MEG response to median nerve stimulation correlates with recovery of sensory and motor function after stroke

OBJECTIVE

Hemiparesis due to damage by stroke in primary motor cortex (MI) or its underlying projections presents a problem for functional neuroimaging technologies that attempt to evaluate the neurophysiological basis for restoration of motor function. Traditional assessments of MI function require patients to move their fingers, hands, or limbs, which can be either impossible or markedly compromised after stroke. We recently demonstrated in normal subjects that magnetoencephalography (MEG), a non-invasive neuromagnetic functional imaging technique, detects neuronal response elicited by electrical median nerve stimulation in MI, as well as primary somatosensory cortex (SI). In the present study, we used the MEG response from median nerve stimulation to investigate the recovery of primary motor and somatosensory in acute ischemic stroke patients.

METHODS

Twelve patients with unilateral ischemic strokes that affected sensorimotor functions of their hand were studied in the acute stage (4.4+/-1.2 days, mean+/-SD) and during a 1-month follow-up (38.6+/-5.6 days, except for one patient's follow-up done 6 month after stroke).

RESULTS

Among the multiple cortical sources localized after median nerve stimulation, one source localized to SI and another localized to the vicinity of MI. Changes in the source strengths of the first component post-stimulus of MI and SI correlated with the extent of recovery of sensorimotor functions as determined by neurological exams.

CONCLUSIONS

This study provides a novel way of indirectly assessing MI function using MEG during the acute stroke phase, when many patients often cannot perform motor tasks due to paralysis.

A partnership of universities and agri-business for an effective dairy herd management learning experience for undergraduates: the Dairy Challenge

The Dairy Challenge contest allows undergraduate students to apply knowledge gained in the classroom in an evaluation of the management practices of commercial dairy farms. University faculty partnered with industry representatives to develop the competition. Participants in the Dairy Challenge do the following: 1) critically evaluate dairy herd management practices and make recommendations for improvements; 2) visit local dairy farms and gain knowledge of different farms' management practices; 3) meet and interact with potential employers from the dairy industry during the contest; 4) evaluate herd records and utilize knowledge of dairy herd management software and computer presentation tools; 5) test their speaking, presentation, and problem-solving skills; and 6) work as a team to build consensus and tag-team speaking formats. Teams of four undergraduate students critically evaluate a commercial dairy farm using herd records, a description of farm operations, and tour of the farm facilities. The farmer answers questions pertaining to management of the farm in a group interview with all teams and in a separate interview with each individual team. Teams give a 20-min presentation that is scored on the description and assessment of the management practices and recommendations for improvements in management and facilities. Additionally, scoring is based on apparent level of preparation, speaking, presentation skills, and responses to judges' questions. The judges are university specialists and dairy industry professionals. This capstone experience allows students to interact with dairy farmers and representatives from the dairy industry and expands their knowledge and skills gained during their academic career.

Oculopharyngeal muscular dystrophy in Hispanic New Mexicans

CONTEXT

Oculopharyngeal muscular dystrophy (OPMD) is a rare myopathy caused by polyalanine triplet repeat expansion in the gene for poly(A) binding protein 2 (PABP2) and is found in isolated cohorts throughout the world. We have observed numerous cases of OPMD in New Mexico.

OBJECTIVE

To characterize the clinical, genetic, and demographic features of the OPMD population in New Mexico.

DESIGN, SETTING, AND PARTICIPANTS

Cohort study with analysis of outpatient clinic medical records from 1965 to 2001 at the University of New Mexico Hospital and the New Mexico VA Health Care System in Albuquerque, which serve the entire state.

MAIN OUTCOME MEASURES

Clinical phenotype, supplemented with genetic confirmation (n = 10 patients) and in-depth clinical evaluations (n = 49 patients).

RESULTS

We identified 216 cases of OPMD (99 women and 117 men) from 39 kindreds of New Mexicans spanning up to 4 generations. All patients were Hispanic, and the majority of probands came from northern New Mexico. In patients who had both ocular and pharyngeal muscle weakness, ptosis was just as likely to occur before or concurrent with dysphagia. Proximal limb muscle weakness and gait abnormalities were common and occurred later than ocular or pharyngeal weakness. The clinical expression of OPMD caused marked debility, although life-table analysis showed no decrease in life expectancy compared with unaffected family members (P =.81). Ten individuals from different kindreds were found to have an identical polyalanine triplet repeat expansion ([GCG](9)) in the PABP2 gene.

