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Biomedical subjects

C R Green

Publications and source records attributed to C R Green.

At least 37 records · Page 2Linked to original sources
PubMed1997

Intrathecal sufentanil for extracorporeal shock wave lithotripsy provides earlier discharge of the outpatient than intrathecal lidocaine.

Many anesthetic techniques are currently used for extracorporeal shock wave lithotripsy (ESWL). This randomized, prospective, double-blind study was designed to examine postoperative recovery with two anesthetic techniques for unilateral ESWL; i.e., intrathecal sufentanil versus intrathecal 5% lidocaine. The incidence of adverse effects was also assessed. Twenty-two ASA physical status I-III patients, 18-70 yr of age who were scheduled for unilateral ESWL under spinal anesthesia were studied. Patients were randomized to receive either intrathecal sufentanil 20 microg + saline (n = 11) or intrathecal 5% lidocaine (n = 11) based on their height. Both patients and observers were blinded to the treatment groups. Patients were assessed for intraoperative and postoperative pain via a 10-cm verbal analog pain scale (VAPS) (0 = no pain, 10 = extreme pain). Stone sizes, number of shock waves, and voltages were also compared. The recovery profile-time to ambulate, void, oral intake, and home discharge-was documented. Antiemetic requirements in the postanesthesia care unit (PACU) and incidence of postoperative nausea and vomiting (PONV), pruritus, and sedation were also recorded. This study showed no differences in VAPS between groups at any time in the perioperative period. Patients who received intrathecal sufentanil ambulated (79 +/- 16 vs 146 +/- 57 min mean +/- SD; P < 0.05), voided (80 +/- 18 vs 152 +/- 54 min, P < 0.05), and were discharged home (98 +/- 17 vs 166 +/- 50 min, P < 0.005) significantly sooner than the patients who received intrathecal lidocaine. Although 27% (3 of 11) of the patients who received sufentanil reported pruritus, respiratory depression was not found. There were no differences in PONV between the two groups. Intrathecal sufentanil provided an enhanced recovery profile with significantly earlier home discharge when compared with intrathecal lidocaine. In conclusion, intrathecal sufentanil is a safe and effective method of anesthesia for outpatient unilateral ESWL.

Adjuvants, Anesthesia↗
PubMed1997

Noncognitive disturbances in Alzheimer's disease: frequency, longitudinal course, and relationship to cognitive symptoms.

OBJECTIVE: To investigate the frequency and longitudinal course of symptoms of depression, agitation, and psychosis in a longitudinally studied sample of patients with Alzheimer's disease (AD). DESIGN: Longitudinal study of AD patients with follow-up assessments at 6-month intervals for an average of more than 3 years. SETTING: Alzheimer's Disease Research Center of the Mount Sinai Medical Center and the Bronx VA Medical Center, New York. PARTICIPANTS: A total of 153 AD patients. MEASUREMENTS: Blessed Test of Information, Memory and Concentration (BIMC) and the Alzheimer's Disease Assessment Scale cognitive (ADAS-Cog) and noncognitive (ADAS-NC) subscales. RESULTS: At entry into the study, more than 90% of patients had a behavioral disturbance that was rated as mild or worse on one of the 10 ADAS noncognitive items; and 40% had at least one rating that was moderate or severe. Correlational analyses indicated that, with the exception of the two mood-related items, noncognitive symptoms on the ADAS were not highly correlated with one another. Only one of the noncognitive items, concentration, was strongly correlated with the severity of cognitive impairment. On average, patients showed progressively worse cognitive functioning over time as measured both by the ADAS-Cog and the BIMC. The mean severity of noncognitive symptoms did not change during the course of a 5-year follow up. The severity of behavioral disturbance at any one evaluation was negatively correlated with change in behavior during the next 6 months and was not correlated with cognitive decline. CONCLUSION: Mild behavioral disturbances are common, whereas moderate to severe behavioral symptoms are less frequent in this population of AD patients. Disturbances in mood and manifestations of agitation and psychotic symptoms are not closely related to one another and show little progressive worsening over time. Rather, they tend to be episodic such that increasing severity at one time is usually followed by improvement later. Concentration problems are a manifestation of cognitive dysfunction rather than behavioral disturbance in AD. Implications of these results for treatment of noncognitive disturbances in AD are discussed.

