Phenotypic variation among three broiler pure lines for Marek's disease, coccidiosis, and antibody response to sheep red blood cells.

To identify candidate genes, chicken lines with the most divergent phenotypes are usually crossed to generate resource mapping populations, for example, either backcrossed or F2 populations. Linkage between the genetic marker and the phenotypic trait locus is then tested in the mapping population. As an initial step in the development of a mapping population from commercial broilers, the goal of the current research was to evaluate the phenotypic variation among three pure lines for antibody response to SRBC and in resistance to two economically important poultry diseases, Marek's disease (MD) and coccidiosis (Eimeria acervulina). Chicks from each line were received and separated into three experimental studies to evaluate each of their responses. In summary, broiler Line 3 had significantly lower antibody responses to SRBC immunizations compared to the other two lines, and nonvaccinated birds from Line 3 were also more susceptible to MD. With coccidiosis, the response was complex, and ranking of the lines was dependent on the age of infection, and whether it was a first or second challenge. With the first challenge, Line 1 was most susceptible at the younger age (Day 30), whereas Line 3 was susceptible at the older age (Day 58). Upon the second challenge, broiler Line 1 remained susceptible at the younger age, but Line 2 was more susceptible at the older age. Line 3 was completely resistant to the second challenge at the older age. Thus, although the broiler lines have been intensively selected for productivity and general livability, this study also demonstrates that the lines differ for immune response and disease resistance. Based on the phenotypic differences between Lines 1 and 3, they were chosen to establish a mapping population for identifying candidate genes that affect MD and coccidiosis in commercial broiler chickens.

Osteomas of the internal auditory canal: a report of two cases.

OBJECTIVES: To determine the optimal medical or surgical treatment of osteomas of the internal auditory canal (IAC) as well as their growth characteristics. STUDY DESIGN: Information was obtained from case histories, images from computed tomography and magnetic resonance imaging, surgical and pathologic findings, and long-term clinical results. METHODS: Two patients, along with 10 additional patients reported in the literature, with osteomas of the IAC with varying symptoms were studied. Clinical history, audiometric and vestibular test results, and radiographic studies were reviewed on all patients. Histopathologic examination of the surgical specimens confirmed the presence of osteomas. The clinical outcomes were studied to determine if the preoperative symptoms had resolved. RESULTS: Eight of 12 patients underwent surgical removal of their IAC osteomas. Three of eight patients had total resolution of all symptoms. Three patients had improvement of their sensorineural hearing loss. Five patients had resolution of their dizziness. Four patients noted resolution of their tinnitus. In the absence of auditory symptoms, vestibular symptoms may be controlled with medical therapy. Long term follow-up of the two patients discussed showed little or no growth over a 4- to 5-year period. CONCLUSIONS: Surgical intervention may be warranted to remove an osteoma of the IAC if symptoms are present. Patients should be made aware that symptoms may or may not improve. Continuation of symptoms may be a result of chronic compression of the auditory and vestibular nerves.

Mechanism of redistribution of cerebral blood flow during hypercarbia and seizures.

After occlusion of an artery to the brain, hypercarbia and seizures may produce a paradoxical reduction in cerebral blood flow to the region supplied by collateral vessels. We measured pressure in an occluded branch of the middle cerebral artery and measured regional cerebral blood flow (rCBF) to collateral-dependent cerebrum in dogs (n = 25) to examine hemodynamic mechanisms that account for the reduction in flow. During hypercarbia (arterial PCO2 = 70 +/- 5 mmHg), rCBF to collateral-dependent cerebrum, measured with microspheres and identified using the shadow flow technique, decreased from 95 +/- 6 (mean +/- SE) to 71 +/- 9 ml.100 g-1.min-1 (P < 0.05), while flow to normal brain increased from 105 +/- 9 to 281 +/- 15 ml.100 g-1.min-1 (P < 0.05). Pressure in a branch of the middle cerebral artery decreased during hypercarbia from 50 +/- 6 to 25 +/- 3 mmHg (P < 0.05), concurrent with a significant increase in resistance of collateral vessels. Small vessel resistance was the same in collateral-dependent and normal brain. During bicuculline-induced seizures, with blood pressure maintained at control levels by withdrawal of blood, rCBF decreased in collateral-dependent cerebrum from 128 +/- 16 to 67 +/- 11 ml.100 g-1.min-1 (P < 0.05), and flow to normal brain increased from 169 +/- 14 to 418 +/- 17 ml.100 g-1.min-1 (P < 0.05). Small vessel resistance decreased in both regions, but the decrease was much greater in normal cerebrum. Changes in cerebral artery pressure and resistance of collateral vessels during seizure were similar to those during hypercarbia.(ABSTRACT TRUNCATED AT 250 WORDS)

Stem pressure at the origin of intracranial collateral vessels.

