Effect of prenatal administration of therapeutic doses of topiramate on ossification of ribs and vertebrae in rat fetuses.

There are few studies that have addressed the effects of prenatal exposure of topiramate on ossification of the bones derived from the paraxial mesoderm. This study aimed to evaluate skeletal ossification of ribs and vertebrae in 20-day-old rat fetuses after maternal exposure to two therapeutic doses of topiramate. Three groups of Sprague-Dawley pregnant rats were used: control, topiramate 50 mg/kg/day and topiramate 100 mg/kg/day treated groups. Topiramate was administered by gavage from day 6-19 of gestation. Fetuses were collected on day 20 by caesarean section. Fetal bones were stained with alizarin red and ossification was assessed. Results showed significant delayed ossification of ribs and vertebrae in topiramate-exposed fetuses at both doses and the effects were not dose dependent. In all examined groups, there was a direct correlation between the fetal weight and the number of complete ossified vertebral centers. Also, there were significant increases in skeletal abnormalities, particularly in ribs in both treated groups when compared to the control group. In conclusion, therapeutic doses of topiramate should be taken cautiously during pregnancy as they lead to fetal growth restriction and increases abnormalities of axial skeleton in rat fetuses.

Incidence and ossification of sesamoid bones in the hands and feet: a radiographic study in an Arab population.

The incidence and ossification of sesamoid bones in the hands and feet were studied in 922 radiographs (400 hands and 522 feet) in an Arab population from Bahrain, 5-83 years of age and consisting of 549 adults (393 men and 156 women) and 373 children (286 boys and 97 girls). All radiographs of the hand and foot in the adult population showed two sesamoid bones in the thumb metacarpophalangeal (MCP) joint and in the hallucal metatarsophalangeal (MTP) joint, respectively. Only 2.3% and 1.5% of hands showed sesamoids at the MCP joints of the middle and ring fingers respectively compared to a reported incidence of 7.1% for each digit in Caucasians. The incidence of sesamoids in the MTP joints of third and fourth toes (0.6% each) and inferior to the hallucal interphalangeal joint (3.1%) is probably the lowest reported so far in the literature. In the hands, ossification commenced first in the thumb sesamoids, at the age of 10 years in females and 11 years in males and was completed by the age of 13 and 14 years, respectively. In the feet, ossification began first in the hallucal sesamoids at the age of 8 years in females and 9 years in males and was completed by the age of 10 years in both sexes. The incidence and ossification of sesamoids in the hands and feet in the Arab population from Bahrain seem to differ considerably from reports in other populations. The clinical significance of our findings is discussed.

The membranous layer of superficial fascia: evidence for its widespread distribution in the body.

A discrete membranous layer, "stratum membranosum", in human subcutaneous tissue is classically described as confined to the lower anterior abdominal wall and perineum and referred to as Scarpa's and Colles' fasciae, respectively. Evidence for its existence elsewhere in the body is scanty and therefore the present study was undertaken. Dissection of six embalmed adult cadavers, along with ultrasound imaging on four living subjects, were carried out to determine the existence, topography, and thickness of the membranous layer of superficial fascia in different regions of the body. In all six cadavers, a continuous layer of fibrous membrane in the superficial fascia was found consistently in all the dissected regions of the body and was also confirmed by ultrasonography. The arrangement and thickness of this membranous layer varied according to body region, body surface, and gender. It was thicker in the lower than in the upper extremity, on the posterior than anterior aspect of the body, and in females than in males. The mean thickness of the membranous layer ranged from 39 to 189 mum, being thickest in the leg and thinnest over the dorsum of the hand. The membranous layer was observed to have two or even three components in regions such as the breast, back, thigh, and arm and was seen to split, forming special compartments around subcutaneous major veins of upper and lower extremities, with fibrous septa extending to attach to the vessel wall. Functionally, the membranous superficial fascia may play a role in the integrity of the skin and support for subcutaneous structures particularly veins, by ensuring their patency. Understanding the topographic anatomy of this fascial layer may help explain body-contour deformities and provide the anatomic basis for surgical correction.

The hamate facet of the lunate: a radiographic study in an Arab population from Bahrain.

