Coumarin-based Fluorescent Probes for Selectively Targeting and Imaging the Endoplasmic Reticulum in Mammalian Cells

Developing improved fluorescent probes for imaging the endoplasmic reticulum (ER) is necessary for structure-activity studies of this dynamic organelle. Two coumarin-based compounds with sulfonamide side groups were synthesized and characterized as ER-targeting probes. Their selectivity to target the ER in HeLa and GM07373 mammalian cells was shown with co-localization experiments using commercially available probes that localize in the ER, mitochondria, or lysozymes. The hydrophobicity of the coumarin-based probes was comparable to known probes that partition into the ER membrane. Their cytotoxicity in mammalian cells was low with IC50 values that range from 205 to 252 μm. The fluorescent quantum yields of the coumarin-based probes when excited with 400 nm light were 0.60, and they have a much narrower emission spectrum (from 435 to 525 nm in methanol) than that of the only commercially available ER probe that is exited with 400 nm light (ER-Tracker™ Blue-White DPX). Thus, the coumarin-based probes are more useful for multicolor imaging with yellow and red emitting fluorophores. In addition to the above benefits, ER labeling was achieved with the coumarin-based probes in both live cells and fixed cells, revealing their versatility for a wide range of cellular imaging applications.

The Synthesis of a New Class of Highly Fluorescent Chromones via an Inverse-Demand Hetero-Diels-Alder Reaction

A new class of fluorophores has been developed utilizing an inverse-demand hetero-Diels-Alder reaction with silyl enol ethers and substituted 3-formylchromones. These compounds yield blue to green fluorescence with quantum yields up to 73%. They also exhibit good potential for use as fluorescent probes in biological systems, as they are cell membrane permeable with low cytotoxicity.

Continuous passive motion after total knee arthroplasty: a prospective study

OBJECTIVE

Continuous passive motion (CPM) has been shown to increase significantly the amount of knee flexion for patients with total knee arthroplasty in the acute care hospital. Whether there is any additional benefit to using CPM for these patients who are transferred to a rehabilitation hospital is not known. There have been no prospective, randomized, controlled studies in this area.

DESIGN

Fifty-one such patients on an inpatient rehabilitation service were randomly assigned to two groups. Group 1 (n = 23) received CPM for 5 consecutive hours per day plus physical therapy, whereas group 2 (n = 28) received only physical therapy. Knee flexion was measured by a blinded physical therapist on admission, on the third and seventh days of hospitalization, and at the time of discharge.

RESULTS

The results indicated no significant difference in passive range of motion between group 1 and group 2. Patients in group 1 achieved an average increase in passive range of motion of 16 degrees, whereas those in group 2 achieved an average of 19 degrees (P = 0.33).

CONCLUSION

Although power analysis indicated the need for differences in results for 32 patients per group to achieve significance, the difference between the two groups suggested neither statistical nor clinical significance. We concluded that the use of CPM in the rehabilitation hospital is likely of no added benefit to patients admitted after single total-knee replacement.

Word finding difficulty as a post-polio sequelae

OBJECTIVE

Seventy-nine percent of respondents to the 1990 National Post-Polio Survey reported difficulty "thinking of words I want to say," with 37% reporting frequent, moderate-to-severe word finding difficulty. This study was undertaken to objectively document polio survivors' word finding difficulty and to identify its relationship to fatigue, neuropsychologic processes requiring cortical activation, and a peripheral marker for brain dopamine secretion.

DESIGN

In this study, 33 polio survivors were administered the Post-Polio Fatigue Questionnaire, Animal Naming and FAS Tests, and tests of attention and information processing speed. Plasma prolactin was also measured as a marker for brain dopamine secretion.

RESULTS

Subjects reporting high fatigue severity and word finding difficulty had clinically abnormal or significantly lower Animal Naming Test scores compared with subjects with low symptom severity. Impaired performance on the most difficult tests of attention and information processing speed were also associated with lower scores on the word finding tests. A significant negative correlation between Animal Naming Test scores and plasma prolactin suggests that a decrement in brain dopamine secretion is related to reduced animal naming ability.

CONCLUSIONS

These data support the hypothesis that decreased dopamine secretion, possibly secondary to poliovirus damage to the basal ganglia, may underlie not only fatigue and impaired attention but also word finding difficulty in polio survivors.

The dynein heavy chain gene family in Tetrahymena thermophila

The dynein ATPases are a family of motor enzymes that drive microtubule sliding in cilia and flagella and contribute to microtubule-based transport inside cells. The multi-dynein hypothesis makes two predictions: 1) Axonemes contain multiple dynein heavy chain (DHC) isoforms, each encoded by a different gene; 2) Each isoform performs a specific role in ciliary beating. We used PCR-based techniques to clone thirteen different DHC sequences from Tetrahymena genomic DNA. All thirteen genes appeared to be expressed in growing cells. Comparisons of the deduced amino acid sequences of the thirteen DHCs with other known DHCs suggested that we have cloned three outer arm DHCs, two cytoplasmic DHCs, and eight inner arm DHCs.

