Cisplatin: a clinical review. Part I--Current uses of cisplatin and administration guidelines

Cisplatin is one of the most active cancer treatment agents available. Unfortunately, however, cisplatin causes many untoward side effects. Nurses play a major role in administering cisplatin and in preventing and managing the adverse effects associated with this drug. In order to maximize the quality of life of patients undergoing cisplatin treatment, nurses need a thorough knowledge of its uses, administration, and side effects. This article is the first of a two-part series about cisplatin. Part I will provide a review of the mechanism of action, current uses, and administration guidelines. Part II will discuss the most common side effects of cisplatin and the appropriate nursing assessment and management of patients undergoing treatment with this agent. In addition, future directions for the use of cisplatin and the use of alternative agents will be discussed.

Danger of corticosteroid administration in meningitis due to misdiagnosed agent

A 3 1/2-year-old child with acute tuberculous meningitis was misdiagnosed as having "partially treated" meningitis and was treated with ampicillin, chloramphenicol, and dexamethasone. She developed obstructive hydrocephalus and miliary spread of tuberculosis which led to death. It is likely that failure to consider alternative diagnoses promptly and the use of corticosteroids along with ineffective antibiotics contributed to the outcome. Although they may lessen some complications of bacterial meningitis, the indiscriminate use of corticosteroids in misdiagnosed bacterial meningitis may be detrimental.

Renal function during chronic anemia in the ovine fetus

Our purpose was to determine how prolonged anemia alters fetal renal function and acid-base balance. In seven ovine fetuses made progressively anemic over 1 wk by serial isovolemic hemorrhage, hematocrit was reduced from 33.3 +/- 4.5 to 14.0 +/- 1.0%. Femoral arterial oxygen content was less and renal plasma flow was greater in anemic fetuses (1.5 +/- 0.1 ml/dl and 339 +/- 58 ml.min-1.100 g kidney-1) than in 6 control fetuses (7.0 +/- 1.3 ml/dl and 160 +/- 34 ml.min-1.100 g kidney-1). Urine flow and sodium excretion were also greater in anemic fetuses (1.2 +/- 0.6 ml/min and 79 +/- 49.5 mumol/min) than in controls (0.5 +/- 0.2 ml/min and 16 +/- 9.8 mumol/min). This higher sodium excretion was apparently due to a lower fractional sodium reabsorption in anemic fetuses compared with controls (84.1 +/- 5.8 vs. 96.5 +/- 1.7%), rather than to differences in either glomerular filtration rate or amount of filtered sodium. In addition, the higher sodium excretion in anemic fetuses was associated with greater urinary lactate and inorganic phosphate excretions and larger amniotic fluid volumes than in controls. From these data we conclude that when fetal renal oxygen delivery is limited by a prolonged reduction in hematocrit, excretions of sodium and water, as well as other osmotically active solutes, increase, and this results in an increase in amniotic fluid volume.

Methylmercury poisoning: long-term clinical, radiological, toxicological, and pathological studies of an affected family

For 3 months in 1969 a family in the United States that included a pregnant mother consumed pork containing methylmercury. Children, aged 20, 13, and 8 years and a neonate, developed severe neurological signs. Twenty-two years later, the 2 oldest had cortical blindness or constricted visual fields, diminished hand proprioception, choreoathetosis, and attentional deficits. Magnetic resonance images showed tissue loss in the calcarine and parietal cortices and cerebellar folia. The youngest had quadriplegia, blindness, and severe mental retardation until their deaths. The brain of the 8-year-old who died at age 30 showed cortical atrophy, neuronal loss, and gliosis, most pronounced in the paracentral and parietooccipital regions. The total mercury level in formalin-fixed, left occipital cortex was 1,974 ng/gm as measured by atomic absorption. Regional brain mercury levels correlated with extent of brain damage. A control patient had 38.5 ng of mercury/gm in the occipital cortex. Systemic organs in the patient and a control subject had comparable mercury levels. In mercury-intoxicated rats, we found that only 5 to 10% of total brain mercury was lost by formalin fixation. Brain inorganic mercury in the patient ranged from 82 to 100%. Since inorganic mercury crosses the blood-brain barrier poorly, biotransformation of methyl to inorganic mercury may have occurred after methylmercury crossed the blood-brain barrier, accounting for its persistence in brain and causing part of the brain damage.

The challenge of racial difference: skills for clinical practice

Just as racial injustice negatively affects the plight of minorities in society, racial tensions impede professional helping. Often, the racially dissimilar social worker and client approach each other with little understanding of each other's social realities and with unfounded assumptions. Unfortunately, professionals find it difficult to acknowledge such differences or their effect on their relationships. Yet the fruitfulness of the helping encounter often depends on the ability to develop and invest in a trusting relationship. This article identifies the societal roots of the stresses associated with cross-racial relationships. Three concerns commonly experienced by clients whose workers are racially different are identified: (1) Is the helper a person of goodwill? (2) Is the helper trained and skilled? (3) Is the help offered valid and meaningful for me and my social reality? Case vignettes are used to illustrate how each concern is typically mishandled. The importance of successfully managing each concern is stressed, and skills for successful management are illustrated.

