia either having been cleaved by hippuricase or by Erlenmeyer's reaction after condensation with an aldehyde. In order to elucidate the possibility of hippurate being a substrate of renal ammoniagenesis, experiments were carried out on cortical kidney slices and on isolated tubular segments of the rat. The incubation medium (pH 7.1) was enriched with 10 mmol/l hippurate spiked with 15N-hippurate, some of the known competitive inhibitors of hippuricase, acivicin and different aldehydes. Factors known to affect hippuricase or gamma GT did not interfere with renal ammonia production. Glyceraldehyde (up to 1.0 mmol/l) but not glycerate had a stimulating effect, especially on the ammoniagenesis from hippurate. In normal rats fed a vegetarian diet, 1% of the added 15N moiety was found to be 15NH3. Renal 15NH3 production was significantly greater if, prior to the experiments, the animals were either acidotic or had a reduced renal mass or were fed animal proteins. These results indicate that hippurate may, to a certain extent, serve as substrate for ammoniagenesis.

Gastric emptying regulates the kinetics of nitrogen absorption from 15N-labeled milk and 15N-labeled yogurt in miniature pigs

Thirty-six miniature pigs divided into two groups of 18 animals were fed 15N-labeled milk or yogurt. Polyethylene glycol 4000 was added to the diets as a non-absorbable marker of the liquid phase. Animals were slaughtered 1, 2, 4, 8 and 12 h after meal ingestion, and the gastrointestinal tract was removed and divided into 10 parts. Polyethylene glycol, total nitrogen and 15N enrichment were measured in the digesta. Both the intestinal delivery of the liquid phase and the nitrogenous fraction of the chyme were delayed more in pigs fed yogurt than in pigs fed milk. No stimulatory effect of diet ingestion on endogenous nitrogen secretion was found. Both milk proteins and yogurt proteins were highly digestible: 93% of the exogenous nitrogen disappeared 12 h after feeding. The kinetics of exogenous nitrogen delivery into the intestine was correlated (r = 0.999 for milk and r = 0.974 for yogurt) with that of exogenous nitrogen absorption. These results suggest that milk proteins are rapidly absorbed after they reach the intestine. Gastric emptying is a major factor controlling the kinetics of milk nitrogen absorption.

True exogenous and endogenous nitrogen fractions in the human jejunum after ingestion of small amounts of 15N-labeled casein

The purpose of this work was to determine exogenous and endogenous contributions to the overall nitrogen flux in the upper jejunum in humans. After the ingestion of water or 8 g of [15N]casein, the behavior of gastro-jejunal nitrogen and electrolyte (Na+, K+, Cl-) movements were studied in seven volunteers using the "slow marker" perfusion technique. The jejunal flow-rate of the chyme peaked during 0-20 min and 20-40 min periods following water and casein ingestion, respectively. Osmolarity, Cl- and Na+ concentrations decreased significantly (P < 0.05) during the first 20 min following meal ingestion and returned to the basal levels in the 20-60 min period. The gastric half-emptying times (min) of the liquid phase differed significantly (P < 0.05) for water (7.9 +/- 0.4) and casein (21.4 +/- 9.1). The basal flow rate of endogenous nitrogen was 9 +/- 3.3 mmol/h in the jejunum. After casein ingestion, the total nitrogen content reached maximum values in the 20-40 min period and then progressively returned to the initial level. The gastro-jejunal casein absorption was 58% and the remaining amount of casein in the jejunum was degraded more than 80% to alcohol-soluble compounds. After the ingestion of a low amount of casein no significant increase in the endogenous nitrogen fraction was observed. The 15N-dilution technique is an appropriate method in humans for the direct measurement of endogenous and exogenous contributions to the intestinal nitrogen fraction.

[Imaging-anatomy correlation of the subrenal part of the inferior vena cava]

A limited number of tomodensimetrical sections, MRI or echographical according to the fundamental, frontal, sagittal or horizontal plans makes possible the exploration of the sub-renal part of the lower vena cava. The comparison of pictures with the corresponding anatomical sections makes possible a detailed analysis of all the visualized structures, around the lower vena cava.

