Stability of C3 convertase in the rat classical complement pathway

It has been reported that rat serum complement causes efficient hemolysis of antibody-sensitized sheep erythrocytes (EA) at 20 C but not at 37 C. In connection with this, we demonstrated that C3 convertase of rat complement was significantly unstable at 37 C using purified components of rat complement.

Cause and repair of flap necrosis over cochlear implant

OBJECTIVE

The aim of this report was to study the cause and treatment of flap-related complications over cochlear implant.

SETTING

The study was performed in an academic tertiary referral center.

PATIENT

A 53-year-old Japanese male patient had had two retro-auricular skin incisions for tympanomastoidectomy in the postauricular region before implantation of a cochlear implant. He also had worn a helmet daily during work in his factory.

INTERVENTIONS

Corrective surgery was performed for reformation of the local blood supply to the overlying skin flap and reinforcement of the tissue overlying the implant by use of a superiorly based temporal muscle and fascia flap that were sutured with an inferiorly based muscle and fascia flap.

RESULTS

We successfully transposed the flap covering the implant without explantation of the implant.

CONCLUSIONS

The delayed development of flap necrosis was thought to be due to pressure necrosis produced by the band in the patient's helmet lying on the skin over the implant and to poor local blood supply in the postauricular area stemming from the two previous skin incisions for mastoid surgery performed for cholesteatoma. In those patients who wear helmets, it is important to position the cochlear implant sufficiently behind the ear and to avoid the use of a helmet.

Physical and functional interactions of Doc2 and Munc13 in Ca2+-dependent exocytotic machinery

Doc2 has two C2 domains that interact with Ca2+ and phospholipid. Munc13 has two C2 domains and one C1 domain that interacts with phorbol ester or diacylglycerol (DAG) and phospholipid. Both Doc2 and Munc13 are implicated in Ca2+-dependent neurotransmitter release, but their modes of action still remain unclear. We show here that Doc2 interacts with Munc13 both in a cell-free system and in intact PC12 cells during the high K+-induced Ca2+-dependent exocytosis. The Doc2-Munc13 interactions are stimulated by phorbol ester through the C1 domain of Munc13. Overexpression of the Doc2-interacting domain of Munc13 reduces the Ca2+-dependent exocytosis from PC12 cells, and co-expression with Doc2 suppresses this reduction. These results, together with the earlier findings that secretagogues produce DAG and elevate cytoplasmic Ca2+, suggest that the DAG-induced Doc2-Munc13 interactions play an important role in Ca2+-dependent exocytotic machinery.

Molecular cloning of mouse Doc2alpha and distribution of its mRNA in adult mouse brain

We have previously isolated from a human brain cDNA library, a new protein having two C2-like domains which interact with Ca2+ and phospholipid, and named Doc2alpha. Doc2alpha is abundantly expressed in brain, where it is highly concentrated on the synaptic vesicle fraction, and is implicated in Ca2(+)-dependent exocytosis. We have isolated here a mouse Doc2alpha cDNA and determined the localization of its mRNA in adult mouse brain. The amino acid sequence of the mouse Doc2alpha cDNA is 92% identical with that of the human counterpart. Northern blot analysis and in situ hybridization on adult mouse brain sections have revealed that Doc2alpha is predominantly expressed in mouse brain, where it is expressed in neuronal cells, but not in non-neuronal cells. Doc2alpha is highly expressed in the olfactory bulb, cerebral cortex, hippocampus, amygdaloid complex, and ventromedial hypothalamus nucleus, but not in the cerebellum, caudate-putamen, or ventral thalamus. These results indicate that Doc2alpha is expressed heterogeneously in mouse brain, where it is predominantly expressed in neuronal cells, and suggest that Doc2alpha plays a specific role in the area where it is expressed.

