Trunk strength testing with iso-machines. Part 1: Review of a decade of scientific evidence

This review of the scientific literature on isokinetic and isoinertial testing of dynamic trunk strength related to low back pain using "iso-machines" identified 108 items published in the past decade. There was inadequate scientific evidence to support the use of iso-machines in preemployment screening, routine clinical assessment or medico-legal evaluation.

Trunk strength testing with iso-machines. Part 2: Experimental evaluation of the Cybex II Back Testing System in normal subjects and patients with chronic low back pain

This experimental evaluation of Cybex II isokinetic measurement was based on 70 normal subjects and 120 patients with chronic low back pain. It considered: reliability and learning effect; discrimination of individual patients versus normal subjects; relationship to clinical measures; assessment of effort; and a prospective 2-year follow-up of normal subjects to predict future low back pain.

A molecular genetic model of human bladder carcinogenesis

Human bladder carcinogenesis stands as a paradigm for research on the molecular genetic mechanisms of chemical carcinogenesis. The pathogenesis of bladder cancer is multistage with a typical onset later in life. Epidemiological studies associate occupational exposure to aromatic amines with increased bladder cancer risk. Biochemical studies show aromatic amine metabolism, covalent binding, and DNA adduct formation in human uroepithelial cells (HUC). Smoking increases bladder cancer risk. A possible link with certain strains of human papilloma virus (HPV) infection has recently been suggested. Molecular analyses of bladder cancers reveal multiple genetic alterations, including mutational activation of oncogenes and inactivation of suppressor genes. A working hypothesis proposes that bladder carcinogens cause mutations in cancer genes (oncogenes and suppressor genes) in HUC that, possibly together with HPV infection and viral DNA integration, lead to the development of bladder cancer. In this review, we describe how this model is currently being tested using a multistep HUC in vitro transformation system.

Assessment of long-term (1 year) graft survival and metabolic and hormonal changes after intrasplenic canine pancreatic microfragment transplantation

Few data have been published so far on the long-term metabolic and endocrine consequences of intrasplenic islet autografts in dogs and the available information mainly deals with glucose response and, more rarely, insulin secretion during intravenous glucose tolerance tests. The effect of islet transplantation on glucagon levels has never been reported. In this study we measured glucose, insulin, total glucagon, and pancreatic glucagon in dogs before and after (up to 1 year) intrasplenic islet autografts. Pancreata were retrieved from 21 adult dogs and the islets were isolated by collagenase digestion. The endocrine tissue was transplanted into the spleen by direct pulp injection. Autografts resulted in normoglycaemia in 19 out of 21 dogs (90%). Among the successfully transplanted dogs, the percentage of functioning grafts was 71% at 1 year. The metabolic and hormonal results of the follow-up showed that fasting glucose and insulin concentrations did not differ significantly before and after transplantation. However, glucose tolerance and insulin secretion on intravenous glucose tolerance testing were significantly reduced in transplanted animals. Fasting total and pancreatic glucagon, and their integrated releases during the test did not change significantly after islet transplantation. These results demonstrate that: 1) long-term function of intrasplenic canine islet autografts can be achieved in high percentages; 2) autotransplanted animals have normal or near normal fasting glucose and insulin levels, but reduced glucose disappearance and insulin secretion on intravenous glucose tolerance tests; 3) normal glucagon secretion is a feature of successful islet grafts.

Objective clinical evaluation of physical impairment in chronic low back pain

The aim of this study was to investigate physical impairment in patients with chronic low back pain, to develop a method of clinical evaluation suitable for routine use, and to consider the relationship between pain, disability, and physical impairment. Twenty-seven physical tests were investigated. Permanent anatomic and structural impairments of spinal deformities, spinal fractures, surgical scarring, and neurologic deficits were excluded as not relevant to the patient with low back pain in the absence of nerve root involvement or previous surgery. Three consecutive 20-patient reproducibility studies were used to develop reliable methods of examination for 23 of the tests. Only four tests were excluded as unreliable: sacral angle, pelvic tilt, and separate lumbar and pelvic extension, none of which are part of routine clinical examination or have any proven relationship to disability. The remaining 23 physical tests were evaluated in 70 asymptomatic subjects and 120 patients with chronic low back pain. Passive knee flexion, passive hip flexion, hip flexion strength, hip abduction strength, pain reproduction on each of these tests, and the prone extension strength test were excluded because they were too closely related to nonorganic and behavioral responses to examination. Eight tests successfully discriminated patients with low back pain from normal subjects and were significantly related to self-report disability in activities of daily living: pelvic flexion, total flexion, total extension, lateral flexion, straight leg raising, spinal tenderness, bilateral active straight leg raising, and sit-up. Factor analysis failed to demonstrate an underlying statistical dimension of physical impairment. However, an empirical combination of total flexion, total extension, average lateral flexion, average straight leg raising, spinal tenderness, bilateral active straight leg raising, and sit-up provided an equally satisfactory alternative. Simple cut-offs from normal subjects made the scale simple and quick to use. This final scale successfully discriminated 78% of patients and normal subjects and explained 25% of the variance of disability, with a specificity of 86% and sensitivity of 76%. This scale provides an objective clinical evaluation that meets the criteria for evaluating physical impairment, yet is simple, reliable, and suitable for routine clinical use. It should, however, be emphasized that all the tests included in the final scale are measures of current functional limitation rather than of permanent anatomic or structural impairment. This raises questions about the physical basis of permanent disability due to chronic low back pain.