CONCLUSIONS

Individuals in this cohort had clinical and genetic characteristics of classic OPMD. Longevity was not affected, but patients experienced considerable morbidity. The origin of the PABP2 mutation in New Mexican OPMD patients is unclear, although the geographic and genetic isolation of northern New Mexicans with a long ancestry in this region may have contributed to the development of this cohort. This disease cohort represents a large and previously unrecognized health care issue in the state of New Mexico and should serve to raise the awareness of this disorder among clinicians who treat Hispanics in the Southwest and throughout the United States.

Experimental influenza B viral myositis

To investigate the pathogenesis of influenza myositis in animals, juvenile BALB/c mice were inoculated with influenza B/Lee virus intramuscularly into the right quadriceps muscle. Chicken normal allantoic fluid (NAF) or phosphate-buffered saline (PBS) was injected into the left quadriceps of control mice and in some virus-infected mice. Serum creatinine phosphokinase (CPK) levels rose significantly on days 1 and 2 post-inoculation (PI) in only virus-inoculated mice. On days 2 and 3 PI, right quadriceps muscles developed scattered foci of a predominantly mononuclear inflammation in the perimysial connective tissue often adjacent to degenerating or necrotic muscle fibers. Immunofluorescent staining with specific anti-influenza B virus antisera showed muscle fibers that contained specific staining in nuclei and adjacent cytoplasm. Skip areas of staining within muscle fibers suggested that not all muscle nuclei within an individual muscle fiber were infected. A continuous fall in infectious virus titer in the right quadriceps muscles suggested the initial virus inoculum became inactivated and progeny virions were not produced. Left quadriceps muscle never had muscle necrosis or endomysial inflammation, specific staining of viral antigen, virus isolation, or viral RNA detected by the reverse transcriptase polymerase chain reaction assay. These findings support the hypothesis that a non-permissive influenza viral infection can develop in murine skeletal muscle that can damage specific nuclear domains of muscle fibers producing muscle degeneration or necrosis. A similar type of muscle infection may develop in humans that occasionally develop focal myositis during influenza.

Epidemic typhus meningitis in the southwestern United States

A patient residing in New Mexico had murine typhus diagnosed. A novel molecular assay was performed at the Centers for Disease Control and Prevention, and Rickettsia prowazekii, the agent of epidemic typhus, was found, rather than R. typhi. To our knowledge, this is the first reported case of epidemic typhus confirmed by means of polymerase chain reaction--based testing of cerebrospinal fluid, and it introduces a novel assay for the molecular diagnosis of both epidemic and murine typhus.

Experimental influenza causes a non-permissive viral infection of brain, liver and muscle

To determine whether some constitutional symptoms of influenza, such as headache, myalgia and nausea, could represent a viral infection of brain, muscle, and liver, we inoculated juvenile Balb/c mice intranasally with 103 plaque forming units of influenza B/Lee virus. Blood, brain, liver, skeletal muscle, and lung tissues were removed aseptically and assayed for infectivity by a plaque assay, viral RNA by reverse transcriptase-polymerase chain reaction (RT - PCR), viral antigen by immunoperoxidase staining, and histologic changes by light microscopy. Mice became ill 2 - 3 days post inoculation (PI). A productive viral infection of the lungs developed from days 1 - 8 with maxima of virus titers, pneumonia, and the number of immunoperoxidase staining lung cells occurring on days 2 - 6 PI. Virus isolation from blood was rare and viral RNA was detected intermittently in blood by RT - PCR. In many animals, a non-permissive or abortive infection of brain occurred from days 1 - 8 and peaked on days 3 - 4 PI. Viral RNA was detected in brain tissue and viral antigen was seen in cerebral endothelial cells but infectious virus was rarely isolated from brain. In liver, viral RNA was detected and viral antigen was seen occasionally in hepatocytes. In skeletal muscle, viral RNA was detected but neither infectious virus nor viral antigen was seen. A correlation existed between the severity of the illness, pneumonia, lung virus titer, viral antigen in lung cells, and extent of a non-permissive viral infection of brain and liver but not muscle. These studies demonstrate that following intranasal infection of influenza virus in mice, a viral pneumonia develops with subsequent intermittent viremia and non-permissive or abortive infection of brain, liver and muscle.