Electromyographic (EMG) study of cold shivering in the chronic spinal dog

Cold shivering in six chronic spinal dogs (T9-10), which became capable of weight-bearing standing and/or walking with their hindlimbs, was studied by electromyography (EMG). In the forequarters, EMG activities in the form of grouping discharges (GD) accompanied by visible tremor (VT) were induced at an ambient temperature of 15 degrees C in all the dogs. In the hindquarters, GD with VT were induced at 3 degrees C in one dog. Although GD with VT were not induced in in the remaining dogs, GD without VT were produced by additional cutaneous stimuli to the hindquarters at 3 degrees C. These stimuli never produced GD in the hindquarters at room temperature. Though the mean frequency of GD in the hindquarters was lower than that in the forequarters, the range of the frequency in the hindquarters was much the same as that in the forequarters. During the experiment, the drop in rectal temperature was less than 0.6 degrees C in all of the dogs. These findings suggest that the chronically isolated spinal cord is responsible for cold shivering, while its excitability to cold exposure is less than that of the spinal cord governed by the supraspinal center.

Fine structures of perikaryal myelin sheaths on statoacoustic ganglion cells in 3-day-old chicks

Perikaryal myelin sheaths on statoacoustic ganglion cells in 3-day-old chicks were studied by electron microscopy. The fixation method with a high-concentrated warm fixative helped in successful demonstrations of perikaryal myelin structures. The sheaths were composed of loose and compact myelin mixed by various arrangements. Twenty-seven percent of perikarya were entirely encircled by compact myelin, 71% were partly wrapped by compact myelin, and 2% were wrapped by just loose myelin. The perikaryal myelin was composed of 3 to 16 layers of loose and compact lamellae, whereas the axonal myelin of 10 to 28 of compact lamellae. Since no unmyelinated perikarya, which are covered by a single layer of Schwann cell cytoplasm, were detected, it is suggested that the perikarya myelination on all the ganglion cells has started before 3 days after hatching.

[Visiting nurse support for patients wishing to die at home]

Thirty-two (1994) and 55 (1995) patients in the terminal stage of many kinds of cancer were cared for satisfactorily at home by a visiting team of nurses from Niigata Cancer Center Hospital. A prostate cancer patient with multiple bone metastasis was suffering from morphine-resistant intractable pain, and highly dependent on medical care. We continued to take care of him by frequent visitation and psychological assist until he eventually died at home according to his wishes. It is important to create a suitable support team for the continual difficult home care of each terminal patient.

Inhibitory projection from brachioradialis to biceps brachii motoneurones in human

Neural projection from the brachioradialis to the biceps brachii motoneurones in human was studied using the method of post-stimulus time histogram. Electrical stimulation to the radial branch innervating the brachioradialis produced inhibition in 11 out of 21 biceps motor units. The central delays of the inhibition were 0.7-1.2 ms longer than those of the homonymous facilitation. The inhibition was evoked with the intensity below the motor threshold. Pure cutaneous stimulation provoked no effects on the motor-unit firing. These findings suggest that group I afferents from the brachioradials mediate an oligosynaptic inhibition of the biceps brachii motoneurones.

Temperature-dependent conformational change of bacteriorhodopsin as studied by solid-state 13C NMR

Cross-polarization and dipolar-decoupled magic-angle spinning 13C-NMR spectra of [3-13C]Ala-labelled bacteriorhodopsin were obtained for hydrated purple membrane in the temperatures range 23 degrees C to -110 degrees C. Well-resolved 13C-NMR signals were observed either at ambient temperature or at -20 degrees C but were broadened considerably at lower temperature below -40 degrees C. This situation was interpreted in terms of the presence of exchange processes with a rate constant of 10(2) s-1 at ambient temperature among several conformations slightly different from each other. We found that such an exchange process was strongly influenced by the manner of organization of the lipid bilayers depending upon the presence or absence of cations responsible for electric shielding of negative charge at the polar head groups. The manner of organization of the lipid bilayers was conveniently characterized by a characteristic temperature at which the methyl peaks of fatty acyl groups of lipids in the purple membrane were suppressed due to interference of motional frequency with the decoupling frequency (10-100 kHz) for preparations containing 10 mM NaCl or CaCl2. No such spectral change in the absence of these cations was noted even if a preparation was cooled to -110 degrees C. The secondary structures of [3-13C]Ala-labelled bacteriorhodopsin was not always identical at temperatures between ambient and low temperatures, since the 13C chemical shifts and relative peak intensities for purple membrane preparations containing these salts changed with temperature in the range -110 degrees C to 23 degrees C. In particular, we found that some residues involving Ala residues at the alpha II-helix and loop region were converted at temperatures below -60 degrees C to a conformation involving alpha 1-helix. In other words, some portion of the alpha-helical conformation of bacteriorhodopsin proposed from results obtained by cryo-electron microscopy, at very low temperatures, is not always retained at ambient temperature.

