Distribution of ten laminin chains in dystrophic and regenerating muscles

Using immunohistochemical methods, we assessed the distribution of all 10 known laminin chains (alpha1-5, beta1-3, gamma1 and gamma2) in skeletal muscles from patients with Duchenne, congenital, limb girdle, or Emery-Dreifuss muscular dystrophies. The alpha2, beta1 and gamma1 chains were abundant in the basal lamina surrounding muscle fibers in normal controls; alpha1, alpha3-alpha5, beta3, and gamma2 were undetectable; and beta2 was present at a low level. Compared to controls, levels of the alpha5 chain were increased in muscles from many dystrophic patients; levels of beta1 were reduced and/or levels of beta2 were increased in a minority. However, these changes were neither specific for, nor consistent within, diagnostic categories. In contrast, levels of alpha4 were increased in muscles from all patients with alpha2 laminin (merosin)-deficient congenital muscular dystrophy. Loss of alpha2 laminin in congenital dystrophy is disease-specific but some other changes in laminin isoform expression in dystrophic muscles could be secondary consequences of myopathy, denervation, regeneration or immaturity. To distinguish among these possibilities, we compared the laminins of embryonic, denervated, regenerating, and mutant mouse muscles with those in normal adult muscle. Embryonic muscle basal lamina contained alpha4 and alpha5 along with alpha2, and regenerating muscle re-expressed alpha5 but not alpha4. Levels of alpha5 but not alpha4 were increased in dystrophin (mdx) mutants and in dystrophin/utrophin double mutants (mdx:utrn -/-), models for Duchenne dystrophy. In contrast, laminin alpha4 was upregulated more than alpha5 in muscles of laminin alpha2 mutant mice (dy/dy; a model for alpha2-deficient congenital dystrophy). Based on these results, we hypothesize that the expression of alpha5 in many dystrophies reflects the regenerative process, whereas the selective expression of alpha4 in alpha2-deficient muscle is a specific compensatory response to loss of alpha2.

Randomized trial of prolonged chloroquine therapy in advanced pulmonary sarcoidosis

Sarcoidosis may cause severe ventilatory impairment requiring corticosteroid treatment. Chloroquine (CQ) can be an effective treatment for lung sarcoidosis with few side effects, but has not been accepted as standard therapy. We investigated the benefits of prolonged CQ therapy in 23 symptomatic patients with biopsy-proven pulmonary sarcoidosis (duration, >/= 2 yr). Patients were initially treated for 6 mo with CQ, 750 mg/d, tapering every 2 mo to 250 mg/d. Eighteen patients were then randomized to either a Maintenance group (CQ, 250 mg/d) or to an Observation group (no CQ). After the initial treatment, significant improvement was observed in symptoms, pulmonary function, angiotensin-converting enzyme, and lung gallium scan. Patients randomized to the Maintenance group showed a slower decline in pulmonary function (FEV1, 51.4 +/- 28.2 ml/yr [Maintenance] versus 196.3 +/- 33.4 ml/yr [Observation], p < 0.02) and had fewer relapses: 2 of 10 patients in the Maintenance group at 29.5 +/- 4.9 mo versus 6 of 8 patients in the Observation group at 15.5 +/- 2.9 mo. Adverse effects were seen mainly during high-CQ dosage. We conclude that CQ should be an important consideration for the treatment and maintenance of chronic pulmonary sarcoidosis.

Paclitaxel-induced apoptosis in Jurkat, a leukemic T cell line, is enhanced by ceramide

We hypothesized that the lipid second messenger, ceramide, and microtubule-directed chemotherapeutic agents might engage converging pathways in inducing apoptosis. Our studies demonstrated that simultaneous treatment of Jurkat cells with paclitaxel and ceramide enhanced paclitaxel-induced cell growth inhibition. Cell cycle analysis indicated a significant increase in the hypodiploid population over that observed with paclitaxel treatment alone. Morphologic evaluation and a TUNEL assay confirmed a dramatic increase in apoptosis in Jurkat cells treated with the combination of these two agents. This is the first demonstration that paclitaxel and ceramide interact in a supra-additive manner to decrease leukemic T-cell growth, suggesting a possible application of paclitaxel and ceramide in combination therapy.

