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Biomedical subjects

A Ammar

Publications and source records attributed to A Ammar.

At least 55 records · Page 3Linked to original sources
PubMed1995

The presence of the antilingula and its relationship to the true lingula.

20 cadaver mandibles were studied for the presence of an antilingula and its relationship to the true lingula and mandibular foramen. Three independent observers evaluated the mandibles for the presence of an antilingula. It could be identified on all 40 sides. On 9 of the sides, there was complete concordance on the position of the antilingula between the three observers. On the other 31 sides, however, there was a variation between observers of up to 11 mm. In only 43% of the cases was the antilingula within 5 mm of the true lingula. In most cases, the true lingula was postero-inferior to the antilingula. There was a negative horizontal and positive vertical correlation between the position of the antilingula on one side and its position on the contralateral side.

Aged↗
PubMed1995

The relationship of the lingual nerve to the mandibular third molar region: an anatomic study.

PURPOSE: This study evaluated the relationship of the mandibular third molar to the lingual nerve. MATERIALS AND METHODS: An anatomic dissection of the lingual nerve in the third molar region was done on 20 cadavers (40 sides). RESULTS: The position of the nerve on one side bore no statistical relationship to the position of the nerve on the opposite side. The position of the lingual nerve was variable in both the sagittal and coronal planes. In two specimens the nerve lay superior to the lingual plate and in another the superior surface of the nerve was level with the crest of the lingual plate. CONCLUSION: These findings have implications for the avoidance of lingual nerve damage during surgery in the third molar and retromolar region of the mandible.

Cadaver↗
PubMed1995

Enzymatic antagonism of mivacurium-induced neuromuscular blockade by human plasma cholinesterase.

BACKGROUND: Mivacurium chloride is a bis-benzylisoquinolinium nondepolarizing neuromuscular blocking agent, hydrolyzed by butyrylcholinesterase (PCHE). The dose-response relationships for PCHE after mivacurium have not been studied. Therefore, this study was designed to establish dose-response relationships for PCHE as an antagonist of mivacurium-induced neuromuscular blockade. METHODS: Forty-eight physical status 1 adults were given 0.15 mg/kg mivacurium during fentanyl-thiopental-nitrous oxide-isoflurane anesthesia. Train-of-four (TOF) stimulation was applied to the ulnar nerve every 12 s, and the force of contraction of the adductor pollicis muscle was recorded. When spontaneous recovery of first twitch height (T1) reached 10% of its initial control value, exogenous PCHE equivalent to activity present in 2.5, 5, 7.5, 15, or 25 ml/kg of human plasma was administered by random allocation to 40 patients. Neuromuscular function in another eight subjects was allowed to recover spontaneously. Two blood samples were taken for determination of plasma cholinesterase activity. The first sample was taken before induction of anesthesia, and the second sample was taken when the TOF ratio had recovered to 0.75. Dibucaine and fluoride numbers were determined from the first assay. RESULTS: Administration of PCHE produced significant increases in PCHE activity in all patients. The larger the dose, the greater was the resultant plasma activity. Human PCHE produced a dose-dependent antagonism of mivacurium-induced neuromuscular blockade and the recovery times correlated inversely with PCHE activity (P < 0.01). The recovery of T1 was greater (P < 0.01) and time to attain a TOF ratio of 0.75 was shorter (P < 0.01) with any dose of PCHE than that observed in the spontaneous recovery group. After the administration of exogenous PCHE equivalent to activity present in 25 ml/kg of human plasma, recovery of TOF ratio to 0.75 or more was observed in all patients in less than 10 min and time to attain a TOF ratio of 0.75 was 55% shorter than the spontaneous recovery group (8.4 [7.1-9.7] vs. 18.7 [15.4-22] min; mean and 95% confidence intervals). CONCLUSIONS: Administration of exogenous PCHE equivalent to activity present in 25 ml/kg of human plasma (in a 65-kg patient, this dose is equivalent to PCHE activity of 1,625 ml of adult human plasma) resulted in reliable antagonism of mivacurium-induced neuromuscular blockade. Nevertheless, because of the prohibitive cost of this compound, this reversal modality is unlikely to have a routine practical application at this time.

