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Biomedical subjects

N Bass

Publications and source records attributed to N Bass.

At least 19 recordsLinked to original sources
PubMed2005

Relationship of primary mitochondrial respiratory chain dysfunction to fiber type abnormalities in skeletal muscle.

Variation in the size and relative proportion of type 1 and type 2 muscle fibers can occur in a number of conditions, including structural myopathies, neuropathies, and various syndromes. In most cases, the pathogenesis of such fiber type changes is unknown and the etiology is heterogeneous. Skeletal muscle mitochondrial respiratory chain analysis was performed in 10 children aged 3 weeks to 5 years with abnormalities in muscle fiber type, size, and proportion. Five children were classified as having definite, four as probable, and one as possible mitochondrial disease. Type 1 fiber predominance was the most common histological finding (six of 10). On light microscopy, four cases had subtle concomitants of a mitochondriopathy, including mildly increased glycogen, lipid, and/or succinate dehydrogenase staining, and one case had more prominent evidence of underlying mitochondrial disease with marked subsarcolemmal staining. Most cases (nine of 10) had abnormal mitochondrial morphology on electron microscopy. All were found to have mitochondrial electron transport chain (ETC) abnormalities and met diagnostic criteria for mitochondrial disease. We did not ascertain any patients who had isolated fiber type abnormalities and normal respiratory chain analysis during the period of study. We conclude that mitochondrial ETC disorders may represent an etiology of at least a subset of muscle fiber type abnormalities. To establish an etiologic diagnosis and to determine the frequency of such changes in mitochondrial disease, we suggest analysis of ETC function in individuals with fiber type changes in skeletal muscle, even in the absence of light histological features suggestive of mitochondrial disorders.

Child, Preschool↗
PubMed2000

Evidence for a locally driven mucosal response and the presence of mitochondrial antigens in saliva in primary biliary cirrhosis.

Primary biliary cirrhosis (PBC) is often considered to be a dry gland disease caused by frequent involvement of salivary and lacrimal glands. Although high titers of antimitochondrial autoantibodies (AMA) have long been recognized in PBC, little is known about the presence of mitochondrial autoantigens in mucosal compartments such as saliva. We investigated saliva and sera in PBC patients and controls for the presence of AMA and mitochondrial antigens. In PBC saliva, AMA were detected in 45 of 49 (92%), with specificity directed against pyruvate dehydrogenase complex (PDC-E2) alone in 22 of 49 (45%), against PDC-E2 and branched-chain 2-oxo-acid dehydrogenase complex E2 (BCOADC-E2) in 4 of 49 (8%), to PDC-E2 and 2-oxoglutarate dehydrogenase complex E2 (OGDC-E2) in 9 of 49 (18%), and to the 3 antigens together in 10 of 49 (20%). Isotyping of the saliva AMA showed that 80% of the patients had immunoglobulin A (IgA) against PDC-E2, 18% had IgM-specific PDC-E2, and 35% had IgG specific PDC-E2. Similar to serum and bile anti-PDC-E2 IgA antibodies, the saliva autoantibodies localized their reactivity to the inner lipoyl domain of PDC-E2. Furthermore, saliva from patients with PBC but not controls inhibited pyruvate dehydrogenase enzyme activity in vitro. In addition, and of particular interest, we detected a molecule with a molecular weight corresponding to PDC-E2 (74 kd) in PBC but not control saliva. These findings make several important points: first, there appears to be localized mucosal immunity in the secretory system of PBC; second, AMA are readily detected in PBC saliva; and third, PDC-E2 may be present in the saliva of PBC.

Antibody Specificity↗
PubMed2000

Raccoon roundworm (Baylisascaris procyonis) encephalitis: case report and field investigation.