Activities of Daily Living↗
PubMed1996

Intraoperative ketorolac has an opioid-sparing effect in women after diagnostic laparoscopy but not after laparoscopic tubal ligation.

Ketorolac tromethamine (Toradol) is a parenteral, nonsteroidal antiinflammatory drug that is being extensively used to provide postoperative analgesia. This study evaluated whether intraoperative ketorolac would act synergistically with fentanyl to decrease postoperative analgesic requirements in outpatients undergoing gynecologic procedures. The patients studied were adult ASA physical status I or II females scheduled for diagnostic laparoscopy (DL) (n = 80) or laparoscopic tubal ligation (TL) (n = 46). Each patient received fentanyl 2 micrograms/kg intravenously (i.v.) before induction, followed by a standardized propofol anesthetic and 2 mL of saline or ketorolac 60 mg i.v. in a randomized double-blind fashion 30 min before the anticipated end of the operative procedure. Patients were assessed for postoperative pain via a 10-cm visual analog scale (VAS) (0 = no pain; 10 = severe pain) before analgesic treatment in the postanesthesia care unit (PACU). Severe postoperative pain (VAS or 5 or more) was treated with incremental doses of fentanyl, 25-50 micrograms i.v. by a blinded PACU nurse. Ibuprofen or acetaminophen with codeine was administered for pain control once the patient tolerated oral medications. This study showed that intraoperative ketorolac (60 mg i.v.) with fentanyl (2 micrograms/kg i.v.) administered at the induction of anesthesia resulted in significant opioid sparing and a diminution in pain in the DL sample but not in the TL sample. The analgesic regimen was also associated with a lower incidence of nausea and vomiting and resulted in earlier discharge, which was not seen after TL. These results demonstrate that pain after TL is far greater than that after DL, which suggests that these procedures should be considered separately when designing analgesic regimens.

Adult↗
PubMed1996

Preoperative fasting time: is the traditional policy changing? Results of a national survey.

Several papers in the 1980s questioned the wisdom of withholding clear liquids for more than 3 h before elective surgery. Furthermore, recent papers have suggested relaxing the current NPO after midnight (Latin: Nulla per os; or "nothing by mouth") practice in children and adults. To see whether the policy and practice regarding NPO status before elective surgery have changed in the United States, we performed a national survey. In November 1992, 300 questionnaires were mailed to the chairpersons of 114 university anesthesiology programs and the medical directors of 186 randomly selected, free-standing ambulatory surgery centers. Seventeen simple questions were asked regarding their NPO policy and practice guidelines before elective operations. Replies were tabulated, and the data were descriptively analyzed via frequency distribution. We received 191 replies, 85 from the university programs and 106 from the free-standing units (75% and 57% response rates, respectively) from all six time zones of the United States. Fifty-seven percent of the responders stated that they had revised their NPO policy during the last 3 yr, whereas 39% reported that they had not changed their NPO policy. One hundred percent of the respondents who allowed clear liquids considered water to be acceptable for adults, whereas 94% considered water acceptable in the pediatric population. Eighty-one percent of the responders denied the use of routine prophylaxis for acid aspiration. None of the responders reported an adverse outcome which could be attributable to the recent change in the NPO guidelines. On a related question, 16% of all the respondents stated that they would cancel the operation if a patient arrived for an elective outpatient surgical procedure after consuming coffee with cream 2 h before operation. In conclusion, our survey revealed that 69% of anesthesiologists in the United States have either changed their NPO policy or are flexible in their practice in allowing clear liquids before elective operation in children and 41% have done so for adult patients. The most frequently allowed clear liquids in the adult and pediatric population were water and apple juice. None of the respondents reported any medical adverse event associated with the institution of a flexible NPO policy.

Adult↗
PubMed1995

Maturation of electroretinograms and visual evoked potentials in preterm infants.

