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Biomedical subjects

D F Landers

Publications and source records attributed to D F Landers.

34 records · Page 2Linked to original sources
PubMed1991

Isoflurane partially preserves energy balance in isolated hepatocytes during in vitro anoxia.

We investigated whether a volatile anesthetic (1.5% isoflurane or 1.0% halothane) or an added anaerobic energy source (10 mM glucose or fructose) could act directly on liver cells to protect energy status during 20-30 min of anoxia. We used hepatocytes freshly isolated from fed rats or rats that had fasted, suspended them in Krebs' buffer, and incubated them in sealed flasks under O2/CO2 or N2/CO2 (95%:5%). The adenosine triphosphate (ATP) to adenosine diphosphate (ADP) ratio (ATP/ADP) measured cellular energy balance--the balance between overall ATP supply and demand. Lactate levels measured the extent to which ATP was supplied by the nonmitochondrial pathway, (anaerobic) glycolysis. Maximum values of energy balance were seen in cells from fed rats incubated in the presence of glucose and O2. When glucose was replaced by fructose, ATP/ADP decreased and lactate increased. During anoxia (O2 replaced by N2), increases in lactate were also seen with glucose; and ATP/ADP decreased to similarly low values with both substrates. In cells from fasted rats, ATP/ADP decreased significantly below the value for cells from fed rats only in the presence of glucose and O2. Compared with cells from fed rats, cells from fasted rats showed decreased lactate in the face of decreased ATP/ADP, suggesting that glycolysis was impaired. Isoflurane partially prevented anoxia-induced decreases in ATP/ADP. This protective effect on energy balance occurred equally with glucose and fructose, but was not seen in cells from fasted rats or with halothane. Thus, 1 MAC isoflurane and some factor(s) related to the fed state combined to protect partially the energy balance in anoxic liver cells through action(s) at the cellular level.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1990

Ischemic brain injury in vitro: protective effects of NMDA receptor antagonists and calmidazolium.

Excessive Ca2+ influx through NMDA receptor-coupled channels has been linked to neuronal cell death. Using an in vitro model of transient brain ischemia, we investigated possible protective effects of NMDA receptor antagonists ketamine or MK-801 and of calmidazolium, an inhibitor of intracellular Ca2(+)-activated proteins. Brain ischemia/recovery was simulated in isolated hippocampal slices and injury monitored by measurement of ATP levels. Omission of both glucose and oxygen (but not oxygen alone) for 20 min led to persistent ATP deficits after 4 h recovery. Addition of ketamine or MK-801 at 1 microM permitted ATP to recover within 1 h, as did addition of calmidazolium at 10 microM. Our findings are consistent with other reports that NMDA receptor antagonists can protect neuronal tissue from ischemic damage. The role of inappropriately activated Ca2(+)-mediated signaling processes in the mechanism(s) of such injury is suggested by the protection also seen with calmidazolium, an inhibitor of calmodulin and other structurally related proteins such as calpain(s) and protein kinase C. The inhibition of intracellular Ca2+ target proteins may be an alternative for protection of the brain against injury due to insults that activate NMDA receptors.

Adenosine Triphosphate↗
PubMed1990

Neuroleptic malignant syndrome.

NMS is an uncommon disorder characterized by hyperthermia, muscle rigidity, autonomic imbalance, altered levels of consciousness and significant mortality. Successful treatment of NMS requires a high degree of suspicion, rapid recognition of clinical signs and symptoms and institution of therapy with dantrolene and possibly dopaminergic agonists. This condition is precipitated by neuroleptic drugs, which are commonly used in many medical specialties. All medical practitioners responsible for primary care, psychiatrists and anesthesiologists should be familiar with the manifestations of the hypermetabolic syndromes of Neuroleptic Malignant Syndrome, Malignant Hyperthermia, and Neuroleptic Malignant-like Syndrome and should be prepared to initiate appropriate therapy.

Adult↗
PubMed1989

Multiple uterine rupture and crushing injury of the fetal skull after blunt maternal trauma. A case report.

Multiple pelvic fractures and explosive-type uterine lacerations occurred in a previously healthy 17-year-old primigravida involved in a motor vehicle accident. The fetus suffered a crushed skull and was completely extruded with the placenta from the uterus. Treatment was complicated by severe disseminated intravascular coagulation with secondary fibrinolysis. Thrombelastography enabled us to rapidly evaluate the patient's coagulation status and to monitor her response to goal-directed therapeutic interventions (surgery, specific blood product therapy and epsilon-aminocaproic acid).

Accidents, Traffic↗
PubMed1983

Alcohol withdrawal syndrome.

The alcohol withdrawal syndrome can be divided into four stages, which should be recognized and treated to prevent progression to the later stages. Delirium tremens, the final stage of withdrawal, is characterized by extreme autonomic hypersensitivity and seizures. Treatment may include prophylactic use of sedatives or acute therapy for the management of seizures. Diazepam and chlordiazepoxide are useful agents.

Alcohol Withdrawal Delirium↗
PubMed1983

Alcoholic coma and some associated conditions.

The diagnosis of alcoholic coma is made only when there is a high blood alcohol level and signs of bilateral cortical dysfunction, without focal neurologic signs, and when all other metabolic and structural causes of coma have been ruled out. The ethanol-induced hypoglycemic coma of youth appears to result from the failure of gluconeogenesis to release glucose into the bloodstream. If the hypoglycemia is not immediately corrected, permanent and possibly lethal brain damage will result.

Alcoholic Intoxication↗
PubMedDate not supplied

Unusual etiology of hyperkalemia in an immunocompromised patient.

Hyperkalemia was found in an immunocompromised patient undergoing emergency cystoscopy. The cause of the hyperkalemia was an intraperitoneal rupture of the bladder. This case report discusses conditions that predispose patients to bladder rupture and anesthetic management of hyperkalemia.

Adult↗
PubMedDate not supplied

Management of a severed endotracheal tube during LeFort osteotomy.

An unusual but serious case in which the endotracheal tube was severed during LeFort osteotomy is presented. The aspects of the surgery that can create this problem are reviewed. Past literature is reviewed, and various procedures for the management of this problem, including the plan followed in this case, are discussed.

Adult↗
PubMedDate not supplied

Anesthetic management for the high-risk ophthalmic patient.

A 69-year-old white female presented for corneal transplant, but her numerous medical problems placed her at unacceptably high risk for prolonged general anesthesia. Routine monitored anesthesia care measures would not have provided her or the surgeon the comfort and repose necessary for a successful outcome. We describe anesthetic management for ophthalmic surgery, using epidural anesthesia in conjunction with retrobulbar block, in an elderly patient at high risk for general anesthesia whose intractable back and leg pain would have otherwise precluded her cooperation in maintaining a motionless operative field.

Aged↗