Conformation and dynamics of [3-13C]Ala- labeled bacteriorhodopsin and bacterioopsin, induced by interaction with retinal and its analogs, as studied by 13C nuclear magnetic resonance

13C nuclear magnetic resonance (NMR) spectra of [3-13C]Ala-labeled bacteriorhodopsin (bR), bacterioopsin (bO), and regenerated bR with retinal or bO complex with retinal analogs were recorded in order to gain insights into how the conformation and dynamics of apoprotein (bO) vary with or without retinal or its analogs. First, we assigned the 13C NMR peak resonating at 16.3 ppm to Ala 53 of both bR and bO, which appears to contact the side chain of Lys 216 at the site of the Schiff base in the former, utilizing the 13C NMR peaks of A53V and A53G proteins in comparison with those of wild-type bR and bO. Characteristic spectral differences between the apoprotein and bR were observed upon removal of the retinal: the changes of the peak intensities at 16.4, 15.9, and 16.9 ppm are notable. We found that the loops (17.4 ppm) and transmembrane alpha II helical region (15.9 ppm) acquired motional freedom with a correlation time of 10(-5)s when the retinal was removed, as detected by proton spin-lattice relaxation times in the rotating frame. A 13C NMR spectrum very similar to that of native bR was recorded when bR was regenerated by addition of retinal to bO. On the other hand, the addition of the retinal analogs retinol or beta-ionone, which are bound in the retinal binding site but are incapable of forming a Schiff base to the apoprotein, caused distinct spectral changes different from those of bR, as manifested from the displacements of 13C chemical shifts. These spectral changes must be ascribed to significant conformational changes of apoprotein at various locations in the protein, including the site of Ala 53 induced by modified interaction between the apoprotein and chromophore.

Involvement of angiotensin II in glomerulosclerosis of stroke-prone spontaneously hypertensive rats

Renal plasma flow (RPF), glomerular filtration rate (GFR), glomerular pathology and glomerular TGF-beta gene expression were examined in 12- and 24-week-old stroke-prone spontaneously hypertensive rats (SHRSP) and Wistar Kyoto rats (WKY). These parameters were also examined in SHRSP treated with equihypotensive doses of angiotensin II receptor antagonist (CV-11974:CV) and hydralazine (Hyd) for 12 weeks. Twelve-week-old SHRSP showed a decrease in RPF and GFR, and an increase in filtration fraction (FF) and urinary protein excretion (UP) compared to WKY. CV normalized these parameters, whereas although Hyd showed improved levels they were not to the levels achieved by the WKY. Glomerular TGF-beta expression was increased 2.0-fold in 12- and 24-week-old SHRSP, and CV, but not Hyd, decreased it to the control levels of WKY. At 24 weeks old, SHRSP showed a higher glomerulosclerosis index (GI) than WKY. CV, but not Hyd, lowered the GI to the level of the WKY controls. These data indicate that renal hemodynamic changes are closely associated with an increased TGF-beta expression in SHRSP and that this condition is caused by angiotensin II.

Early diagnosis and stage classification of vocal cord abductor paralysis in patients with multiple system atrophy

OBJECTIVES

Vocal cord abductor paralysis (VCAP) is a life threatening complication which may cause nocturnal sudden death in patients with multiple system atrophy. However, the early diagnosis of VCAP is often difficult to make on routine laryngoscopy performed during wakefulness, as stridor, which is the sole symptom of VCAP in the early stage, develops only during sleep. The aim was to investigate laryngeal dysfunction in patients with multiple system atrophy while awake and asleep.