Bone composition measured by x-ray scattering

Ten composite samples consisting of cortical bone and adipose tissue, in known proportions, were made. The intensity of monochromatic x-rays (energy 8 keV) scattered by these samples was determined as a function of the modulus of the scattering vector, K. The ratio of the heights of peaks at K values of around 134 and 22 nm-1 provided a measure of the ratio of adipose tissue to bone mineral in these samples. This method was then used to determine the ratio of adipose tissue to mineral in samples of trabecular bone from 16 vertebral bodies. The results were correlated with measurements of the bone composition determined by ashing (r = 0.66) and histomorphometry (r = 0.66). Furthermore, the ashing and histomorphometry results were correlated with each other (r = 0.68). The feasibility of using higher energy x-rays (35-80 keV) for obtaining the same information from bone within the body is briefly discussed.

Use of the polymerase chain reaction for homology probing of butyrylcholinesterase from several vertebrates

Genomic blots from man, monkey, cow, sheep, pig, rabbit, dog, rat, mouse, guinea pig, and chicken DNA were hybridized with probes derived from the four exons of the human butyrylcholinesterase gene (BCHE) (Arpagaus, M., Kott, M., Vatsis, K. P., Bartels, C. F., La Du, B. N., and Lockridge, O. (1990) Biochemistry 29, 124-131). Results showed that the BCHE gene was present in a single copy in the genome of all these vertebrates. The polymerase chain reaction was used to amplify genomic DNA from these animals with oligonucleotides derived from the human BCHE coding sequence. The amplified segment contained 423 bp of BCHE sequence including the active site serine of the enzyme (amino acid 198) and a component of the anionic site, aspartate 70. Amplification was successful for monkey, pig, cow, dog, sheep, and rabbit DNA, but unsuccessful for rat, guinea pig, mouse, and chicken DNA. Amplified segments were cloned in M13 and sequenced. The mouse sequence was obtained by sequencing a genomic clone. The highest identity of the human amino acid sequence was found with monkey (100%) and the lowest with mouse (91.5%). The sequence around the active site serine 198, Phe-Gly-Glu-Ser-Ala-Gly-Ala, was conserved in all eight animals as was the anionic site component, aspartate 70. A phylogenetic tree of mammalian butyrylcholinesterases was constructed using the partial BCHE sequences.

The effects of exercise in a coronary rehabilitation programme

Twenty-two male and female patients who had recently suffered a myocardial infarction were randomly assigned to a treatment group who participated in a 10-week exercise-based cardiac rehabilitation programme or a routine care group who did not participate in the rehabilitation programme. Physiological and psychological function were assessed before the programme started and after it finished. Results indicated that the treatment group did not improve physiological functioning more than the control group but they did evidence statistically significant improved psychological functioning. This investigation appears to be the first attempt to assess the potential benefits of an exercise-based cardiac rehabilitation programme in Glasgow and supports the suggestion that exercise-based cardiac rehabilitation has psychological benefits.

Molecular cloning of mouse acetylcholinesterase: tissue distribution of alternatively spliced mRNA species

We have isolated cDNA clones encoding acetylcholinesterase from mouse muscle and brain. The polymerase chain reaction was used to amplify cDNA clones from C2 myotubes encoding the entire open reading frame and large segments of the 5' and 3' untranslated regions. The muscle cDNA clones were used to isolate clones from a brain library encoding the same mRNA species. The mouse clones encode a catalytic subunit containing a C-terminal sequence similar to that of the hydrophilic species of Torpedo. The mouse acetylcholinesterase sequence shares approximately 88% and 61% amino acid identity with bovine and Torpedo acetylcholinesterases, respectively, but only 52% identity with mouse butyrylcholinesterase, the sequence of which we have also deduced by molecular cloning. Northern blot and RNAase protection analyses indicate that the cDNA clones were derived from the acetylcholinesterase transcript that predominates in most expressing tissues. In contrast, erythroid cells are enriched in an mRNA species whose sequence diverges from that of the cDNA in the region encoding the C-terminus of the enzyme.