[Cephalometric study of the pterygoid process linear parameters in the human adult and child]

A cephalometric investigation of the lateral plate of the pterygoïd process was conducted in the sagittal, frontal and axial plane. The aim of this study was to make linears observations on the pterygoïd process. A biostatistical method helped comparing the variations of the lateral pterygoïd plate in relation to the variations of the basi-cranium and the face with special interest given to the mandible, because of its tight muscular connection to the pterygoïd process.

High resolution MRI of the normal finger at 0.1 T: anatomic correlations

MR images of the fingers are obtained in a 128 x 128 or 256 x 256 matrix format using a prototype of a mini imager dedicated to the hand. The vertical field of 0.1 T is provided by an electro-magnet with an air gap of 15 cm equipped with a single solenoidal coil. No Faraday cage is used. The maximum in plane pixel resolution of 100 mu is obtained for a field of view of 2.5 cm with a slice thickness of 2 mm. The identification of fine structures of the finger is demonstrated by the anatomical and histological correlations. This type of imager which is adapted to very limited field of views demonstrate that high resolution MRI of limb extremities can be achieved at 0.1 T.

[Methods for the anthropologic and teleradiographic study of the pterygoid process]

The relationships of the external pterygoid plate with the other components of the craniofacial building has hardly been explored because of recording difficulties. A method to accurately identify in a reproducible way the main axis of the pterygoid process with the help of two small iron balls was contrasted with other methods seen in the literature. The iron balls technique was shown to be the method of choice with regard to biostatistical consistency.

Cow's milk protein allergy--results of skin-prick test with purified milk proteins

The diagnosis of milk-protein allergies is difficult. Therefore, the main cow's milk proteins (alpha-lactalbumin, beta-lactoglobulin A + B, alpha s-casein, beta-casein, kappa-casein), purified to the highest available standards, were used for differential diagnosis of allergic individuals by applying skin-prick test. In the case of adults with uncertain medical history, milk proteins rarely caused skin reactions, while distinct skin reactions were observed in 11 of 13 children with strongly suspected milk-protein allergy. In the presented study alpha-lactalbumin and beta-lactoglobulin B were the main allergens, because skin reactions to these proteins were provoked with highest prevalence and intensity. Intensity and prevalence of reactions to alpha- and kappa-casein were significantly less. In two cases skin reactions to alpha-lactalbumin were observed exclusively.

La microvascularisation du sternum chez I’enfant

46 sternums originating from 1-day- to 17-year-old children were injected with India ink and transparified.The intraosteal and medullary vasculature is described at different stages, as well as cartilage canals, vessels of the isolated ossification center, vessels of the ossification center connected with peripheral vascular structures or neighboring cartilage canals, and finally the transition to the adult pattern. With age, the centrifugal vascular distribution develops to a centripetal pattern.

CT-anatomic correlations of the normal capsulo-ligamentous bands of the extrinsic joints of the thoracic spine

Five anatomic specimens were studied in an attempt to visualize by high-resolution computed tomography (HRCT) the ligamentous bands of the costotransverse and costovertebral joints. HRCT-anatomic comparison is presented to relate the CT views to the anatomic structures. The authors demonstrate that axial, sagittal and, to a lesser extent, coronal HRCT views perfectly outline the ligamentous structures, although these are flattened, short, deep and free from calcium deposit. The method may be valuable in disease states such as ankylosing spondylitis.

A suprasternal approach to the mediastinum using real-time ultrasonography. Echoanatomical correlations

This work was undertaken in order to define the potential capabilities of real-time echography for the exploration of the mediastinum by a suprasternal approach. We present the results of a comparative study between anatomical frontal oblique sections of the mediastinum and echographic slices performed along the same planes from the suprasternal fossa. From these data, it seems possible to enlarge the applications of echography in the study of mediastinal pathology.

Anatomy and computed tomography of the normal lumbosacral plexus

The main nerves of the pelvis and lower limbs arise from the lumbar and sacral plexuses. These nerves can be affected by any of a large number of pathologic processes that occur in the paravertebral and pelvic regions. Understanding of the neurological findings related to paravertebral and pelvic pathology needs complete and accurate knowledge of the anatomy of these regions. The axial transverse sections of computed tomography give perfect visualisation of the anatomy of osseous, muscular, and vascular structures of the vertebral and paravertebral area and pelvic walls. Visualisation of the nerves in this regions is much more difficult, because direct demonstration of nervous structures by computed tomography is usually impossible. To be able to identify components of the lumbosacral plexus on axial CT sections the radiologist has to know the location of the nervous structures and the relationships of these structures to vascular, muscular and osseous structures which are easily demonstrated.