Effect of atrial natriuretic peptide on vascular permeation in the ovine fetus

To study the effect of atrial natriuretic peptide (ANP) on vascular permeation of albumin in the fetus, ANP (167-600 ng/min) was infused into eight ovine fetuses and saline vehicle was infused into eight twin controls (gestational age 127 +/- 3 d) over a 50-min period. Using two different radiolabeled albumin markers, we determined the tissue to blood isotope ratio (TBIR), an index of albumin permeation, and the albumin clearance. Although ANP had no hemodynamic effect, a marked increase in the hematocrit was observed in ANP-infused fetuses compared with initial values (0.37 +/- 0.04 vs 0.42 +/- 0.04, p < 0.005) but was unchanged in the twin fetuses receiving saline vehicle (0.35 +/- 0.03 versus 0.35 +/- 0.02). TBIR and albumin permeation were increased in combined tissues of ANP-infused fetuses compared with saline controls (TBIR: 1.49 +/- 0.58 versus 1.29 +/- 0.3, p < 0.001; albumin clearance: 1091 +/- 1279 versus 827 +/- 1464 nL/g/min, p < 0.01). In individual tissues, TBIR was significantly increased in skin (2.88 +/- 0.67 versus 1.55 +/- 0.35, p < 0.02), muscle (1.6 +/- 0.27 versus 1.24 +/- 0.26, p < 0.02), adrenal (1.33 +/- 0.10 versus 1.13 +/- 0.15, p < 0.02), bone (1.67 +/- 0.45 versus 1.20 +/- 0.40, p < 0.02), kidney (1.52 +/- 0.25 versus 1.24 +/- 0.26, p < 0.03), and gut (1.69 +/- 0.20 versus 1.39 +/- 0.34, p < 0.03).(ABSTRACT TRUNCATED AT 250 WORDS)

An assessment of practitioner cross-racial treatment experiences

This study sought to determine differences in the cross-racial practice experiences of white and minority social services practitioners. Fifty-three counselors in a Veterans Administration outreach center evaluated various aspects of their cross-racial practice experiences. Both white and minority counselors perceived themselves to work equally well with white clients, but white counselors perceived themselves to be less effective when working with minority clients. The majority of white and minority counselors reported identifying the source of white clients' problems as being internal and that of minority clients' problems as being external. This finding was interpreted as being a possible bias against white clients on the part of both white and minority practitioners. White counselors reported experiencing less client credibility, and minority counselors reported more incidents of racism. Implications for social work are discussed.

Cortical organization in adulthood is modified by neonatal infarct: a case study

PURPOSE

To assess anomalous cortical organization of somatosensory function in a 23-year-old man who had had a neonatal infarct involving the left middle cerebral artery.

MATERIALS AND METHODS

The infarct destroyed the primary and secondary somatosensory areas of the subject's left hemisphere but caused only mild perturbation of somatosensation on the right side of his body. With magnetic source imaging, the authors integrated magnetoencephalographic data with magnetic resonance imaging data to create magnetic source localization images that showed the mapping between brain function and structure.

RESULTS

Electrical stimulation of the right median nerve evoked activity in two nontraditional areas: (a) an intact region of the left inferior temporal gyrus and (b) the ipsilateral right medial parietal cortex.

CONCLUSION

These data suggest that bilateral neural reorganization can be induced by unilateral neonatal damage.

The effect of dietary protein depletion on hepatic 5-fluorouracil metabolism

BACKGROUND

Protein calorie malnutrition, which is highly prevalent in tumor-bearing hosts, increases toxicity to 5-fluorouracil (5-FU), but the mechanisms are unclear. This study investigated the effects of protein depletion on 5-FU in vivo hepatic metabolism using F19-nuclear magnetic resonance spectroscopy (19F-NMRS).

METHODS

Rats received normal (21.5%) or low (2.5%) protein diet for 25 days. 5-FU was injected intraperitoneally, and hepatic fluorine spectra were obtained. Parallel experiments were conducted to determine serum 5-FU pharmacokinetics using high-performance liquid chromatography (HPLC) and to measure hepatic dihydropyrimidine dehydrogenase (DPD) activity.

RESULTS

The mean time of initial detection of fluoro-beta-alanine and the mean duration of the 5-FU signal in the liver were significantly prolonged in the low-protein group. 5-FU clearance and hepatic DPD activity were significantly lower in the low-protein group. Low-protein animals demonstrated increased toxicity, with diarrhea, weight loss, leukopenia (P < 0.001), and an 85% mortality, compared with regular diet animals, who had mild diarrhea and weight loss but no leukopenia and a 12% mortality.

CONCLUSION

Protein depletion results in increased toxicity to 5-FU, which is associated with a significantly decreased rate of hepatic metabolism and clearance of 5-FU and a significant decrease in hepatic DPD activity. 19F-NMRS can noninvasively identify these alterations of 5-FU metabolism in vivo and may serve as a useful guide to determining chemotherapy dosage adjustments to reduce toxicity.

Tuberculous meningitis in the southwest United States: a community-based study

This community-based study analyzed 54 patients with definite or probable tuberculous meningitis (TBM) in New Mexico from 1970 through 1990. Patients ranged in age from 4 months to 86 years. The highest age-specific incidence occurred in the elderly, but 22% of patients were less than 10 years old. Native American patients were overrepresented. Patients were as likely to live in small towns as in large urban cities. Symptoms were present for a median of 13 days before admission. The majority of patients had fevers, headache, stiff neck, and mental changes, such as confusion or lethargy. No patient was admitted comatose. Focal neurologic signs were present in 33%. Laboratory testing found hyponatremia in 79%, pulmonary infiltrates on chest x-ray in 40%, ventricular dilatation on CT or MRI in 52%, and tuberculomas in 16%. PPD skin tests were positive in 64%. CSF cultures grew Mycobacterium tuberculosis in 50%, but colony counts were always lower than 10(2)/ml. As a consequence, acid-fast stains of CSF sediment were reported as positive in only 4%. Six patients were not diagnosed during the hospitalization and died of complications. Twenty-three percent of patients who were appropriately treated also died of complications during the initial hospitalization. Tuberculous meningitis continues to be an important disease in small communities, and affects all ages and ethnic and socioeconomic backgrounds.

Devic's neuromyelitis optica: a clinicopathological study of 8 patients

We report the clinical, imaging, and laboratory features of 8 patients with Devic's neuromyelitis optica. All patients had severe myelopathy and optic neuritis. In no patient was the brain, the brainstem, or the cerebellum affected, even after several years of disease. Various immunosuppressive treatments failed to benefit the patients, 5 of whom died. Autopsies of these 5 patients demonstrated a severe necrotizing myelopathy with thickening of blood vessel walls and no lymphocyte infiltrates. In the appropriate clinical setting, the lack of white matter abnormalities demonstrated by magnetic resonance imaging of the head facilitates the recognition of Devic's syndrome during life. Inasmuch as Devic's myelopathy is necrotizing, rather than demyelinating, the prognosis of this syndrome is poor.

