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Biomedical subjects

H B Pinkofsky

Publications and source records attributed to H B Pinkofsky.

At least 19 recordsLinked to original sources
PubMed2000

The inhibition of GLUT1 glucose transport and cytochalasin B binding activity by tricyclic antidepressants.

Under normal metabolic conditions glucose is an important energy source for the mammalian brain. Positron Emission Tomography studies of the central nervous system have demonstrated that tricyclic antidepressant medications alter cerebral metabolic function. The mode by which these drugs perturb metabolism is unknown. In the present study the interactions of tricyclic antidepressants with the GLUT1 glucose transport protein is examined. Amitriptyline, nortriptyline, desipramine, and imipramine all inhibit the influx of 3-O-methyl glucose into resealed erythrocytes. This inhibition is observed with drug concentrations in the millimolar range. All four antidepressants also noncompetitively displace cytochalasin B binding to GLUT1. The K(I) for this displacement ranges from 0.56 to 1.43 millimolar. This value is in a range greater than that associated with clinical doses and this effect may not be directly applicable to side effects observed with normal use. The observed interaction of these drugs with GLUT1 may reflect an affinity for other glucose-transport or glucose-binding proteins, and may possibly contribute to tricyclic antidepressant toxicity.

Antidepressive Agents, Tricyclic↗
PubMed1999

Antipsychotic drugs affect glucose uptake and the expression of glucose transporters in PC12 cells.

1. Adherence of the PC12 cell line to poly-l-lysine (PLL) on tissue culture dishes stimulated glucose transport into the cells. Fluphenazine, chlorpromazine, clozapine and haloperidol inhibited glucose uptake in this system after a short (30 min) preincubation with drug. The IC50's for this effect were typically in the range of 5-40 microM. 2. Following longer exposures of the drugs (24 hr), there was a significant increase (approximately 3-fold) in the cellular levels of the glucose transporter (GLUT) isoforms, GLUT1 and GLUT3. 3. Long-term incubation (48 hr), especially with the phenothiazine drugs, was accompanied by a marked reduction in cell growth and proliferation. The rank ordering of the potencies of the drugs was essentially the same for these various effects: fluphenazine > chlorpromazine > clozapine approximately haloperidol. 4. It is suggested that the effects on glucose transport reported here may complicate the interpretation of positron emission tomography (PET) studies that rely on the uptake of radiolabeled glucose analogs to measure the physiological response to these drugs.

Animals↗
PubMed1999

Carisoprodol (soma): abuse potential and physician unawareness.

Carisoprodol is a noncontrolled skeletal muscle relaxant whose active metabolite is meprobamate, a Schedule IV controlled substance. Although several case reports have shown that carisoprodol has abuse potential, it continues to be widely prescribed. The usage patterns of 40 patients who had taken carisoprodol for three or more months (20 of whom had no history of substance abuse and 20 of whom carried a diagnosis of substance abuse or dependence) were reviewed and compared and a survey was conducted to assess physician awareness of the abuse potential of the drug. Findings showed that some patients using carisoprodol for over three months may abuse the medication, especially those individuals with a history of substance abuse. A significant percentage of the physician population is unaware of the potential of carisoprodol for abuse and of its metabolism to meprobamate, a controlled substance. Physicians should exercise caution when prescribing carisoprodol, especially if the patient has a history of substance abuse.

Adult↗
PubMed1998

Mnemonics for DSM-IV substance-related disorders.

A series of acronyms was developed to assist in recalling the DSM-IV diagnostic criteria for substance-related disorders. In order to facilitate recall, most of the mnemonics are related in some way to the disorder itself. In general, each letter of the acronym relates to an element of the diagnostic criteria. These mnemonics are intended to be helpful in a variety of academic and medical settings.

Abbreviations as Topic↗
PubMed1998

Medicolegal errors in the ED related to the involuntary confinement of psychiatric patients.

To determine the effectiveness of emergency department (ED) physicians properly and correctly completing documents required for emergency confinement of psychiatric patients, 1,000 Physician Emergency Certificates filed by ED physicians in the Shreveport, Louisiana, region were reviewed for appropriateness and for correctness of completion based on the applicable state law. Of the Physician Emergency Certificates reviewed 4.2% were incomplete or inappropriate. The most significant sources of error involved incomplete documentation of the mental status examination and not documenting the specific reason (dangerous to self, dangerous to others, or gravely disabled) for the patient meeting requirements for involuntary confinement. Other errors included confinement for reasons not appropriate for a psychiatric unit. This study suggests that ED physicians should be more cautious and thorough in completing the documents required for emergency confinement of psychiatric patients, so that the physician is less likely to be sued for malpractice or charged with the false imprisonment of such patients, and the patient's civil liberties are protected.

Emergency Medical Services↗
PubMed1998

Attachment of PC12 cells to adhesion substratum induces the accumulation of glucose transporters (GLUTs) and stimulates glucose metabolism.