Adolescent↗
PubMed1995

Melanin production in medullary thyroid carcinoma.

A case of melanin-producing medullary thyroid carcinoma is reported in a 51-year-old man. Histologically, the tumour had a typical pattern of medullary thyroid carcinoma with numerous scattered pigmented cells which contained large amounts of melanin pigment as confirmed by bleached Fontana-Masson stain. Immunohistochemical staining revealed positivity of almost all tumour cells for calcitonin and chromogranin, whereas S-100 protein and HMB-45 staining was positive only in the pigmented tumour cells. This finding confirms the ability of medullary thyroid carcinoma cells to have multidirectional differentiation, although melanocytic differentiation remains an exceptional phenomenon.

Amyloid↗
PubMed1995

[Microcystic adenoma of the pancreas].

Microcyst adenomas of the pancreas are rare tumours with characteristic cysts lining the cubic and cylindric epithelia with a clear cytoplasm rich in glycogen. Unlike, mucinous cyst adenomas, there is no tendency toward malignancy. We report a case in a 58-year-old woman and emphasize the importance of precise pre- or per-operative diagnosis in order to avoid excessive exeresis for benign tumour. Certain authors propose abstention and follow up.

Cystadenoma, Serous↗
PubMed1995

[Breast myoepithelioma. Report of a case].

Myoepithelial cell tumors of the breast are rare. They present diagnostic difficulties not only on frozen sections but also after fixation and paraffin embedding. These tumors can give rise to a wide range of clinical evolution... Treatment vary from simple excision for myoepitheliosis to mastectomy with axillary node dissection for malignant myoepitheliomas. Large excision is necessary for adenomyoepitheliomas because of the risk of recurrence and, more uncommonly, their proclivity to metastasis. We report the case of breast myoepithelioma in a 42 years old woman. The tumor was clinically, radiologically and macroscopically well demarcated. Histologically the tumor was composed of myoepithelial cells with few cellular atypias and a low mitotic activity. Tumor cells expressed vimentin, actin, S100 protein and cytokeratin. This particular immunohistochemical phenotype allows the differential diagnosis with other breast tumors.

Adult↗
PubMed1994

The spine in sickle cell disease.

Bone changes in sickle cell disease occur due to marrow hyperplasia, tissue ischaemia and infarction due to vaso-occlusion. Between 1982 and 1991 thirty four patients were treated in the Orthopaedic and Neurosurgery Departments of the Kind Fahd University Hospital, Al-Khobar, with spinal complications due to sickle cell disease. There were 21 males and 13 females aged between 4 and 28 years (mean 17.4 years). Structural changes in the vertebral bodies due to marrow hyperplasia occurred in 44% of the patients. Avascular necrosis leading to collapse of the vertebral bodies was seen in 9 (27%) patients. Infective spondylitis was the most serious complication seen in 8 (24%) patients; the majority needed anterolateral decompression and bone grafting. The spine is often affected in sickle cell disease and aggressive treatment with close follow-up is required to avoid disabling complications.

Adolescent↗
PubMed1994

Distribution of submental fat in relationship to the platysma muscle.

The results of submental lipectomy often remain suboptimal, and in some cases this may be due to the presence of residual fat deep to the platysma muscle. This study was undertaken to determine the relative amounts of fat superficial and deep to the platysma muscle. A dissection of the submental region of 20 cadavers revealed a mean weight of fat lying superficial to the platysma muscle of 8.4 grams. The mean weight of fat lying deep to the platysma muscle but superficial to the mylohyoid muscle was 3.7 grams. In three cases (15%), the weight of fat deep to the platysma muscle was greater than 50% of the total fat. This is of significance with respect to those submental lipectomy procedures that normally address only the fat superficial to the platysma.