Contribution of nitric oxide synthases 1, 2, and 3 to airway hyperresponsiveness and inflammation in a murine model of asthma

Asthma is a chronic disease characterized by increased airway responsiveness and airway inflammation. The functional role of nitric oxide (NO) and the various nitric oxide synthase (NOS) isoforms in human asthma is controversial. To investigate the role of NO in an established model of allergic asthma, mice with targeted deletions of the three known isoforms of NOS (NOS1, 2, and 3) were studied. Although the inducible (NOS2) isoform was significantly upregulated in the lungs of ovalbumin (OVA)-sensitized and -challenged (OVA/OVA) wild-type (WT) mice and was undetectable in similarly treated NOS2-deficient mice, airway responsiveness was not significantly different between these groups. OVA/OVA endothelial (NOS3)-deficient mice were significantly more responsive to methacholine challenge compared with similarly treated NOS1 and NOS1&3-deficient mice. Airway responsiveness in OVA/OVA neuronal (NOS1)-deficient and neuronal/endothelial (NOS1&3) double-deficient mice was significantly less than that observed in similarly treated NOS2 and WT groups. These findings demonstrate an important function for the nNOS isoform in controlling the inducibility of airway hyperresponsiveness in this model of allergic asthma.

Serum autoantibodies to brain in Landau-Kleffner variant, autism, and other neurologic disorders

OBJECTIVE

Etiologically unexplained disorders of language and social development have often been reported to improve in patients treated with immune-modulating regimens. Here we determined the frequency of autoantibodies to brain among such children.

DESIGN

We collected sera from a cohort of children with (1) pure Landau-Kleffner syndrome (n = 2), (2) Landau-Kleffner syndrome variant (LKSV, n = 11), and (3) autistic spectrum disorder (ASD, n = 11). None had received immune-modulating treatment before the serum sample was obtained. Control sera (n = 71) were from 29 healthy children, 22 with non-neurologic illnesses (NNIs), and 20 children with other neurologic disorders (ONDs). We identified brain autoantibodies by immunostaining of human temporal cortex and antinuclear autoantibodies using commercially available kits.

RESULTS

IgG anti-brain autoantibodies were present in 45% of sera from children with LKSV, 27% with ASD, and 10% with ONDs compared with 2% from healthy children and control children with NNIs. IgM autoantibodies were present in 36% of sera from children with ASD, 9% with LKSV, and 15% with ONDs compared with 0% of control sera. Labeling studies identified one antigenic target to be endothelial cells. Antinuclear antibodies with titers >/=1:80 were more common in children with ASD and control children with ONDs.

CONCLUSION

Children with LKSV and ASD have a greater frequency of serum antibodies to brain endothelial cells and to nuclei than children with NNIs or healthy children. The presence of these antibodies raises the possibility that autoimmunity plays a role in the pathogenesis of language and social developmental abnormalities in a subset of children with these disorders.

Glucocorticoids inhibit the expression of calcium-dependent potassium channels in vascular smooth muscle