The levels of glucose transporters (GLUTs), specifically GLUT3 and GLUT1, increased dramatically in PC12 cells that were cultured on suitable adhesion substrata (poly-1-lysine [PLL]) and induced to differentiate with nerve growth factor (NGF). Closer examination of this response revealed that: (1) cellular attachment to PLL was sufficient to stimulate the increase in GLUT immunoreactivity, and (2) NGF alone was not effective unless the cells were cultured on PLL-treated surfaces. The response to PLL was detected as early as 4 hr after plating the cells and peaked within 24-48 hr. Other adhesion substrata, such as collagen and poly-1-ornithine, evoked a similar response, although the latter polymer was far less effective. The increase in GLUTs appeared to result from an accumulation of existing transporters because this response was not blocked by inhibiting protein synthesis. Cellular adhesion to PLL was also accompanied by a rapid activation of glucose metabolism. Thus, specific recognition of the adhesion substratum not only provides a context for cell attachment, but also elicits important functional changes in GLUT activity.

Animals↗
PubMed1997

The effect of donor age on human erythrocyte density distribution.

Erythrocyte density has been reported to increase with in vivo aging. Gradient centrifugation techniques allow different density erythrocyte fractions to be purified from whole blood. As the donor age increases there is a concomitant increase in the percentile contribution of whole blood by a light density fraction. Similarly, a heavy density component of erythrocytes decreases with increasing donor age. In the present study these changes were investigated and found to exhibit a logarithmic relationship to donor age. The etiology of this is unknown but may be due to a decreased erythrocyte lifespan in older individuals.

Adult↗
PubMed1997

Psychosis during pregnancy: treatment considerations.

The onset of psychosis during pregnancy presents several difficult management decisions and a careful risk-benefit analysis is required. Withholding antipsychotic treatment may produce more risks than benefits. Studies on neuroleptic teratogenicity are contradictory. Most of the commonly used neuroleptics exhibit a pregnancy risk of category C. Neuroleptic use during pregnancy may be associated with adverse effects in the pre- and postnatal period. These concerns include compromising uterine blood flow, post-partum neonatal sedation, and extrapyramidal signs expressed in the neonate. Each neuroleptic exhibits a unique pharmacokinetic profile. The antipsychotic properties and side effects considered most significant include sedation, half-life, hypotension, and apparent hydrophilicity. In this case study a decision to select molindone was based on these parameters.

Adult↗
PubMed1997

Mnemonics for DSM-IV personality disorders.

The paper presents several mnemonics to assist clinicians in recalling DSM-IV diagnostic criteria for personality disorders. The mnemonics are acronyms, and each letter is associated with a specific criterion. Each acronym reflects a facet of the related disorder; for example, the acronym for the diagnostic criteria for paranoid personality disorder is SUSPECT, and for histrionic personality disorder it is PRAISE ME. The mnemonics have been used to teach students and residents the conceptual nature of DSM-IV disorders and to help them remember the criteria.

Humans↗
PubMed1997

Decreased multi-band posterior interhemispheric coherence with a lipoma on the corpus callosum: a case report of a possible association.

The corpus callosum plays a role in mediating interhemisphere communication. Coherence may be a quantitative EEG-based measure of this communication. The present report is of a female schizophrenic patient with a marked coherence deficit in the temporal-parietal-occipital region involving multiple frequency bands. An MRI scan of her brain revealed a lipoma involving the splenium of the corpus callosum. It is speculated that this lipoma may have caused a physical impingment on or developmental aberration of adjacent callosal fibers, resulting in the observed coherence deficit. Further studies of coherence measures in patients with collosal lipomas are proposed.

Adult↗
PubMed1997

Carisoprodol: a drug of continuing abuse.

Carisoprodol (Soma) is a noncontrolled, skeletal-muscle relaxant whose active metabolite is meprobamate. Despite previous indications that the drug may be abused, it continues to be widely prescribed for musculoskeletal conditions involving muscle spasm. Presented here are three cases demonstrating patterns of carisoprodol abuse not previously reported. Carisoprodol usage should be limited to short-term treatment. Patients for whom carisoprodol is prescribed are at risk for meprobamate dependence.

Adult↗
PubMed1997

Postpartum psychosis induced by bromocriptine and pseudoephedrine.

Bromocriptine is an ergot-derived dopamine agonist sometimes used for postpartum suppression of lactation. On rare occasions (a total of seven previous reports in the literature), use of the medication has been associated with psychotic symptomatology in postpartum patients. This case report describes a 19-year-old postpartum woman who developed severe psychotic symptoms while taking low doses of bromocriptine and pseudoephedrine. The use of bromocriptine for suppression of lactation is controversial. If prescribed for postpartum patients, bromocriptine alone or in combination with sympathomimetic drugs should be used only with caution.

Adult↗