Adipose Tissue↗
PubMed1994

Anatomic evaluation of anterior platysma muscle.

The structure of the submental platysma muscle was evaluated in 20 preserved cadavers. Four distinct patterns were identified, depending on the pattern of merging of the right and left platysma bundles. Fifteen percent of cases showed a complete platysma diaphragm submentally, while in the other 85% there was some degree of midline dehiscence. In the 85% of cases where right and left fibers merged or crossed to form a V or U shape, the apex of the V or U was measured relative to the chin point. The distance between right and left fibers was measured at two locations posterior to the chin point. The width of the midline dehiscence (when present) was 6-24 mm (mean 11.8 mm) 1 cm posterior to its apex and 10-44 mm (mean 20.00 mm) 2 cm posterior to the apex. The wider and more divergent the dehiscence and the more U-shaped the dehiscence between left and right platysma bundles, the greater may be the tendency to a "turkey gobbler" deformity with inadequate medial support for the skin and subcutaneous tissues.

Anthropometry↗
PubMed1994

Stroke in children: a study of 21 cases from Saudi Arabia.

Twenty-one cases of stroke were observed in children aged between 4 months and 15 years attending two large hospitals in Saudi Arabia over a 10-year period. The number constitutes two per cent of all cases of stroke managed in these hospitals during that period. Eleven cases were associated with cerebral arterial infarction, nine with cerebral haemorrhage and one with venous infarction. The main aetiological factors were attributable to embolism of cardiac origin, infections, coagulation disorders, haemoglobinopathies and arteriovenous malformations. Although stroke in children is regarded as rare, its relative frequency in Saudi society is probably higher than in western societies.

Adolescent↗
PubMed1994

Frog glomerular vasotocin receptors resemble mammalian V1b receptors.

Vasotocin receptors were investigated in glomeruli and nephron segments microdissected from collagenase-treated kidneys of Rana ridibunda, using [d(CH2)5Tyr(Me)2,Thr4,Orn8,125I-Tyr-NH2(9)]vasotocin (125I-OVTA) as a radioligand. Specific 125I-OVTA binding sites were found only in glomeruli and not in all tubule segments tested. Glomerular receptors exhibited the following stereospecificity for recognition of vasotocin analogues: Tyr-NH2(9)-LA-V1a > 125I-OVTA > arginine vasotocin (AVT) > or = [d(CH2)5Tyr-(Me)2]AVP > OVTA > or = [Phe2,Orn8]VT > oxytocin (OT) > or = [d(CH2)5-Sar7]AVP > desGly9[d(CH2)5Tyr(Et)2]VAVP > or = [d(CH2)5Tyr(Et)2]VAVP > AVP > [1-desamino-8-D-arginine]vasopressin (DDAVP) > [Thr4,Gly7]OT. In addition, vasotocin enhanced [3H]inositol phosphate production in sieved glomeruli labeled with myo-[3H]inositol; the rank order of structural vasotocin analogues for stimulation of phosphoinositidase C was [Phe2,Orn8]VT > AVT > OT > AVP > DDAVP, whereas [Thr4,Gly7]OT was almost inactive, and the rank order of antagonists for inhibition of hormone-induced enzyme activation was Tyr-NH2(9)-LA-V1a > [d(CH2)5Tyr(Me)2]AVP = OVTA > [d(CH2)5Sar7]AVP > [d(CH2)5Tyr(Et)2]VAVP > or = desGly9[d(CH2)5Tyr(Et)2]VAVP. Results indicate that the 125I-OVTA-labeled binding sites detected in frog glomeruli reveal the pharmacological properties of mammalian V1b-pituitary vasopressin receptors and might be physiological vasotocin receptors involved in phosphoinositidase C stimulation.

Animals↗
PubMed1994

Vimentinoma, an unusual neoplasm of the skin.