Temporal bone histopathology 14 years after cytomegalic inclusion disease: a case study

Temporal bones were examined from a 14-year-old male who died of sequelae of congenital cytomegalic inclusion disease (CID). Cytomegalovirus (CMV) was not isolated from inner ear fluid or multiple systemic tissues at the time of death. Examination of temporal bones revealed chronic pathology of both cochlear and vestibular sensory and nonsensory tissues. Endolymphatic hydrops was observed in the basal turn of the cochlear duct, while Reissner's membrane was collapsed in the more apical turns. Strial atrophy and a loss of cochlear hair cells were observed along the entire length of the basilar membrane. Vestibular neuroepithelial regions were degenerated and fibrosis was seen within the vestibular perilymphatic tissue spaces, suggesting prior labyrinthitis within the perilymph compartment in addition to the more typical pattern of endolabyrinthitis associated with human CMV infection. Distention of the saccular membrane was evident. In both cochlear and vestibular tissues, there were isolated regions of calcifications that appeared characteristic to that reported in other organ systems of individuals with CID. Collectively, these chronic, pathological findings in this case of CID demonstrate more extensive injury than has been identified in the previously reported acute temporal bone pathology of CID.

Positive end-expiratory pressure lowers the risk of laser-induced polyvinylchloride tracheal-tube fires

BACKGROUND

The possibility of ignition of polyvinylchloride (PVC) tracheal tubes by a CO2 laser is of concern in patients undergoing CO2 laser surgery of the airway. The authors analyzed the ignition of PVC tracheal tubes by a CO2 laser beam to determine what variables were involved, and then designed a study to determine how they affect the incidence of such fires.

METHODS

For the analysis, PVC tracheal tubes were enclosed in a clear plexiglass enclosure and a laser beam was focused on the tubes. The enclosure contained one of three different gas combinations. A high-speed camera photographed the tubes during the analysis and showed that tracheal tube perforation always preceded ignition in all three gas combinations. These results led to the hypothesis that intraluminal gauge pressure (IGP) may be an important variable, because it would affect the flow of O2 across the perforation. This hypothesis was tested by aiming a CO2 laser beam at PVC tracheal tubes and varying IGP in 0.25-cm H2O increments, from 0.25 to 28 cm H2O, while nitrogen or helium containing O2 at 40, 50, or 60% flowed through the tubes. To simulate the clinical effect of IGP on PVC tracheal tube ignition, we used a mechanical lung model connected to an anesthesia breathing circuit with a standing bellows ventilator in which 60% He and 40% O2 flowed through a PVC tracheal tube. Laser beam exposure was started at three different times during the respiratory cycle: at the start of inspiration, at the end of inspiration, or at the end of expiration. Also, for each condition, trials were made at baseline circuit pressure (2.5 cm H2O) and at 5.0 cm H2O by the addition of 2.5 cm H2O positive end-expiratory pressure (PEEP) applied to the circuit.

RESULTS

The incidence of tracheal tube ignition decreased as IGP increased. The IGP at which ignition did not occur (which increased as O2 concentration increased) did not differ between N2 and He at 40% O2, but was twice as high with N2 as with He at O2 of 50% and 60%. Fires never occurred when PEEP was added to the system and, when PEEP was not added, always started during the last 2 s of end expiration (when airway pressure is lowest), regardless of when the laser beam was activated.

CONCLUSIONS

It is recommended that, in addition to other safety practices, PEEP be added to the breathing circuit during CO2 laser operations on the airway in which PVC tracheal tubes or laser-resistant tracheal tubes with PVC components are used.

Neuromagnetic mapping of brain function

Magnetic source imaging, a technique that combines magnetoencephalography (MEG) and magnetic resonance (MR) imaging, was used to localize the somatosensory and auditory cortex in seven healthy subjects. Functional neuromagnetic data were obtained with a 37-channel biomagnetometer. Structural MR imaging data were obtained with a 1.5-T superconducting imager. Coordinates used in defining MEG and MR imaging space were reconciled to produce magnetic source images that displayed the putative locations of somatosensory and auditory activity in relation to brain anatomy. Sources of somatosensory activity were typically localized to the postcentral gyrus; sources of auditory activity were localized to the superior temporal plane. Extension of these results to patients with tumors (or other disorders) that distort normal brain anatomy has the potential to make noninvasive magnetic source imaging examinations clinically useful in guiding neurosurgical interventional procedures.

The influenza B virus mouse model of Reye's syndrome: pathogenesis of the hypoglycaemia

Up to 40% of children with Reye's syndrome have hypoglycaemia that could contribute to the patient's encephalopathy. We developed a mouse model in which intravenous inoculation of influenza B/Lee virus produced a non-permissive infection of hepatocytes and cerebral endothelial cells and caused many clinical, biochemical and pathologic features of Reye's syndrome. We used this model to study the pathogenesis of the hypoglycaemia. Beginning 6 hours after virus inoculation and persisting to death 18-30 hours later, blood glucose levels fell by 40% and glycogen disappeared from the liver. Gluconeogenesis in liver slices from a pyruvate substrate was significantly impaired. Pyruvate carboxylase, normally present in hepatocyte mitochondria, was largely displaced into the cytosol, rendering that enzyme fraction relatively useless in the gluconeogenesis pathway. Brain glucose levels fell proportionately to the depressed blood glucose level to a mean of 44 mg/100 g compared to 108 mg/100 g in control brains. We conclude that hypoglycaemia in the mouse model developed largely as a result of a non-permissive influenza viral infection of hepatocytes which impaired the mitochondrial phase of gluconeogenesis. The hypoglycaemia may have contributed to, but did not solely account for, the encephalopathy. A similar non-permissive influenza B infection may cause hypoglycaemia in Reye's syndrome.