Baylisascaris procyonis is a common and widespread parasite of raccoons in the United States and Canada. With large raccoon populations occurring in many areas, the potential risk of human infection with B procyonis is high. We report a case of severe raccoon roundworm (B procyonis) encephalitis in a young child to illustrate the unique clinical, diagnostic, and treatment aspects, as well as public health concerns of B procyonis infection. Acute and convalescent serum and cerebrospinal fluid samples from the patient were tested for antibodies against B procyonis to assist in documenting infection. An extensive field survey of the patient's residence and the surrounding community was performed to investigate raccoon abundance and to determine the extent of raccoon fecal contamination and B procyonis eggs in the environment. The patient evidenced serologic conversion, and the field investigation demonstrated a raccoon population far in excess of anything previously reported. There was abundant evidence of B procyonis eggs associated with numerous sites of raccoon defecation around the patient's residence and elsewhere in the community. Because B procyonis can produce such severe central nervous system disease in young children, it is important that pediatricians are familiar with this infection. The public should be made aware of the hazards associated with raccoons and B procyonis to hopefully prevent future cases of B procyonis infection.

Animals↗
PubMed1999

Cerebral palsy and neurodegenerative disease.

Cerebral palsy refers to a neurologic disorder of motor skills that is static in nature and is the result of injury to the brain before its development is complete. Many neurodegenerative or metabolic disorders have a slow rate of progression and can be misdiagnosed as cerebral palsy. Diseases that have been misdiagnosed as cerebral palsy are presented here to provide the clinician with framework for the complex evaluation of these patients.

Cerebral Palsy↗
PubMed1998

Evidence for linkage to psychosis and cerebral asymmetry (relative hand skill) on the X chromosome.

The hypothesis that psychosis arises as a part of the genetic diversity associated with the evolution of language generates the prediction that illness will be linked to a gene determining cerebral asymmetry, which, from the evidence of sex chromosome aneuploidies, is present in homologous form on the X and Y chromosomes. We investigated evidence of linkage to markers on the X chromosome in 1) 178 families multiply affected with schizophrenia or schizoaffective disorder with a series of 16 markers spanning the centromere (study 1), and 2) 180 pairs of left-handed brothers with 14 markers spanning the whole chromosome (study 2). In study 1, excess allele-sharing was observed in brother-brother pairs (but not brother-sister or a small sample of sister-sister pairs) over a region of approximately 20 cM, with a maximum LOD score of 1.5 at DXS991. In study 2, an association between allele-sharing and degree of left-handedness was observed extending over approximately 60 cM, with a maximum lod score of 2.8 at DXS990 (approximately 20 cM from DXS991). Within the overlap of allele-sharing is located a block in Xq21 that transposed to the Y chromosome in recent hominid evolution and is now represented as two segments on Yp. In one of two XX males with psychosis we found that the breakpoint on the Y is located within the distal region of homology to the block in Xq21. These findings are consistent with the hypothesis that an X-Y homologous determinant of cerebral asymmetry carries the variation that contributes to the predisposition to psychotic illness.

Female↗
PubMed1998

Imaging patterns of neonatal hypoglycemia.

PURPOSE: Our purpose was to report the patterns of injury observed in five patients who suffered brain damage consequent to neonatal hypoglycemia. METHODS: The imaging studies and clinical records of five patients with brain damage caused by neonatal hypoglycemia were reviewed retrospectively. Patterns of injury were compared with those described in the literature and those seen in neonatal hypoxic-ischemic injury. RESULTS: Diffuse cortical and subcortical white matter damage was seen, with the parietal and occipital lobes affected most severely. Globus pallidus injury was present in one patient who had the most severe cortical injury. CONCLUSION: We found a specific pattern of injury that correlates well with the sparse pathologic and imaging reports on neonatal hypoglycemia. We speculate that the patterns of damage are the result of regional hypoperfusion and excitatory toxicity with cell-type-specific injury.

Brain↗
PubMed1997

Grepafloxacin pharmacokinetics in individuals with hepatic dysfunction.

