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Biomedical subjects

M A Mandour

Publications and source records attributed to M A Mandour.

16 recordsLinked to original sources
PubMed1995

Broncho-alveolar lavage in chronic upper respiratory tract infections.

The relationship between upper and lower respiratory tract infections has been demonstrated previously, although the effect of chronic infection of one tract on the other has not been well studied. This work analyses the broncho-alveolar lavage fluid of patients with chronic purulent rhino-sinusitis and reveals an increase in total and neutrophil cell counts as well as an increase in immuno-globulin A levels. The associated increase in the neutrophil nitro-blue tetrazolium dye reduction test positivity provides evidence for increased phagocytosis to compensate for the increased contamination of the lower respiratory tract.

Adolescent↗
PubMed1983

Characteristic functions of point monodirectional electron beams.

Narrow electron beams with approximately Gaussian radial fluence distributions were extracted from a clinical 42 MeV betatron by means of a special multi-diaphragm lead collimator with either 3 or 7.5 mm diameter of the effective diaphragm. From each narrow beam the dose distribution in water, was measured with an automated scanning system, and the corresponding dose distribution of the point monodirectional source was obtained by deconvolution. As a reference, the fluence distribution in air at the same distance z was used, corrected for multiple scattering in air where necessary. At 10, 20 and 40 MeV, non-linear pear-shaped curves for the root mean square radial excursion, sigma(z), as functions of the depth, with maxima of 12, 19.7 and 27.8 mm at about 70 per cent of the practical range were obtained. The second characteristic function, I(z), the integral of the dose over the transverse plane at depth z, was obtained from the measured broad beam depth dose curve and the associated transverse dose distributions.

Computers↗
PubMed1979

Changes in the lower respiratory epithelia induced by oestrogen intake. An experimental histopathological study.

Fifty-eight male and non-pregnant female guinea pigs with an average weight of 400 gm were used in this work, ten animals as a control group, the remaineder receiving oestrogen in the form of ethanyl oestradiol in a dose of 10 microgram/animal/day. Histopathological studies were carried out after periods of one, two, three, four and eight weeks, and three, six and twelve months respectively. The respiratory mucosa, at the different levels mentioned, showed definite changes. The surface epithelium showed metaplastic changes with mitotic figures, until complete and definite stratifications were reached. The cilia decreased and then disappeared completely, while the mucus-secreting goblet cells showed an initial augmentation in number and increased activity, followed by a gradual decrease in their number, until total disappearance occurred at the stage of stratification in the surface epithelium.

Animals↗
PubMed1979

The ceruminous glands in chronic suppurative otitis media. A histological and histochemical study.

The ceruminous glands have been studied histologically and histochemically in twenty patients suffering from chronic suppurative otitis media with discharging ears, and in ten patients with dry central perforations, in comparison with normal ears. The present study revealed hyperactivity of the glands initially; later on, atrophy and fibrosis took place. Thus the diminution of wax may be due to: (1) The washing effect of the discharge. (2) Atrophy of the glandular structures. (3) Periglandular fibrosis. As the discharge stops, regeneration of the glands occurs.

Acid Phosphatase↗
PubMed1978

Systematic optimization of the double-scatterer system for electron beam field-flattening.

The scattering foil widely used for field flattening in electron therapy produces a distortion of the electron spectrum which significantly reduces the slope of the descending part of the depth dose curve. It is already known that this effect can be drastically reduced by replacing the scattering foil by a two-foil scatterer. The second foil, fit with a radial thickness profile, acts as a compensator, attenuating the central part and enhancing the peripheral part of the beam by electron scattering. Calculations of the optimal foil combinations and radial thickness profiles are presented and numerical values of smooth (Gaussian) and three-step profiles for various field sizes are provided. The results are applicable to a variety of electron energies and scattering foil materials.

Electrons↗
PubMed1978

[Calculation of the dose distribution of high-energy electrons within and behind tissue inhomogeneities of any width. II. Influence of multiple scattering (author's transl)].