Transverse myelitis. Retrospective analysis of 33 cases, with differentiation of cases associated with multiple sclerosis and parainfectious events

OBJECTIVE

A study was undertaken to determine whether cases of parainfectious-associated transverse myelitis (TM) and multiple sclerosis-associated TM could be distinguished on the basis of clinical criteria, radiologic features, or cerebrospinal fluid examination. A secondary objective was to determine the incidence of TM in a US population.

DESIGN

A retrospective analysis of 33 cases was conducted. Cases were classified as being related to parainfectious multiple sclerosis, or spinal cord ischemia, or idiopathic.

SETTING

All cases occurring in the Albuquerque, NM, area from 1960 through 1990 were reviewed. The population base was 500,000.

OUTCOME MEASURES

Clinical presentation, radiologic features, cerebrospinal fluid, recovery of ambulation and bladder function, and recurrence rates were compared.

RESULTS

Thirty-three patients satisfied study criteria, corresponding to an incidence of 4.6 per million per year. Forty-five percent of these cases were categorized as parainfectious, 21% as associated with multiple sclerosis, 12% as associated with spinal cord ischemia, and 21% as idiopathic. Patients with parainfectious TM suffered from spinal shock more frequently than did those with multiple sclerosis-associated TM. Patients with parainfectious TM showed evidence of spinal cord swelling, whereas patients with multiple sclerosis-associated TM had spinal cord plaques on magnetic resonance images but none showed swelling. Oligoclonal bands were absent in patients with parainfectious TM and present in three of five patients with multiple sclerosis-associated TM.

CONCLUSIONS

Parainfectious TM may be distinguishable from that associated with multiple sclerosis on the basis of presentation, findings on imaging, and the presence of cerebrospinal fluid oligoclonal bands.

Estrogen-induced left ventricular chamber enlargement in ewes

We studied the chronic effect of administration of a single large intramuscular dose of 17 beta-estradiol on left ventricular chamber size and output in the ewe. Fourteen oophorectomized ewes were successfully instrumented and studied, with measurements made of left ventricular, aortic, right and left atrial pressures, left ventricular stroke volume, and left ventricular minor axis dimension. Unanesthetized ewes were studied before and 1, 2, and 3 wk after intramuscular administration of 0.6 mg/kg 17 beta-estradiol (7 ewes) or 1.5 ml sesame oil placebo (7 ewes). Left ventricular end-diastolic pressure-end-diastolic dimension (LVEDP-EDD) and left ventricular end-diastolic pressure-stroke volume (LVEDP-SV) relationships were quantified during graded inferior vena caval occlusion and volume infusion. Left ventricular end-diastolic diameter was larger after estrogen but not after placebo administration. The LVEDP-EDD relationship shifted progressively rightward, indicating left ventricular chamber enlargement in the estrogen group but was unchanged in the placebo group. The plateau limb of the LVEDP-SV relationship in the estrogen group shifted up from a mean stroke volume of 77.1-89.5 ml/beat and did not change in the placebo group. We conclude that administration of a single large intramuscular dose of 17 beta-estradiol resulted in left ventricular chamber enlargement and increased stroke volume in the ewe.

Botulinum toxin. From poison to medicine

Although thousands of people in the world each year continue to be poisoned with botulinum toxin-food-borne, infantile, or wound botulism-the neurotoxin is now sufficiently understood to allow it to be used as a medicinal agent to paralyze specific muscles, giving temporary symptomatic relief from a variety of dystonic neurologic disorders. I review some of the epidemiologic, clinical, and pathophysiologic aspects of botulinum toxin and how the neurotoxin may act as a poison or a medicine.

Viruses and vestibular neuritis: review of human and animal studies

There is increasing evidence in man and animals that several human viruses can damage the vestibular labyrinth. Clinical and serologic studies of patients with vestibular neuritis suggest that the viruses may play a role in the pathogenesis of this disease. Temporal bone studies of patients dying after vestibular neuritis have found maximal damage in the distal branches of the vestibular nerve. These changes are felt to be consistent with a viral etiology. No satisfactory animal viral model of vestibular neuritis currently exists. However, animal studies have demonstrated that several human viruses including rubeola, herpes simplex, reovirus, mouse and guinea pig cytomegalovirus, and neurotropic strains of influenza A and mumps virus, can infect the vestibular nerve and the vestibular membranous labyrinth.

Hepatitis A post-viral encephalitis

We report a seven-year-old girl who developed a hepatitis A viral infection and encephalitis. The patient developed fever, abdominal pains and jaundice. Five days later she became delirious, combative, and did not respond to verbal commands. Laboratory studies showed elevated liver enzymes and elevated serum immunoglobulin M (IgM) and immunoglobulin G (IgG) antibodies to hepatitis A virus. Cerebrospinal fluid contained IgG antibodies to hepatitis A virus but not IgM antibodies. Polymerase chain reaction, which amplifies a portion of the hepatitis A virus genome, did not demonstrate viral nucleic acid in cerebrospinal fluid. These studies suggest that the patient may have suffered from a post-viral hepatitis A encephalitis from which she fully recovered.

Role of angiotensin II and alpha-adrenergic receptors during estrogen-induced vasodilation in ewes

Estradiol-17 beta (E2 beta) produces uterine and systemic vasodilation in nonpregnant ewes without altering mean arterial pressure (MAP). Mechanisms responsible for maintaining MAP and thus uterine blood flow (UBF) may include activation of the renin-angiotensin and/or adrenergic systems. We therefore investigated the effects of systemic blockade of angiotensin II (ANG II) and/or alpha-adrenergic receptors in nonpregnant, castrated ewes, using saralasin (Sar) and/or phentolamine (Phen) in the presence or absence of intravenous E2 beta (1.0 microgram/kg). In nonestrogenized ewes neither antagonist alone had substantial cardiovascular effects; however, Sar + Phen decreased systemic vascular resistance (SVR) 20 +/- 7.4% (SE) and increased heart rate (HR) 50 +/- 19% (P < 0.01); MAP and UBF were unaffected. Following E2 beta treatment SVR fell 17 +/- 2.4% (P < 0.01), UBF increased more than fourfold, and MAP was unchanged. Compared with E2 beta alone, Phen + E2 beta decreased SVR 42 +/- 4.7%, and MAP fell 11 +/- 1.8% (P < 0.05) despite 40-50% increases in HR and cardiac output (P < 0.05). Responses to Sar + E2 beta were similar to E2 beta alone, except for a fall in MAP, whereas responses to Sar + Phen + E2 beta resembled those of Phen + E2 beta. E2 beta-induced uterine vasodilation was unaltered by Sar and/or Phen. During E2 beta-induced vasodilation, MAP is maintained by enhanced activation of the alpha-adrenergic and renin-angiotensin systems; however, uterine vascular responses to E2 beta are independent of both systems and perfusion pressure.