METHODS

Seven patients with multiple system atrophy with nocturnal stridor and five control patients were studied. Vocal cord movement was analysed by laryngoscopy while the patients were awake and also during sleep induced by intravenous diazepam.

RESULTS

When awake, for the seven patients with multiple system atrophy normal movement of the vocal cords occurred in three, mild abduction restriction in three, and paradoxical movement in one. When asleep, however, all showed obvious paradoxical movement with high pitched inspiratory stridor. In controls, there were no differences in the vocal cord movement between wakefulness and sleep. From these findings, VCAP could be divided into four stages: stage 0 (normal) with normal vocal cord movement during both wakefulness and sleep, stage 1 (mild VCAP) with normal movement during wakefulness and paradoxical movement during sleep, stage 2 (moderately severe VCAP) with abduction restriction during wakefulness and paradoxical movement during sleep, and stage 3 (severe VCAP) with an almost midline position for the vocal cords during both wakefulness and sleep.

CONCLUSIONS

Laryngoscopy during sleep can disclose subclinical VCAP, making an early diagnosis of VCAP in patients with multiple system atrophy. Stage 2 of VCAP seems to be a suitable stage for tracheostomy in patients with multiple system atrophy.

Myocardial sympathetic dysinnervation in doxorubicin cardiomyopathy

Single photon emission computed tomography (SPECT) using I-123 metaiodobenzylguanidine (MIBG) was evaluated for the detection of doxorubicin (DXR) cardiomyopathy in seven patients with malignant lymphoma receiving DXR doses ranging from 70 to 530 mg (DXR group), and 20 normal subjects without hypertension, diabetes mellitus or electrocardiographic abnormalities (control group). The ratio of the heart to mediastinal counts (H/M) and the washout rate (WR) in MIBG SPECT images were compared between the two groups. Correlation of total doses of DXR with H/M and the relationship of H/M to WR were investigated. The H/M of the DXR group was lower than that of the control group (3.00 +/- 0.97 vs 4.90 +/- 1.08, p < 0.001). The WR of the DXR group was higher than that of the control group (30.9 +/- 10.5% vs 16.5 +/- 9.1%, p < 0.001). Total DXR doses were inversely correlated with H/M (r = -0.86), H/M correlated inversely with the WR (r = -0.83) only in the DXR group. Pathological findings of one patient, who died of DXR cardiomyopathy, showed atrophic and fibrotic nerve fibers in the apical inferior segment of the left ventricle where MIBG uptake was reduced markedly. DXR cardiomyopathy can be detected with MIBG SPECT as cardiac sympathetic nervous dysinnervation. The pathological findings correspond to the MIBG SPECT findings.

Dynamics of the three methionyl side chains of Streptomyces subtilisin inhibitor. Deuterium NMR studies in solution and in the solid state

