Selective labeling of sensory hair cells and neurons in auditory, vestibular, and lateral line systems by a monoclonal antibody

This study reports that zn-1, a monoclonal antibody, labels hair cells but not supporting cells in the inner ear and the lateral line of the axolotl salamander, Ambystoma mexicanum. Zn-1 immunocytochemically labels the cytoplasm and stereocilia of mature hair cells in the sacculus, in the utriculus, and in the mechanoreceptive neuromast organs of the lateral line. Lower levels of labeling mark newly formed hair cells in the periphery of the sacculus and in regenerating neuromasts. Zn-1 also selectively labels neuronal processes and perikarya in the lateral line nerves and ganglia and the VIIIth cranial nerve and ganglion. Processes and perikarya are labeled by zn-1 in the dorsolateral medulla oblongata, at sites of termination of the afferent octaval and lateral line neurons. Western blot analysis revealed that zn-1 labels one or more proteins with molecular weights of 80 and 160 kDa. The identity of these protein bands remains to be determined. The presence of a specific epitope expressed in both hair cells and neurons, but not in supporting cells, in the vestibular and auditory epithelia of the ear and in the mechanoreceptive neuromasts of the lateral line suggests shared cytogenetic heritages. These findings are consistent with a close evolutionary relationship between otic and lateral line senses, such as that inherent to the theoretical evolutionary scheme outlined in van Bergeijk's "acousticolateralis hypothesis." The protein recognized by zn-1 is as yet unidentified, but its conservative evolution suggests that it may serve an important function in the statoacoustic and lateral line systems.     

New insights into the metabolic consequences of large-scale mtDNA deletions: a quantitative analysis of biochemical, morphological, and genetic findings in human skeletal muscle

In order to study putative genotype phenotype correlations in mitochondrial disorders due to large-scale mtDNA deletions we performed a quantitative analysis of biochemical, morphological, and genetic findings in 20 patients. The size of the mtDNA deletions varied from 2 to 7.5 kb with a degree of heteroplasmy ranging from 16% to 78%. Applying improved methods for measuring respiratory chain enzyme activities, we found highly significant inverse correlations between the percentage of cytochrome c oxidase (COX)- negative fibers and citrate synthase (CS) normalized COX ratios. Significant correlations were also established between CS normalized complex I and complex IV ratios as well as between the degree of heteroplasmy of mtDNA deletions and the percentage of ragged red fibers, COX-negative fibers, and CS normalized complex I and complex IV ratios. Our results indicate that the degree of heteroplasmy of mtDNA deletions is mirrored on the histological as well as the biochemical level. Furthermore, our findings suggest that single large-scale deletions equally influence the activities of all mitochondrially encoded respiratory chain enzymes. Even low degrees of heteroplasmy of mtDNA deletions were found to result in biochemical abnormalities indicating the absence of any well-defined mtDNA deletion threshold in skeletal muscle.     

Stimulation of adrenergic activity by desipramine enhances hematopoietic stem and progenitor cell mobilization along with G‐CSF in multiple myeloma: A pilot study

Hematopoietic stem cell (HSC) release is positively regulated by the sympathetic nervous system through the β3 adrenergic receptor. Preclinical studies have demonstrated that the combination of desipramine and G‐CSF resulted in improved HSC mobilization. Here, we present the results of an open‐label single‐arm pilot study in patients with multiple myeloma undergoing autologous stem cell transplantation (ASCT) to assess the safety and efficacy of desipramine combined with G‐SCF to induce HSC mobilization. The primary endpoint was safety of the combination including engraftment kinetics. The secondary endpoint was the proportion of patients who collected ≥5 × 10⁶ CD34⁺ cells/kg. Outcomes were compared with historical matched controls during the same time period with multiple myeloma mobilized with G‐CSF. All study patients received desipramine 100 mg daily for 7 days, starting 4 days prior to G‐CSF administration (D‐3) and continued taking it along with G‐CSF for a total of 7 days. Six of ten patients enrolled completed the protocol with minimal side effects. All of them achieved the target collection of 5 × 10⁶ CD34 cells/kg in a median of 1.5 apheresis session with two patients needing additional plerixafor (16%), while 11 out of 13 patients (85%) achieved the target of 5 × 10⁶ CD34 cells/kg in the historical control group in a median of 2 apheresis procedures and seven patients needed plerixafor (54%). The combination of desipramine and G‐CSF is safe and signals improved mobilization over G‐CSF alone, providing a possible alternative means of mobilization that needs further investigation.     