Quinolinic acid and kynurenine pathway metabolism in inflammatory and non-inflammatory neurological disease

Neurological dysfunction, seizures and brain atrophy occur in a broad spectrum of acute and chronic neurological diseases. In certain instances, over-stimulation of N-methyl-D-aspartate receptors has been implicated. Quinolinic acid (QUIN) is an endogenous N-methyl-D-aspartate receptor agonist synthesized from L-tryptophan via the kynurenine pathway and thereby has the potential of mediating N-methyl-D-aspartate neuronal damage and dysfunction. Conversely, the related metabolite, kynurenic acid, is an antagonist of N-methyl-D-aspartate receptors and could modulate the neurotoxic effects of QUIN as well as disrupt excitatory amino acid neurotransmission. In the present study, markedly increased concentrations of QUIN were found in both lumbar cerebrospinal fluid (CSF) and post-mortem brain tissue of patients with inflammatory diseases (bacterial, viral, fungal and parasitic infections, meningitis, autoimmune diseases and septicaemia) independent of breakdown of the blood-brain barrier. The concentrations of kynurenic acid were also increased, but generally to a lesser degree than the increases in QUIN. In contrast, no increases in CSF QUIN were found in chronic neurodegenerative disorders, depression or myoclonic seizure disorders, while CSF kynurenic acid concentrations were significantly lower in Huntington's disease and Alzheimer's disease. In inflammatory disease patients, proportional increases in CSF L-kynurenine and reduced L-tryptophan accompanied the increases in CSF QUIN and kynurenic acid. These responses are consistent with induction of indoleamine-2,3-dioxygenase, the first enzyme of the kynurenine pathway which converts L-tryptophan to kynurenic acid and QUIN. Indeed, increases in both indoleamine-2,3-dioxygenase activity and QUIN concentrations were observed in the cerebral cortex of macaques infected with retrovirus, particularly those with local inflammatory lesions. Correlations between CSF QUIN, kynurenic acid and L-kynurenine with markers of immune stimulation (neopterin, white blood cell counts and IgG levels) indicate a relationship between accelerated kynurenine pathway metabolism and the degree of intracerebral immune stimulation. We conclude that inflammatory diseases are associated with accumulation of QUIN, kynurenic acid and L-kynurenine within the central nervous system, but that the available data do not support a role for QUIN in the aetiology of Huntington's disease or Alzheimer's disease. In conjunction with our previous reports that CSF QUIN concentrations are correlated to objective measures of neuropsychological deficits in HIV-1-infected patients, we hypothesize that QUIN and kynurenic acid are mediators of neuronal dysfunction and nerve cell death in inflammatory diseases. Therefore, strategies to attenuate the neurological effects of kynurenine pathway metabolites or attenuate the rate of their synthesis offer new approaches to therapy.

No-scalpel vasectomy: a technique for family physicians

Family physicians frequently perform outpatient vasectomies. A new approach to exposing the vas deferens, called the no-scalpel vasectomy, results in fewer complications and, the authors believe, improved patient acceptance. This technique, which calls for two specialized instruments, is described, along with patient selection and education issues, vasal occlusion techniques and post-vasectomy follow-up.

Early viral brain invasion in iatrogenic human immunodeficiency virus infection

We report a 68-year-old man who received an IV inoculation of WBCs for an indium radionuclide scan containing 600 to 700 tissue culture infectious doses of human immunodeficiency virus type 1 (HIV-1) from an HIV-1-infected individual. The recipient immediately received zidovudine, then was switched to dideoxyinosine and interferon-alpha, but died of hepatorenal syndrome and hepatic encephalopathy 15 days later. HIV-1 cultures were positive from the recipient's blood on day 14 but not days 0, 1, and 8. At autopsy, cultures of parietal lobe isolated HIV-1. HIV-1 nucleic acid was present in several brain areas, but not in several other organs, by two independent laboratories using the polymerase chain reaction. The brain showed mild perivascular cuffing and a mild lymphocytic meningitis, but there was no evidence of glial nodules, giant cells, or white matter abnormalities. HIV-1 pg41 viral antigen was seen by immunoperoxidase staining in rare infiltrating cells within perivascular and subpial spaces. Thus, HIV-1 was isolated from brain 15 days after mistaken HIV-1 inoculation and 1 day after virus was first recovered from blood.

Human type A botulism and treatment with 3,4-diaminopyridine

3,4-diaminopyridine was evaluated for its ability to improve muscle strength, respiratory function and electromyographic compound muscle action potentials in human botulism. In a double blind, placebo controlled study, 3,4-diaminopyridine failed to improve these parameters in a 31-year old patient with severe food-borne type A botulism. The addition of an anti-cholinesterase medication to the 3,4-diaminopyridine did not add any benefit. Lack of clinical improvement from 3,4-diaminopyridine in this patient differed from some reports of benefit in animals experimentally poisoned with type A botulinum toxin.

Noninvasive preoperative cortical localization by magnetic source imaging

The authors successfully used magnetoencephalography and MR data to localize the sensorimotor cortex in two patients prior to neurosurgery; preoperative localization influenced surgical management.