Streptomyces subtilisin inhibitor (SSI) contains three methionine residues in a subunit: two (at positions 73 and 70) in the crucial enzyme-recognition sites P1 and P4, respectively, and one (Met 103) in the hydrophobic core. The motions of the side chains of these three Met residues and the changes in mobility on binding with subtilisin were studied by deuterium NMR spectroscopy in solution and in crystalline and powder solids. For this purpose, the wild-type SSI was deuterium-labeled at the methyl groups of all three Met residues, and three artificial mutant proteins were labeled at only one specific Met methyl group each. In solution, for methionines 73 and 70, the effective correlation times were only 0.8-1.0 x 10(-10)s indicating that the two side chains on the surface fluctuate almost freely. On formation of a complex with subtilisin, however, these high mobilities were quenched, giving a correlation time of 1.1 x 10(-8)s for the side chains of methionines 70 and 73. The correlation time of Met 103, located in the hydrophobic core, was at least 1.0 x 10(-8)s in free SSI, showing that its side chain motion is highly restricted. The nature of the internal motions of the three Met side chains was examined in more detail by deuterium NMR spectroscopy of powder and crystalline samples. The spectral patterns of the powder samples depended critically on hydration: immediately after lyophilization, the side-chain motions of the three Met residues were nearly quenched. With gradual hydration to 0.20 gram of water per gram protein-water, the orientational fluctuation of the methyl axes of methionines 70 and 73 was selectively enhanced in both amplitude and frequency (to about 1 MHz) and, at nearly saturating hydration (0.60 gram of water per gram protein-water), became extremely high in amplitude and frequency (> 10 MHz). In contrast, the polycrystalline wild-type SSI spectrum showed fine structures, reflecting characteristic motions of the Met side chains. The polycrystalline spectrum could be reproduced reasonably well by the same motion models and parameters used to simulate the powder spectrum at the final level of hydration, suggesting that the side-chain motions are similar in the fully hydrated powder and in crystals. Spin-lattice relaxation measurements gave evidence that, even in crystals, the methyl axes of all three Met residues undergo rapid motions with correlation times between 10(-8) and 10(-10)s, comparable to the correlation times in solution. Finally, in the hydrated stoichiometric complex of SSI with subtilisin BPN' in the solid state, large-amplitude motions are absent, but the side chains of methionines 70 and/or 73 are likely to have small-amplitude motions.

Antioxidative action of the beta-adrenoceptor antagonist bopindolol and its metabolite 18-502

The antioxidative effects of beta-adrenoceptor antagonists and related compounds were investigated. Among the beta-adrenoceptor antagonists, the agents with a potent membrane-stabilizing activity such as bopindolol and propranolol strongly inhibited the hydrogen peroxide (H2O2)-induced lipid peroxidation of liver microsomes. Fifty percent inhibition concentration values for the lipid peroxidation of bopindolol, 18-502 (metabolite of bopindolol) and propranolol were calculated to be 1.8 microM, 10 microM and 2.3 microM, respectively. The same potency order of the agents for the inhibition of lipid peroxidation was observed in rat heart homogenates. Furthermore, cytochrome P-450-catalyzing lipid peroxidation in microsomes and H2O2-induced lipid peroxidation in coronary arteries or cardiac muscles of pigs were also inhibited by bopindolol, whereas propranolol was less effective. Bopindolol and 18-502, but not propranolol, scavenged a stable free radical 1,1-diphenyl-2-picrylhydrazyl. Thus it was concluded that bopindolol that has membrane-stabilizing and radical scavenging activities is a more potent antioxidant than propranolol and may produce a beneficial effect for the treatment of ischemic cardiac diseases.

Electromyographic (EMG) study of the elbow flexors during supination and pronation of the forearm

Activities of the elbow flexors during supination and pronation of the forearm in a normal human volunteer were studied by an electromyography (EMG). The volunteer performed the movement slowly or quickly holding elbow flexion at various angles with or without a load. The biceps brachii showed an increase and a decrease of EMG activities during supination and pronation, respectively. The brachialis and brachioradialis showed a reduction and an increment of EMG activities accompanied by an increase and a decrease of EMG activities in the biceps brachii, respectively. These findings seem to indicate that reciprocal contractions among the elbow flexors permit the biceps brachii to work for supination without an induction of elbow flexion.

Doc2: a novel brain protein having two repeated C2-like domains

Two repeated C2-like domains interacting with Ca2+ and phospholipid are found in synaptotagmin and Rabphilin-3A which are implicated in neurotransmitter release. Here we have isolated a cDNA encoding a novel protein having two repeated C2-like domains from a human brain cDNA library. The isolated cDNA encodes a protein with 400 amino acids and a M(r) of 44,071. The purified recombinant protein indeed interacts with Ca2+ and phospholipid. We have named this protein Doc2 (Double C2). Doc2 is exclusively expressed in brain and is highly concentrated in the synaptic vesicle fraction. These results suggest that Doc2 is a novel brain protein and serves as a Ca2+ sensor in neurotransmitter release.