Proton-magnetic-resonance investigation of the dynamics of the conformational transition in allosteric monomeric insect hemoglobins

1H-NMR spectra of the monomeric insect (Chironomus thummi thummi) hemoglobins CTT III and CTT IV were investigated in the pH range 5-10 to gain insight into the dynamics of the tense to relaxed (t in equilibrium r) conformational transition in the deoxy (at 200 MHz) and cyano-met (at 360 MHz) form. These hemoglobins exhibit a pH-sensitive O2 affinity (Bohr effect) which is linked to the conformational transition. Both hemoglobins are comprised of two components which show heme rotational disorder due to a 180 degrees rotation of the heme group about the alpha,gamma-meso axis. The heme rotational components differ remarkably in their Bohr effects [Gersonde, K. et al. (1986) Eur. J. Biochem. 157, 393-404]. Several of the hyperfine-shifted heme proton resonances in these hemoglobin derivatives show pH-induced line-broadening which is largest at pK = 7.46 (for the heme rotational component with large Bohr effect) or pK = 7.06 (for the heme rotational component with small Bohr effect) determined from the plots of chemical shift versus pH. The line broadening at pK approximately equal to 7.5, shown for the heme rotational component of cyano-met CTT IV with the largest Bohr effect, decreases in the following order in parallel with the pH-induced shift change: 4-H beta-c (1.20 ppm) greater than 3-CH3 (0.80 ppm) approximately greater than 4H alpha (0.76 ppm) approximately greater than 4H beta-t (0.73 ppm) greater than 8-CH3 (0.35 ppm). Decrease in temperature at the pK value also leads to line-broadening. At 4 degrees C the hyperfine-shifted resonance attributed to 3-CH3 is split into two resonances assigned to the t (low-pH form) and r (high-pH form) conformation, respectively. This temperature dependence confirms the t in equilibrium r exchange process as the origin of the pH-induced line-broadening. The Bohr proton exchange rate at the allosteric site is orders of magnitude larger than the t in equilibrium r exchange rate. Therefore, the proton-linked t in equilibrium r transition appears as a first-order reaction. The rate constant ktr for the t in equilibrium r transition at the pK in different hemoglobin derivatives ranges over 0.2-7 ms-1. Surprisingly, ktr is identical for deoxy and cyano-met CTT IV.(ABSTRACT TRUNCATED AT 400 WORDS)

Bohr effect in monomeric insect haemoglobins controlled by O2 off-rate and modulated by haem-rotational disorder

The monomeric insect (Chironomus thummi thummi) haemoglobins CTT III and CTT IV show an alkaline Bohr effect. The amplitude of the Bohr effect curve of CTT IV is about twice as large as that of CTT III. In particular, at low pH a time-dependent 'slow' decrease in p50 upon cyclic oxygenation/deoxygenation is observed which is larger if dithionite, instead of ascorbate, is the reducing agent. The decrease of p50 (increase in affinity) correlates with the ratio of haem-rotational components exhibiting an increase of the 'myoglobin-like' haem-rotational component with high O2 affinity and high stability of the globin-haem complex. The replacement of protohaem IX by mesohaem IX and deuterohaem IX, respectively, causes an increase in O2 affinity following the order: proto less than meso less than deutero CTT Hbs. The Bohr effect, however, seems not to be affected by these porphyrin side-group substitutions. The O2 affinity is modulated by steric effects due to the substituents in position 2 and 4 via variation of the protein-haem interactions which influence the O2 release. The replacement of iron by cobalt in proto and meso CTT IV leads to an increase of the p50 by two to three orders of magnitude. Neither central metal nor vinyl replacement affect the Bohr effect. The natural CTT Hbs III and IV analyzed for mono-componential kinetic systems exhibit pH-dependent O2 off-rate constants: 300 s-1 (at pH 5.6) and 125 s-1 (at pH 9.7) for CTT III, and 550 s-1 (at pH 5.4) and 100 s-1 (at pH 9.0) for CTT IV. Inflection points and amplitudes of the log koff/pH plots correspond to those obtained from the Bohr effect curves indicating again a larger Bohr effect for CTT IV than for CTT III. In contrast, the O2 on-rate constants are pH-independent (kon = 1.15-1.26 X 10(8) M-1 s-1). Thus, the Bohr effect is completely controlled by the off-rate constants. Analysis for bi-componential kinetic systems employing the eigenfunction expansion method clearly identifies two kinetic components for proto-IX and deutero-IX CTT Hbs which can be attributed to the two haem-rotational components x and y (x and y differ due to an 180 degree rotation of the haem group about the alpha,gamma-meso axis; y is the myoglobin-like haem-rotational component).(ABSTRACT TRUNCATED AT 400 WORDS)

