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Biomedical subjects

M K Khalil

Publications and source records attributed to M K Khalil.

At least 19 recordsLinked to original sources
PubMed2005

Using computer-based interactive imagery strategies for designing instructional anatomy programs.

In an effort to design and implement effective anatomy educational programs, this study was conducted to evaluate students' perceptions toward using two computer-based self-directed instructional modules (e.g., digestive system and canine skull) that were designed utilizing interactive imagery strategy for teaching and learning veterinary anatomy. Sixty-eight freshmen veterinary students and one graduate student participated in this study. Open-ended and close-ended questionnaires were administered to evaluate the utilization of computer-based interactive imagery strategy in developing anatomy instructional programs, and to collect data about the students' perceptions toward the use of interactive images in teaching and learning of anatomy. Means and standard deviations were calculated and analyzed for close-ended items. The open-ended questionnaire items were analyzed to identify shared patterns or themes in the students' experience after using the two instructional anatomy modules. Students reported positive attitudes toward the interactive imagery strategy used in the development of computer-based anatomy modules. Based on our findings, this study outlines the characteristics of effective instructional images that will serve as guidelines for the preparation and selection of anatomical images, as well as, how to utilize these images to develop computer-based instructional anatomy programs. Students perceived interactive imagery as an effective design strategy that helped them learn anatomical concepts.

Adult↗
PubMed2005

Comparison of computer-based and paper-based imagery strategies in learning anatomy.

This study evaluated the use of computer-based interactive imagery on students' achievement scores when compared with paper-based static imagery. It also assessed students' perceptions about the two imagery strategies and their different components. Sixty-four freshmen veterinary students (50 females, 14 males), enrolled in a comparative anatomy course, volunteered to participate in the study. This study used a pretest/posttest comparison group design and data was examined by analysis of covariance (ANCOVA). A close-ended questionnaire was administered to collect students' perceptions about the two imagery strategies. The mean difference in students' perceptions between the two strategies was analyzed using a two-tailed paired t-test. No significant differences were observed between computer-based interactive imagery and paper-based static imagery in the immediate recall of anatomical information. There was a significant difference in students' opinions toward the two strategies: students perceived computer-based interactive imagery as a better strategy in the assimilation of anatomical information than paper-based static imagery.

Anatomy, Comparative↗
PubMed2000

Vaccines: World Health Organization versus Federal Drug Administration recommended formula.

Vaccines produced in accordance with WHO formulas, differ in concentration from those used in United States according to FDA formulas. We aimed to compare the immunogenicity of both formulas. Infants who were 6 weeks old were randomly put into 3 groups to receive 3 doses of vaccines at 6 weeks, 3 months and 5 months of age. The vaccines consisted of Haemophilus influenzae type b vaccine, diphtheria-tetanus-pertussis and oral polio vaccine. Antibody levels for polyribosylribitol phosphate (PRP), tetanus, diphtheria and poliovirus were measured 1 month after the third dose of vaccines. Although diphtheria and tetanus antigens in the FDA formula are half the concentration of the WHO formula, anti-tetanus and anti-diphtheria antibodies were significantly higher. No difference was found between groups regarding oral poliovirus vaccine.

Antibodies, Bacterial↗
PubMed1999

Postnatal differentiation of the ductus deferens, tail of the epididymis, and distal body of the epididymis in goats occurs independently of rete testis fluid.

Observations from extratesticular rete-ligated, mature goats indicated that epithelial morphology in the tail of the epididymis can be maintained without any input from testicular fluid (Goyal et al., Acta Anat., 1994;150: 127-135). Hence, the objective of this study was to determine whether the tail of the epididymis and/or other regions of the male excurrent ducts can differentiate prior to the appearance of lumen in the seminiferous tubules, which is an indicator for the onset of seminiferous tubular fluid secretion. Based on age and scrotal circumference (SC), 20 male goats were divided into four groups of five animals each: 1-4 weeks (SC, 6.5-7.5 cm), 7-10 weeks (SC, 8.5-11.0 cm), 12-15 weeks (SC, 11.0-14.0 cm), and 15-25 weeks (SC, 16.0-19.0 cm). Tissues were collected from the testis, six regions of the epididymis (proximal, middle and distal head; proximal and distal body; and tail), and the ductus deferens, and were processed for light and electron microscopic examination. Changes in epithelial height and cytological features associated with absorption (microvilli, pinocytotic and coated vesicles) and protein secretion (RER, Golgi body) were used as markers for differentiation. Differentiation of all of these features was comparable to that observed in the 15-25-week-old animals in the ductus deferens by > or = 1 week, in the tail of the epididymis by > or = 7 weeks, in the distal body of the epididymis by > or = 12 weeks, and in the proximal body of the epididymis and all three regions of the head of the epididymis by > or = 15 weeks. Seminiferous tubules developed lumens between 12 and 15 weeks. In conclusion, epithelial differentiation in the ductus deferens, tail of the epididymis, and distal body of the epididymis follows a time-dependent, spatial, ascending order and is achieved before lumen formation in the seminiferous tubules. Conversely, epithelial differentiation in all three regions of the head and the proximal body of the epididymis occurs simultaneously and after lumen formation in the seminiferous tubules.

