This work presents an investigation of the experimental measurements that carried out to study the
breakdown threshold dependence on gas pressure in the breakdown of molecular oxygen by a Nd: YAG laser source
operating at wavelengths 1064 nm with a pulse duration of 5.5 ns over a gas pressure range varies between 190-
3000 torr. The study is devoted to find out the role played by the physical processes in determining the threshold
intensity of molecular oxygen breakdown as a function of gas pressure. In doing so a previously developed electron
cascade model is modified and applied. The modification assigned the inclusion of an electron diffusion term to
account for electron losses out of the focal volume on the experimentally tested low pressure regime. Besides, the
model takes into account most of the physical processes which might take place during the interaction between the
laser beam and the oxygen molecules. The result of computations showed reasonable agreement between the
calculated threshold intensities and the experimentally measured ones over the tested gas pressure range. This
proves the validity of the model. In addition the study of the performed of the electron energy distribution function,
EEDF, and its correlated parameters viz, temporal evolution of: electron density, excitation rate, ionization rate and
electron mean energy as well as the variation of the EEDF during the laser pulse verified the exact correlation
between gas pressure and the physical process responsible for the production and loss of electrons or their energy
during the breakdown phase.

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The effect of methyl alcohol poisoning on blood gases and serum electrolytes in addition to its effect on the ultrastructure of the retina were estimated in male albino rats. A significant increase in potassium level and pCO2 was accompanied by depletion in pO2. Sodium and chloride levels were unchanged. A calculated increase in anion gap was due mainly to the increase of potassium level.
Methyl alcohol also effected edema of all layers of the retina, fragmentation and ultrastructural changes of the photoreceptor outer segments, agglomeration of chromatin, dissolution of Nissl granules, swelling and degeneration of mitochondria. These necrotic changes were attributable mainly to the hypoxic state caused by the toxin and possibly aggravated by the resultant acidosis.

The effect of one month treatment with Hydrochlorothiazide (HCT); Captopril, angiotensin converting enzyme inhibitor (ACEI), Diclofenac, nonsteroidal anti-inflammatory drug (NSAID) and their different combinations was studied in DOCA-salt hypertensive rats (HR). It was observed that HCT causes a reduction of serum sodium, potassium and creatinine levels concomitant with an increase in serum aldosterone. Captopril also reduced serum sodium and creatinine but increased serum potassium and had no effect on aldosterone. The administration of HCT with Captopril produced a simple additive interaction, thus reducing serum sodium and creatinine, prevented hyperaldosteronism and reversed the hypokalemic effect induced by HCT. On the other hand, Diclofenac alone exerted a significant increase in serum sodium and creatinine while its biosynthesis of renal and/or extrarenal prostaglandins which are compounds known to modulate the vasoconstrictive effect of norepinephrine and to represent important mediators for the activation of the renin-angiotensin-aldosterone system (Brown et al., 1986). Moreover, Brown et al. (1986) reported that sodium retention is a characteristic effect of virtually all NSAIDs.

Male albino rats were administered methyl alcohol in their drinking water as 2,4 ad 6% solutions for four weeks. Methyl alcohol concentration was determind in the sera of rats after 1,2 and 4 weeks and was found too increase significantly.

Retinal tissue was removed at similar time intervals for histopathologic and histoenzymologic examination. The retinal damage was directed at the photoreceptors primarily and the neuronal elements. A significant finding was the loss of outer layers of the retina after prolonged methyl alcohol intake. Succinic dehydrogenase (SDH) increased and NAD-linked lactate dehydrogenase (LDH) decreased indicating enhanced aerobic glycolysis and depressed anaerobic glycolysis. Acid phosphatase (ACP), alkaline phosphatase (ALP) and adenosine triphosphatase (ATPase) activities were notably increased in the pigment epithelium, choroid and sites of enzyme activities in the retina. The increase in ALP and ATPase in the pigment epithelium may be attributable to the increased demands of the retina for metabolic exchange and reflect modified membrane permeability induced by the toxin.

