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Biomedical subjects

M Orenstein

Publications and source records attributed to M Orenstein.

11 recordsLinked to original sources
PubMed1999

Optical vortices crystals: spontaneous generation in nonlinear semiconductor microcavities

Broad-area, vertical-cavity surface-emitting lasers were shown to switch their emission mode from the regular single or multilobed light fields to exhibit complex arrays of "dark beams." Examination of these dark spot arrays revealed that they consist of multiple, closely packed optical vortices: optical fields that have phase singularities and show increased complexity as the injection current level is raised. Contrary to their complex appearance, most of these light distributions are not the result of a multimode (multiple-frequency) operation but exhibit single-frequency characteristics. The dark beam patterns can be described as emanating from a spontaneous process of transverse mode locking of nearly degenerate modes, assisted by the laser nonlinearity. Surprisingly, these patterns show high resemblance to patterns generated in other nonlinear scenarios that are completely different both in scale and in mechanism.

Journal Article↗
PubMed1990

The locked-in syndrome: a review and presentation of two chronic cases.

The locked-in syndrome (LIS) is a state of an upper motor neurone quadriplegia involving the cranial nerve pairs with usually a lateral gaze palsy, paralytic mutism, full consciousness and awareness by the patient of his environment. A historical presentation of the LIS is given as well as a short description of the clinicoanatomic lesion causing LIS. The usual cause is vascular and corresponds to a pontine infarction due to an obstruction of the basilar artery but other lesions in the brainstem can also be the cause. Non-vascular aetiologies, especially traumatic, are reviewed. The use of electroencephalography (EEG), brain auditory evoked potentials (BAEP) and somesthesic evoked potentials (SEP) are discussed as well as the use in the acute stage of computed tomography (CT), angiography, and magnetic resonance imagery (MRI). The last method may show well delineated ischaemic lesions some time after the event. The communication disability is probably the most difficult to overcome. Two cases of LIS are presented.

Adult↗
PubMed1990

[A post-traumatic locked-in syndrome with delayed onset].

We report a case of locked-in syndrome occurring two days after a cranio-cervical trauma in a 28 years old male patient. It was a consequence of basilar thrombosis after left vertebral artery dissection secondary to a vertebral fracture at the C6 level. Decerebrate rigidity and apparent unconsciousness led to misdiagnosing it for post traumatic coma. It took several days to correct this mistake. To avoid this pitfall, we insist on the clinical features of this syndrome and discuss which investigations are needed and which therapy is available.

Accidents, Traffic↗
PubMed1986

Value of bronchoalveolar lavage in the diagnosis of pulmonary infection in acquired immune deficiency syndrome.

Seventy five patients with pulmonary disease and suspected acquired immune deficiency syndrome (AIDS) underwent fibreoptic bronchoscopy with bronchoalveolar lavage. Of 54 cases of Pneumocystis carinii pneumonia, 53 (98%) were diagnosed by bronchoalveolar lavage. Complications were recorded in 12 instances and included pneumothorax in two and transient increase in fever and hypoxaemia in the remainder. Bronchoalveolar lavage is a safe, easy, and effective procedure for diagnosing pneumocystis pneumonia in patients at high risk of AIDS and should be done routinely when fibreoptic bronchoscopy is performed in such patients.

Acquired Immunodeficiency Syndrome↗
PubMed1986

Pulmonary manifestations of AIDS: review of 106 episodes.

We reviewed the clinical records and chest radiographs of all patients admitted to our institution between 1982 and 1984 who had pulmonary disease and who were later proved to have acquired immunodeficiency syndrome (AIDS) (95 patients). Diffuse parenchymal lung disease was the most common finding. These infiltrates were usually interstitial and caused by Pneumocystis carinii pneumonia or P. carinii combined with cytomegalovirus infection. Focal, multilobar, interstitial infiltrates were also often seen and usually caused by P. carinii or P. carinii and cytomegalovirus infections. Rarely, well-defined, multiple, interstitial nodules less than 10 mm in diameter were the only or predominant characteristic and were seen only in association with Mycobacterium tuberculosis or Cryptococcus neoformans infections or Kaposi sarcoma. Hilar or mediastinal adenopathy occurred in 17 of the 21 patients with M. tuberculosis or C. neoformans infections. In contrast, only 4% of patients with P. carinii infections presented with these findings. We also found that hilar or mediastinal adenopathy was not significantly associated with peripheral adenopathy. Lung cavitation, pleural effusion, or a normal chest radiograph was uncommon.

Acquired Immunodeficiency Syndrome↗
PubMed1984

Chemotherapy-associated pulmonary toxic reactions during treatment for breast cancer.

Chemotherapy-related pneumonitis developed in eight patients during treatment for breast cancer. Six were receiving adjuvant therapy and two were being treated for metastatic disease. Fever, chills, dyspnea, and dry cough were the initial symptoms. Observations from chest roentgenograms varied from normal to bilateral interstitial-alveolar infiltrates. Results of pulmonary function tests were markedly abnormal, with a decreased diffusing capacity being the most characteristic abnormality. The pneumonitis developed in six patients while receiving 20 mg or less per day of prednisone and appeared temporarily related to tapering of steroid therapy in four patients. All patients recovered clinically, although prednisone therapy of 60 mg/day or its equivalent was required in three cases. Mild pulmonary function abnormalities persisted. Drug-induced pneumonitis should be considered in the differential diagnoses of patients with breast cancer in whom unexplained fever, dyspnea, or infiltrates develop during multidrug chemotherapy.

Adult↗
PubMedDate not supplied

Cytologic diagnosis of Pneumocystis carinii infection by bronchoalveolar lavage in acquired immune deficiency syndrome.

Twenty-six patients with pulmonary infiltrates and suspected acquired immune deficiency syndrome (AIDS) underwent 29 fiberoptic bronchoscopies, including bronchoalveolar lavage. Seventeen of the 18 patients (94.4%) shown to have Pneumocystis carinii pneumonia were diagnosed by examination of the bronchoalveolar lavage specimen. Minor complications occurred in 7 of 29 total bronchoscopies and included transient fever and hypoxemia. Bronchoalveolar lavage is a safe, easy and effective procedure for making the diagnosis of P. carinii pneumonia in patients at high risk for AIDS and should be included routinely when performing fiberoptic bronchoscopy.

Acquired Immunodeficiency Syndrome↗