The relationship between pressure at the functional site of origin of intracranial collateral channels (Pstem) and systemic pressure allows an estimation of the size of vascular channels from which collateral vessels originate. In this study, Pstem was determined in anesthetized dogs. A branch of the middle cerebral artery was perfused through a closed system with autologous blood. Tissues with regional cerebral blood flow (rCBF) less than or equal to 10 ml.100 g-1.min-1 (collateral-dependent zone) were identified using radioactive microspheres. Sequential injections of nonradioactive microspheres were made into the cannulated vessel to progressively occlude the terminal capillary bed. Injection of nonlabeled spheres was terminated when backpressure no longer increased, and the final rCBF measurement was made. There was a linear relationship between backpressure and flow to the collateral-dependent tissues. When rCBF within these tissues was zero, the corresponding value for backpressure (Pstem) was 79 +/- 4% (mean +/- SD) of mean arterial pressure. The high value for Pstem suggests that cerebral collateral channels arise in part from large vessels.

MR evaluation of CNS tumors: dose comparison study with gadopentetate dimeglumine and gadoteridol.

In phase II and III trials of gadoteridol (Gd-HP-D03A), a new nonionic, low-osmolar contrast agent, 40 patients with intracranial neoplasms underwent magnetic resonance (MR) imaging with experimental doses of 0.05-0.3 mmol/kg. Fifteen patients also underwent contrast studies with the standard dose (0.1 mmol/kg) of gadopentetate dimeglumine. Both gadopentetate dimeglumine and gadoteridol appear to have a similar effect when given in equal doses (0.1 mmol/kg, n = 5). Lesion enhancement and delineation were better at higher experimental doses (0.2 or 0.3 mmol/kg, n = 7) and worse at a lower experimental dose (0.05 mmol/kg, n = 3). Quantitative analysis of 10 lesions examined with identical imaging protocols revealed a directly proportional relationship (r = .975) between lesion contrast ratio and dose over a range of 0.05-0.3 mmol/kg. Phantom experiments support the clinical results. Improved enhancement, detection, and delineation of central nervous system (CNS) neoplasms resulting from increased injected doses of gadoteridol have the potential to be clinically significant and may justify the possibly higher cost of increased contrast material dosage. Lower doses may not be adequate for the evaluation of most CNS tumors.

Cerebral ischemia: evaluation with contrast-enhanced MR imaging.

Eighty patients with a total of 82 ischemic lesions were examined with contrast-enhanced MR imaging 1 hr to 1 month after onset of symptoms. The studies were reviewed retrospectively to determine the presence of arterial enhancement and the patterns of parenchymal enhancement. Arterial enhancement was often detected on the initial MR examination (45%), was frequently demonstrated in cortical infarction (86%), in some cases preceded the development of signal changes on T2-weighted images, and resolved by 11 days. The presence of arterial enhancement appeared to be a better indicator of clinical severity than was the presence of proximal vessel occlusion on MR or angiographic studies. Two patterns of parenchymal enhancement were seen: progressive enhancement and early and/or intense enhancement. In patients with the progressive pattern, parenchymal enhancement on postcontrast T1-weighted images was rarely seen before 7 days, while signal abnormalities on T2-weighted images were intense during the first few days. The early and/or intense enhancement pattern was usually present within the first 3 days, approximated or exceeded the area and intensity of signal changes on T2-weighted images, and was usually associated with minimal or reversible neurologic sequelae (except when located in or near a watershed zone), suggesting a lesser degree of ischemic insult than was associated with the progressive pattern.(ABSTRACT TRUNCATED AT 250 WORDS)

MR imaging of cerebral ischemia: findings in the first 24 hours.