Intranuclear inclusions in oculopharyngeal muscular dystrophy contain poly(A) binding protein 2

Intranuclear inclusions are one of the ultrastructural hallmarks of oculopharyngeal muscular dystrophy (OPMD), a disorder caused by small polyalanine (GCG) expansions in the gene that codes for a ubiquitous nuclear protein called poly(A) binding protein 2 (PABP2). We studied OPMD skeletal muscle and found that 1.0 to 10.0% of myocyte nuclei contained discreet PABP2 immunoreactive intranuclear inclusions, providing the first direct evidence of the relation between the proposed gene for OPMD and the pathology of OPMD.

Fungal infections of the central nervous system

This review discusses a practical approach to the patient with possible fungal infection of the central nervous system (CNS). Difficulties in establishing the diagnosis come from the nonspecific clinical syndromes (subacute meningitis, meningoencephalitis, and brain abscess) and the low isolation rate of fungi from cerebrospinal fluid (CSF). Helpful diagnostic clues often come from knowledge of the patient's geographic travels, risk factors, evidence of systemic organ infection, and fungal serologic tests. Standard and new antifungal agents are evaluated and the initial and suppressive drug management of the common fungal infections is presented.

Hemodynamic effects of ionized calcium in horses anesthetized with halothane or isoflurane

OBJECTIVES

To evaluate the effects of halothane and isoflurane on cardiovascular function and serum total and ionized calcium concentrations in horses, and to determine whether administration of calcium gluconate would attenuate these effects.

ANIMALS

6 clinically normal adult Thoroughbreds.

PROCEDURE

Catheters were inserted for measurement of arterial blood pressures, pulmonary arterial blood pressures, right ventricular pressure (for determination of myocardial contractility), right atrial pressure, and cardiac output and for collection of arterial blood samples. Anesthesia was then induced with xylazine hydrochloride and ketamine hydrochloride and maintained with halothane or isoflurane. An i.v. infusion of calcium gluconate was begun 75 minutes after anesthetic induction; dosage of calcium gluconate was 0.1 mg/kg of body weight/min for the first 15 minutes, 0.2 mg/kg/min for the next 15 minutes, and 0.4 mg/kg/min for an additional 15 minutes. Data were collected before, during, and after administration of calcium gluconate.

RESULTS

Halothane and isoflurane decreased myocardial contractility, cardiac index, and mean arterial pressure, but halothane caused greater depression than isoflurane. Calcium gluconate attenuated the anesthetic-induced depression in cardiac index, stroke index, and maximal rate of increase in right ventricular pressure when horses were anesthetized with isoflurane. When horses were anesthetized with halothane, a higher dosage of calcium gluconate was required to attenuate the depression in stroke index and maximal rate of increase in right ventricular pressure; cardiac index was not changed with calcium administration.

CONCLUSIONS AND CLINICAL RELEVANCE

I.v. administration of calcium gluconate may support myocardial function in horses anesthetized with isoflurane.

Myocardial blood flow and coronary reserve in chronically anemic fetal lambs

Chronic fetal anemia produces large compensatory increases in coronary blood flow in the near-term fetal lamb. To determine if increased coronary flow in anemic fetuses is associated with decreased coronary flow reserve or, alternatively, an increase in coronary conductance, we measured maximal coronary artery conductance during adenosine infusion before and during anemia. Isovolemic hemorrhage over 7 days reduced hematocrit from 30.6 +/- 2. 7 to 15.8 +/- 2.4% (P < 0.02) and the oxygen content from 7.3 +/- 1. 4 to 2.6 +/- 0.4 ml/dl (P < 0.001). Coronary blood flow increased from control (202 +/- 60) to 664 +/- 208 ml. min(-1). 100 g(-1) with adenosine to 726 +/- 169 ml. min(-1). 100 g(-1) during anemia and to 1,162 +/- 250 ml. min(-1). 100 g(-1) (left ventricle) during anemia with adenosine infusion (all P < 0.001). Coronary conductance, determined during maximal vasodilation, was 18.2 +/- 7.7 before and 32.8 +/- 11.9 ml. min(-1). 100 g(-1). mmHg(-1) during anemia (P < 0. 001). Coronary reserve, the difference between resting and maximal myocardial blood flow interpolated at 40 mmHg, was unchanged in control and anemic fetuses (368 +/- 142 and 372 +/- 201 ml/min). Because hematocrit affects viscosity, anemic fetuses were transfused with blood to acutely increase the hematocrit back to control, and conductance was remeasured. Coronary blood flow decreased 57.3 +/- 18.9% but was still 42.6 +/- 18.9% greater than control. We conclude that in chronically anemic fetal sheep coronary conductance is increased and coronary reserve is maintained, and this is attributed in part to angiogenesis as well as changes in viscosity.