Hemodynamics and organ blood flow in fetal sheep subjected to chronic anemia

To investigate cardiovascular adaptation to chronic anemia we studied eight ovine fetuses made anemic by serial isovolemic hemorrhage and seven nonanemic controls. After 1 wk carotid arterial oxygen content was reduced to 1.6 +/- 0.2 ml/dl and hematocrit to 13.3 +/- 1.6% in anemic fetuses compared with 6.9 +/- 1.2 ml/dl and 32.4 +/- 3.9% in controls. Cardiac output was higher in the anemic group (753 +/- 102 vs. 490 +/- 66 ml.min-1.kg fetus-1) as stroke volume and heart rate both increased. Blood flow to the carcass, skin, kidneys, intestines, brain, and heart was increased. Vascular resistance fell in all tissues except the placenta. Central venous pressure, arterial pH, plasma total protein, and blood volume were not different although extravascular fluid accumulated in six of the anemic fetuses. The estimated capillary hydrostatic pressure was greater in anemic (7.6 +/- 1.8 mmHg) than control fetuses (5.0 +/- 1.5 mmHg) and the ratio of precapillary to postcapillary resistance was less. We conclude that reduction in the ratio of precapillary to postcapillary resistance in chronic fetal anemia increases blood flow, oxygen delivery, and capillary hydrostatic pressure.

Aiding the Alzheimer's dementia patient to live in safety and security

Alzheimer's is truly a "family" disease, affecting not only the patient but the entire family. The patient's emotional/psychological safety and security are as important as his or her physical condition, and therefore must be addressed. Families should be encouraged to use every resource that is available. The nurse/caregiver is in an excellent position to offer support and suggest resources. The key is understanding the course of the disease and measures that can be employed to maintain the patient in optimal safety and security.

Advances in the treatment of unstable angina pectoris

The pathogenesis, clinical manifestations and diagnosis, and drug and nondrug therapies of unstable angina pectoris are reviewed. Coronary-artery plaque fissure and rupture, with subsequent platelet aggregation and thrombosis, are the primary underlying stimuli for unstable angina. Unstable angina has been defined as consisting of new-onset angina; angina that is increasing in frequency, intensity, or duration (crescendo angina); or angina at rest. The diagnosis of unstable angina is based on the clinical presentation, electrocardiographic findings, the lack of evidence of myocardial infarction (MI), exercise testing, and coronary angiography. I.V. nitroglycerin is the cornerstone of medical therapy for unstable angina, it relieves chest pain and has a short onset of action. I.V. nitroglycerin, however, has not been shown to reduce the occurrence of MI or death, and its beneficial effects may decrease over time. Aspirin reduces the occurrence of MI and death in patients with unstable angina, but the ideal dosage has not been established. Heparin may reduce the frequency of angina and MI, but its effect on mortality is unknown. Nifedipine has produced beneficial effects in small trials, whereas larger trials have suggested that the drug has deleterious effects when used in the treatment of unstable angina. Verapamil and diltiazem may be effective in relieving chest pain. Calcium-channel blockers have generally not been proved to reduce the risk of MI and death. Data evaluating the efficacy of beta-adrenergic blockers as monotherapy for unstable angina are lacking; these drugs should not be used in patients with vasospastic or Prinzmetal's angina. Thrombolytic therapy has produced mixed results when used in the treatment of unstable angina. Nondrug therapies for unstable angina include intra-aortic balloon counterpulsation, percutaneous transluminal coronary angioplasty, and coronary-artery bypass surgery. Numerous drug and nondrug therapies may be employed in the treatment of unstable angina pectoris.

Displacement of hepatic ornithine carbamoyltransferase from mitochondria to cytosol in Reye's syndrome

In two patients with fatal Reye's Syndrome, total ornithine carbamoyltransferase (OCTase) activity in the liver was 50 and 75% of that found in three control livers. The levels of enzymatic activity would not be expected to have resulted in the 7- and 17-fold elevations in plasma ammonia levels found in the patients. Levels of 47 and 60% of the OCTase activity, however, were found in the cytosolic fraction compared to an average of 7% for control livers. Thus, the amount of enzymatic activity in the mitochondrial fractions was only 20 and 30% of that found in control mitochondrial fractions. This study suggests that, if only mitochondrial OCTase is active in the urea cycle, the decreases in functional enzyme found in Reye's Syndrome may be considerably greater than that reflected in total enzyme assays.

Successful term delivery by cesarean section in a patient with a continent ileocecal urinary reservoir

Childbirth in a mother with a continent urinary reservoir to our knowledge has not been previously reported. The effects of the gravid uterus on the reservoir are presented, as well as management of the pregnancy and delivery.

Influenza A virus in the mouse: hepatic and cerebral lesions in a Reye's syndrome-like illness

To develop an animal model of Reye's syndrome using a virus associated with the human disease, mice were intravenously inoculated with influenza A/PR8 virus (LD50 4000 haemagglutinin units). One to 3 days later the mice developed lethargy, seizures, coma and death. The cerebrospinal fluid cell count was normal. Serum aspartate aminotransferase levels increased 24-fold. Diffuse microvesicular fatty metamorphosis along with multiple small foci of necrosis developed in the liver. Influenza virus-like particles were seen by electron microscopy in the liver, primarily in areas of liver necrosis, but were not seen in the brain. Cerebral oedema without inflammation developed in the brain. Limited viral replication occurred within the liver. Influenza viral antigens were seen in 5-20% of hepatocytes from both necrotic and non-necrotic areas as well as in brain endothelial cells. Many of the clinical, biochemical and pathologic features of the mouse illness resemble those seen in Reye's syndrome. However, this model differs from the human disease in that focal areas of liver necrosis occurred along with limited complete viral replication in liver.

Metabolic emergencies in obstetrics

This article reviews maternal and fetal aspects of diabetic ketoacidosis, thyroid storm, Cushing's syndrome, addisonian crisis, pheochromocytoma, and hyper- and hypothyroidism.