The pharmacokinetics of grepafloxacin, a new broad spectrum fluoroquinolone antibiotic, were studied in 2 trials involving 14 healthy volunteers, 10 individuals with mild (Child-Pugh Class A) impairment of liver function, and 12 with moderate (Child-Pugh Class B or C) hepatic impairment. All participants received an oral dose of grepafloxacin 400 mg, daily for 7 days, and plasma and urine grepafloxacin concentrations were measured over 7 days. The pooled data from participants with impaired liver function showed that, compared with healthy individuals, peak plasma grepafloxacin concentrations, area under the plasma concentration-time curve and proportion of the dose excreted in the urine were increased. In addition, apparent total clearance was reduced in the presence of hepatic dysfunction. Peak concentrations were increased by 36% and 48% in individuals with Class A and B disease, respectively; the corresponding reductions in clearance were 33% and 55%, respectively. Child-Pugh scores and components of the scores showed no correlation with any pharmacokinetic variables. Based on these findings, we recommend a daily grepafloxacin dose of 400 mg in patients with mild hepatic impairment, irrespective of the severity of infection. Grepafloxacin should not be used in patients with moderate or severe liver disease.

Administration, Oral↗
PubMed1997

Involvement of the pontomedullary corticospinal tracts: a useful finding in the diagnosis of X-linked adrenoleukodystrophy.

PURPOSE: To determine whether pontomedullary corticospinal tract involvement is a common and specific finding of adrenoleukodystrophy on MR images. METHODS: MR images of 10 patients with biochemically proved adrenoleukodystrophy who were examined during the last 6 years were reviewed retrospectively to determine the frequency of corticospinal tract involvement in the medulla, pons, mesencephalon, internal capsules, and corona radiata. MR images of 10 patients with other leukodystrophies (three with Krabbe disease, two with Alexander disease, two with metachromatic leukodystrophy, two with Pelizaeus-Merzbacher disease, and one with Canavan disease) were reviewed with specific attention to the pontomedullary corticospinal tracts. RESULTS: Medullary and pontine corticospinal tract involvement was present in eight of the 10 patients with adrenoleukodystrophy. Mesencephalic and internal capsular involvement was present in three patients. The coronal radiata portion of the corticospinal tracts was not involved in any of the 10 patients. No pontomedullary corticospinal tract involvement was identified in any of the 10 patients with other leukodystrophies. The difference in the frequency of pontomedullary corticospinal tract involvement between the two groups was highly significant. CONCLUSION: Pontomedullary corticospinal tract involvement is a common finding in adrenoleukodystrophy and is unusual in other leukodystrophies. Awareness of this finding can facilitate the radiologic diagnosis of this disease and may expedite management of affected patients.

Child↗
PubMed1996

Assessment of noninvasive lower extremity arterial testing versus pulse exam.

Palpation of pedal pulses was compared to noninvasive testing in 100 patients referred to a vascular laboratory. Subjects were 65 +/- 13 (mean +/- s.d.) years old. The right dorsalis pedis (DP) artery served as the reference artery for comparison of Doppler studies with physical examination of the pulses. Absolute Doppler pressures in the right DP were 129 +/- 50 mm Hg. The right ankle:brachial index (ABI) was 0.86 +/- 0.32. There were significant differences in ABI in those with (0.68 +/- 0.28) vs without (0.95 +/- 0.31) claudication in either extremity (p < 0.001). Rest pain was also associated with lower ABI (P < 0.04). Diabetics, hypertensives, claudicants and those with ischemic rest pain were less likely to have palpable pulses (P < 0.035). With right DP pressure >/= 118 mm Hg, 63 per cent of subjects had a palpable DP pulse, whereas 68 per cent with ABI > 0.82 had a palpable right DP. Of those (n = 35) with a right DP pressure < 118 mm Hg, only 6 per cent (n = 2) had a palpable pulse, whereas 5 per cent (2/40) with ABI </= 0.82 had palpable DP pulses. Based on these findings, it was predicted that a pulse would likely not be palpable in the left DP with a pressure < 118 mm Hg or with AB </= 0.82. The prediction based on systolic ankle pressures was correct, with 66 per cent sensitivity and 91 per cent specificity. The predication that a left DP pulse would not be palpable with AB </= 0.82 was more accurate (78% sensitive, 97% specific). Presence of a palpable DP pulse suggests the presence of a Doppler pressure >/= 188 mm Hg and ABI > 0.82. The range of ankle pressures with palpable right DP pulses was 64-220 mm Hg, whereas the range with nonpalpable DP was 42-300 mm Hg. Given the frequent disparity of pulse exam and ankle pressures, noninvasive Doppler testing may be necessary for many patients to accurately assess the vascular status of the leg.