Techniques for evaluation of right ventricular relaxation rate in horses and effects of inhalant anesthetics with and without intravenous administration of calcium gluconate

OBJECTIVES

To determine the most repeatable method for evaluating right ventricular relaxation rate in horses and to determine and compare effects of isoflurane or halothane with and without the added influence of intravenously administered calcium gluconate on right ventricular relaxation rates in horses.

ANIMALS

6 Thoroughbred horses from 2 to 4 years old.

PROCEDURE

6 models (2 for monoexponential decay with zero asymptote, 3 for monoexponential decay with variable asymptote, and 1 for biexponential decay) for determining right ventricular relaxation rate were assessed in conscious and anesthetized horses. The 2 methods yielding the most repeatable results then were used to determine right ventricular relaxation rates in horses anesthetized with isoflurane or halothane before, during, and after i.v. administration of calcium gluconate. Right ventricular pressure was measured, using a catheter-tip high-fidelity pressure transducer, and results were digitized at 500 Hz from minimum rate of change in ventricular pressure.

RESULTS

2 models that used monoexponential decay with zero asymptote repeatedly produced an estimate for relaxation rate and were used to analyze effects of anesthesia and calcium gluconate administration on relaxation rate. Isoflurane and halothane each prolonged right ventricular relaxation rate, with greater prolongation evident in halothane-anesthetized horses. Calcium gluconate attenuated the anesthesia-induced prolongation in right ventricular relaxation rate, with greater response obtained in isoflurane-anesthetized horses.

CONCLUSIONS AND CLINICAL RELEVANCE

Right ventricular relaxation rate in horses is assessed best by use of a monoexponential decay model with zero asymptote and nonlinear regression. Intravenous administration of calcium gluconate to isoflurane-anesthetized horses best preserves myocardial relaxant function.

Differentiation of atrioventricular blocks

In closing, it has been the purpose of this article to present and elaborate on the types of AV blocks, their clinical significance and causes, nursing interventions, and treatments associated with their management. The nurse that has knowledge of these heart blocks will be well equipped and prepared to promptly treat a patient suffering from AV block.

Autosomal dominant cerebral arteriopathy: neuropsychiatric syndrome in a family

Though familial vascular leukoencephalopathy was described two decades ago, recent studies focus on a disorder termed Cerebral Autosomal Dominant Arteriopathy with Subcortical Infarcts and Leukoencephalopathy (CADASIL), a dominantly inherited disorder causing recurrent strokes and eventual dementia. The phenotypic boundaries of CADASIL remain indistinct and novel clinical features continue to arise in the literature. However, the associated histopathology is fairly consistent, typically demonstrating granular thickening of cerebral arterioles. The authors evaluated a 38-year-old man who suffered from progressive change in personality and intellect. His father, paternal aunt, and older sister had succumbed to a similar disorder. The authors examined relatives from three generations, including another sister with transient focal symptoms followed by persisting psychiatric disorder, and reviewed the radiographic studies from the propositus and his siblings. All the siblings showed diffuse white matter signal change on magnetic resonance imaging. Brain biopsy from the propositus revealed normal cortex and white matter but granular sclerosis of leptomeningeal arterioles. While the family's illness likely represents another instance of CADASIL, their presentation is unique because neuropsychiatric disorders predominate over focal ischemic symptoms.