Bromocriptine in the treatment of post-polio fatigue: a pilot study with implications for the pathophysiology of fatigue

Fatigue is the most commonly reported and most disabling of all post-polio sequelae (PPS). Bromocriptine mesylate (Parlodel) was employed in a placebo-controlled trial in five survivors of paralytic polio who continued to report moderate to severe daily fatigue after complying with the conservative treatments prescribed for PPS. Placebo was given for 4 wk followed by increasing doses of bromocriptine mesylate, administered at 12:00 pm for 28 days, which reached a total dose of 12.5 mg/day. Three subjects reported marked symptom improvement on bromocriptine but not on placebo. Their reported difficulty with attention, concentration, word finding, mind wandering, memory, thinking clearly, and fatigue on awakening was significantly negatively correlated with days on bromocriptine but not with days on placebo. Before the drug trial began, responders had clinically impaired performance on neuropsychologic tests of attention and information processing speed, more than twice as many hyperintensities on magnetic resonance imaging of the brain, abnormally low fasting adrenocorticotropic hormone levels, and nearly double the mean plasma prolactin level compared with nonresponders. The implications of these findings for the pathophysiology of fatigue are discussed. A double-blind, placebo-controlled, multicenter study will be needed to confirm bromocriptine's efficacy in treating attentionally and neurophysiologically impaired polio survivors whose severe and disabling fatigue does not respond to conservative therapies.

Case report: CT and MRI of intracranial dermoid causing headache

This case shows an unusual intracranial cause of chronic headache in a 30-year-old female. Computerized tomography and magnetic resonance imaging were used to demonstrate an intracranial, dermoid cyst located in the left middle cranial fossa. Droplets of fat-like material, which leaked from this cyst, were present in the basilar subarachnoid spaces and left sylvian fissure. Since the surgical excision of the cyst, the patient has not had any severe headaches.

Continuous passive motion in the rehabilitation setting. A retrospective study

Continuous passive motion (CPM) has been commonly used in the postoperative rehabilitation of patients after total knee arthroplasty. In the acute care hospital, most studies have found CPM to be useful in improving range of motion and reducing length of stay. The benefit of CPM in the rehabilitation hospital has not been studied. The charts of 61 patients who had undergone total knee arthroplasty and subsequently were admitted to the East facility of the Kessler Institute for Rehabilitation were reviewed. Patients were separated into two groups: Group 1 received CPM for 3 to 4 hours/day and physical therapy for 2 hours/day. Group 2 received only physical therapy. There was no significant difference in passive range of motion or length of stay between Group 1 and Group 2. An analysis of the 16 patients who underwent bilateral replacement was undertaken. Patients in Group 1 (n = 7) achieved an average increase in passive range of motion of 20.1 degrees, whereas those in Group 2 (n = 9) achieved an increase of 12.7 degrees (P = 0.18). Power analysis demonstrated the need for 50 patients per subgroup to achieve significance. The lack of statistical significance in this subgroup may be a reflection of the small study population (n = 16). The following conclusions can be drawn concerning the use of CPM in the rehabilitation setting: (1) CPM was of no added benefit to those patients admitted after single knee replacement, and (2) CPM may be beneficial to those patients admitted after bilateral knee replacement.

Dislocations after total hip-replacement arthroplasties

In a series of 300 total hip replacements, nine (3 per cent) dislocated. Precise measurements of the orientation of the acetabular cup were made and it was found that anterior dislocations were associated with increased acetabular-component anteversion. There was no significant correlation between cup-orientation angle and posterior dislocation. The dislocation rate for cup orientation with anteversion of 15 +/- 10 degrees and lateral opening of 40 +/- 10 degrees was 1.5 per cent, while outside this "safe" range the dislocation rate was 6.1 per cent. Other factors that were documented include time after surgery (with the greatest risk in the first thirty days) and surgical history (with a greater risk in hips that have had prior surgery).

The number of total joint replacements in the United States

By comparing estimates from several sources an assessment can be made of the number of total joint replacement procedures performed annually in the United States. Approximately 80,000 hips and 40,000 knee joints were replaced in the U.S. during 1976. Total hip replacement has been accepted by the orthopedic community as an efficacious mode of treatment of the many painful and disabling forms of arthritis. A substantial patient population could benefit from perfection of designs for treating joints other than the hip.

Fossil and Living Conchostracan Distribution in Kansas-Oklahoma across a 200-Millon-Year Time Gap

Fifty-nine of 493 ponds sampled in the Wellington fossil conchostracan belt contained Cyzicus mexicanus (Claus). Persistent habitat preference and faunal association were also found for four orders of insects (Odonata, Ephemeroptera, Neuroptera, and Homoptera). Comparative limnology is detailed. Greater geographic fractionation of Permian conchostracan gene-pools is attributed to a more arid climate indicated by evaporites.

New Permian Insects Discovered in Kansas and Oklahoma

The Midco insect bed of Oklahoma and a newly discovered insect bed above this were traced across Kay County, Okla., into Sumner County, Kan. As a result, a greater time span is available for study of insect evolution during the mid-continent Permian, and the exact stratigraphic correlation of the Wellington of Oklahoma and Kansas can now be demonstrated. Four insect orders have thus far been identified from the new insect bed: Protodonata, Odonata, Protoperlaria, and Ephemeroptera. Numerous new species and higher categories are included in the collections from the two insect beds.