MCNP5 evaluation of photoneutron production from the Alexandria University 15 MV Elekta Precise medical LINAC.

Photoneutron production, and the dose equivalent, in the head assembly of the 15 MV Elekta Precise medical linac; operating in the faculty of Medicine at Alexandria University were estimated with the MCNP5 code. Photoneutron spectra were calculated in air and inside a water phantom to different depths as a function of the radiation field sizes. The maximum neutron fluence is 3.346×10-9 n/cm2-e for a 30×30 cm2 field size to 2-4 cm-depth in the phantom. The dose equivalent due to fast neutron increases as the field size increases, being a maximum of 0.912 ± 0.05 mSv/Gy at depth between 2 and 4 cm in the water phantom for 40×40 cm2 field size. Photoneutron fluence and dose equivalent are larger to 100 cm from the isocenter than to 35 cm from the treatment room wall.

Toxicity of the Red Sea pufferfish Pleuranacanthus sceleratus "El-Karad".

The pufferfish Pleuranacanthus sceleratus (El-Karad) represents serious public health problems, because of its responsibility for many incidents in Egypt, especially in the Suez Gulf. In the present study, samples of this fish were collected monthly and the toxins were extracted from gonads, liver, digestive tract, muscles, and skin, then purified and identified using TLC and electrophoresis. The alkaline hydrolyzates of these toxins were also detected using UV absorption and GC-mass spectra of their trimethylsilyl derivatives.

Nucleolus organizer region heteromorphism in patients with Down syndrome and their parents.

The study aimed to evaluate the role of nucleolus organizer region (NOR) heteromorphism as an etiological factor for parental nondisjunction in Down syndrome by comparing 25 patients affected by Down syndrome, and their parents with a control group of 80 non-affected Egyptians. All parents had normal karyotypes. The average modal number per parent of Ag-positive NORs was significantly higher in parents than controls. A significant difference in the size of the double-NOR variants (dNORs) was found. The mean maternal and paternal ages were significantly lower, with a significant increase in spontaneous abortions, for dNOR(+) couples compared with dNOR(-) couples.

A diagnostic clinical genetic study of craniofacial dysmorphism.

A diagnostic evaluation of craniofacial anomalies, either isolated or as part of a genetic syndrome was conducted on 25 patients (8 females, 17 males), age range 2 months to 47 years. Complete genetic examination, pedigree analysis, anthropometric measurements and radiological studies were carried out. Cytogenetic studies included fluorescence in situ hybridization (FISH) when indicated. In all, 15 patients had chromosomal abnormalities. Five patients had unbalanced chromosome rearrangements and six had chromosome markers. Three patients were FISH-positive for William syndrome and one was positive for Prader-Willi syndrome. Ten patients had monogenic disorders. Five were diagnosed as craniosynostosis syndromes. We conclude that minor features are useful for making a diagnosis of congenital anomalies.

Nucleolus organizer region heteromorphism in patients with Down syndrome and their parents

The study aimed to evaluate the role of nucleolus organizer region [NOR] heteromorphism as an etiological factor for parental nondisjunction in Down syndrome by comparing 25 patients affected by Down syndrome, and their parents with a control group of 80 non-affected Egyptians. All parents had normal karyotypes. The average modal number per parent of Ag-positive NORs was significantly higher in parents than controls. A significant difference in the size of the double-NOR variants [dNORs] was found. The mean maternal and paternal ages were significantly lower, with a significant increase in spontaneous abortions, for dNOR[+] couples compared with dNOR[-] couples

Autosomal recessive disorders among patients attending the genetics clinic in Alexandria

A total of 660 patients referred to the genetics clinic, Medical Research Institute, Alexandria were assessed to determine the frequency of genetic disorders and the proportion of autosomal recessive disorders. It was found that 298 [45.2%] patients had genetic disorders, 100 [33.6%] of whom had an autosomal recessive disorder; these included 32 patients with metabolic defects, 18 with haemoglobinopathies and 50 with syndromes and single defects. The frequency of consanguinity among parents of patients with autosomal recessive disorders was high [60%, with 48% first cousins]. The average inbreeding coefficient was higher [0.03] than that reported for the Egyptian population in general [0.01]

Chromosome anomalies in normal androgenized infertile males.

Chromosome anomalies are known to play a role in human infertility. Chromosome analysis of 103 normal androgenized infertile azoospermic (97.1%) or oligospermic (2.9%) males revealed that the frequency of chromosomal abnormalities was 8.7%. Two patients (1.94%) had a 46,XX chromosome complement, one patient (0.97%) had a 45,X karyotype, two patients (1.94%) had a 45,XY,t(13;14)(p11;q11) karyotype, one patient (0.97%) had a 46,XY,inv(9)(p12;q13) chromosome constitution, two patients (1.94%) had a 46,XY,del(Y)(q12) karyotype, and one patient (0.97%) had a 45X/46,X+marker the nature of which was not clarified.

Duplication 3q(q21----qter) without limb anomalies.

We report on a 2.5-month-old boy with hypertelorism, hypertrichosis, anteverted nostrils, malformed ears, thin lips, downturned corners of the mouth, micrognathia, short neck, cryptorchidism, and bilateral simian creases without limb anomalies. Cytogenetic studies showed a duplication 3q----qter 46,XY,der(6),t(3;6)(q21;p25)pat. The absence of limb anomalies is noteworthy; all 12 previously reported patients with the same duplication had limb anomalies. The uniqueness of this report provokes speculations regarding limb morphogenesis in embryos with chromosome anomalies. The concepts of chronogenetics, heterochrony, and developmental field defects appear relevant to yet another set of patients with chromosome anomalies.