Electroretinograms (ERGs) and visual evoked potentials (VEPs) to flash stimulation were recorded from 51 infants (gestational age 26 to 42 weeks; post-conceptional age (PCA) 31 to 47 weeks) to give cross-sectional data on the maturation of these responses. Sequential recordings were taken from a separate group of 24 preterm infants (gestational age 28 to 33 weeks) to give longitudinal data. There was a significant decrease in ERG a-wave latency and increase in a-b amplitude with increasing PCA in both groups. For the VEPs there was a significant decrease in latency of the early negative component (N1) and the major positive component (P2). Comparison between recordings made on preterm infants with those from term infants at an equivalent PCA suggested faster maturation of VEPs in the extra-uterine environment, but no difference in maturation of the ERG.

Brain↗
PubMed1995

Upregulation of connexin43 gap junctions during early stages of human coronary atherosclerosis.

Interactions between cells form the framework for understanding the pathogenesis of atherosclerosis, but little information is available on the role of direct intercellular communication via gap junctions in this process. To investigate gap junction expression in the pathogenesis of human atherosclerosis, lesions representing different stages of the disease were obtained from coronary arteries of hearts removed from patients undergoing cardiac transplantation. Twelve hearts, each providing 1 to 3 segments of artery, were used in the study. Sections were examined by confocal laser scanning microscopy after immunofluorescent labeling with a specific antibody against connexin43, the major gap-junctional protein of smooth muscle cells, to permit high-definition visualization of immunolabeled gap junctions through the depth of the specimen. Double labeling using anti-connexin43 and cell type-specific antibodies demonstrated colocalization of gap junctions with smooth muscle cells but not with macrophages, a relationship confirmed by electron microscopy. Regions of intimal thickening and early atheromatous lesions showed markedly increased expression of connexin43 gap junctions between intimal smooth muscle cells compared with the undiseased vessels. This increase in gap junctions was most marked in regions of intimal thickening, semiquantitative analysis of the confocal digital images revealing a > 10-fold increase compared with the undiseased vessel. The quantity of labeled gap junctions in early atheromatous lesions, although higher than that of the undiseased vessel, was lower than that of intimal thickenings, and this trend toward reduced levels of gap junction immunolabeling with lesion progression continued, the value observed in the most advanced atheromatous lesions being lower than that of the undiseased vessel. As the quantity of gap junctions declined, their distribution became more patchy and the sizes of individual junctions larger. The results suggest that enhanced expression of gap junctions between smooth muscle cells may play a role in maintaining the synthetic phenotype during early growth of the atherosclerotic plaque.

Aged↗
PubMed1995

Functional analysis of amino acid sequences in connexin43 involved in intercellular communication through gap junctions.

Gap junctions allow direct communication between cells without recourse to the extracellular space and have been widely implicated as important mediators of cell-cell signalling. They are constructed from the connexin proteins, which form a large family, and individual connexins show complex spatial and temporal variations in their expression patterns. Understanding how this variation contributes to the control of intercellular signalling, both in the adult and during embryonic development, is an important problem that would be aided by reagents that interfere with gap junctional communication through specific connexins. We have begun to address this issue by raising antibodies to peptides derived from connexin43 and connexin32. Connexin43 peptides were located in the amino terminus, cytoplasmic loop and carboxytail. Connexin32 peptides came from the cytoplasmic loop and the first extracellular loop. Immunoblotting and immunostaining properties of purified IgGs were characterized on mouse heart, liver and the 8- to 16-cell mouse embryo. Effects on transfer through gap junctions were assessed in the fully compacted 8-cell mouse embryo by co-injection with Lucifer Yellow or Cascade Blue. Embryos were maintained in culture to assess the developmental consequences of injection. Peptide competition was used to confirm the specificity of immunostaining and inhibition of dye transfer. All connexin specific antibodies recognized their parent connexin on immunoblots and showed no 43/32 cross-reactivity. The connexin32 extracellular loop antibody recognized both connexin 32 and 43 on immunoblots, as predicted by the amino acid sequence homology in this region, but did not immunostain intact gap junctions. Connexin specific antibodies that immuno-stained showed the predicted connexin specificity. Antibodies to either connexin43 amino acids (AA) 1-16 (amino terminus) or AA 101-112 (cytoplasmic loop) neither immunostained nor prevented functional communication through 8-cell embryo gap junctions. Antibodies to AA 123-136 and AA 131-142 in the cytoplasmic loop immunostained heart and 8-cell embryo gap junctions and blocked transfer through them with high efficiency. Fab' fragments were equally effective. Peptide competition showed that both antibodies contained epitopes within AA 131-136 of connexin43. Antibodies against AA 313-324 in the carboxytail immunostained heart and the 8-cell embryo and, as IgGs, prevented dye transfer. Fab' fragments were ineffective. All connexin43 antibodies that blocked gap junctional communication between cells of the 8-cell mouse embryo induced non-communicating cells subsequently to withdraw from compaction.(ABSTRACT TRUNCATED AT 400 WORDS)