Ascertaining hypoglycorrhachia in an acute patient

A study was undertaken in an urgent clinical setting to determine whether the use of a cerebrospinal fluid (CSF) to blood glucose ratio is appropriate for describing the relationships between CSF glucose and blood glucose in patients who had not fasted. Blood glucose levels were obtained before a lumbar puncture in 79 adults who had normal CSF findings. Regression analysis of CSF glucose and blood glucose levels of these patients who had not fasted, as well as data from four published studies of normal blood and CSF glucose levels, indicated that a ratio was not a valid measure of the normal relationship between CSF and blood. Only when the blood glucose level was between 89 and 115 mg/dL was the relationship within the expected "ratio" of 0.60 to 0.70. In hyperglycemic states, the normal relationship may be substantially lower than 0.50. a nomogram is presented which is useful in determining hypoglycorrhachia when the patient is hyperglycemic.

Office procedures. No-scalpel vasectomy

Vasectomy is a safe, permanent, and inexpensive method of surgical sterilization for men. No-scalpel vasectomy is an innovative approach for exposing the vas deferens that is associated with fewer complications than the standard technique of vasectomy (incisional). It has been used in this country since 1986. The no-scalpel vasectomy, preoperative counseling, management of complications, and evaluation of the postvasectomy semen specimen are described.

Purine metabolism and inhibition of xanthine oxidase in severely hypoxic neonates going onto extracorporeal membrane oxygenation

The effect of allopurinol to inhibit purine metabolism via the xanthine oxidase pathway in neonates with severe, progressive hypoxemia during rescue and reperfusion with extracorporeal membrane oxygenation (ECMO) was examined. Twenty-five term infants meeting ECMO criteria were randomized in a double-blinded, placebo-controlled trial. Fourteen did not receive allopurinol, whereas 11 were treated with 10 mg/kg after meeting criteria and before cannulation, in addition to a 20-mg/kg priming dose to the ECMO circuit. Infant plasma samples before cannulation, and at 15, 30, 60, and 90 min, and 3, 6, 9, and 12 h on bypass were analyzed (HPLC) for allopurinol, oxypurinol, hypoxanthine, xanthine, and uric acid concentrations. Urine samples were similarly evaluated for purine excretion. Hypoxanthine concentrations in isolated blood-primed ECMO circuits were separately measured. Hypoxanthine, xanthine, and uric acid levels were similar in both groups before ECMO. Hypoxanthine was higher in allopurinol-treated infants during the time of bypass studied (p = 0.022). Xanthine was also elevated (p < 0.001), and uric acid was decreased (p = 0.005) in infants receiving allopurinol. Similarly, urinary elimination of xanthine increased (p < 0.001), and of uric acid decreased (p = 0.04) in treated infants. No allopurinol toxicity was observed. Hypoxanthine concentrations were significantly higher in isolated ECMO circuits and increased over time during bypass (p < 0.001). This study demonstrates that allopurinol given before cannulation for and during ECMO significantly inhibits purine degradation and uric acid production, and may reduce the production of oxygen free radicals during reoxygenation and reperfusion of hypoxic neonates recovered on bypass.

Hemodynamic effects of calcium gluconate administered to conscious horses

Calcium gluconate was administered to conscious horses at 3 different rates (0.1, 0.2, and 0.4 mg/kg/min for 15 minutes each). Serum calcium concentrations and parameters of cardiovascular function were evaluated. All 3 calcium administration rates caused marked increases in both ionized and total calcium concentrations, cardiac index, stroke index, and cardiac contractility (dP/dtmax). Mean arterial pressure and right atrial pressure were unchanged; heart rate decreased markedly during calcium administration. Ionized calcium concentration remained between 54% and 57% of total calcium concentration throughout the study. We conclude that calcium gluconate can safely be administered to conscious horses at 0.1 to 0.4 mg/kg/min and that administration will result in improved cardiac function.