Age Factors↗
PubMed1999

Orbital infarction and melting in a patient with systemic lupus erythematosus.

OBJECTIVE: To present a patient with systemic lupus erythematosus who developed infarction and melting of the orbit secondary to her systemic disease. DESIGN: A case report. PARTICIPANT: A 61-year-old white woman with a 5-year history of systemic lupus erythematosus. METHODS: The patient presented with left orbital pain, limitation of extraocular movements, and a fistula from the ethmoid sinus to the upper eyelid. A detailed examination with computerized tomography, ultrasound, and a comprehensive medical evaluation with laboratory testing was performed. Histopathologic analysis with special stains of the orbital tissues was also performed. RESULTS: Histopathologic examination of the biopsy specimens revealed the features of an inflammatory process involving the orbit, similar to a panniculitis. These include a lymphocytic reaction with a predominance of plasma cells, vasculitis with occlusion, and thickening of the vessel walls, necrosis, and hyalinization of fat. CONCLUSION: This is a unique case in which infarction and melting of the entire orbital structures occurred in the presence of systemic lupus erythematosus. The underlying disease process is a lupus-related panniculitis. The authors stress that this is a very rare entity and that other diseases should be ruled out before entertaining this diagnosis.

Eye Diseases↗
PubMed1998

Regulation of androgen and estrogen receptors in male excurrent ducts of the goat: an immunohistochemical study.

BACKGROUND: Since androgens and/or estrogens must bind with specific receptors in order to elicit a response at the target organ(s), it is important to understand factors that regulate expression of androgen receptors (AR) and estrogen receptors (ER). Hence, the objective of the study is to determine the relative significance between circulating androgen (CA) and luminal androgen (LA) in maintaining normal expression of AR and ER in male excurrent ducts. METHODS: Mature Nubian goats were subjected for 15 days each to the following treatments: (1) bilateral orchidectomy, (2) bilateral orchidectomy and testosterone treatment, (3) unilateral ligation of the extratesticular rete, and (4) unilateral orchidectomy. Tissues from different segments of the excurrent ducts were fixed in 4% paraformaldehyde and embedded in Paraplast-plus. Antigenic sites for AR and ER were immunolocalized using PG-21 rabbit antirat/human antibody and H-222 rat antihuman monoclonal antibody, respectively. The avidin-biotin horseradish peroxidase procedure was used to identify positive immunoreactivity. Negative controls included incubation of sections with irrelevant IgG in place of primary antibody. RESULTS: In intact animals, whereas AR were found in epithelial, connective tissue, and peritubular smooth muscle cells of the efferent ductules, regions I-V of the epididymis, and ductus deferens, ER were confined to nonciliated cells of the efferent ductules. Bilateral orchidectomy caused a severe loss of both AR and ER staining. Testosterone replacement to orchidectomized animals restored staining of both AR and ER to the intact level. Neither unilateral ligation of the extratesticular rete nor unilateral orchidectomy had any effect on AR or ER immunostaining. CONCLUSION: Circulating androgen alone, without any input from luminal androgen or other rete fluid contents, can regulate expression of both androgen receptor and estrogen receptor.

Animals↗
PubMed1997

Immunolocalization of androgen receptor and estrogen receptor in the developing testis and excurrent ducts of goats.

BACKGROUND: Because of the significance of androgens and estrogens in prenatal and postanatal differentiation of the testis and excurrent ducts, it is important to understand the developmental pattern of androgen receptor (AR) and estrogen receptor (ER) in these organs. METHODS: Tissues from 1-23-week-old goats were fixed in 4% paraformaldehyde and embedded in Paraplast-plus. Antigenic sites for AR and ER were immunolocalized using the PG-21 rabbit anti-rat/human antibody and the H-222 rat anti-human monoclonal antibody, respectively. The avidin-biotin horseradish peroxidase procedure was used to identify positive immunoreactivity. Controls included incubation of sections with irrelevant IgG in place of primary antibody. RESULTS: Within the testis, immunostaining for AR in the nuclei of Sertoli cells increased gradually from mild at week 1 to strong at week > or = 19. In contrast, nuclei of peritubular myoid cells and Leydig cells exhibited moderate to strong reaction for AR in all animals. Germ cells were negative. Within the rete testis, efferent ductules, regions I-V of the epididymis, and ductus deferens, nuclei of all epithelial cells, peritubular myoid cells, and intertubular connective tissue cells expressed moderate to strong staining for AR at all ages. ER were confined to nonciliated cells of the efferent ductules, which displayed moderate staining in all animals, beginning from week 1. CONCLUSIONS: Nuclear AR staining, found in all testicular cells (except germ cells) and excurrent duct cells examined, was observed to change in an age-related manner only in Sertoli cells, where staining intensity increased between week 1 and week 19. Staining for ER, confined to nonciliated epithelial cells of the efferent ductules, was not affected by postnatal age.