Adult↗
PubMed1995

Failure to find a chromosome 18 pericentric linkage in families with schizophrenia.

A recent report of a possible linkage of bipolar affective disorder to a pericentric region of chromosome 18 initiated the present investigation to search for a similar linkage in 32 families with schizophrenia. The results of a study using 5 markers mapped to this region show negative lod scores and only weak evidence for any linkage by nonparametric analyses. If the previously reported finding is a true positive linkage for bipolar disorder, then either it is unlikely to be related to the genetics of schizophrenia, or the proportion of families linked to this region is small.

Chromosome Mapping↗
PubMed1995

Affective illness and schizophrenia in families with multiple schizophrenic members: independent illnesses or variant gene(s)?

Affective disorder occurs in some families with schizophrenia, and schizophrenic patients often describe concurrent episode(s) of depression that may lead them to be diagnosed schizoaffective. The present study examines the pattern of affective disorder in families with two or more members with schizophrenia or schizoaffective disorder. We find that affective disorders are more frequently inherited from the same parental side of the family as schizophrenia-like psychosis. When unipolar, it more often is expressed in female than male relatives (particularly mothers), and when bipolar it is more likely in males. In contrast, schizophrenia with and without depression is equally prevalent in both sexes. Unipolar illness was more common in relatives of schizophrenics whose illnesses are characterized by recurrent episodes of depression than in those whose are not. These data are consistent with the hypothesis that the same genes could contribute to susceptibility to both schizophrenia and affective disorder in some families, and that sex and phenotypic expression are in some way related. However, the phenomenon of high rates of depression in mothers of schizophrenic patients needs explanation.

Adult↗
PubMed1995

Supplementary sensorimotor area seizures in children and adolescents.

RATIONALE: Some types of seizures in children may be difficult to recognize; the diagnosis of seizures arising near the mesial posterior frontal supplementary sensorimotor area (SSMA) may be especially challenging. Such seizures have been well described in adults, but few pediatric cases have been reported even though onset is typically in childhood. METHODS: We studied 11 children and adolescents with SSMA seizures diagnosed by prolonged video electroencephalography (EEG). RESULTS: Mean age at onset was 5.8 years, and diagnosis by video EEG was made at a mean age of 12 years. Children had at least borderline intelligence and few abnormal findings on neurologic examination. Seizures were typically brief, frequent, and predominantly nocturnal, with bilateral tonic posturing, gross proximal limb movements, and preserved consciousness. Magnetic resonance imaging showed normal findings or a superior or mesial posterior frontal tumor or cortical dysplasia. Routine EEG findings were usually normal, but prolonged EEG showed epileptiform discharges over the vertex. Seizure onset in the region of the SSMA was confirmed by subdural EEG in six patients who were studied for epilepsy surgery. Five patients had seizure-free outcome or worthwhile improvement after operation. Two nonoperated patients are seizure-free on antiepileptic medication, and three are undergoing surgical evaluation. CONCLUSIONS: Diagnosis of SSMA seizures in children may be challenging because of unusual symptoms (bilateral tonic limb involvement with preserved consciousness) and frequently normal routine EEG findings. Video EEG may be necessary for diagnosis, and magnetic resonance imaging may reveal a focal lesion. Increased recognition of this seizure type in pediatric patients should lead to earlier diagnosis for optimal medical or surgical treatment.

Adolescent↗
PubMed1994

Search for linkage to schizophrenia on the X and Y chromosomes.