Enhanced diallyl trisulfide has in vitro synergy with amphotericin B against Cryptococcus neoformans

Although amphotericin B remains the drug of choice for systemic fungal infections, its use is limited by considerable side effects. In The Peoples' Republic of China, commercial Allium sativum derived compounds are widely used as an antifungal drug to treat systemic fungal infections. To evaluate the scientific merit of using A. sativum derived compounds as antifungal agents, we studied a Chinese commercial preparation, allitridium. This preparation contained mainly diallyl trisulfide as confirmed by high performance liquid chromatography. Allitridium, with and without amphotericin B, was tested to determine its efficacy in killing three isolates of Cryptococcus neoformans. The minimum inhibitory concentration of the commercial preparation was 50 micrograms/ml and the minimum fungicidal concentration was 100 micrograms/ml against 1 x 10(5) organisms of C. neoformans. In addition, the commercial preparation was shown to be synergistic with amphotericin B in the in vitro killing of C. neoformans. This study demonstrates that diallyl trisulfide and other polysulfides possess potent in vitro fungicidal effects and their activity is synergistic with amphotericin B. These observations lend laboratory support for the treatment of cryptococcal infections with both amphotericin B and the Chinese commercial preparation.

Renal responses to amino acids in the sheep fetus

Adult animals and humans are known to increase renal blood flow and glomerular filtration rate (GFR) in response to an acute protein load or amino acid infusion; however, the ontogeny of this phenomenon is not known. This study was designed to test the hypothesis that, despite normally high baseline amino acid levels in the fetus, increases in plasma amino acids stimulate increases in GFR before birth. Eight chronically instrumented fetal sheep (126 +/- 1 days gestation) were infused with a mixture of amino acids (0.15 and 0.30 mmol . kg-1 . min-1 i.v.). Plasma alpha-amino nitrogen levels increased significantly from 7.1 +/- 0.3 to 13.0 +/- 0.9 and 25.5 +/- 2.1 mg/dl, respectively, in response to the two doses, and GFR increased significantly from 3.2 +/- 0.4 to 4.0 +/- 0.5 and 4.6 +/- 0.5 ml/min, respectively. Arterial pressure did not change. Renal amino acid reabsorption was significantly increased at all time points during the amino acid infusion, reaching a value nearly five times that of control by the last clearance period. Na+ reabsorption was also increased throughout the infusion. Na+, K+, and Cl- excretions increased significantly only at the very last time point. These data indicate that the mechanism or mechanisms responsible for amino acid-induced hyperfiltration are present and functional even before birth in the sheep. Because maternal eating patterns and protein intake are known to change maternal plasma amino acid levels and amino acids are actively transported across the placenta, our findings suggest that both acute and chronic changes in maternal protein intake may alter fetal renal function.

Changes in left thoracic duct lymph flow during progressive anemia in the ovine fetus

OBJECTIVE

The purpose of this study was to evaluate the extent to which increased lymph flow can return fluid and protein to the circulation in the chronically anemic fetus.

STUDY DESIGN

Thoracic duct lymph flow rate over a range of outflow pressures was measured in 8 near-term fetal sheep 4 to 5 days after surgery and daily thereafter for 5 days. After each day's study 60 to 150 ml of blood was withdrawn at a rate of 1 ml per minute. Regression analysis was used to establish the lymph flow function curve. Lymph and plasma protein concentrations and lymph flow rate were compared by analysis of variance for repeated measures.

RESULTS

As the hematocrit was reduced from 34.6% +/- 1.3% (mean +/- SE) to 14.4% +/- 1.0%, thoracic duct lymph flow increased from 0.12 +/- 0.01 to 0.28 +/- 0.02 ml/min/kg. Plasma total protein concentration did not change, lymph protein concentration fell (2.6 +/- 0.1 to 2.4 +/- 0.1 gm/dl), and the difference between plasma and lymph protein concentrations increased (1.04 +/- 0.05 to 1.34 +/- 0.10 gm/dl). Protein returned to the circulation increased from 11.5 +/- 0.3 to 23.7 +/- 1.5 mg per minute. Central venous pressure did not change and remained less than the breakpoint pressure. Although the plateau lymph flow rate increased, neither the breakpoint or stopflow pressures of the lymph flow function curve were altered.

CONCLUSIONS

Fetal lymph flow and thereby capillary filtration increased progressively as anemia became more severe. The increase in lymph flow did not appear to be limited by outflow pressure. By returning protein to the circulation, an increase in thoracic duct lymph flow helped to limit expansion of extravascular fluid volume during chronic fetal anemia.

Right ventricular function in chronically anemic fetal lambs

OBJECTIVE

Our purpose was to determine whether the increase in extravascular fluid in chronic fetal anemia occurs either because of heart failure or despite successful cardiac adaptation.

