Improved myocardial ischemic response and enhanced collateral circulation with long repetitive coronary occlusion during angioplasty: a prospective study

OBJECTIVES

The goal of the study was to evaluate the progressive increase in ischemic threshold with multiple sequential transient coronary occlusions and to assess the role of the collateral circulation in adaptation to ischemia.

BACKGROUND

It has been observed that the duration of balloon inflations during coronary angioplasty can be gradually prolonged during subsequent dilations with a reduction in patient symptoms and diminished ischemic electrocardiographic (ECG) changes. Although the mechanism has not been fully explained, recruitment of coronary collateral circulation induced by repeated coronary occlusion has been reported. The stimuli for recruitment and the natural history of coronary collateral circulation are not understood.

METHODS

Seventeen patients with isolated stenosis of the left anterior descending coronary artery and a normal left ventricle were enrolled. Angioplasty consisted of five successive prolonged inflations. Sequential changes in clinical, intracoronary ECG and left ventricular indexes of myocardial ischemia were examined. Coronary collateral channels were evaluated during balloon inflations by ipsilateral and contralateral injections of contrast medium and hemodynamically by occlusion pressure.

RESULTS

An improved tolerance to myocardial ischemia with repetitive coronary occlusions was demonstrated by a significant reduction of angina, ST segment deviation, left ventricular filling pressure and less impairment of ejection fraction. Left ventricular wall motion abnormalities remained unchanged. Collateral angiographic grade did not change in 7 patients and increased in 10.

CONCLUSIONS

This study confirms a progressive adaptation of myocardial ischemia to repetitive coronary occlusions and supports the concept that sequential episodes of myocardial ischemia are a stimulating factor for the recruitment of collateral channels in humans. These results also suggest that enhancement of recruitable collateral circulation might be an underlying mechanism of myocardial ischemic preconditioning.

A resonance Raman study of octopus bathorhodopsin with deuterium labeled retinal chromophores

The resonance Raman spectrum of octopus bathorhodopsin in the fingerprint region and in the ethylenic-Schiff base region have been obtained at 80 K using the "pump-probe" technique as have its deuterated chromophore analogues at the C7D; C8D; C8,C7D2; C10D; C11D; C11, C12D2; C14D; C15D; C14, C15D2; and N16D positions. While these data are not sufficient to make definitive band assignments, many tentative assignments can be made. Because of the close spectral similarity between the octopus bathorhodopsin spectrum and that of bovine bathorhodopsin, we conclude that the essential configuration of octopus bathorhodopsin's chromophore is all-trans like. The data suggest that the Schiff base, C = N, configuration is trans (anti). The observed conformationally sensitive fingerprint bands show pronounced isotope shifts upon chromophore deuteration. The size of the shifts differ, in certain cases, from those found for bovine bathorhodopsin. Thus, the internal mode composition of the fingerprint bands differs somewhat from bovine bathorhodopsin, suggesting a somewhat different in situ chromophore conformation. An analysis of the NH bend frequency, the Schiff base C = N stretch frequency, and its shift upon Schiff base deuteration suggests that the hydrogen bonding between the protonated Schiff base with its protein binding pocket is weaker in octopus bathorhodopsin than in bovine bathorhodopsin but stronger than that found in bacteriorhodopsin's bR568 pigment.

Replacement of leucine-93 by alanine or threonine slows down the decay of the N and O intermediates in the photocycle of bacteriorhodopsin: implications for proton uptake and 13-cis-retinal----all-trans-retinal reisomerization

We report that the replacement of Leu-93 in bacteriorhodopsin by Ala (L93A) or Thr (L93T) slows down the photocycle by approximately 100-fold relative to wild-type bacteriorhodopsin. Time-resolved visible absorption spectroscopy and resonance Raman experiments, respectively, show the presence of long-lived O-like and N-like intermediates in the photocycles of the above mutants. We infer the existence of an equilibrium between the N and O intermediates in the photocycles of these mutants. The L93A and L93T mutants exhibit normal proton pumping under continuous illumination, suggesting that the decay of the N and/or O intermediate, and consequently, proton translocation, can be accelerated by the absorption of a second photon. Since the 13-cis----all-trans reisomerization of retinal is completed during the decay of the N and O intermediates, we conclude that the interaction of Leu-93 with retinal is important in this phase of the photocycle. This conclusion is supported by a recent structural model of bacteriorhodopsin that suggests that Leu-93 is near the C-13 methyl group of retinal.

