Neutralisation of Local Haemorrhage Induced by the Saw-Scaled Viper Echis carinatus sochureki Venom Using Ethanolic Extract of Hibiscus aethiopicus L.

The objective of the study is to investigate the anti-snake venom activities of a local plant, Hibiscus aethiopicus L. The H. aethiopicus was dried and extracted with ethanol. Different assays were performed according to standard techniques, to evaluate the plant's acute toxicity and its antivenom activities. The results of evaluating the systemic acute toxicity of the H. aethiopicus extract using "oral and intra-peritoneal" route were normal even at the highest dose (24 g/kg) tested. All guinea pigs (n = 3) when treated with venoms E. c. sochureki (75 µg) alone induced acute skin haemorrhage. In contrast, all guinea pigs (n = 18) treated with both venom and the plant extract at a concentration between 500 and 1000 mg/kg showed no signs of haemorrhage. Moreover, all guinea pigs (n = 18) treated with venom and the plant extract below 400 mg/kg showed acute skin haemorrhage. All guinea pigs treated with venom E. c. sochureki (75 µg) alone induced acute skin haemorrhage after both 24 and 32 hours. In contrast, all guinea pigs treated with both venom and the plant extract (administered independently) at concentrations between 500 and 1000 mg/kg showed no signs of haemorrhage after 32 hours. However, after 24 hours all tested guinea pigs showed less inhibition (<60%) compared to that obtained after 32 hours. The outcome of this study reflects that the extract of H. aethiopicus plant may contain an endogenous inhibitor of venom induced local haemorrhage.

Antibacterial activity of Lawsonia inermis Linn (Henna) against Pseudomonas aeruginosa.

OBJECTIVE: To investigate the antibacterial activity of henna (Lawsonia inermis Linn) obtained from different regions of Oman against a wide array of micro-organisms. METHODS: Fresh henna samples were obtained from different regions of Oman as leaves and seeds. 100 g fresh and dry leaves and 50 g of fresh and dry seeds were separately soaked in 500 mL of ethanol for three days, respectively, with frequent agitation. The mixture was filtered, and the crude extract was collected. The crude extract was then heated, at 48 °C in a water bath to evaporate its liquid content. The dry crude henna extract was then tested for its antibacterial activity using well-diffusion antibiotic susceptibility technique. Henna extracts were investigated for their antibacterial activity at different concentrations against a wide array of different micro-organisms including a laboratory standard bacterial strain of Pseudomonas aeruginosa (NCTC 10662) (P. aeruginosa) and eleven fresh clinical isolates of P. aeruginosa obtained from patients attending the Sultan Qaboos University Hospital (SQUH). 2-Hydroxy-p-Nathoqinone-Tech (2-HPNT, MW=174.16, C10H6O3) was included as control (at 50% concentration) along with the henna samples tested. RESULTS: Henna samples demonstrated antibacterial activity against all isolates but the highest susceptibility was against P. aeruginosa with henna samples obtained from Al-sharqyia region. CONCLUSIONS: Omani henna from Al-sharqyia region demonstrates high in vitro anti-P. aeruginosa activity compared with many henna samples from different regions of Oman.

Circadian rhythm and the immune response: a review.

For long, the immune system has been thought of as an effector mechanism reacting to antigenic challenge with defensive responses designed to eliminate 'foreign' material and return to a standby or surveillance mode. However, the recent concept now supported by substantial evidence suggests that immunity is not effector biased but is also a sensory organ and forms part of an integrated homeostatic network. The bidirectional information flow between the neuroendocrine and immune systems functions to maintain and protect the internal homeostasis of the organism. The paradox of this interwined function is that homeostasis may require the neuroendocrine system to work for or against the immune system, as is the case in infection. Potential dangers necessitate activation of the immune system, and such a response may pose risks to the integrity of the host. This occurs when an overly vigorous response may be detrimental and kill the host, as is the case of toxic shock syndrome. Therefore, the constant monitoring role of the neuroendocrine system to control and, when necessary, regulate the function of the immune system is crucial for the homeostatic integrity of the host. This reciprocity of functional need determines the mode of action to determine the context of a perceived threat and the best way to respond. Any breakdown in this two-way communication may manifest itself in problems such as autoimmunity, septic shock, or chronic infection. In this article, we review our current knowledge of circadian rhythm and its relation to the immune response.

Acardia syndrome coexisting with gastroschisis in the co-twin.

Acardia syndrome is a rare complication affecting monozygotic twins, wherein one twin fails to develop brain and thoracic structures, while the co-twin most often develops normally. In this report we present an acardiac anencephalic monozygotic twin with an omphalocoele and a co-twin with severe intrauterine growth retardation and gastroschisis. The presence of gastroschisis in the co-twin of an acardiac foetus is rare. The embryologic basis of the twin reversed arterial perfusion (TRAP) sequence is outlined and the observed anomalies in the co-twin traced to a similar pathophysiology.