Based on the presence of a facet for the hamate two types of lunate bone have been described in the wrist; type I is without a facet for the hamate while type II bears a facet on the medial surface for articulation with the proximal pole of the hamate. Compared to type I lunates, type II lunates have been shown to have different kinematics, are more prone to clinically relevant degenerative changes in the hamato-lunate joint and may cause ulnar-sided wrist pain. The incidence of type II lunates seems to vary in different populations. Postero-anterior (PA) view of plain radiographs of the hand was studied in Arab subjects from Bahrain (n=381; 307 males and 74 females) to determine the incidence of type I and type II lunates. The mean age of the subjects was 31.1 years, the range being 18-80 years. In the population studied, only 148 (38.8%) of the 381 wrists showed type II lunate; 121 (31.7%) were found in males and 27 (7.1%) in females. There was no significant difference in the mean age of subjects with type I or type II lunates (P=0.16). There was no correlation between side and gender with the presence or absence of a hamate facet on the lunate. The incidence of type II lunate was much lower than reports in the literature of populations from the Western world, which could be attributed to a genetic variation in the Arab population in Bahrain. These data indicate that osteoarthritis of the hamate or lunate is less likely to be a cause of ulnar-sided wrist pain in Bahraini Arabs.

Integrating applied anatomy in surgical clerkship in a problem-based learning curriculum.

Little attention has been given to structured teaching of applied anatomy to senior medical students in problem-based learning (PBL) medical schools. A course named "Anatomical Principles in Surgical Practice" was introduced at the Arabian Gulf University (AGU) in 2001 for fifth- and sixth-year medical students during their surgical clerkship rotation. The course aims to emphasize, update and integrate applied anatomical concepts that are essential for surgical practice. The course consists of 15 interactive sessions held weekly to ensure topics coincide with the surgical problem-solving sessions. A questionnaire was administered to students completing their surgical rotations (n = 131) seeking their perceptions about the new course during the academic years 2001, 2002 and 2003. To measure learning outcome, 70 students were also given pre- and post-tests. Positive responses were given by 85.2% of the students for course arrangement, by 92.0% for course content, by 88.3% for clinical correlation, by 95.2% for level of teaching and by 87.2% for overall judgment. The students' mean scores in the post-test (71.7%+/-11.7) was significantly higher than their mean scores in the pre-test (42.3%+/-12.6, p < 0.001). Students liked the course and reported feeling more confident in correlating anatomy with surgery during their rotations. By extending anatomical teaching into the clerkship phase, a link between basic medical and clinical sciences has been established that further enhances vertical integration within a PBL curriculum in a spiral fashion.

Thymic proliferative response during different physiological states: a comparative study.

OBJECTIVE: To study the thymic proliferative response during different physiological states to distinguish those changes due to alterations in steroid hormone secretion from those resulting from the presence of spermatozoa and/or early conceptual products in the female reproductive tract. METHOD: Using mature female rats of an inbred AO(RT1(u)) strain, observations on the thymus were made at 24 hour intervals during the oestrous cycle, early pseudopregnancy and early syngeneic pregnancy. Each daily group contained a minimum of 6 animals. RESULTS: During the oestrous cycle, a significant mid-cycle increase of thymocyte proliferation occurred during dioestrus which peaked on day 2, and as a repetitive response may be a preparation for a coital challenge. This response may be oestrogen-dependent since oestrogen levels begin to increase during early dioestrus. The induction of pseudopregnancy generates a comparable but delayed increase in thymic proliferative activity. Since thymocyte proliferation and oestrogen secretion both peak on day 3 of pseudopregnancy, such a response may indeed also be oestrogen-dependent. After syngeneic mating, there was a significant depression in thymic proliferative activity on day 3 followed by a significant increase on day 5 compared with the same days of pseudopregnancy. CONCLUSION: This initial depression of proliferative activity may be induced by the immunosuppressive action of seminal plasma, to safeguard the preimplantation conceptus while the day 5 increase in cellular proliferation suggests a response to implantation.

Attitudes and reactions of Arab medical students to the dissecting room.

A questionnaire on the emotional and psychological reactions of Arab medical students to the dissecting room (DR) was distributed to 272 students in four successive pre-clinical and clinical years in the same academic year (1993-1994) at Sultan Qaboos University (SQU) Medical College; 205 students responded. Varying degrees of fear on first entering the DR was reported by 46%. The most frequent reactions were recurring visual images of cadavers (total 38%) and temporary loss of appetite (total 22.5%). Students' reactions were most commonly elicited by the smell of the DR (total 91%) and by fear of infection (total 62%). The most frequent method of coping with such fears was by rationalization (total 65%). Significant gender differences (P < 0.05) were found concerning all aspects of the DR experience. Female students showed higher levels of fear, reported stronger physical and behavioral reactions, were more disturbed by certain stimuli in the DR, and used certain coping methods more frequently than their male peers. The need for appropriate psychological preparation of students before studying human cadaveric anatomy is discussed.