MR changes of cerebral ischemia have been shown to occur as early as 1-2 hr after vessel occlusion in experimental models of stroke. However, the MR findings in the early stages of ischemic stroke in the clinical population have not been well established. We studied 41 lesions in 39 patients in whom MR was performed within the first 24 hr after onset of ischemic symptoms. Twenty-five lesions were studied with gadopentetate dimeglumine. Vascular flow-related abnormalities, including absence of normal flow void and presence of arterial enhancement, were the earliest MR findings, detected within minutes of onset. Morphologic changes (brain swelling) on T1-weighted images without signal changes on T2-weighted images could be detected within the first few hours. Signal changes were not usually found before 8 hr on T2-weighted images or before 16 hr on T1-weighted images. In contrast to the absence of parenchymal enhancement typically found in cortical infarctions in the first 24 hr, a few lesions (including transient occlusions, partial occlusions, and isolated watershed infarctions) exhibited early, exaggerated parenchymal enhancement. We conclude that signal changes may not be reliable in detecting ischemic stroke within the first 8 hr after onset. Vascular abnormalities, when present, are the most reliable and earliest findings. Other MR findings of early ischemic stroke, including morphologic changes and early, exaggerated parenchymal enhancement, may also precede signal changes. Paramagnetic contrast administration often provides valuable information in the detection and evaluation of acute ischemia.

Surgical experience with cerebral amyloid angiopathy.

Cerebral amyloid angiopathy can present as lobar intracerebral hemorrhage in an elderly person, presumably due to increased fragility of the vessels affected by amyloid deposition. For this reason, patients presenting with intracerebral hemorrhage and suspected of having cerebral amyloid angiopathy have often been treated nonsurgically. Since 1983 we have evaluated 11 patients with cerebral amyloid angiopathy (nine women and two men, mean age 73 years) who have undergone either intracerebral hematoma evacuation or brain biopsy. Nine of the 11 patients presented with intracerebral hemorrhage, which was unilobar in three patients and multilobar in six and involved the parietal lobes seven times, the frontal lobes four times, the temporal lobes four times, and the occipital lobes twice. These nine patients underwent hematoma removal, with no cases of abnormal intraoperative bleeding or recurrent hemorrhage. Six patients improved neurologically, and two were unchanged after hematoma evacuation; the remaining patient had a fatal cardiopulmonary arrest during the immediate postoperative period. During follow-up in seven patients (median 11 months, range 1 week to 74 months) none experienced a recurrent intracerebral hemorrhage and four continued to improve. Two of the 11 patients had cerebral amyloid angiopathy diagnosed by brain biopsy as part of an evaluation for dementia, also without surgical complications. This series suggests that patients with cerebral amyloid angiopathy may safely undergo operative procedures, and patients presenting with intracerebral hemorrhage may show neurologic improvement following evacuation of the hematoma.

Studies of collateral perfusion to canine middle cerebral artery territory.

Previous studies of intracranial collateral circulation have not distinguished between true "collateral" blood flow (flow to a region that occurs only when a primary artery is occluded) and "overlap" flow (flow to a region that is present under both normal and demand conditions). These experiments had three purposes: 1) to identify tissues that were truly collateral dependent, 2) to determine potential for true collateral flow in the absence of overlap flow, and 3) to determine whether an anatomical basis for overlap flow could be demonstrated. Branches (700-900 microns) of the dog middle cerebral artery (MCA) were perfused with autologous blood. The perfused region, which was the area at risk, was identified by intravenous injection of neutral red dye. Microspheres were used to measure regional cerebral blood flow (rCBF). Overlap flow was determined by perfusion of the artery with microsphere-free blood. True collateral flow (total rCBF minus overlap flow) was determined by analysis of rCBF to the risk area after cessation of vessel perfusion. Most of the risk area had substantial levels of overlap flow (about one-third of base line). In the center of the area at risk, the true collateral-dependent area was identified [mean overlap flow 4 +/- 1 (mean +/- SE) ml.min-1.100 g-1], which had high levels of perfusion from collateral vessels (102 +/- 14) within 30 s of vascular occlusion. Microfil injection into two adjacent MCA branches showed discrete borders between vascular territories, with no overlapping vessels.(ABSTRACT TRUNCATED AT 250 WORDS)

Carcinoma metastatic to a cerebellar vascular malformation: case report.