The algorithn proposed in 1976 to allow for the influences of tissue inhomogeneities in electron beam dose distributions has been improved. A factor adopted from Sternheimer corrects for differences in lateral displacement by multiple scattering within the inhomogeneity resp. the equivalent layer of the homogeneous medium. The algorithm has been tested by direct comparison with Monte Carlo computations for the example of cylindrical cavities in carbon at Eo=10 MeV and resulted in a very close approximation.

Carbon↗
PubMed1977

Effect of tympanic neurectomy on human parotid salivary gland. Histopathologic, Histochemical, and Clinical Study.

Five patients with bilateral chronic recurrent parotiditis and ten patients with unilateral persistent paratoid gland fistulas underwent tympanic neurectomies. Two biopsy specimens from the diseased gland were examined. The first biopsy specimen was taken at the time of operation, while the second one was taken six months later. All specimens were subjected to both histopathologic and histochemical investigations. Definite degenerative and atrophic changes occured in all parotid gland specimens taken six months after selective tympanic neurectomy. All patients were completely cured at about that time. This supported the practical indication of the selective tympanic neurectomy for treating certain benign disorders or diseases of the parotid gland that require persistent arrest of the function of its secretory units.

Atrophy↗
PubMed1976

Tympanic neurectomy for parotid fistula.

Complete excision of the trophic secretomotor parasympathetic nerve supply of the parotid gland produces abolition of its salivary secretion and ends in atrophy of the gland units. We report 20 patients treated by tympanic neurectomy to relieve the distressing problem of parotid fistulas. The tympanic nerve was identified and excised at its appearance through the hypotympanic floor. In seven of our cases, we found an early division of the main nerve that crossed the promontory anteriorly-hence, the importance of excising the tympanic nerve as proximal as possible. All patients observed for more than two years had complete dryness and cure of their fistulas. We describe the basis of tympanic neurectomy and its results compared with other forms of treatment.

Adolescent↗
PubMed1976

[Calculation of dose distribution of fast electrons within and behind tissue inhomogeneities of any width].

A new algorithm allowing for the effects of tissue inhomogeneities on dose distributions of high-energy electrons is presented for the purposes of treatment planning computations. Starting from the electron dose distribution for homogeneous tissue the doses contributed by the partial beam hitting the tissue inhomogeneity are substituted by those arising from a partial beam which was alterated by stopping, scattering and changed distances in the inhomogeneity. Since actual data for partial beams of limited cross-section are used and the scatter contributions from the rest of the total beam into and behind the inhomogeneity remain unchanged, good approximation compared to measured values is achieved.

Electrons↗
PubMed1975

The effect of oestrogen on the nasal respiratory mucosa. An experimental histopathological and histochemical study.

An experimental histopathological and histochemical work carried out in thirty guinea-pigs of an average weight of 475 gm. receiving oestrogen in the form of ethynyl oestradiol in a dose of 10 microgram/animal/day and aiming at a study of the effects of oestrogen on the respiratory nasal mucosa. The histopathalogical lesions of the respiratory nasal mucosa were in the form of squamous metaplasia and spongiosis of the lining epithelium, with oedema of the underlying corium, glandular hyperplasia submucosal cellular infiltration, increased vascularity and some vascular changes in the form of endothelial proliferation with intimal thickening. Histochemical enzymatic alterations were in the form of increased succinic dehydrogenase activity in the epithelium as well as in the hyperplastic submucous glands, intensified reaction of the acid phosphatase in the cells of the corium, and the appearance of alkaline phosphatase activity in the apical parts of the cells lining the glands, indicating increased secretory activity. All the changes obtained in the histopathological and histochemical studies can be attributed to hormonal stimulation of the nasal mucosa.

Acid Phosphatase↗
PubMedDate not supplied

[Effects of neurectomy of the tympanic plexus on secretion of the parotid gland in man. Histopathological, histochemical and clinical study (author's transl)].

This study involved five patients suffering from bilateral chronic parotiditis and then with a persistent unilateral fistula of the parotid gland. Two types of parotid biopsy were examined: the first taken during surgery and the second six months later. All of the specimens underwent histopathological and histochemical investigations. Definitive degeneration and atrophic type changes were seen in all the parotid fragments removed six months after selective neurectomy of the tympanic plexus. Six months after surgery, all of the patients were cured.

Atrophy↗