Hospital image based on quality, fact, perception

Quality "in fact"--appropriate clinical outcomes--and quality in "perception"--consumer evaluation--are two important parts of the "image equation" for a hospital. But, how do administrators use either to promote their institutions? The authors explain how to use both to give your institution the competitive edge.

Tropical spastic paraparesis and human T cell lymphotropic virus type 1 in the United Kingdom

Twenty-one patients with tropical spastic paraparesis (TSP), all of whom were born in the Caribbean and who had migrated to the United Kingdom, are described. All had a progressive spastic paraparesis developing many years after immigration and all 19 tested had antibodies to the human T cell lymphotropic retrovirus type 1 (HTLV1). The clinical and laboratory features and visual, auditory and somatosensory evoked potentials are described. Details of magnetic resonance scanning of the brain and, in a few cases, the spinal cord are compared with those found in multiple sclerosis. The antibody titres to HTLV1 assessed by particle agglutination, Western blot, antibody-directed cell mediated cytotoxicity and pseudotype neutralization were higher than in asymptomatic infected relatives and in patients with adult T cell leukaemia. Some, but not all, of the IgG oligoclonal bands in the CSF were directed against HTLV1. IgM oligoclonal bands directed against HTLV1 were found in 2 patients. Sixty of the 64 first degree relatives of 11 Jamaican patients with TSP were traced in the UK and the Caribbean; 20-30% of those born in the Caribbean had antibodies to HTLV1, irrespective of their present place of residence, whilst none of those born in the UK, who were the children of the patients, had antibodies. The original pathological material obtained from the Caribbean by Montgomery et al. (1964) is reviewed. These results are discussed in relation to animal retroviral neurological diseases, particularly visna in sheep which has clinical and pathological features closely similar to TSP. It is proposed that TSP is due to a HTLV1 infected lymphocyte/macrophage immune-mediated inflammatory response in the spinal cord.

Coping with diagnosis related groups. The changing role of the nursing home

In an attempt to document the changing role of a specific nursing home in the delivery of medical care since the initiation of diagnosis related groups (DRGs), we studied 100 consecutive patients initially admitted to the Veterans Administration Medical Center-Milwaukee Nursing Home Care Unit (NHCU) during the first 23 weeks of 1986 (post-DRGs). Patient characteristics, reason for NHCU admission, and patients' final disposition were determined and compared with those of consecutive patients admitted to the same facility during an identical time period in 1983 (pre-DRGs). More than seven times as many patients were admitted in 1986, and prior to NHCU admission the acute care hospital stay was significantly shorter in 1986 (22 vs 60 days). Whereas in 1983, most patients (94%) were admitted to the NHCU for long-term care placement, in 1986, the majority of patients (64%) were admitted for continuation of therapy started in the acute care hospital. In 1983 only two patients (9%) required hospital readmission within ten days of NHCU admission, compared with 22 (22%) of the patients in 1986. At the termination of the study period, none of the 31 patients admitted to the NHCU in 1983 had been discharged; in comparison, 33% of the patients in 1986 were discharged home. We conclude that in 1986 certain nursing homes drastically changed their role in the delivery of medical care, and are now functioning as extensions of acute care hospitals. Such a role is advantageous in allowing patients to be quickly discharged from the acute care hospital; however, the changing role presents new problems and challenges.

Nurse-identified problems in the management of alcoholic patients

The purpose of this exploratory study was (1) to identify and rank the patient problems of hospitalized alcoholics that medical-surgical nurses view as difficult to manage, (2) to identify the factors that contribute to the difficulty in care, (3) to identify interventions used by nurses in an attempt to resolve patient problems and (4) to describe relationships between nurses and the identified patient problems. Subjects (N = 83) completed and returned an open-ended questionnaire by listing the physiological and psychosocial patient problems, factors and interventions. Selected demographic and biographic data were also collected. A nursing diagnosis classification described by others served as a basis and was adapted for the nursing diagnosis categories. Nominal data were analyzed using frequency distributions and percentages. The most difficult physiological problems in caring for alcoholic persons were categorized from subjects' responses using the nursing diagnoses of "potential for injury," "alterations in nutrition-elimination" and "fluid volume deficit." The nursing diagnosis categories of "ineffective individual coping," "ineffective family coping" and "noncompliance" comprised the most difficult psychosocial patient problems. A majority of subjects reported having limited classroom and clinical experience with alcoholism; 80% expressed a need for additional inservice education. It is recommended that nursing educational programs include didatic and clinical content about alcoholism, focusing on problem areas identified and on family dynamics, communication, coping strategies and time-management strategies.