Amino Acid Sequence↗
PubMed1994

Expression of the connexin43 gap junctional protein in tissues at the tip of the chick limb bud is related to the epithelial-mesenchymal interactions that mediate morphogenesis.

The pattern of connexin43 expression in developing chick limb buds was examined using a site-specific polyclonal antibody and confocal microscopy. Connexin43 is expressed at stages of limb development when epithelial-mesenchymal interactions are occurring that mediate morphogenesis. Extensive labeling was observed in the apical ectodermal ridge and labeling was also found in underlying mesenchyme cells at the tip of the bud. In mouse limb buds, the same gap junction protein is expressed only in the apical ridge. Manipulations of developing chick wing buds show that mesenchymal expression of connexin43 appears to be controlled by the apical ectodermal ridge. When the apical ridge is surgically removed and limb truncations result, mesenchymal labeling is markedly reduced and conversely the grafting of an additional ridge induces connexin43 expression between underlying mesenchymal cells which do not normally show expression at this stage of development. In addition, a treatment with retinoic acid that flattens the apical ridge and inhibits bud outgrowth reduces expression in both mesenchymal and epithelial tissues. The abolition of connexin43 expression in mesenchymal and epithelial domains when bud outgrowth is halted suggests that synthesis of this gap junction protein is related to the epithelial-mesenchymal interactions that mediate morphogenesis of the bud.

Animals↗
PubMed1994

The Wolff-Parkinson-White syndrome: the cellular substrate for conduction in the accessory atrioventricular pathway.

The longstanding quest for the anatomical basis of the Wolff-Parkinson-White syndrome has left many unanswered questions. The ultrastructural morphology of the myocytes comprising accessory atrioventricular pathways, which are capable of rapid and variable conduction, is central to understanding the development and behaviour of this congenital anomaly, but remains unknown. Examination of three surgically resected pathways was performed to determine their underlying cellular morphology and the pattern of intercellular coupling, by correlative light microscopy, electron microscopy and confocal scanning laser microscopy combined with immunohistochemical localization of the cardiac gap-junctional protein, connexin43. Two left-sided pathways were composed of myocardium of 'normal working ventricular' type. The right-sided pathway was composed almost entirely of highly abnormal myocytes characterized by aberrant myofibril organisation, with a lack of A-band material and abnormal mitochondria, but normal intact intercalated disks no different from those seen in left-sided pathways. The gap junctions of all pathways were composed of connexin43 distributed as in ventricular myocardium, and not as found in atrial or atrioventricular nodal tissues. While myocytes of abnormal structure were present in one of the accessory atrioventricular pathways examined, all pathways had morphologically normal gap junctions, the structures responsible for efficient intercellular coupling, with a pattern of distribution suggestive of working ventricular myocardium.

Adolescent↗
PubMed1994

General anesthetic techniques.

General anesthesia is the most common form of anesthetic management for ambulatory surgery. Patients, in general, prefer general anesthesia because it is less anxiety provoking. During the last decade, the availability of several short-acting agents with high clearance has made general anesthetic techniques much safer and more predictable for outpatients. Besides, general anesthesia today is associated with a quick and full recovery with minimal postoperative side effects. Proper preanesthetic psychological and, when necessary, pharmacological preparation as well as proper selection of anesthetic agents are the keys to the success of general anesthetic technique for ambulatory surgery. Although both TIVA and total inhalation anesthetic techniques have their advocates, balanced anesthesia is most popular. The introduction of several new agents (e.g., propofol, desflurane, vecuronium, atracurium, mivacurium, rocuronium, alfentanil, ondansetron, ketorolac) has made ambulatory general anesthesia less challenging and more interesting. In the future, the new anesthetic sevoflurane, and the new opioid remifentanil, may prove useful for ambulatory anesthesia. The LMA has all but revolutionized airway management during general anesthesia for ambulatory surgery.