Control of thumb movements: EMG analysis of the thumb and its application to functional electrical stimulation for a paralyzed hand

This paper describes the control of thumb movements by functional electrical stimulation (FES). In order to determine stimulation data of thumb muscles, activities of nine thumb muscles and the palmaris longus were analyzed in normal subjects by averaging their EMGs. In this analysis, it was found that well coordinated contractions of these thumb muscles were required for finer movements and precise positioning of the thumb. Based upon this analysis, several standard stimulation data for the thumb muscles were programmed and stored into a computer-controlled FES system. Input of the threshold and maximum stimulating voltages for individual thumb muscles of normal subjects to the system enabled automatic creation of stimulation data for each subject. The thumb movements of the normal subjects induced by these data were very smooth and their trajectories were reproducible. In addition, precise thumb positioning and joint stability were easily obtained. These standard stimulation data for the thumb muscles were also applied to FES control of a C4 quadriplegic. The controllability of the thumb movements was improved and the reliability of hand tasks achieved by FES was increased.

Embolization of a ruptured middle colic artery aneurysm

Middle colic artery aneurysms are very uncommon. A few cases of occlusion of superior mesenteric artery aneurysms without bowel ischemia are reported. We describe successful uncomplicated embolization of a ruptured middle colic artery aneurysm with a Gelfoam plug.

13C NMR study on conformation and dynamics of the transmembrane alpha-helices, loops, and C-terminus of [3-13C]Ala-labeled bacteriorhodopsin

We have recorded 13C CP-MAS and DD-MAS NMR spectra of untreated and deionized [3-13C]-Ala-labeled bacteriorhodopsin (bR) and those cleaved with carboxypeptidase A and papain to gain insight into the conformation and dynamics of the transmembrane alpha-helices, loops, and C-terminus. It turned out that the C-terminus does not contribute to the 13C CP-MAS NMR spectra of [3-13C]Ala-bR recorded at ambient temperature owing to its rapid reorientational motions, since the relative peak intensities were unchanged in spite of the enzymatic cleavages. Therefore, the 13C CP-MAS NMR peaks of bR should be ascribed both to the transmembrane alpha-helices and loops. We further distinguished the peaks of the alpha II-helix form at 16.3 ppm (60%) from those of the alpha I-helix form at 14.9 ppm (20%) by deconvolution of the respective peaks of the hydrated [3-13C]Ala-bR, as referred to the 13C chemical shift of polyalanine in hexafluoroisopropyl alcohol. The remaining CP-MAS NMR peak of [3-13C]Ala-bR at 17.2 ppm was ascribed to the loops (20%) taking a variety of turn structures. In contrast, the 13C NMR signals from the C-terminal residues were significantly enhanced by recording the dipolar-decoupled (DD)-MAS NMR spectra. Conformational features of the two different portions of the C-terminus, residues 245-248 and 231-244, were revealed by the conformation-dependent 13C signals of bR successively cleaved by carboxypeptidase A and papain, respectively. The terminal end, residues 245-248, containing two Ala residues is virtually disordered and undergoing rapid motions.(ABSTRACT TRUNCATED AT 250 WORDS)

Study on the elbow movement produced by functional electrical stimulation (FES)

Functional electrical stimulation (FES)-induced movements of the upper extremity using the electromyography (EMG)-based stimulation data, which were created on the basis of EMG analysis of elbow flexion and extension in a normal human subject, were examined. As a result of the FES to the elbow flexors and extensors in another normal subject, smooth and reproducible elbow flexion and extension were controlled. This result seems to indicate not only an advantage of EMG-based stimulation data in the FES but also a great potential of FES as a new technique for the functional anatomy of the human extremities.

Patients' reactions to angioplasty: realistic or not?

BACKGROUND

A major problem limiting the success of angioplasty is the high restenosis rate. In addition, coronary artery disease is an ongoing process requiring lifestyle changes to prevent disease progression.

OBJECTIVE

To examine patient concerns and risk factor modification behaviors during early recovery from angioplasty. Specific attention was directed to: (1) expectation of restenosis, (2) occurrence of angina, (3) achievement of expected benefits, (4) tension/anxiety levels, (5) self-efficacy for and actual performance of needed lifestyle changes.