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.

Teaching of human anatomy: a role for computer animation.

Computer-assisted learning fulfils an important need for pictorial representation of the functions of organs and systems. The various computer techniques of animation and morphing provide promising horizons for medical educational technology. Image acquisition is one of the most resource-intensive components of animation sequence development. Images can be drawn as originals or can be copied/scanned from various sources. By standardizing the initial (starting) image to the particular/basic need of the teacher and projecting the end-point image by using a vector animation package, 'films' can be created to demonstrate any form of movement. In the Anatomy Department, Sultan Qaboos University in Muscat, computer-animated tutorials are being introduced to illustrate normal and abnormal functional anatomy. The heart and its valve mechanisms have been selected as a pilot study. The student response is very positive and the technique has great potential. Embryology animations showing the formation and growth of organs such as the brain and spinal cord are also being developed.

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.

The immune response to coitus and conception.

It is well recognized that cells or tissues exchanged between genetically dissimilar members of the same species will be destroyed by a specific immune response. This process of destruction is initiated by the expression of histocompatibility antigens on the surface of the donor cells which provoke a reaction by the immune system of the recipient. Successful reproduction even through a fundamental process is thought to expose the female to significant antigenic challenge. Numerous hypotheses have been proposed to account for the survival of the semiallogeneic conceptus, although the immunological consequences of coitus are frequently ignored. The possible immunosuppressive role of seminal plasma in normal reproduction is clearly of great clinical importance. Its exclusion from the in vitro fertilization techniques of human reproduction may partially account for the high failure rates associated with this form of assisted reproduction. Its presence in the normal ejaculate may explain the vulnerability of the female reproductive tract to virally inducted neoplasms and be a relevant factor in the etiology of the acquired immune deficiency syndrome.

An increase in thymocyte proliferation during pseudopregnancy in two inbred strains of rat.

Coitus is a unique physiological event which may result in internal fertilization, whereby active allogeneic spermatozoa are presented to the female host which can invade her tissues. Sterile coitus on the other hand, stimulates the uterine cervix in the rat and induces a physiological state of pseudopregnancy which interrupts the normal pattern of the oestrous cycle and establishes a persistent dioestrous state. This state is hormonally controlled and in its early stages is not dissimilar from that of true pregnancy. Pregnancy hormones are known to influence the immunological status of the female. Thymic observations during early pseudopregnancy showed interstrain differences in weight, cell content and thymocyte proliferation. Pooled data indicated increased cell density on days 3, 4 and 5 of pseudopregnancy associated with a peak of mitotic activity on day 3 in both strains. The timing of this proliferative activity seems to reflect the needs of the immune system in its putative response to mating and implantation.

Lymphoid tissue changes during early syngeneic pregnancy in the RT1u rat.

An active immunological response by the female to mating and pregnancy is important, if not essential, to successful reproduction. Alloantigens which have been demonstrated on spermatozoa include histocompatibility antigens. In the enigmatic success of the fetal allograft, the conceptus survives owing to failure of the mother either to initiate or complete the process of rejection. In this study, AO(RT1u/AgB2) female rats were caged with male rats of the same strain. Observations were obtained from the first 5 days of their postcoital period, identifying lymphoid tissue changes which are due to the presence of the ejaculate and early products of conception in the female reproductive tract. A significant increase in intrathymic proliferation by day 3 is thought to be a hormonal effect induced by the cervical stimulation at mating. The postcoital exodus of lymphocytes from the thymus is possibly in response to coitus and induced by the seminal plasma to safeguard the implanting conceptus.

Cellular proliferation in the lymphoid tissues of an inbred (RT1a) rat strain during the oestrous cycle.

Changes in body weight, uterine weight and tissue weight, cell content and cellular proliferation of the thymus and uterine regional and popliteal lymph nodes were examined at daily intervals during the oestrous cycle of the DA (RT1a) inbred rat strain. Thirty-nine sexually mature virgin animals, aged between 13 and 15 weeks were used in this investigation. During dioestrus body weight and uterine weight fell significantly, while intrathymic and intranodal cellular proliferation increased significantly. These findings are discussed in relation to ovarian hormone secretion and it is suggested that increased thymocyte and lymphocyte proliferation occurs in response to rising oestrogen levels. This proliferative response prepares the female for the immunological challenge with allogeneic spermatozoa should mating occur during the subsequent oestrous phase.

A dioestrous increase in thymocyte proliferation during the oestrous cycle.

Coitus, which precedes internal fertilisation, is a unique physiological event which allows motile allogeneic spermatozoa to enter the female host and invade her tissues. The cyclic cellular proliferation observed in the thymus of the female rat may be an important preparation of her immune system for this event.