Resonance Raman studies of the HOOP modes in octopus bathorhodopsin with deuterium-labeled retinal chromophores

Resonance Raman spectra of the hydrogen out-of-plane (HOOP) vibrational modes in the retinal chromophore of octopus bathorhodopsin with deuterium label(s) along the polyene chain have been obtained. In clear contrast with bovine bathorhodopsin's HOOP modes, there are only two major HOOP bands at 887 and 940 cm-1 for octopus bathorhodopsin. On the basis of their isotopic shifts upon deuterium labeling, we have assigned the band at 887 cm-1 to C10H and C14H HOOP modes, and the band at 940 cm-1 to C11H = C12H Au-like HOOP mode. Except for a 26 cm-1 downward shift, the C11H = C12H Au-like wag appears to be little disturbed in octopus bathorhodopsin from the chromophore in solution since its changes upon deuterium labeling are close to those found in solution model-compound studies. We found also that the C10H and C14H HOOP wags are also similar to those in the model-compound studies. However, we have found that the interaction between the C7H and C8H HOOP internal coordinates of the chromophore in octopus bathorhodopsin is different from that of the chromophore in solution. The intensity of the C11H = C12H and the other HOOP modes suggests that the chromophore of octopus bathorhodopsin is somewhat torsionally distorted from a planar trans geometry. Importantly, a twist about C11 = C12 double bond is inferred. Such a twist breaks the local symmetry, resulting in the observation of the normally Raman-forbidden C11H = C12H Au-like HOOP mode. The twisted nature of the chromophore, semiquantitatively discussed here, likely affects the lambda max of the chromophore and its enthalpy.(ABSTRACT TRUNCATED AT 250 WORDS)

Fourier transform infrared evidence for a predominantly alpha-helical structure of the membrane bound channel forming COOH-terminal peptide of colicin E1

The structure of the membrane bound state of the 178-residue thermolytic COOH-terminal channel forming peptide of colicin E1 was studied by polarized Fourier transform infrared (FTIR) spectroscopy. This fragment was reconstituted into DMPC liposomes at varying peptide/lipid ratios ranging from 1/25-1/500. The amide I band frequency of the protein indicated a dominant alpha-helical secondary structure with limited beta- and random structures. The amide I and II frequencies are at 1,656 and 1,546 cm-1, close to the frequency of the amide I and II bands of rhodopsin, bacteriorhodopsin and other alpha-helical proteins. Polarized FTIR of oriented membranes revealed that the alpha-helices have an average orientation less than the magic angle, 54.6 degrees, relative to the membrane normal. Almost all of the peptide groups in the membrane-bound channel protein undergo rapid hydrogen/deuterium (H/D) exchange. These results are contrasted to the alpha-helical membrane proteins, bacteriorhodopsin, and rhodopsin.

Neoadjuvant chemotherapy in early-stage and locally advanced small bulk squamous cell carcinoma of the oral cavity and oropharynx

Thirty patients with Stages I, II and III squamous cell carcinoma of the oral cavity and oropharynx (6, 12 and 12 patients, respectively) were entered into a combined modality protocol using preoperative chemotherapy, followed by resection with or without radical neck dissection and radiotherapy. None of the patients received prior treatment and all had good performance status. Primary sites included alveolar ridge (in nine patients), buccal mucosa (in eight), tongue (in six), floor of mouth (in five), and hard palate and tonsillar fossa in one each. Chemotherapy was given as a neoadjuvant debulking procedure using two courses of the Price-Hill regimen (5FU, methotrexate with citrovorum rescue, vincristine, bleomycin, and hydrocortisone) followed in 10 to 14 days by local resection for Stage I-II patients and radical neck dissection plus radiotherapy for Stage III patients. Response to chemotherapy alone was observed in 70% (21 of 30), with 17% (5 of 30) complete responders. Responses were seen in 100% of Stage I, 75% of Stage II, and 50% of Stage III patients. Age greater than 80 years was a poor prognostic indicator. Both men and women responded equally well. Of the 25 patients not entering CR with chemotherapy, a further 75% (11 of 15) did so after local resection and 50% (5 of 10) after local resection, radical neck dissection, and radiotherapy. Overall salvage rate post chemotherapy was 64% (16 of 25). All five patients in CR with chemotherapy alone are alive at a median follow-up time of greater than or equal to 43 months; full survival data are discussed. Toxicity was minimal and did not affect change in treatment course in any patient. These results show that further investigations on the use of neoadjuvant chemotherapy in early-stage and locally advanced squamous cell carcinoma of the oral cavity and oropharynx are indicated.