Ambulatory Surgical Procedures↗
PubMed1994

Spatiotemporal relation between gap junctions and fascia adherens junctions during postnatal development of human ventricular myocardium.

BACKGROUND: The growing postnatal human heart maintains electromechanical function while undergoing substantial changes of cellular topology and myocardial architecture. The capacity for growth and remodeling of ventricular myocardium in adaptation to the hemodynamic changes of early infancy later declines. This decline is associated with changes in electromechanical properties of the myocardium, which suggest that the electrical and mechanical interactions between the myocytes may change in an age-dependent manner. Thus, reduction in the capacity for myocardial growth and adaptability may relate to age-dependent alterations in the patterns of the intercellular junctions that mediate electrical and mechanical coupling. We therefore examined the hypotheses that (1) age-dependent changes in the distribution patterns of gap junctions and fasciae adherentes, the intercellular junctions responsible, respectively, for electrical and mechanical coupling, accompany postnatal development in the human heart and that (2) such changes continue into the first few years of childhood. Further, the spatial relation between the two types of junction, for which a close association has been hypothesized as necessary, was explored. METHODS AND RESULTS: Ventricular myocardial gap-junction distribution was investigated in 23 pediatric surgical patients (4 weeks to 15 years old) by quantitative immunohistochemical localization of the principal cardiac gap-junctional protein, connexin43, using confocal microscopy. Immunolocalization of fascia adherens junctions by labeling N-cadherin, and correlative immunogold and standard electron microscopy, were performed in parallel. In the neonate, connexin43 gap junctions have a punctate distribution over the entire surface of the ventricular myocytes. With advancing age, gap junctions become progressively confined to the transverse terminals of the cell, ie, toward the distribution within the intercalated disk characteristic of the adult ventricle. The transversely arrayed proportion of gap-junctional label showed a linear increase with age (R = .88, P < .001), reaching the adult pattern at about 6 years, and the fascia adherens junctions showed a similar progression. Electron microscopy confirmed the changing pattern of junctional contacts and demonstrated that initially gap junctions and adhering junctions are frequently not closely adjacent but become increasingly so with maturation of the intercalated disk. CONCLUSIONS: Changes in the spatiotemporal patterns of the intercellular junctions responsible for electrical and mechanical coupling are closely coordinated in postnatal human ventricular myocardium and continue to about 6 years of age. Over this period there is a close and increasing association between the gap junctions and fascia adherens junctions. These changes in the distribution of intercellular electrical and adhering junctions may parallel the changing functional requirements of the ventricle, from a distribution that facilitates the remodeling necessitated by rapid growth and changing hemodynamics to that of the relatively stable and rapidly conducting adult myocardium. These age-related changes may also diminish the ability for appropriate myocardial remodeling in response to physiological, pathological, or surgical hemodynamic alterations.

Adolescent↗
PubMed1994

Up-regulation of the connexin43+ gap junction network in haemopoietic tissue before the growth of stem cells.