Double-wire angioplasty of the right coronary artery bifurcational stenosis

Two cases of distal right coronary artery (RCA) bifurcational stenoses involving ostia of the posterolateral (PLA) and the posterior descending (PDA) branches in patients who underwent successful coronary angioplasty using a double-wire technique are reported. A single guiding catheter and sequential balloon inflations were utilized in one, and two guiding catheters and simultaneous balloon inflations in the other. The indications, techniques, and outcomes are described.

The prevalence of indoor allergens in the Baltimore area: house dust-mite and animal-dander antigens measured by immunochemical techniques

Mattress dust samples from 42 homes in Baltimore, Md., were analyzed by ELISA and rocket immunoelectrophoresis (RIE) for major excrement allergens (P1 [equal to Dp 42], Df 6, and Dm 6) of house dust mites, Dermatophagoides pteronyssinus, D. farinae, and D. microceras, by RIE for cat major epithelial allergen (cat Ag 1) and horse major epithelial antigen (horse Ag 11), and by counter-current immunoelectrophoresis (CCIE) for cat and dog antigens. Dp 42 was detected by ELISA in 24 samples (57%) and Df 6 in 39 samples (92%). All samples were negative to Dm 6. Recorded levels varied from 50 ng of allergen per gram of dust (detection limit) to 15,000 ng/gm. A combined content of Dp 42 and Df 6 greater than 700 ng/gm was associated with a positive reaction in RIE. Concentrations of Dp 42 and Df 6 did not correlate (rS = 0.21; p greater than 0.05). Cat and dog antigens were frequently detected by CCIE (77% and 63%, respectively). CCIE titer to cat correlated well with quantitation of cat Ag 1 by RIE (p less than 0.01). Horse antigen was detected in few homes (5%). None of the specific allergen determinations correlated with levels of human serum albumin determined by RIE.

Blindness in schoolchildren: importance of heredity, congenital cataract, and prematurity

Of 99 children in the Royal Blind School, Edinburgh (which serves Scotland and part of N E England), 15 had optic atrophy (hydrocephalus 4, intracranial haemorrhage 2, prematurity 2, fetal distress 2, birth asphyxia 2, cerebral atrophy 1, cardiac arrest during hernia operation 1, and leukaemia 1). Fourteen had congenital cataract, 12 congenital retinal aplasia (Leber's congenital amaurosis) and 11 retinopathy of prematurity. There were small numbers in many other diagnostic categories, including three with non-accidental head injury. Mental retardation, spasticity, and nystagmus were frequent other correlates in all diagnostic categories. 'Very probably hereditary' was a conservative attribution in 36, while 'probable' seemed appropriate for 12-that is, almost 48% were hereditary. Only about 11 cases might have been prevented through genetic counselling, which testifies to the frequency of autosomal recessive hereditary disease, although no parents were consanguineous.

Hexamethylmelamine in ovarian cancer after failure of cisplatin-based multiple-agent chemotherapy

A prospective study was initiated in 1979 to investigate the effect of hexamethylmelamine (HMM) as a second-line chemotherapeutic agent in the treatment of advanced adenocarcinoma of the ovary after failure of cisplatin-based multiple-agent chemotherapy. Of 20 evaluable patients, there were 5 patients (25%) who had objective responses (4 complete and 1 partial). Four additional patients have remained without evidence of disease. Six of these 9 patients are still alive, disease free. There were significant differences (P less than 0.001) in both the progression-free interval and survival time for these 9 patients, 13.3 and 15.1 months, respectively, as compared to the 15 nonresponders, 0.8 and 5.8 months, respectively. There was no significant difference in survival between the 4 patients with stable disease and the 11 patients with progressive disease. Performance status less than 2 (P less than 0.05) and absence of clinically measurable disease at the time of entry into the study (P less than 0.05) were found to be significant variables with regard to determining outcome. Only 2 of 24 patients suffered severe enough side effects from the HMM to warrant its discontinuation. This study demonstrates that HMM at doses of 6-8 mg/kg/day for 21 out of every 28 days can induce a complete response and provide an extended disease-free interval and prolonged survival with tolerable side effects in a significant number of patients with ovarian cancer who have previously failed cisplatin-based multiple-agent chemotherapy.