STUDY DESIGN

Right ventricular function curves were obtained in five ovine fetuses at the start, midpoint, and end of 5 to 8 days of anemia induced by isovolemic daily hemorrhage. Least-squares fit of the ascending and plateau lines of stroke volume versus right atrial pressure were used to establish breakpoints (intersection of the ascending and plateau lines), which were compared by analysis of variance for repeated measures. Myocardial blood flow was measured by microspheres.

RESULTS

Carotid arterial oxygen content was reduced from 7.0 +/- 0.3 to 2.1 +/- 0.1 ml/dl and the hematocrit from 29% +/- 1.8% to 13% +/- 0.6%. Breakpoint analysis of function curves showed that although right atrial pressure remained unchanged (3.4 +/- 0.7 and 3.6 +/- 0.6 mm Hg) stroke volume increased from 1.03 +/- 0.14 to 1.62 +/- 0.25 ml/kg. Both right and left ventricular coronary blood flow were increased, 1351 +/- 313 and 1166 +/- 264 ml/min per 100 gm. Excess fluid was present in abdomen and chest of most animals at autopsy.

CONCLUSION

Tissue edema during severe anemia occurs despite normal right atrial pressure, increased stroke volume, and markedly increased coronary blood flow, markers of successful cardiac adaptation.

Clinical Viral Infections and Temporal Bone Histologic Studies of Patients with AIDS

The brain, eye, and inner ear are each protected from blood-borne infectious agents by a barrier that has some anatomic and functional differences. In patients with AIDS, opportunistic infections of the central nervous system and eye are frequent. Little is known about the incidence of middle and inner ear infections in patients with AIDS, but deafness and severe vertigo are uncommon. We studied 14 homosexual men with AIDS, aged 28 to 55 years, for 1 to 2 years until death. No patient had deafness, but one had vertigo. Adenovirus type 6 and cytomegalovirus were isolated from the middle ear cavity in four patients. Temporal bone histology demonstrated acute otitis media in four, chronic otitis media in two, and serous otitis media in three. Adenovirus type 6 and cytomegalovirus, either alone or with herpes simplex virus type 1, were isolated from inner fluids of three patients. Histologic inner ear findings were abnormal in only one patient. Viruses were isolated or histologically identified in the brains of four patients and in the eyes of five patients. In our patients viral infections were nearly as common in the inner ears as in the brain and eye, suggesting that protection from the blood-labyrinth barrier was similar to that from the other barriers. Because the inner ear viral infections were asymptomatic and there was an absence of pathologic damage and inflammation, we suggest that some viral inner ear infections in patients with AIDS are nonpathogenic and elicit no inflammation or that the viral infections occur terminally and elicit no inflammation because of immunosuppression from the AIDS.

Clinical viral infections and temporal bone histologic studies of patients with AIDS

The brain, eye, and inner ear are each protected from blood-borne infectious agents by a barrier that has some anatomic and functional differences. In patients with AIDS, opportunistic infections of the central nervous system and eye are frequent. Little is known about the incidence of middle and inner ear infections in patients with AIDS, but deafness and severe vertigo are uncommon. We studied 14 homosexual men with AIDS, aged 28 to 55 years, for 1 to 2 years until death. No patient had deafness, but one had vertigo. Adenovirus type 6 and cytomegalovirus were isolated from the middle ear cavity in four patients. Temporal bone histology demonstrated acute otitis media in four, chronic otitis media in two, and serous otitis media in three. Adenovirus type 6 and cytomegalovirus, either alone or with herpes simplex virus type 1, were isolated from inner fluids of three patients. Histologic inner ear findings were abnormal in only one patient. Viruses were isolated or histologically identified in the brains of four patients and in the eyes of five patients. In our patients viral infections were nearly as common in the inner ears as in the brain and eye, suggesting that protection from the blood-labyrinth barrier was similar to that from the other barriers. Because the inner ear viral infections were asymptomatic and there was an absence of pathologic damage and inflammation, we suggest that some viral inner ear infections in patients with AIDS are nonpathogenic and elicit no inflammation or that the viral infections occur terminally and elicit no inflammation because of immunosuppression from the AIDS.