METHODS

For this descriptive study the Self-Report of Recovery (a project-derived questionnaire) and the Profile of Mood States were mailed to 54 patients at 1, 6, and 12 weeks of recovery. The study group comprised 37 men and 17 women (mean age, 57 years) who had undergone first-time successful angioplasty at a midwestern medical center. At 12 weeks 78% remained.

RESULTS

A majority of patients did not expect restenosis to occur. At 3 months 83% reported that they were angina-free, 90% reported that they would repeat the procedure if needed, all scores on the tension/anxiety scale were normal, and 86% had achieved some benefits they had expected. Most expressed high confidence in their ability to reduce risk factors, with 90% reporting initiation of at least one lifestyle change.

CONCLUSION

We concluded that patients had positive feelings about their angioplasty experience and were not overly concerned about restenosis.

Patients' reactions to angioplasty: realistic or not?

BACKGROUND: A major problem limiting the success of angioplasty is the high restenosis rate. In addition, coronary artery disease is an ongoing process requiring lifestyle changes to prevent disease progression. OBJECTIVE: To examine patient concerns and risk factor modification behaviors during early recovery from angioplasty. Specific attention was directed to: (1) expectation of restenosis, (2) occurrence of angina, (3) achievement of expected benefits, (4) tension/anxiety levels, (5) self-efficacy for and actual performance of needed lifestyle changes. METHODS: For this descriptive study the Self-Report of Recovery (a project-derived questionnaire) and the Profile of Mood States were mailed to 54 patients at 1, 6, and 12 weeks of recovery. The study group comprised 37 men and 17 women (mean age, 57 years) who had undergone first-time successful angioplasty at a midwestern medical center. At 12 weeks 78% remained. RESULTS: A majority of patients did not expect restenosis to occur. At 3 months 83% reported that they were angina-free, 90% reported that they would repeat the procedure if needed, all scores on the tension/anxiety scale were normal, and 86% had achieved some benefits they had expected. Most expressed high confidence in their ability to reduce risk factors, with 90% reporting initiation of at least one lifestyle change. CONCLUSION: We concluded that patients had positive feelings about their angioplasty experience and were not overly concerned about restenosis.

A high-resolution 15N solid-state NMR study of collagen and related polypeptides. The effect of hydration on formation of interchain hydrogen bonds as the primary source of stability of the collagen-type triple helix

High-resolution solid-state 15N-NMR was used to clarify the effect of hydration on the stability of the coiled-coil triple-helix conformation of Gly-Xaa-Yaa repeating units in collagen and the collagen-like polypeptides, (Pro-Ala-Gly)n and (Pro-Pro-Gly)10, because the stability is thought to be related to the presence of (Gly)NH ... O = C(Xaa or Pro) hydrogen bonds. The 15N-NMR signals of these samples were narrowed upon hydration, mainly due to hydration-induced conformational change or rearrangement of the repeating units. In particular, the 15N chemical shifts of the Gly N-H group and the high-field (low-frequency) shoulder peak of Pro nitrogen signals in (Pro-Pro-Gly)10 were shifted downfield (4.9 ppm and 6.8 ppm, respectively) with increasing relative humidity, while the corresponding peaks for collagen and (Pro-Ala-Gly)n were unchanged and close to the 15N shift of (Pro-Pro-Gly)10 in the hydrated state. Such downfield shifts are consistent with the formation of N-H ... O = C hydrogen bonds. In agreement with the NMR results, it was found that the (Gly)NH ... O = C (Xaa or Pro) hydrogen bonds are retained in dehydrated collagen fibrils but not in partially dehydrated (Pro-Pro-Gly)10. No evidence was obtained for the partial formation of the 3(1) helix form (Pro)n or (Gly)n either under hydrated or dehydrated conditions. It is concluded that the Gly 15N chemical shift is a very sensitive probe for studying supercoiling in collagen and collagen-like polypeptides.