The early developmental stages of haemopoiesis are thought to be regulated by paracrine growth factors and by the haemopoietic environment. Are gap junctions involved here? Gap junctions are structures in cell membranes allowing the direct transfer of ions and small molecules between adjacent cells and are known to be involved in development. We have found that although connexin43 gap junctions are rare (0.00016 +/- 0.0002/microns2 tissue) in normal adult mouse marrow their expression is 80-fold higher (0.0292 +/- 0.0147/microns2) in neonatal marrow. One difference between neonatal and adult haemopoietic tissue is that in the latter more haemopoietic cells are dividing. To test if more gap junctions were due to increased division we altered adult blood-formation by mobilizing or destroying end cells--granulocytes and red cells--or by forcing stem cells to divide by making them regenerate an ablated blood-forming system. Mobilizing end cells had no effect on the number or distribution of gap junctions in marrow but forced stem cell division caused a 100-fold increase in gap junction expression and did so before any recognizable haemopoietic cells formed. There were greater than normal numbers of gap junctions in radio-protected adult mouse marrow. The cells coupled by gap junctions are TE-7+ mesodermally derived fibroblasts, STRO-1+ stromal cells, and CD45+ and CD34+ haemopoietic cells. We propose that there is a latent network of Cx43+ gap junctions in normal quiescent marrow. In response to events that call for active division of stem cells this network is amplified and coupled to haemopoietic stem cells, perhaps enabling them to divide.

Animals↗
PubMed1993

Expression of connexin43 gap junctions between cultured vascular smooth muscle cells is dependent upon phenotype.

The smooth muscle cell is the predominant cell type of the arterial media. In the adult vascular system, smooth muscle cells are found primarily in the contractile phenotype, but following injury or during atherosclerotic plaque formation the secretory synthetic phenotype is expressed. Recently it has been shown that gap junction connexin43 messenger RNA levels are six times higher in cultured smooth muscle cells in the synthetic phenotype than in intact aorta. We have modulated rabbit aortic smooth muscle cells in culture between the synthetic phenotype and one resembling the contractile phenotype, and correlated gap junction expression with phenotype. A dual labelling technique with antibodies against smooth muscle myosin and a synthetic peptide constructed to match a portion of the connexin43 gap junction protein was used for these experiments. Gap junctions are numerous between synthetic phenotype cells but few are observed between contractile cells. Rat aortic smooth muscle cells were also cultured and the growth and structure of gap junctions followed in the synthetic phenotype by use of freeze-fracture electron microscopy and immunohistochemical techniques. Junctional plaques are similar in structure to those observed in cardiac muscle, their size and number increasing with time in culture. The increased numbers of gap junctions between synthetic phenotype smooth muscle cells may be important during vessel development, following injury, or in atherosclerotic plaque formation.

Animals↗
PubMed1993

Robert Feulgen Prize Lecture. Distribution and role of gap junctions in normal myocardium and human ischaemic heart disease.

In the heart, individual cardiac muscle cells are linked by gap junctions. These junctions form low resistance pathways along which the electrical impulse flows rapidly and repeatedly between all the cells of the myocardium, ensuring their synchronous contraction. To obtain probes for mapping the distribution of gap junctions in cardiac tissue, polyclonal antisera were raised to three synthetic peptides, each matching different cytoplasmically exposed portions of the sequence of connexin43, the major gap-junctional protein reported in the heart. The specificity of each antiserum for the peptide to which it was raised was established by dot blotting. New methods were developed for isolating enriched fractions of gap junctions from whole heart and from dissociated adult myocytes, in which detergent-treatment and raising the temperature (potentially damaging steps in previously described techniques) are avoided. Analysis of these fractions by SDS-polyacrylamide gel electrophoresis revealed major bands at 43 kDa (matching the molecular mass of connexin43) and at 70 kDa. Western blot experiments using our antisera indicated that both the 43-kDa and the 70-kDa bands represent cardiac gap-junctional proteins. Pre-embedding immunogold labelling of isolated gap junctions and post-embedding immunogold labelling of Lowicryl-embedded whole tissue demonstrated the specific binding of the antibodies to ultrastructurally defined gap junctions. One antiserum (raised to residues 131-142) was found to be particularly effective for cytochemical labelling. Using this antiserum for immunofluorescence labelling in combination with confocal scanning laser microscopy enabled highly sensitive detection and three-dimensional mapping of gap junctions through thick slices of cardiac tissue. By means of the serial optical sectioning ability of the confocal microscope, images of the entire gap junction population of complete en face-viewed disks were reconstructed. These reconstructions reveal the presence of large junctions arranged as a peripheral ring around the disk, with smaller junctions in an interior zone: an arrangement that may facilitate efficient intercellular transfer of current. By applying our immunolabelling techniques to tissue from hearts removed from transplant patients with advanced ischaemic heart disease, we have demonstrated that gap junction distribution between myocytes at the border zone of healed infarcts is markedly disordered. This abnormality may contribute to the genesis of reentrant arrhythmias in ischaemic heart disease.