Markers for X chromosome loci were used in linkage studies of a large group of small families (n = 126) with at least two schizophrenic members in one sibship. Based on the hypothesis that a gene for schizophrenia could be X-Y linked, with homologous loci on both X and Y, our analyses included all families regardless of the pattern of familial inheritance. Lod scores were computed with both standard X-linked and a novel X-Y model, and sib-pair analyses were performed for all markers examining the sharing of maternal alleles. Small positive lod scores were obtained for loci pericentromeric, from Xp11.4 to Xq12. Lod scores were also computed separately in families selected for evidence of maternal inheritance and absence of male to male transmission of psychosis. The lod score for linkage to the locus DXS7 reached a maximum of 1.83 at 0.08% recombination, assuming dominant inheritance on the X chromosome in these families (n = 34). Further investigation of the X-Y homologous gene hypothesis focussing on this region is warranted.

Chromosome Mapping↗
PubMed1994

Lipopeliosis. An immunohistochemical and clinicopathologic study of five cases.

Lipopeliosis is an unusual liver lesion in which sinusoids become engorged by fat globules. It arises in newly transplanted donor livers that display varying degrees of fatty change. If, after transplantation, hepatocyte necrosis secondary to ischemic or preservation injury occurs, the fat escaping the hepatocytes becomes sequestered in the sinusoidal spaces. We previously described this lesion in a case report; we now describe four more cases to define better the incidence, immunohistochemical features, and clinical spectrum. Of 101 transplanted livers, the lesion was noted in five of 28 (18%), with both preservation injury and mild to moderate fatty change present 1 week following transplantation. Factor VIII-related antigen, collagen IV immunoperoxidase, and oil red O stains confirmed the engorgement of sinusoids by fat droplets, and a stain for CD68-positive cells identified a macrophage reaction around the fat droplets. The patient in our original report developed severe graft dysfunction with residual scarring of the centrilobular zone. Two of the four additional cases had no residual side effects from the lipopeliosis; however, two cases were associated with loss of graft. We conclude that lipopeliosis may be fairly common (5% of transplants). Its clinical outcome can vary greatly and most probably depends on the extent of hepatocellular necrosis.

Adult↗
PubMed1994

Doppler echocardiography and the early diagnosis of carditis in acute rheumatic fever.

BACKGROUND: The incidence of acute rheumatic fever in New Zealand remains relatively high. Reliable early diagnosis of carditis is difficult and important in management. AIM: To determine if Doppler echocardiography contributed to the early diagnosis of carditis in acute rheumatic fever. METHODS: Forty-seven patients admitted to hospital with suspected acute rheumatic fever and 19 control patients, with a febrile illness due to a documented non-cardiac bacterial infection, were assessed two days and two weeks following admission. Presence or absence of clinical carditis was determined by a cardiologist unaware of the suspected diagnosis, from clinical examination, chest radiograph, electrocardiogram (ECG) and two dimensional echocardiogram. Doppler echocardiography was then performed and interpreted by a second cardiologist unaware of the diagnosis. After completion of the study the Jones criteria were applied, to categorise the patients with suspected acute rheumatic fever into four groups for the final diagnosis: no acute rheumatic fever, possible acute rheumatic fever, definite acute rheumatic fever without carditis, and definite acute rheumatic fever with carditis. RESULTS: In 19 patients with a final diagnosis of acute rheumatic fever and carditis at the baseline assessment carditis was detected by clinical assessment in 15 patients, compared with 19 patients with evidence of significant valve regurgitation by Doppler echocardiography. Following the two week assessment, all 19 patients had both clinical and Doppler evidence of carditis. Five patients with a final clinical diagnosis of possible acute rheumatic fever or definite acute rheumatic fever without carditis, had a Doppler abnormality detected. There was no clinical or Doppler abnormality in the febrile controls. CONCLUSIONS: Doppler echocardiography is more sensitive than clinical assessment in the detection of carditis in acute rheumatic fever, and can contribute to earlier diagnosis.

Acute Disease↗