Pharmacokinetics and elimination of salicylic acid in rabbits

Sodium salicylate was administered to rabbits in order to compare its disposition with that in other major and minor agricultural species. A dose of 44 mg/kg was given orally (p.o.) or intravenously (i.v.), and plasma and urine samples were collected for 36 h and 96 h, respectively. The majority of the drug was excreted as salicylic acid (SA) within 12 h. The major metabolites following an oral dose were salicyluric acid (SUA) and the glucuronide conjugates of SA and SUA. Following i.v. dosing, sulfate conjugates of both SA and SUA were also evident. Both SA and SUA were detected in plasma. Following i.v. administration, SA was distributed with a Vss of 0.249 +/- 0.082 l/kg and cleared at a rate of 0.0432 +/- 0.006 l/h/kg. The biological half-life, calculated from the terminal disposition-rate constant, was 4.3 h (i.v.) or 9.7 h (p.o.). The urinary elimination pattern of SA and metabolites in the rabbit was similar to that previously reported by our laboratories for cattle and goats, although total recovery of the administered dose was not as high as for the latter two species. However, the volume of distribution was larger than for cattle and goats, and rabbits cleared the drug more slowly than those species. As a consequence, the biological half-life was eight to ten times longer than in the ruminants studied previously.

Neurocysticercosis: neurologic, pathogenic, diagnostic and therapeutic aspects

Worldwide neurocysticercosis is the most common parasitic infection of the human brain and meninges. Clinical features of the illness vary with the stage of ova infection, but most problems arise when the mature cyst degenerates. Seizures, increased intracranial pressure, and focal neurologic signs then often develop. Computed tomography and magnetic resonance usually demonstrate Cysticercus cellulosae cysts in the brain. A new immunoblot test for antibodies to the cysticercus seems both sensitive and specific. Treatment with praziquantel or albendazole has hastened the disappearance of the cysts on computed tomography and improved clinical symptoms.

Neuropathologic findings in Reye syndrome

Brain tissue from three patients with a clinical diagnosis of Reye syndrome was compared with tissue from three control patients. All Reye syndrome patients demonstrated cytotoxic cerebral edema, with swelling of astrocyte foot processes, which was not seen in controls. Myelin sheath splitting was seen both in controls and patients, but myelin blebs were uncommon in both. Mitochondrial changes also were not seen. Although cerebral edema is a nonspecific finding, it appears to be characteristic of Reye syndrome.

Comparative experimental viral labyrinthitis

Because of difficulties in studying acute deafness and vertigo in humans, animal models of viral labyrinthitis have played an important role in increasing our understanding of how viruses damage the inner ear. Investigators have been able to correlate viral labyrinthine infection to histopathologic changes and electrophysiologic consequences in experimental animals. Experimental viral labyrinthitis studies have convincingly demonstrated the selective vulnerability of inner ear cell types to different viruses. These findings are relatively consistent across animal species for many viruses. By understanding the pathogenesis of viral labyrinthitis in an animal model, we may learn how better to prevent or treat virus-induced deafness and vertigo in humans.

Pre-mortem diagnosis of Creutzfeldt-Jakob disease by detection of abnormal cerebrospinal fluid proteins

Creutzfeldt-Jakob disease (CJD) may be difficult to diagnose early or when it has an atypical presentation. We describe two patients with progressive dementia in whom the results of diagnostic brain biopsies were unhelpful. Spinal fluid from these patients, analyzed by two-dimensional electrophoresis, contained two abnormal proteins (Nos. 130 and 131, with relative molecular masses of 26,000 and 29,000 daltons and isoelectric points of 5.2 and 5.1). These findings suggested a provisional diagnosis of Creutzfeldt-Jakob disease, which was confirmed in both patients at autopsy. Detection of these abnormal cerebrospinal fluid proteins appears to be a valuable laboratory adjunct in evaluating patients with an unexplained progressive dementia.

Pharmacokinetics of flunixin meglumine in lactating cattle after single and multiple intramuscular and intravenous administrations

The pharmacokinetics of flunixin were studied in 6 adult lactating cattle after administration of single IV and IM doses at 1.1 mg/kg of body weight. A crossover design was used, with route of first administration in each cow determined randomly. Plasma and milk concentrations of total flunixin were determined by use of high-pressure liquid chromatography, using an assay with a lower limit of detection of 50 ng of flunixin/ml. The pharmacokinetics of flunixin were best described by a 2-compartment, open model. After IV administration, mean plasma flunixin concentrations rapidly decreased from initial concentrations of greater than 10 micrograms/ml to nondetectable concentrations at 12 hours after administration. The distribution phase was short (t1/2 alpha, harmonic mean = 0.16 hours) and the elimination phase was more prolonged (t1/2 beta, harmonic mean = 3.14 hours). Mean +/- SD clearance after IV administration was 2.51 +/- 0.96 ml/kg/min. After IM administration, the harmonic mean for the elimination phase (t1/2 beta) was prolonged at 5.20 hours. Bioavailability after IM dosing gave a mean +/- SD (n = 5) of 76.0 +/- 28.0%. Adult, lactating cows (n = 6) were challenge inoculated with endotoxin as a model of acute coliform mastitis. After multiple administration (total of 7 doses; first IV, remainder IM) of 1.1 mg/kg doses of flunixin at 8-hour intervals, plasma flunixin concentrations were approximately 1 microgram/ml at 2 hours after each dosing and 0.5 micrograms/ml just prior to each dosing. Flunixin was not detected in milk at any sampling during the study.(ABSTRACT TRUNCATED AT 250 WORDS)

The sequence of changes in liver and brain in the influenza B virus mouse model of Reye's syndrome

The time course of morphologic changes in the influenza B mouse model of Reye's syndrome is described and compared to the clinical, virologic, and biochemical changes. Following an intravenous inoculation of a lethal dose of an egg adapted strain of influenza B/Lee/40 virus, mice first showed clinical signs of lethargy and ruffled fur at 12 hours (h) post inoculation (pi). The earliest morphologic changes in the liver occurred at 12 h pi, and consisted of a slight increase in fat and loss of glycogen in hepatocytes. Over the next 36 h, the accumulation of microvesicular fat increased, and mitochondrial abnormalities such as pleomorphism and loss of dense bodies developed. There was no increase in peroxisomes. In the brain, focal cerebral edema was detected as early at 6-12 h pi. The edema, manifested as swelling of astrocytic foot processes, increased in severity with time. Endothelial cells were not abnormal. Myelin sheath splitting rarely was observed. Since changes occurred simultaneously in the liver and in the brain, we suggest that influenza B virus caused a simultaneous primary insult to both organs.