Increased calcium-activated potassium channel (KCa) activity in vascular smooth muscle (VSM) cells leads to a relaxation response counteracting the effects of high blood pressure. Since chronic exposure to glucocorticoids (GC) can be associated with an increase in blood pressure, we reasoned that GCs might modify the expression of KCa channels resulting in a net rise in vascular tone. To test this hypothesis, primary cultures of rat VSM cells were exposed to (a) RU 28362 (a pure glucocorticoid receptor agonist), 1 microM; (b) corticosterone 10 nM + carbenoxolone (an inhibitor of bidirectional VSM 11beta-OH steroid dehydrogenase), 1 microM; (c) 11-dehydrocorticosterone (a biologically inactive metabolite), 10 nM + carbenoxolone; (d) carbenoxolone alone; or (e) aldosterone 10 nM for periods of up to 72 h. Proteins were then extracted and Western blots prepared. Gels were probed with a rabbit-derived polyclonal antibody directed against KCa channel protein. The experimental procedure was repeated on separate sets of VSM cells to ensure reproducibility. Expression of KCa channel protein was diminished in VSM cells incubated with corticosterone + carbenoxolone and with RU 28362 after 24 h and remained low at 72 h. Expression of KCa protein in cells exposed to 11-dehydrocorticosterone + carbenoxolone, carbenoxolone alone, and aldosterone was either similar to controls or mildly increased over the 72 h. These data are consistent with the hypothesis that GCs diminish the expression of KCa protein. Diminished KCa expression could contribute to the observed increase in vascular tone following chronic GC exposure.

Hepatic sickling crisis mimicking recurrent cholangitis

A 22-year-old man with homozygous sickle cell disease presented with recurrent fever, right upper quadrant pain and jaundice. Liver biopsy confirmed the diagnosis of hepatic sickling crisis; the symptoms responded to hydroxyurea therapy. Hepatic vasocclusive crisis can diagnosed on liver biopsy, and need not be a diagnosis of exclusion.

Akt-dependent potentiation of L channels by insulin-like growth factor-1 is required for neuronal survival

The insulin-like growth factor-1 (IGF-1)/receptor tyrosine kinase recently has been shown to mediate neuronal survival and potentiate the activity of specific calcium channel subtypes; survival requires Akt, a serine/threonine kinase. We demonstrate here that Akt mediates the IGF-1-induced potentiation of L channel currents, but not that of N channels. Transient expression of wild-type, dominant-negative, and constitutively active forms of Akt in cerebellar granule neurons causes, respectively, no change in IGF-1/L channel potentiation, complete inhibition of potentiation, and a dramatic increase in basal L currents accompanied by the loss of ability to induce further increases. In no case is the IGF-1 potentiation of N currents affected. We additionally find that IGF-1 partially mediates granule neuron survival via L channel activity and that Akt-dependent L channel modulation is a necessary component. Interestingly, very brief exposure (1 min) to IGF-1 triggers nearly complete survival and requires L channel activity. These results strongly suggest that neuronal receptor tyrosine kinases can control long-term calcium-dependent processes via the rapid control of voltage-sensitive channels.

Leg symptoms, the ankle-brachial index, and walking ability in patients with peripheral arterial disease

OBJECTIVE

To determine how functional status and walking ability are related to both severity of lower extremity peripheral arterial disease (PAD) and PAD-related leg symptoms.

DESIGN

Cross-sectional study.

SETTING

Academic medical center.

PARTICIPANTS

Patients aged 55 years and older diagnosed with PAD in a blood flow laboratory or general medicine practice (n = 147). Randomly selected control patients without PAD were identified in a general medicine practice (n = 67).

MEASUREMENTS

Severity of PAD was measured with the ankle-brachial index (ABI). All patients were categorized according to whether they had (1) no exertional leg symptoms; (2) classic intermittent claudication; (3) exertional leg symptoms that also begin at rest (pain at rest), or (4) exertional leg symptoms other than intermittent claudication or pain at rest (atypical exertional leg symptoms). Participants completed the 36-Item Short-Form Health Survey (SF-36) and the Walking Impairment Questionnaire (WIQ). The WIQ quantifies patient-reported walking speed, walking distance, and stair-climbing ability, respectively, on a scale of 0 to 100 (100 = best).

MAIN RESULTS

In multivariate analyses patients with atypical exertional leg symptoms, intermittent claudication, and pain at rest, respectively, had progressively poorer scores for walking distance, walking speed, and stair climbing. The ABI was measurably and independently associated with walking distance (regression coefficient = 2.87/0.1 ABI unit, p =.002) and walking speed (regression coefficient = 2.09/0.1 ABI unit, p =.015) scores. Among PAD patients only, pain at rest was associated independently with all WIQ scores and six SF-36 domains, while ABI was an independent predictor of WIQ distance score.