Adult peripheral blood contains a limited number of endothelial progenitor cells that can be isolated for treatment of ischemic diseases. The adipose tissue became an interesting source of stem cells for regenerative medicine. This study aimed to investigate the phenotype of cells obtained by culturing adipose-derived mesenchymal stem cells (ad-MSCs) in the presence of endothelial growth supplements compared to endothelial cells obtained from umbilical cord blood (UCB). Passage 3 ad-MSCs and mononuclear layer from UCB were cultured in presence of endothelial growth media for 3 weeks followed by their characterization by flow cytometry and polymerase chain reaction. After culture in endothelial inductive media, ad-MSCs expressed endothelial genes and some endothelial marker proteins as CD31 and CD34, respectively. Adipose tissue could be a reliable source for easy obtaining, expanding and differentiating MSCs into endothelial-like cells for autologous cell-based therapy.

Although animal research ethics committees (AREC) are well established in Western countries this field is weakly developed and its concept is poorly understood in the Middle East and North Africa region. Our main objective was to establish the first animal ethics committee to introduce the concept and requirements of ethical approaches in dealing with experimental animal models in Egypt.
To achieve this we established our standard operating producers (SOP) according to international
guidelines. Our SOP constituted the AREC responsibilities, committee member
s selection, evaluationprocedures emphasizing the regional cultures, etc. T
he challenges encountered by the committee were diverse such as the absence of laws that control the
use of animal models in scientific research, lack of guidelines (protocols for animal subjects in research) and mandatory ethical approval for any experimental animal research. To ov ercome the challenges, high univer
sity authorities were approached
to approve the establishment of an AREC committee.
Moreover, workshops were instigated in different
universities to: 1) emphasize the legal requirement
of animal research ethics approval; 2) describe the guidelines how ethical evaluation of scientific proposal will be carried out; 3) facilitate interaction with best practices and research experts and 4) teach young researches how to write protocol involving the use of animal subjects in research. In three months, we were able to conduct three workshops after each workshop questionnaire and evaluation was obtained to overcome weak points.

Objectives: To evaluate the levels of some parameters related to bone metabolism during pregnancy i.e. total calcium (CA), 1,25-dihydroxyvitamin D (Vit.D), parathormone hormone (PTH), phosphorous, osteocalcin, total acid phosphatase and its tartrate resistant isoform (TrACP), total alkaline phosphatase (TALP) and its isoenzmes activities, total protein, albumin, globulin in sera and haemoglobin in blood in a group of egyptian pregnant women who are living in cairo and under reasonable medical care.
Cases: The study was conducted on 33 healthy pregnant women (age range from 20 to 38 years) and 16 healthy non-pregnant women within the same age range to serve as controls. Twenty blood samples were collected from the pregnant women at the end of first trimester of pregnancy (Week-11), twenty four were collected at the end of third trimester (Week-38).
Results: Regarding the osteoblastic activity, the T.ALP was significantly increased due to placental T.ALP and to a lesser degree to bone ALP, while osteocalcin levels. Showed a non significant increment in the 1st and 2nd trimesters of pregnancy with significant increase in the 3rd trimester of pregnancy .concerning the osteoclastic activity, The TrACP isoform decreased significantly in the 2nd trimester of pregnancy, Then returned to the normal values of non-pregnant control levels. Women in the last trimester of pregnancy have higher estrogen level than any other time of life. Although, estrogens at physiologic concentration inhibit osteoclastic activity, hight estrogen concentration increases osteoclastic activity.
As regards the factors that responsible for calcium homeostasis, significant decrease in serum intact PTH was concurrent with significant increase in Vit.D. The total serum calcium level was significantly decreased through the pregnancy, while the ionized calcium did not change, and the serum phosphorus was highly significantly increased.
Conclusion: From these results it has been concluded that, the pregnancy imposes major changes in the mother's nutritional requirement and causes physiological alternation in maternal bone metabolism. Minimal changes affecting the bone turnover were demonstrated among egyptian women throughout pregnancy due to the nutritional statue of the women and thier supplementation with Ca and/or Vit.D. Also,the changes in the haemodynamic parameters of the mother may be due to heamodilution that occur during pregnancy. The obtained patterns showed that the egyptian women who are living in urban areas (e.g. cairo), and under reasonable medical care are in good health compared to other communities in which the nutritional status and the poor medical care are the main reasons for the dramatic changes in the bone metabolism.