Acid Bohr effect of a monomeric haemoglobin from Dicrocoelium dendriticum. Mechanism of the allosteric conformation transition

The dioxygen affinity of Dicrocoelium dendriticum haemoglobin was determined as a function of pH with a thin-layer diffusion technique. From the oxygen dissociation and association curves Hill coefficients h equal 1 were obtained throughout. Ultracentrifugation studies prove this haemoglobin to be monomeric irrespective of pH and ligation state. Thus, Dicrocoelium haemoglobin is a non-cooperative monomer. It has the highest O2 affinity so far known for any monomeric haemoglobin: its half-saturation pressure, p50 value, ranges at 25 degrees C from 0.016 mm Hg to 0.15 mm Hg (2.13-20.0 Pa) dependent on pH. Dicrocoelium haemoglobin shows an acid Bohr effect only and as such it constitutes a new class of haemoglobins. Its log p50 versus pH plot (Bohr effect curve) is characterized by a large amplitude, delta log p50 = 0.96, and an inflection point (Bohr effect pK) at pH 5.0. A model for the acid Bohr effect of D. dendriticum haemoglobin is proposed. By generalization, both the alkaline and the acid Bohr effect in various monomeric haemoglobins may arise from a single Bohr group complex (salt bridge).

Section of the odontoid process by a shortened transverse ligament (a possible etiology for the mobile odontoid)

The authors propose a theory concerning the pathogeny of the mobile odontoid. They believe that this malformation could result from abnormal shortness of the transverse ligament of the atlas.

Continuous gas-depletion technique for measuring O2-dissociation curves of high-affinity hemoglobins

The O2-depletion technique allows a continuous measurement of the complete O2-dissociation curve of high-affinity hemoglobins in the O2-partial pressure range of 700 to 10(-4) mm Hg. With this technique p50 values greater than or equal to 0.01 mm Hg (approximately equal to 1.3 Pa) can be determined for 3-microliter hemoglobin samples. As examples, O2-dissociation curves of sperm whale myoglobin (p50 = 0.9 mm Hg, 25 degrees C, pH 8.0) and Dicrocoelium hemoglobin (p50 = 0.06 mm Hg, 25 degrees C, pH 4.9) are demonstrated which show Hill coefficients of n = 1.0 over the complete O2-saturation range.

CT of the main ligaments of the cervico-occipital hinge

The results of a CT-anatomical correlative study of the main ligaments of the cervico-occipital hinge are reported. CT criteria of normal ligamentous structure of this region are presented in axial, coronal and sagittal views with a special attention to the transverse ligament of the Atlas. Examples of pathological transverse ligaments are illustrated and emphasis is laid upon the better statement CT allows in such cases.

[Echographic study of the normal adrenal gland during development and in the adult]

An echographic study of the normal adrenal glands is realized on normal out patients, and anatomic slices. A comparison is made between echographic and anatomic images. This study demonstrates the image of the normal adrenal gland in the fetus, newborn and adult, and reveals a different echo pattern in the cortex (sonolucent) and the medulla (echogenic).

[Local thermal stress tolerance of human skin]

The local heat tolerance of human skin is investigated by the use of a thermostat-controlled heat-probe of 1 cm2 contact area. 43 degrees C is the highest skin temperature which is tolerated for about 8 hours with no restricted blood flow. The safe time of heat exposure is decreased to less than one half on increasing the temperature by one degree. Heat application at 44 degrees C skin temperature produces strong thermal injury of the skin within 8 hours. The heat exposure time without causing thermal injury is shorter at restricted blood flow.