CONCLUSIONS

Both PAD-related leg symptoms and ABI predict patient-perceived walking ability in PAD.

Exertional leg symptoms other than intermittent claudication are common in peripheral arterial disease

BACKGROUND

Epidemiological data show that most community-dwelling men and women with lower-extremity peripheral arterial disease (PAD) do not have typical symptoms of intermittent claudication. We compared the prevalence of intermittent claudication, leg symptoms other than intermittent claudication, and absence of exertional leg symptoms between patients with PAD identified from a blood flow laboratory (group 1), patients with PAD in a general medicine practice (group 2), and control patients without PAD (group 3).

METHODS

Numbers of participants in groups 1, 2, and 3 were 137, 26, and 105, respectively. Patients with previously diagnosed PAD were excluded from groups 2 and 3. All participants underwent ankle-brachial index measurement and were administered the San Diego claudication questionnaire to assess leg symptoms.

RESULTS

Within groups 1, 2, and 3, prevalences of intermittent claudication were 28.5% (n = 39), 3.8% (n = 1), and 3.8% (n= 4), respectively. Prevalences of exertional leg symptoms other than intermittent claudication were 56.2% (n= 77), 42.3% (n= 11), and 19.0% (n = 20), respectively. Absence of exertional leg symptoms was reported by 15.3% (n= 21), 53.8% (n= 14), and 77.1% (n=81), respectively. Among patients with PAD, older age, male sex, diabetes mellitus, and group 2 vs group 1 status were associated independently with absence of exertional leg symptoms in multivariable regression analysis. Lower ankle-brachial index levels and group 1 vs group 2 status were associated with intermittent claudication.

CONCLUSIONS

Clinical manifestations of PAD are diverse, particularly among patients identified by ankle-brachial index screening. Exertional leg symptoms other than intermittent claudication are common in PAD. Patients with PAD who are older, male, diabetic, or identified with ankle-brachial index screening in a primary care setting are more likely to have asymptomatic PAD.

Porcine endotoxemic shock is associated with increased expired nitric oxide

OBJECTIVES

Nitric oxide (NO) is believed to decrease systemic vascular resistance in sepsis, but the data are mainly from studies on rats and mice. We tested this hypothesis in pigs and also whether there is induction of the inducible form of nitric oxide synthase (iNOS).

DESIGN

Animal study.

SETTING

University center.

SUBJECTS

Ten pigs.

INTERVENTIONS

The pigs were anesthetized and mechanically ventilated.

MEASUREMENTS AND MAIN RESULTS

Pulmonary and systemic hemodynamics were monitored and mixed expired NO was measured by chemiluminescence. Animals received 20 microg/kg of endotoxin over 2 hrs. We then infused 25 mg/kg of N(omega)-nitro-L-arginine methyl ester (L-NAME) over 10 mins, followed by 0.5 g/kg of L-arginine, the precursor of NO, for 30 mins more to reverse the effects of L-NAME. Five additional pigs were treated with 20 microg/kg of endotoxin for 2 hrs and followed for another hour. Plasma nitrite/nitrate was measured by Greiss reaction. The animals were then killed and tissues were sampled for iNOS by Western blot, and iNOS messenger RNA by reverse transcriptase polymerase chain reaction. After endotoxin infusion, arterial pressure (BP) initially increased, then decreased to 62+/-1 mm Hg from the baseline of 115+/-4 mm Hg (p<.001). Cardiac output initially decreased, then increased slightly from the baseline of 3.7+/-0.2 to 4.2 +/-0.3 L/min (p<.05). The BP pattern was mirrored by an increase in expired NO concentration from 6.4+/-0.8 to 10.4+/-1.4 parts per billion (p<.05) and increased rate of pulmonary NO excretion in expired gas (VeNO) from 71+/-10 to 146+/-24 pmol/kg/min (p<.05). Inhibition of NOS with L-NAME decreased expired NO concentration and VeNO and increased BP; however, cardiac output decreased. The vasoconstriction produced by L-NAME was partially reversed by L-arginine, and this also increased VeNO from 80+/-18 after L-NAME to 132+/-31 pmol/kg/min (p<.05). Plasma nitrite (n = 5) did not change and there was no iNOS by Western blot analysis in multiple tissues. However, there was a small increase in messenger RNA by reverse transcriptase polymerase chain reaction.