We report an unusual benign neoplasm that developed in a child. Tumoral cells were filled with vimentin intermediate filaments. No other features of differentiation were found by immunohistochemistry and electron microscopy. 'Vimentinoma' appears to be the most appropriate name for this neoplasm.

Child↗
PubMed1994

[Granular cell tumors of the breast. Apropos of two cases].

Granular cell tumors of the breast are rare. The clinical presentation, the poor macroscopical delimitation and the infiltrating appearance of the tumor cells between the mammary lobules and within the adipose tissue may lead to a diagnosis of carcinoma, especially on frozen section. The authors present two cases of granular cell tumor of the breast occurring in two women aged 19 and 59 respectively. Before surgery, the diagnosis was that of a malignant tumor. In both cases, frozen section suggested the diagnosis of a granular cell tumor, which was confirmed by immunohistochemical study in one patient.

Adult↗
PubMed1994

[Tumoral calcinosis: a clinical and pathological study of 8 cases reported in Tunisia].

Tumoral calcinosis is a distinct clinicopathological entity characterized by periarticular soft-tissue calcium deposits. It is a rare condition in Tunisia (8 cases during 23 years). Six patients were aged 14 years or younger. There was male predominance (SR: 7/1). Lesions were located about the hip in five patients and the elbow in three patients. Multiple localisations occurred in two patients. Histologically, all cases exhibited active phase of the disease. In our patients lesions were only surgically excised.

Calcinosis↗
PubMed1994

[Synovial sarcoma. Anatomoclinical aspects apropos of 8 cases].

Synovialosarcoma is a rare tumor, of difficult diagnosis. Authors report 8 cases diagnosed in the two pathology departments of Salah Azaïz Institute and the Universitary Hospital of Sfax, from 1985 to 1991. This tumor represents 2.96% of all soft tissues sarcomas treated in Salah Azaïz Institute. It occurs in young adults (the average age in our series: 28.8 years) with a male predominance (6 out of 8 cases), localized preferentially in the lower extremity. In the histological study, immunohistochemistry provides a great contribution in the diagnosis and classification of these tumors. The histoprognosis grading of Trojani applied to our cases shows the good correlation between the grade and the prognosis. Treatment is primarily surgical, consisting in wide excision to avoid recurrences that are unfortunately very frequent. Radiotherapy and chemotherapy give very inconstant results. Some authors recommend radiotherapy to sterilize the tumor field, and chemotherapy to prevent metastasis. The clinical course is characterized by a high frequency of local recurrences and pulmonary metastases.

Adolescent↗
PubMed1993

IL2-R alpha chain inhibitory factor (p29) produced by HIV-infected macrophages: cell target and mode of action.

We recently reported that HIV-infected adherent cells spontaneously produce a 29-kDa protein (p29), most probably of nonviral origin, which inhibits expression of the IL2R alpha chain on activated normal T cells. Studying the mode of action of this molecule, we observed that monocyte depletion of normal PBMC either by plastic adherence or by complement-mediated cytotoxicity using macrophage-specific monoclonal antibodies abrogated the inhibitory effect of p29. The biological activity of p29 in adherent cell-depleted PBMC could be restored either with rIL1 or with as little as 10(5) autologous adherent cells/ml. Moreover, p29 could not inhibit IL1 biologic activity, nor its binding to IL1 receptor. In addition, p29 could not inhibit the production of IL1 and TNF alpha by normal adherent cells. Positive and negative cell sorting of normal T cells as well as two-color immunofluorescence studies revealed that CD8+ subsets are the main cell targets of p29, which also mediated an impaired generation of alloantigen-specific CTL. Conversely, only a slight inhibitory activity could be detected in highly purified CD4+ cells. Our findings suggest that HIV-induced production of p29 inhibitory factor by adherent cells may be involved in mechanisms responsible for some of the impaired cytotoxic functions observed in AIDS patients.

CD8 Antigens↗