Amino Acid Sequence↗
PubMed1993

Intercellular junctions and the application of microscopical techniques: the cardiac gap junction as a case model.

Intercellular junctions are fundamental to the interactions between cells. By means of these junctions, the activities of the individual cells that make up tissues are co-ordinated, enabling each tissue system to function as an integrated whole. In this review, the work of the authors on one specific type of junction--the cardiac gap junction--is presented as a case model to illustrate how the application of a range of microscopical methods, as part of a multidisciplinary approach, can help extend our understanding of cell junctions and their functions. In the heart, gap junctions form the low-resistance pathways for rapid impulse conduction and propagation, enabling synchronous stimulation of myocyte contraction. Gap junctions also form pathways for direct intercellular communication, a function of particular importance for morphogenetic signalling during development. The work discussed demonstrates some of the applications of techniques in electron microscopy, immunocytochemistry and confocal scanning laser microscopy to the understanding of the structural basis of the function of gap junctions in the normal adult heart, the developing heart and the diseased heart. Freeze-fracture electron microscopy of heart tissue prepared by rapid freezing techniques, in which excision-related structural damage to the cells is minimized or avoided, makes it possible to deduce the structure of the functioning gap junction in vivo. Gap junctions in hearts that are beating normally in the living animal until the very instant of freezing consist of connexons (transmembrane channels) organized in a quasi-crystalline arrangement, not a 'random' arrangement as proposed in the original hypothesis on the structural correlates of gap junction function. Alterations in connexon arrangement occur in response to ischaemia and hypoxia, though the relationship of these to gap-junctional permeability is indirect. To obtain probes for mapping the distribution of gap junctions in cardiac tissue, polyclonal antisera to synthetic peptides matching portions of the sequence of connexin43, the major gap-junctional protein reported in the heart, were raised. The specificity of the antisera was confirmed by dot blotting, Western blotting and by immunogold labelling of isolated gap junctions. One antiserum (that raised to residues 131-142) was found to be particularly effective as a cytochemical probe. An immunofluorescence labelling procedure for use with confocal scanning laser microscopy was developed to enable the three-dimensional precision mapping of gap junctions through thick slices of cardiac tissue.(ABSTRACT TRUNCATED AT 400 WORDS)

Animals↗
PubMed1993

Functional decline in Alzheimer's disease: a longitudinal study.

OBJECTIVE: To assess the reliability of activities of daily living (ADL) measures and determine the rate and pattern of longitudinal ADL change in patients with Alzheimer's disease (AD). DESIGN: Longitudinal study with evaluations every 6 months. SETTING: Alzheimer's Disease Research Center Clinics at Mount Sinai Medical Center, New York, and the Veterans Affairs Medical Center, Bronx, New York. PATIENTS: 104 patients meeting NINCDS-ADRDA criteria for probable AD were followed an average of 31 months. MEASUREMENTS: Physical Self-Maintenance Scale (PSMS) and Instrumental Activities of Daily Living Scale (IADLS) of Lawton and Brody and the Blessed Test of Information, Memory, and Concentration. RESULTS: For men there was inconsistency over time in the decision about whether or not some IADLS items such as "Laundry" were appropriate for a given patient. Test-retest and inter-rater reliabilities were high for all PSMS items and for IADLS items that were judged to be appropriate. IADLS scores changed an average of 2.06 (+/- 3.27) points annually, and change scores were smaller for patients with severe dementia. PSMS scores changed an average of 2.44 (+/- 3.87) points annually with virtually all change occurring in severely demented patients. There was a marked ceiling effect for the IADLS and a curvilinear relationship of PSMS annual change with PSMS baseline. CONCLUSIONS: Both PSMS and IADLS measures can be reliable in AD patients, but better IADLS items for males need to be developed. IADLS scores are sensitive to change in mild and moderately demented AD patients, while PSMS scores are sensitive to change in more severely demented patients.

Activities of Daily Living↗