Resonance raman spectroscopy of an ultraviolet-sensitive insect rhodopsin

We present the first visual pigment resonance Raman spectra from the UV-sensitive eyes of an insect, Ascalaphus macaronius (owlfly). This pigment contains 11-cis-retinal as the chromophore. Raman data have been obtained for the acid metarhodopsin at 10 degrees C in both H2O and D2O. The C = N stretching mode at 1660 cm-1 in H2O shifts to 1631 cm-1 upon deuteriation of the sample, clearly showing a protonated Schiff base linkage between the chromophore and the protein. The structure-sensitive fingerprint region shows similarities to the all-trans-protonated Schiff base of model retinal chromophores, as well as to the octopus acid metarhodopsin and bovine metarhodopsin I. Although spectra measured at -100 degrees C with 406.7-nm excitation, to enhance scattering from rhodopsin (lambda max 345 nm), contain a significant contribution from a small amount of contaminants [cytochrome(s) and/or accessory pigment] in the sample, the C = N stretch at 1664 cm-1 suggests a protonated Schiff base linkage between the chromophore and the protein in rhodopsin as well. For comparison, this mode also appears at approximately 1660 cm-1 in both the vertebrate (bovine) and the invertebrate (octopus) rhodopsins. These data are particularly interesting since the absorption maximum of 345 nm for rhodopsin might be expected to originate from an unprotonated Schiff base linkage. That the Schiff base linkage in the owlfly rhodopsin, like in bovine and in octopus, is protonated suggests that a charged chromophore is essential to visual transduction.

Prophylactic oophorectomy in premenopausal women with stage II breast carcinoma

Prophylactic oophorectomy, as an additional treatment for stage II breast cancer, is controversial. In a retrospective study, a group of 37 premenopausal women with stage II infiltrating duct carcinoma and one to three positive axillary lymph node involvement after modified radical mastectomy and bilateral oophorectomy were compared to a matched group of 34 women treated by modified radical mastectomy only. Prophylactic oophorectomy prolonged the disease free interval significantly as compared to the control group. However, it did not prolong survival. This raises the question whether the prolongation of survival achieved by late oophorectomy in women with advanced breast cancer is preferable to an improvement in quality of life resulting from longer disease free intervals.

Survival data of Israeli Jewish patients with squamous cell carcinoma of the cervix treated by irradiation

During a 9-year period 61 Israeli Jewish Patients with histologically confirmed invasive squamous cell carcinoma of the uterine cervix (SUC) were treated by irradiation alone. A large proportion of the patients (44.2%) were more than 60 years old and only 27.9% were diagnosed as having stage IB disease. This is attributed to low awareness and infrequent cytologic screening. There is a trend for a large proportion of stage IB patients among those younger than 59 compared to those older than 60 years. The overall 5-year survival rate was 52.2% and the survival of patients with stage IB (72.6%) was significantly higher than in more advanced stages. In addition to clinical stage, age at diagnosis and method of irradiation also influenced survival rates.

Selective splenectomy in Hodgkin's disease, stages I and II. Results of treatment

Sixty-three patients with Hodgkin's disease, in stages I or II, asymptomatic (A) or symptomatic (B), were diagnosed and followed at the Chaim Sheba Medical Center from 1969 to 1976. Only 14 were staged pathologically. Until 1971, the patients received mantle or "inverted Y" therapy only; thereafter, an extended field that included mantle, upper abdomen and spleen irradiation was given. Symptomatic patients, as well as patients with extranodal involvement, received MOPP chemotherapy (nitrogen mustard, vincristine, procarbazine and prednisone) after termination of radiotherapy. Of 51 patients who were in stage IA or IIA, six relapsed 20 to 43 months after irradiation. Three had a pelvic recurrence; two of them were surgically staged. Thus, in only 1 of 51 patients could staging laparotomy possibly have detected pelvic disease and resulted in different therapy. Our results suggest that total nodal irradiation and staging laparotomy are not mandatory in stages IA and IIA of Hodgkin's disease. The group of 12 symptomatic patients is too small to allow us to draw definite conclusions as to the role of staging laparotomy and adjuvant chemotherapy. However, in view of the high relapse rate in the upstaged symptomatic patients, it seems that chemotherapy should be given to these patients.