CONCLUSIONS

The time course and pattern of changes in expired NO during endotoxemia followed the change in systemic hemodynamics, which supports a causal role for NO in sepsis. However, this is not due to a large production of NO by iNOS induction. The hemodynamic pattern, nitrite in blood, and changes in expired NO also differed markedly from those findings in rodent models and caution should be used in extrapolating from rodents to higher order animals.

Autoimmune sclerosing cholangitis: an overlap syndrome in a child

We report an overlap syndrome of autoimmune chronic liver disease and primary sclerosing cholangitis in a young girl. This could be the first such report from India.

Inflammatory bowel disease in children: Indian perspective

The magnitude of inflammatory bowel disease in childhood in India is largely unknown. At the Pediatric Gastroenterology section of PGIMER, Chandigarh, 15 out of 294 children (5%) admitted for colonic disorders were diagnosed to have ulcerative colitis. Diagnosis is suspected on the basis of clinical presentation and established by sigmoidoscopy, rectal biopsy and double contrast barium enema. Widely prevalent bacillary dysentery, acute amoebic colitis and antibiotic induced colitis need to be kept in differential diagnosis of acute presentation of ulcerative colitis. Chronic or recurrent colitis needs to be differentiated from tuberculous colitis. Inflammatory bowel disease deserves clinical suspicion in all unusual cases of colitis which do not respond to treatment of common infective agents.

Repression of enzymes of the pentose phosphate pathway by glucose in fission yeast

We examine here the effect of carbon sources on the synthesis of the shunt pathway enzymes in the fission yeast Schizosaccharomyces pombe growing on a mixture of ethanol and glycerol. Delta-gluconolactone induces practically every one of these enzymes. Glucose in contrast tends to attenuate the synthesis of the majority of them. RNA analysis confirms that their induction and repression reflect changes in the levels of their transcripts.

What do parents know about lead poisoning? The Chicago Lead Knowledge Test. Pediatric Practice Research Group

OBJECTIVES

To examine the extent of parental knowledge about lead poisoning and its prevention and to determine characteristics associated with accurate lead knowledge.

SETTING

Twenty-three pediatric practices and 1 family practice in Chicago, Ill, and its suburbs.

METHODS

A 24-question test regarding lead poisoning and its prevention (Chicago Lead Knowledge Test) was developed based on lead specialists' review and parental test-retest reliability. One point was assigned for each correct response. It was self-administered by a sample of 2225 parents of 0- to 6-year-old children visiting study practices. A 1-way analysis of variance (ANOVA) was used to determine the association of demographic descriptors with test scores.

RESULTS

Respondents had a mean age of 33 years. Ninety percent were mothers, 49% were college graduates, and 80% were home owners. Fifteen percent lived in homes built before 1950, of which 36% were remodeled or renovated during the last 6 months. Respondents' youngest children were 80% white, 10% Hispanic, 5% African American, and 5% other. Ten percent received Medicaid and 86% had other medical insurance. Thirty-four percent recalled receipt of lead information from a health care provider, and 2.4% had had a child with a blood lead level of 0.48 micromol/L (10 microg/dL) or higher. The mean Chicago Lead Knowledge Test score was 12.2 (SD, 3.7). Questions related to lead exposure were more often answered correctly than those related to prevention and diet. In the ANOVA model, those who recalled receipt of lead information from a health care provider, college graduates, respondents aged 30 years or older, Hispanic respondents, and those living in homes built before 1950 had higher scores (all ANOVA P< or =.001).

