Biomedical subjects

M Girgis

Publications and source records attributed to M Girgis.

At least 19 recordsLinked to original sources

PubMed1992

Evaluation of Klippel-Trenaunay syndrome with radionuclide total body angiography. A case report.

A 21-year-old Italian woman with extensive Klippel-Trenaunay syndrome (KTS) developed recurrent pulmonary embolism in spite of the insertion of a Greenfield filter in the inferior vena cava. Clinical and radiologic diagnostic tests failed to demonstrate the pathway of the emboli. Radionuclide venography and intravenous radionuclide total body arteriography were performed. These radionuclide procedures helped to evaluate the extent of KTS and to detect the route of the emboli. This is the first case of KTS studied with intravenous total body arteriography reported in the literature.

Adult↗

PubMed1989

The interface between bone, soft tissue, and dental implants.

The normal healing responses of soft tissues and bone to injury, including the sequence of cellular activity, are presented. The nature of the attachment of the implant to the biological tissues may be either poorly differentiated fibrous tissue or direct anchorage in vital bone (preferred). Attachment by a highly differentiated periodontal ligament is presently not possible. The gingival seal has been found to be similar to that around the natural tooth. Commercially pure titanium is one of the best materials to use in terms of its biological compatibility with bone; polymers, carbons and controlled surface, i.e. active bioglasses, are also satisfactory. A porous low modulus coating is useful. Design of the implant and force transfer, as well as surgical treatment are among the important factors that determine how the interface will develop.

Alveolar Process↗

PubMed1981

Electrical versus cholinergic kindling.

The present investigation was designed to test the hypothesis that cholinergic neurones may constitute a critical element in the neuronal circuitory of kindling. Chemitrodes implanted in monkey and rabbit brain enabled both electrical and chemical stimulations of limbic structures. The results indicated that only few electrical kindling stimuli produce prolonged supersensitivity to intracerebrally injected physostigmine. A subsequent electrical stimulus continues the kindling progression. The cholinergic supersensitivity persists for a long time and is only suppressed by intramuscular injections of scopolamine. These findings fit best with the hypothesis that participation of muscarinic cholinergic receptors may be an important requirement of the kindling process. It appears likely that similar types of mechanisms are involved both in chemical and electrical kindling.

Amygdala↗

PubMed1980

Psychotic depression: the common therapeutic principle.

Cholinergic prevalence together with a monaminergic deficit characterize the neurotransmitter imbalance underlying psychotic depression. Correction of this neurotransmitter imbalance is the principal purpose and goal of all treatment methods for the relief of psychotic depression. This can be accomplished by reducing the acetylcholine predominance or increasing the level of monaminergic functioning, or a combination of both approaches. The antidepressant tricyclic drugs combine a central anticholinergic action with an aminergic potentiating function. Electroconvulsive therapy is effective through activation of both cholinergic and aminergic systems, with removal of excess acetylcholine into the cerebrospinal fluid. Psychiatric surgery restores neurotransmitter balance by blocking excessive acetylcholine synthesis and activity.

Acetylcholine↗

PubMed1978

Neostigmine activated epileptiform discharge in the amygdala: electrographic-behavioral correlations.

This investigation was carried out to test the hypothesis that amygdaloid epileptiform activity is due to cholinergic hyperactivity. It was designed to study the underlying physiopathology of, and to act as an experimental model for, psychomotor epilepsy. Neostigmine was injected intracerebrally into the amygdala of the cebus monkey with chronically implanted "chemitrodes" fitted with EEG recording electrodes. The injections were made in the basal amygdaloid nucleus which normally shows very high acetylcholinesterase (AChE) enzymatic activity in histochemical preparations. Neostigmine injection resulted in very high amplitude spike activity in the amygdala only. Other brain areas, including the neighboring temporal cortex, did not show any marked EEG changes. In the first day or two, these EEG changes were associated with myoclonus localized in the ipsilateral muscles of facial expression and also associated with masticatory seizures. Subsequently the animal became aggressive and remained so several months after the injection of neostigmine. The EEG changes continued for approximately 6 weeks. Intramuscular injections of atropine diminished the amplitude of the epileptiform EEG discharges and modified slightly the animal's behavior.

Aggression↗

PubMed1977

Social implications of the "dyscontrol syndrome" (neuropsychiatric correlates).

The recent literature contains numerous publications which have tried to stimulate a new and biologically oriented approach to the problem of violence. Experimental brain research indicates that biologically important predatory and aggression responses have multiple representations in the nervous system. However, knowledge gained so far concerning emotional brain function in violent persons with brain disease, or from experimental research, can only infrequently be applied to combat the violence-triggering mechanisms in the brains of the non-diseased. In the hope of determining the neurological basis of aggression, the present author studied the brains of forty-two patients whose clinical history indicated definite aggressive behaviour. Results are reported and discussed. It is also the aim of this paper to discuss the social implications of the surgical treatment of patients with a "dyscontrol syndrome" whose investigations do not reveal definite evidence of "hard" signs and symptoms of brain pathology.

Aggression↗

PubMed1974