Effect of blood substitute, recombinant hemoglobin, on in vivo hematopoietic recovery from AZT toxicity.

We determined the in vivo ability of infused human recombinant hemoglobin 1.1 (hr-Hb) and erythropoietin to rescue the hematopoietic activity from the suppressive effects of AZT in normal and in a murine model of AIDS (MAIDS) mice. Mice were fed with AZT for 8 weeks with or without treatment in the last 4 weeks by administering various concentrations of hr-Hb and/or erythropoietin (Epo). Blood parameters, body weight (BW) and erythroid burst-forming units (BFU-E) for all mice were determined. AZT-treated normal and MAIDS mice showed a significant decrease in hematocrit (64 and 78.1%), hemoglobin (27.2 and 45.5%), BW (17.5 and 35.5%), number of white (66.9 and 42.1%) and red blood cells (65.5 and 38%), and the number of BFU-E (73 and 59%), whereas the AZT-treated normal and MAIDS mice that received hr-Hb (5 mg/kg BW/day) and/or Epo (2 U/mouse/day) showed significant alleviation of AZT cytotoxicity. This was evident by the recovery in all blood indices examined, the number of BFU-E and the BW of mice treated. BFU-E recovery in MAIDS (97%) was greater than that in normal mice (63%) as compared to their controls. hr-Hb produced a similar response as the combination, however recovery was slightly better with the latter in some hematological parameters. Higher concentrations of hr-Hb (10-15 mg) did not result in a more significant increase in most blood indices. Our results indicate that infusion with hr-Hb can alleviate AZT toxicity in normal and in immunodeficient mice, and that hr-Hb may be clinically useful in preventing severe bone marrow depression brought about by various drugs or agents such as AZT.

Brachial plexus palsy and spinal subarachnoid pneumatosis following trauma.

The case of a 33-year-old male involved in a road traffic accident, resulting in brachial plexus palsy associated with subarachnoid pneumatosis, is described. A knowledge of the regional anatomy at the root of the neck is used to explain the patient's neurological signs and the mechanism of entry of air into the subarachnoid space.

Studies on haemolymph nodes. IV. Comparison of the route of entry of carbon particles into parathymic nodes after intravenous and intraperitoneal injection.

Haemolymph nodes are found in certain mammals including man. In the rat they are located near the kidneys, spleen and thymus. A distinctive feature is that their sinuses contain numerous erythrocytes. For renal and splenic haemolymph nodes, the erythrocytes appear to be extrinsic in origin, entering the node via its afferent lymphatics (Hogg et al. 1982; Abbas et al. 1983). In the present study we investigated the drainage of carbon particles injected intraperitoneally or intravenously into the parathymic haemolymph nodes. Carbon particles injected intraperitoneally reached the nodes rapidly, within minutes and in large quantities, via the afferent lymphatics draining principally from the diaphragmatic peritoneum. Carbon particles injected intravenously entered the nodes much more slowly, reaching a maximum after 5-7 d, and in much smaller amounts, although the pattern of distribution was similar, spreading from the subcapsular sinus into the intermediate and medullary sinuses. No carbon particles were found crossing the walls of high endothelial venules. Carbon particles injected intravenously reach the parathymic nodes from peripheral lymph via the afferent lymphatics. Whilst accepting that there are significant biological differences between carbon particles and erythrocytes it seem possible that erythrocytes, like injected carbon particles, may enter the nodes by a similar route.

The role of the diaphragm in lymphatic absorption from the peritoneal cavity.