A 73-year-old woman with a spontaneous intracerebellar hemorrhage was seen and was found to have metastatic adenocarcinoma within a vascular malformation. There was no evidence of other metastatic disease. The association of these two lesions is uncommon and has rarely been reported. The rich vascularity of the malformation may explain the hematogenous deposition of metastatic neoplasm at this site.

Diagnostic yield in CT-guided stereotactic biopsy of gliomas.

Twenty-seven patients underwent 29 computerized tomography (CT)-guided stereotactic biopsy procedures for untreated or recurrent malignant astrocytomas. Biopsies were obtained from the hypodense center, enhancing margin, and hypodense periphery as seen on contrast-enhanced CT scans, with diagnostic yields of (number of biopsies yielding tumor/number of biopsies obtained): 34/61 (56%), 68/101 (67%), and 8/22 (36%) from these three zones, respectively. Although tumor was identified in all three zones, diagnostic yield was significantly higher in the hypodense center and enhancing margin. Comparison of patients with untreated tumors to those with recurrent tumors demonstrated no statistical difference in tumor distribution, although there was a trend toward a higher yield from the hypodense periphery in the recurrent tumor group. Tumor was found up to 15 mm beyond the CT-enhancing margin, in addition to extending beyond the area of abnormality on T2-weighted magnetic resonance images. These findings suggest that serial stereotactic biopsies should be targeted to the hypodense center and enhancing margin for improved diagnostic yield. Biopsy material obtained from the hypodense periphery that demonstrates tumor also indicates that a tumor volume beyond the confines of the CT-enhancing margin should be considered when calculating dosimetry for interstitial radiation.

Stereotaxic surgery in the treatment of multiple brain abscesses.

Controversy exists regarding the optimal treatment for patients with multiple brain abscesses. These lesions are often small and located deep in the brain and close to vital structures, making surgery difficult. With this in mind the authors review their experience in treating multiple abscesses using computerized tomography (CT)-guided stereotaxic aspiration. From 1983 to 1985, 15 patients were treated for multiple brain abscesses, of whom eight underwent stereotaxic aspiration. There were a total of 28 abscesses in these eight patients: 11 abscesses were aspirated and two excised using CT-guided techniques. Most were cortical in location, although there were 12 in the deep white matter, one in the thalamus, and two in the caudate nucleus. All patients received a total of 6 weeks of antibiotic therapy. Follow-up CT showed resolution of the abscesses in all patients. Currently, four are neurologically normal, one has a mild hemiparesis, one has a well-controlled seizure disorder, and one requires supportive care. A single death occurred 5 weeks postoperatively of unrelated causes. Location, size, and age of an abscess all have bearing upon the response to management and outcome of the patient. Stereotaxic surgery is a procedure with minimal morbidity and mortality. Stereotaxic aspiration should be considered in patients with small, multiple, or deep-seated abscesses, in those who are poor operative candidates, and in those who have failed prior therapy.

Juvenile polysaccharidosis with cardioskeletal myopathy.

Polysaccharidoses with ultrastructural features reminiscent of glycogenosis type IV, but without enzymatic correlation, have been observed in several adolescent and adult patients. Little is known of the clinical, pathologic, or biochemical nature of these disorders. We describe a patient with ultrastructural characteristics consistent with glycogenosis type IV, but with normal brancher enzyme activity in dermal fibroblasts and cardiac muscle. During life and at autopsy, electron microscopy revealed amylopectin-like polysaccharide deposits present in a wide variety of tissues. The polysaccharidosis of our patient and similar patients may be a variant of glycogenosis type IV with a yet to be defined enzymatic defect.

Giant cell arteritis of the legs. Clinical isolation of severe disease with gangrene and amputations.

Giant cell arteritis rarely presents as clinically advanced extra-ocular ischemia or gangrene. Clinically isolated leg involvement with amputation is even more unusual. A 69-year-old woman is described who had giant cell arteritis necessitating bilateral leg amputations. No other clinical sequelae have ensued during a four-year follow-up period. Temporal artery biopsy subsequent to the amputations revealed no arteritis. Disparities between the usual patterns of clinical and anatomic involvement in giant cell arteritis underlie the potential diagnostic difficulties in this disease. Although typically diagnostic, temporal artery biopsy does not always bridge the clinical and anatomic disparities.