CONCLUSIONS

Parents do not have much knowledge of ways to prevent childhood lead poisoning. Information from a health care provider can aid parental knowledge. The Chicago Lead Knowledge Test is a new self-administered tool to help evaluate lead education programs.

Characterizing alterations in the pulmonary surfactant system in a rat model of Pseudomonas aeruginosa pneumonia

Bacterial pneumonia remains a significant cause of patient morbidity and mortality worldwide. Pulmonary surfactant serves to maintain homeostasis in the lung through the maintenance of alveolar stability and the regulation of the alveolar immune response. The purpose of this study was to characterize the lung injury and associated surfactant alterations in a rat model of acute Pseudomonas aeruginosa pneumonia. Pneumonia was induced in male Sprague-Dawley rats via intratracheal injection of 0.2 ml, phosphate-buffered saline (PBS) containing P. aeruginosa (6x10(8) colony-forming units x mL(-1)). Control animals received 0.2 mL sterile PBS. Twenty-four hours after inoculation, the pneumonia group (PN) exhibited clinical signs of pneumonia including deficits in gas exchange, leukopenia and elevated arterial lactate levels. Morphological assessment confirmed the presence of pneumonia with airspaces filled with polymorphonuclear cells. Lung homogenate analysis demonstrated evidence of bacterial colonization of pneumonic lung tissue. Lung compliance was also significantly lower in the PN group. Lung lavage analysis of PN rats revealed the pooled surfactant levels to be lower and the surfactant function reduced compared to control rats. Surfactant composition was also found to be altered in PN rats. These results demonstrate that in Pseudomonas aeruginosa pneumonia, the pulmonary surfactant system is both poorly functioning and reduced in quantity. These alterations may contribute to the lung dysfunction characteristic of this disorder.

Regional changes in 5-HT1A but not in 5-HT2A receptors in mouse brain after Semliki Forest virus infection: radioligand binding and autoradiographic studies

Dysfunction of brain 5-hydroxytryptaminergic systems has been associated with several neurological and psychiatric diseases which may have a viral aetiology. The effect of Semliki Forest virus (SFV) on 5-hydroxytryptamine (5-HT1A and 5-HT2A) receptors in mouse brain has been assessed by membrane homogenate binding and autoradiography. Adult mice were injected with saline or virus and brains removed 2, 6, 14, 22 and 35 days after infection. 5-HT1A and 5-HT2A receptors were characterised by saturation studies using [3H] 8-OH-DPAT and [3H] Ketanserin respectively. SFV infection increased 5-HT1A receptor numbers by up to 80% in the cortex on days 6, 14, and 22 but had no effect on Bmax in the midbrain, pons/medulla and the hypothalamus. SFV infection did not affect 5-HT2A receptor number in any of the brain regions studied and the affinity (Kd) of either ligand for 5-HT1A or 5-HT2A receptors was unaffected. Autoradiographic mapping of 5-HT1A receptors in SFV-infected brain showed substantially higher binding in nucleus accumbens, tenia tecta, septohippocampal nucleus, septum, medial and basolateral amygdaloid nucleus, anterioventral preoptic nucleus, hippocampus, interpeduncular nucleus, frontal, lateral orbital, and entorhinal cortex and claustrum on days 6 and 14. Elevated binding persisted in tenia tecta, frontal, lateral orbital, entorhinal cortex, and hippocampal formation to day 22. Autoradiography of 5-HT2A receptors using [3H] Ketanserin showed no difference in the binding in SFV-infected brains. A decrease in plasma corticosterone levels in SFV-infected mice was observed on post infection days 6 and 22. These results show SFV infection induces a regionally selective upregulation of 5-HT1A but not 5-HT2A receptors.