Lymphatics in the diaphragm form a specialised system draining fluid from the peritoneal cavity and returning it to the vascular system. Fluid enters subperitoneal lymphatic lacunae, between muscle fibres of the diaphragm, the lacunae being separated from the peritoneal cavity by a barrier comprising, successively, lymphatic endothelium, a layer of collagenous fibres, a thin fenestrated layer of elastic tissue, and the peritoneal mesothelium. To reach the lacunae, peritoneal fluid passes through stomata located between cuboidal mesothelial cells of the lacunar roof. Whilst the distribution of mesothelial stomata and subjacent lymphatic lacunae varies in different species, stomata appear to be exclusive to the diaphragm and may serve as the main drainage channels for absorption from the peritoneal cavity. Clinically, they may provide escape for tumour cells, pathogens and toxins from the peritoneal cavity. They could provide access for blood transfusions, for intraperitoneal chemotherapy to treat malignancies, and for peritoneal dialysis in treating chronic renal failure. From the lacunae, fluid traverses the diaphragm via intrinsic lymphatics to reach collecting lymphatics beneath the diaphragmatic pleura. Both intrinsic and collecting lymphatics contain valves. The collecting lymphatics drain principally into retrosternal (parasternal) lymphatic trunks that carry lymph to the great veins after it filters through mediastinal lymph nodes.

Assessment of basic medical sciences in an integrated systems-based curriculum.

Basic medical sciences at Sultan Qaboos University (SQU) are taught in a systems-based curriculum. During the development of the courses different formats have been used for the written examinations and also different types of questions. This paper compares students' performance in relation to examination format and to types of questions used. The formats were non-coordinated (NCAs), each discipline having a separate paper; coordinated (CAs), questions from various disciplines being given in the same paper but with separate sections for each discipline; and integrated assessments (IAs), questions being grouped under structure, function, and problem-based integrated long essays. The types of questions used were multiple choice (MCQs), short essays (SEQs), and structured integrated long essays (SILEQs). Students performed better in SEQs than in MCQs. Our analyses also show that SILEQs measure skills similar to those of MCQs and SEQs combined. Students performed best in NCAs. In CAs, students concentrated on those disciplines carrying most weight in the final grade. Currently we use IAs consisting of two parts: part I, comprising MCQs and SEQs, and part II, comprising SILEQs. To date, students are performing better in part II than in part I. We suggest that it is prudent to use different types of questions to measure students' knowledge and skills when IAs are used for systems-based courses.

Hemopoietic recovery from AZT toxicity with recombinant hemoglobin in a murine model of AIDS.

We studied the toxic effects of azidothymidine (AZT) on the hemopoietic colony growth (CFU-E, BFU-E and CFU-GM) of bone marrow in a murine model of AIDS (MAIDS). A sparing effect by recombinant hemoglobin (r-Hb) on AZT suppression of MAIDS bone marrow was found when 10 microM of r-Hb was included in bone marrow cultures. The AZT toxicity dose response curve showed that at a concentration of 0.1 microM, AZT inhibited CFU-E by 66%, BFU-E by 55% and CFU-GM by 67%. The addition of r-Hb (10 microM) to AZT-treated cultures stimulated CFU-E, BFU-E and CFU-GM by 89, 125 and 160%, respectively, as compared with AZT-treated (control). The addition of r-Hb to non AZT-treated cultures showed further stimulation of CFU-E, BFU-E and CFU-GM to 100, 160 and 187% of the control, respectively. These results indicate that exogenous r-Hb reverses AZT-induced hemopoietic toxicity and may prove to be useful in ameliorating AZT toxicity in immunosuppressive diseases.

Bilateral extensor medii digiti: a rare anatomical variation.

A supernumerary extensor muscle to the middle finger was found to be present bilaterally in a male cadaver. It originated from the distal end of the ulna and its tendon inserted into the proximal phalanx of the middle finger. The bilateral presence and manner of insertion appear to be unique from a review of the literature. Morphological variability and clinical significance are reviewed. Such variations may be clinically significant during hand surgery, especially tendon transfer procedures.

Extensor pollicis tertius: an additional extensor muscle to the thumb.

This is the first reported case in the literature of an extra extensor muscle and tendon to the right thumb. It was discovered during routine dissection of a male cadaver. The muscle originated from the dorsal surface of the lower third of the ulna immediately proximal to the origin of the extensor indicis proprius. Its tendon, after passing through the dorsal fourth synovial compartment, turned obliquely and laterally to insert independently into the base of the proximal phalanx of the thumb. The common origin of the muscle with the deep forearm extensors and their common nerve supply suggest a common embryologic origin. For precise descriptive purposes, the name extensor pollicis tertius is proposed. A knowledge of the existence of such anatomic variation may be useful in surgical identification and in planning tendon repairs and/or transfers.