Creatine has no beneficial effect on skeletal muscle energy metabolism in patients with single mitochondrial DNA deletions: a placebo-controlled, double-blind 31P-MRS crossover study

The purpose of our randomized, double-blind, placebo-controlled crossover study in 15 patients with chronic progressive external ophthalmoplegia (CPEO) or Kearns-Sayre syndrome (KSS) because of single large-scale mitochondrial (mt) DNA deletions was to determine whether oral creatine (Cr) monohydrate can improve skeletal muscle energy metabolism in vivo. Each treatment phase with Cr in a dosage of 150 mg/kg body weight/day or placebo lasted 6 weeks. The effect of Cr was estimated by phosphorus-31 magnetic resonance spectroscopy ((31)P-MRS), clinical and laboratory tests. (31)P-MRS analysis prior to treatment showed clear evidence of severe mitochondrial dysfunction. However, there were no relevant changes in (31)P-MRS parameters under Cr. In particular, phosphocreatine (PCr)/ATP at rest did not increase, and there was no facilitation of post-exercise PCr recovery. Clinical scores and laboratory tests did not alter significantly under Cr, which was tolerated without major side-effects in all patients. Cr supplementation did not improve skeletal muscle oxidative phosphorylation in our series of patients. However, one explanation for our negative findings may be the short study duration or the limited number of patients included.     

Persistence of fluoroquinolone-resistant, multidrug-resistant Streptococcus pneumoniae in a long-term-care facility: efforts to reduce intrafacility transmission.

OBJECTIVE: We describe an effort to reduce transmission of a multidrug-resistant Streptococcus pneumoniae (MDRSP) in a long-term-care facility (LTCF). DESIGN: Longitudinal cross-sectional study. SETTING: An LTCF in New York City with ongoing disease due to an MDRSP strain among residents with AIDS since a 1995 outbreak. The MDRSP outbreak strain was susceptible to vancomycin but not to other antimicrobials tested, including fluoroquinolones. PARTICIPANTS: Residents and staff members of the LTCF during 1999 through 2001. INTERVENTION: Implementing standard infection control measures, and developing and implementing "enhanced standard" infection control measures, modified respiratory droplet prevention measures to reduce inter-resident transmission. RESULTS: Before the intervention, nasopharyngeal carriage of the MDRSP outbreak strain was detected in residents with AIDS and residents with tracheostomies who were not dependent on mechanical ventilation. The prevalence of nasopharyngeal carriage of the MDRSP outbreak strain was 7.8% among residents who had AIDS and 14.6% among residents with tracheostomies. After training sessions on standard and enhanced standard infection control measures, the staff appeared to have good knowledge and practice of the infection control measures. After the intervention, new transmission among residents with tracheostomies was prevented; however, these residents were prone to persistent tracheal carriage and needed ongoing enhanced standard infection control measures. Ongoing transmission among residents with AIDS, a socially active group, was documented, although fewer cases of disease due to the outbreak strain occurred. CONCLUSIONS: Infection control contributed to less transmission of MDRSP in the LTCE Additional strategies are needed to reduce transmission and carriage among certain resident populations.     

Developmental expression of glial fibrillary acidic protein mRNA in mouse forebrain germinal zones--implications for stem cell biology

Postnatal neural stem cells (NSCs) express the "traditional" astrocyte marker, glial fibrillary acidic protein (GFAP). Here, we analyze the ontogeny of GFAP mRNA in mouse forebrain germinal zones (GZ). On embryonic day 15, mRNA distribution is highly restricted. Subsequently, expression expands to include many cells in the GZ regions adjacent to the cortex and septum but not to the striatum. Double immunostaining for GFAP and nestin did not demonstrate extensive overlap in the GZ of adult rats, suggesting that either few of the GFAP-expressing cells are stem cells, or that nestin is not a reliable marker for stem cells in the adult rat brain. The current findings indicate that while some GFAP-expressing cells in the GZ may be NSCs, most are not likely to function in a neurogenic capacity.