Elimination of salicylic acid in goats and cattle

Sodium salicylate was administered to cattle and goats IV and PO according to a crossover design. Total urinary excretion of SA and its metabolites was measured for 3 days after dosing. Salicyluric acid (SUA) was the only metabolite detected in urine of either species. Recovery of sodium salicylate and SUA in goats amounted to 67.9 and 34.6% of the dose, respectively, after IV administration. After oral dosing, total recoveries were 30.2% (sodium salicylate) and 71.7% (SUA) of dose. By comparison, cattle excreted significantly (P less than 0.05) less sodium salicylate (54.0%) and more SUA (49.9%) after IV dosing. The same pattern was observed after oral administration, wherein cattle excreted less than 12% as sodium salicylate and more than 99% as SUA. In both species, almost 90% of the drug excreted as sodium salicylate was found in urine within the first 12 hours after an IV dose and within 24 hours after oral dosing. The excretion of SUA was somewhat slower in both species, especially after oral administration. The data suggested that there were only quantitative differences in the metabolism and elimination of sodium salicylate between the 2 species, with cattle excreting a higher proportion of the drug as the glycine conjugate SUA.

The influenza B virus mouse model of Reye's syndrome: clinical, virologic and morphologic studies of the encephalopathy

The influenza B virus mouse model of Reye's syndrome was studied to learn more about the encephalopathy in Reye's syndrome. One to 3 days after intravenous influenza B/Lee virus, Balb/c mice became lethargic, seized and lapsed into a fatal coma. Wide-spread cerebral edema without inflammation developed 1-3 days after virus inoculation. Swollen astrocytic foot processes containing increased glial fibrillary acidic protein were located around capillaries. Viral particles were not seen by electron microscopy and complete viral replication did not occur. Immunohistochemical studies demonstrated influenza B viral antigen within many endothelial cells but not within other brain cells. Qualitative (Evans blue dye) and quantitative (percent brain water and technetium -99 pertechnetate) studies of the blood-brain barrier demonstrated abnormalities. This model reproduced many clinical, virologic and pathologic features of the Reye's syndrome encephalopathy. In addition, a non-permissive viral infection of brain endothelial cells occurred which may be important in the pathogenesis of the mouse encephalopathy and may participate in the encephalopathy of Reye's syndrome.

Influence of Rhodococcus equi on the respiratory burst of resident alveolar macrophages from adult horses

Opsonized Rhodococcus equi activated the respiratory burst of resident alveolar macrophages (AM) from adult horses in a logarithmic-linear, mass-related manner. The effect of R equi was not significantly different from that of equal masses of opsonized zymosan A. Therefore, R equi does not appear to attenuate the respiratory burst of equine AM. The stimulatory effect of R equi was not reflected by increased production of superoxide anion (O2-), but increased activity of the hexose monophosphate shunt was observed. These results suggest a similarity between the respiratory burst of AM from horses and that of AM from rabbits. We concluded that resident AM from adult horses do not produce O2- concurrently with an increase in activity of the hexose monophosphate shunt when stimulated with either opsonized zymosan A or opsonized R equi. This suggests that O2- is not an important component of the antibacterial defenses of equine AM. Whether equine AM are incapable of producing O2- or require different stimuli to produce it was not determined.

A possible receptor-binding function for the N-terminus of connective tissue activating peptide III

Connective tissue activating peptide III (CTAP-III) is an 85-residue peptide which has been purified from platelets and shown to possess mitogenic activity toward a variety of fibroblastic cell lines. beta-Thromboglobulin (beta TG) is an 81-residue peptide which is derived from CTAP-III by cleavage of the N-terminal tetrapeptide Asn-Leu-Ala-Lys which results in the loss of mitogenic activity. The near-UV CD spectra for the two proteins indicated that the conformations as well as the electronic environments of the two disulfide bonds, and also of the single aromatic tyrosine residue, were similar in CTAP-III and beta TG. However, differences in the far-UV CD spectra of these proteins indicated a substantial decrease in alpha-helical content for beta TG (29%) as compared to CTAP-III (38%). Structure prediction analysis also suggested that the longer N-terminal segment of CTAP-III may form an alpha-helix. The N-terminal region of beta TG, which lacks this tetrapeptide, was predicted to be in an unordered, or possibly a turn, conformation. This predicted structural difference appears to be due to the high helix-forming potential of the N-terminal tetrapeptide Asn-Leu-Ala-Lys in CTAP-III. These results suggest a possible structural role for the N-terminal region of CTAP-III in the expression of the biologic activities of this protein. On the basis of these studies, a reasonable hypothesis to account for the difference in mitogenic activity between beta TG and CTAP-III is that the N-terminal region must be helical for receptor binding to occur.

Antifungal activity in human cerebrospinal fluid and plasma after intravenous administration of Allium sativum

Commercial Allium sativum (garlic) extract was given intravenously to two patients with cryptococcal meningitis and three patients with other types of meningitis. Plasma titers of anti-Cryptococcus neoformans activity rose twofold over preinfusion titers. Anti-C. neoformans activity was detected in four of five cerebrospinal fluid samples but not in pooled normal cerebrospinal fluid.

Deep cerebral infarcts in the People's Republic of China

We reviewed computed tomograms and clinical characteristics for 1,124 consecutive stroke patients from Shanghai, People's Republic of China. While there were many similarities between lacunar syndromes in these patients and patients from Europe and the United States, several differences were noted. Deep cerebral infarcts identified by computed tomography were more common in patients from Shanghai and accounted for 27% of all ischemic infarcts. Small deep infarcts occurred more commonly in women from Shanghai (44%) than in women from the West. Deep cerebral infarcts in patients from Shanghai were larger than those usually seen in patients from the West. The mean infarct volume in patients from Shanghai was 2.4 ml, and 49% were giant lacunes (greater than 15 mm in maximal diameter).