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Biomedical subjects

R C Alexander

Publications and source records attributed to R C Alexander.

46 records · Page 3Linked to original sources
PubMed1987

Pulmonary infiltrates and hypoxemia in patients with the acquired immunodeficiency syndrome re-exposed to trimethoprim-sulfamethoxazole.

Fever, hypotension, pulmonary infiltrates, and hypoxemia developed upon re-exposure to trimethoprim-sulfamethoxazole in 2 patients with the Acquired Immunodeficiency Syndrome. This reaction can mimic sepsis or the clinical worsening of underlying pulmonary opportunistic infection. The literature concerning adverse pulmonary effects of trimethoprim-sulfamethoxazole is reviewed.

Acquired Immunodeficiency Syndrome↗
PubMed1987

Microwave oven burns to children: an unusual manifestation of child abuse.

Two children sustained full-thickness burns as a result of being placed in microwave ovens. Well demarcated burns occurred on the skin surfaces closest to the microwave-emitting devices. Morbidity was limited to complications of direct thermal effects. One of the children sustained a distinctive pattern of relative sparing of tissue layers without electrical burn features, such as nuclear streaming and charring, at the entrance site. In both instances eventual identification of this unusual etiology was initiated by child abuse concerns.

Burns↗
PubMed1986

Magnetic resonance imaging of intracranial injuries from child abuse.

Magnetic resonance imaging (MRI) and computed tomography (CT) were compared in four children who had evidence of intracranial injury caused by shaking. All children had intracranial bleeding, neurologic impairment, and history or physical examination findings suggestive of child abuse. Three had bilateral retinal hemorrhages, and three had visual impairment. MRI revealed bilateral subdural hematomas in all four children, but CT showed this in only one. Skull fractures in one patient were visualized by CT alone. MRI alone demonstrated posterior fossa bleeding in one patient and intraparenchymal bleeding in another; an additional patient in whom CT showed relatively diffuse atrophy also had defined areas of focal atrophy apparent on MRI. Subarachnoid hemorrhages were equally well detected using CT or MRI. Overall, MRI was superior to CT for detection of intracranial injury caused by shaking, and may help to document milder instances of this form of child abuse.

Brain Injuries↗
PubMed1986

Monoamine oxidase inhibitors and tricyclic antidepressants: comparison of their cardiovascular effects.

The cardiovascular effects of monoamine oxidase inhibitors (MAOIs) are contrasted with those of the tricyclic antidepressants (TCAs). At therapeutic doses, MAOIs lower supine blood pressure and increase the postural fall in blood pressure, whereas TCAs have only the latter effect. MAOIs have little effect on heart rate and do not prolong cardiac conduction; TCAs increase heart rate and prolong cardiac conduction. Neither class of drugs appears to impair cardiac mechanical functioning. For patients with certain cardiac problems, MAOIs may have an advantage over TCAs.

Angina Pectoris↗
PubMedDate not supplied

Schizophrenia, just the facts. What do we know, how well do we know it?

The basic facts of schizophrenia are subjectively reviewed in terms of their reproducibility and significance for understanding the disorder. Some of the facts that are either less well known or of greater importance for future investigation are discussed in more detail. The purpose of establishing what we know about schizophrenia is to develop firm ground for generating hypotheses. One attempt to synthesize these facts is outlined.

Humans↗
PubMedDate not supplied

Aspects of angiotensin action in the adrenal. Key roles for calcium and phosphatidyl inositol.

The steps between exposure of bovine adrenal glomerulosa cells to angiotensin and the stimulated increase in aldosterone production were studied in two ways. Binding of angiotensin to receptors, and hormone effects on phosphatidyl inositol turnover, 45Ca2+ fluxes, and aldosterone production were measured directly. Other potential intermediate steps were investigated indirectly by use of inhibitors. Angiotensin slowed calcium influx and accelerated phosphatidyl inositol turnover in proportion to hormone dose. The effects correlated with receptor binding and aldosterone production. None of the inhibitors tested, except saralasin, inhibited angiotensin's effect on phosphatidyl inositol turnover. Altered calcium flux and stimulated aldosterone production were affected by the calmodulin inhibitor trifluoperazine and the intracellular calcium antagonist 8-(N,N-diethylamino)-octyl 3,4,5-trimethoxybenzoate hydrochloride (TMB-8). Several reagents did not affect angiotensin binding, its effect on phosphatidyl inositol, or 45Ca2+ flux, but severely inhibited steroidogenesis. These included the phospholipase A2 inhibitor mepacrine, the protein synthesis inhibitor cycloheximide, and the Na+/k+-ATPase inhibitor ouabain. Colchicine had very little effect on the processes we measured, suggesting that microtubules play no role in angiotensin action in the adrenal. Based o these observations, we propose that angiotensin II affects the adrenal glomerulosa cell by first interacting with receptors, then increasing phosphatidyl inositol turnover, then altering cellular calcium distribution. Step distal to altered calcium distribution that contribute to increased steroid output include altered phospholipid metabolism, protein synthesis, and Na/k metabolism.

Adrenal Cortex↗