Animals↗
PubMed1987

Neurotropic malignant melanoma of right temple with orbital metastasis: a clinicopathological case report.

A case is reported of neurotropic melanoma developed from a superficial spreading melanoma with minimal cytological deviation, situated in the right temple. The nine-year course was clinically characterised by local recurrences, involvement of the orbit and the parotid region via neurogenic invasion, and systemic metastases to lung, seventh rib, and the brain. The histopathology was characterised by fascicles of dysplastic spindle cells, neuroid arrangement in loose fibrillary matrix, and peri- and intraneural permeation of the nerve trunks. Despite minimal atypism the neoplasm metastasised and had a fatal outcome. The spindle cell component of the neurotropic melanoma lacked melanogenesis; Fontana stains were negative. As previously demonstrated, the histogenesis of the neurotropic melanoma is possibly a Schwann cell differentiation of the dysplastic atypical melanocytes, as shown by the positive reactions to Bodian's stain.

Bone Neoplasms↗
PubMed1986

Lens-induced inflammations.

The authors report six cases of lens-induced inflammations that help to illustrate the wide variability and clinical overlap of these conditions. Using cytological and histopathological findings, they attempt to clarify the confusion surrounding the terminology used to label these inflammations, and outline the immune factors responsible for them. With the recent upsurge in extracapsular cataract surgery, it is important to consider lens-induced inflammations in the differential diagnosis of any postoperative uveitis or endophthalmitis.

Adult↗
PubMed1983

Balloon cell malignant melanoma of the choroid: ultrastructural studies.

I reported the clinical, pathological, and ultrastructural findings in 2 cases of balloon cell malignant melanoma of the choroid. Degradation of the melanosomes of the tumour cells appeared to be the primary biological disturbance in the cell organelles, followed by secondary increase in intracellular lipid secretion and accumulation, leading ultimately to the formation of the balloon cells. Despite the fact that balloon cells are indicative of degeneracy and impending necrosis of the tumour cells, metastases were present in both cases. One of the conclusions this article provides is that the presence of balloon cells does not alter the prognosis of malignant melanomas of the choroid.

Aged↗
PubMed1983

Subhyaloid hemorrhage in osteogenesis imperfecta tarda.

The clinical characteristics of osteogenesis imperfecta are the result of a defect in the collagen fibrils. This paper presents a case of osteogenesis imperfecta tarda in which a large subhyaloid hemorrhage occurred. This complication, which has never before been reported in the literature, could be the result of a deficiency of collagen in and around the blood vessels of the eye.

Adult↗
PubMed1982

Histopathology of presumed ocular histoplasmosis.

A 46-year-old man with the clinical picture of presumed ocular histoplasmosis had its right eye removed because of an associated choroidal malignant melanoma. Histopathologically, the choroidal foci disclosed the different stages of inflammatory evolution; from granulomatous foci with caseation, macrophages, and giant cells, to nongranulomatous lesions composed of lymphocytes, and finally to the healing stage of fibrohyaline scarred lesions. The granulomatous lesions contained PAS-positive and Grocott-positive bodies and dead Histoplasma organisms. Electron microscopy demonstrated that the dead fungi did not disappear from the tissue and were detected nine years after the initial infection.

Adult↗
PubMed1981

Meningioma and the ophthalmologist: diagnostic pitfalls.

In seven patients with intracranial meningioma whose presenting signs and symptoms were ophthalmologic the underlying problem was initially misdiagnosed. Three patients had sphenoidal meningiomas with compression of the anterior visual pathways, but the initial diagnoses were acute optic neuritis, chronic optic neuritis and glaucoma. Two other patients had large frontal meningiomas causing in one case unilateral pain and swelling of the upper lid plus ptosis and hypotropia, and in the other case bilateral frontal morning headaches and intermittent blurring of vision in one eye; they were thought to have a frontal lobe osteoma and migraine respectively. A sixth patient had a large parietal meningioma causing unilateral papilledema in an eye with a corneal graft; the papilledema was not initially recognized because of severe astigmatism in that eye. The last patient had an occipital meningioma that had caused a fixed homonymous field defect and many years of "classic migraine".

Adult↗
PubMed1980

Eye manifestations in medullary carcinoma of the thyroid.

Multiple endocrine adenomatosis type III (MEA--III) in a 32-year-old white woman is reported. The initial manifestation, a thyroid nodule, was detected at the age of 4 years. The characteristic ocular manifestation of MEA--III are discussed.

Adrenal Gland Neoplasms↗