Molecular events involved in regulating human interferon-gamma gene expression during T cell activation

The human T cell line Jurkat is a useful model of regulated T cell activation. After in vitro treatment of Jurkat with phytohemagglutinin (PHA) and phorbol ester (PMA), RNA transcripts of both interleukin 2 (IL 2) and interferon-gamma (IFN-gamma) appear, followed by secretion of both biologically active lymphokines. Employing the nuclear run-on technology, we first confirmed that the expression of both lymphokines after T cell activation is regulated at the transcriptional level. By using the recombinant approach of DNase I hypersensitivity mapping, we had previously localized a structurally unique, lymphocyte-specific genomic domain in the first intron of the human IFN-gamma gene that correlated with the transcriptional potential of that gene. By using several T cell lines that differ in their inducible expression of IFN-gamma, we have now localized several additional structural domains within the human IFN-gamma gene that appear to be coordinately involved in regulating expression. These include: a distal 5' flanking region site also seen only in T lymphocytes that can express the gene, a proximal, promoter-associated site that appears only after PHA/PMA-mediated IFN-gamma induction, and a second intronic site seen only in T cells whose IFN-gamma gene is selectively inactive. Collectively, our data suggest that T cell activation is accompanied by transcriptional level induction of lymphokine gene expression. In the case of IFN-gamma, T cell nuclei possess specific structural domains within the gene itself that seem to participate both positively and negatively in activation-mediated regulatory events.

Ligand-receptor interactions required for commitment to the activation of the interleukin 2 gene

Concanavalin A (Con A), which together with phorbol myristate acetate (PMA) can activate the human T cell line Jurkat to produce interleukin 2 (IL 2), is shown to depend on the expression of the T3/T cell antigen receptor heterodimer (T3/Ti) complex to induce activation. alpha-methyl mannoside was able to reverse all of the observed effects of Con A on intracellular biochemical events. Therefore, ligand-receptor occupancy appears to be required for sustaining biochemical events associated with triggering the T3/Ti complex. Studies of the time-dependent requirements for the two stimuli required for activation revealed that simultaneous stimulation with both Con A and PMA is required for 2 to 4 hr for the cell to commit itself to activation, as measured by the appearance of secreted IL 2. This 2- to 4-hr requirement correlated precisely with the appearance of IL 2 mRNA, and the appearance of IL 2 transcripts depended on protein synthesis during this critical time period.

Ligand-receptor interactions required for commitment to the activation of the interleukin 2 gene

Concanavalin A (Con A), which together with phorbol myristate acetate (PMA) can activate the human T cell line Jurkat to produce interleukin 2 (IL 2), is shown to depend on the expression of the T3/T cell antigen receptor heterodimer (T3/Ti) complex to induce activation. alpha-methyl mannoside was able to reverse all of the observed effects of Con A on intracellular biochemical events. Therefore, ligand-receptor occupancy appears to be required for sustaining biochemical events associated with triggering the T3/Ti complex. Studies of the time-dependent requirements for the two stimuli required for activation revealed that simultaneous stimulation with both Con A and PMA is required for 2 to 4 hr for the cell to commit itself to activation, as measured by the appearance of secreted IL 2. This 2- to 4-hr requirement correlated precisely with the appearance of IL 2 mRNA, and the appearance of IL 2 transcripts depended on protein synthesis during this critical time period.

Molecular events involved in regulating human interferon-gamma gene expression during T cell activation

The human T cell line Jurkat is a useful model of regulated T cell activation. After in vitro treatment of Jurkat with phytohemagglutinin (PHA) and phorbol ester (PMA), RNA transcripts of both interleukin 2 (IL 2) and interferon-gamma (IFN-gamma) appear, followed by secretion of both biologically active lymphokines. Employing the nuclear run-on technology, we first confirmed that the expression of both lymphokines after T cell activation is regulated at the transcriptional level. By using the recombinant approach of DNase I hypersensitivity mapping, we had previously localized a structurally unique, lymphocyte-specific genomic domain in the first intron of the human IFN-gamma gene that correlated with the transcriptional potential of that gene. By using several T cell lines that differ in their inducible expression of IFN-gamma, we have now localized several additional structural domains within the human IFN-gamma gene that appear to be coordinately involved in regulating expression. These include: a distal 5' flanking region site also seen only in T lymphocytes that can express the gene, a proximal, promoter-associated site that appears only after PHA/PMA-mediated IFN-gamma induction, and a second intronic site seen only in T cells whose IFN-gamma gene is selectively inactive. Collectively, our data suggest that T cell activation is accompanied by transcriptional level induction of lymphokine gene expression. In the case of IFN-gamma, T cell nuclei possess specific structural domains within the gene itself that seem to participate both positively and negatively in activation-mediated regulatory events.

Characterization of an expressed CD3-associated Ti gamma-chain reveals C gamma domain polymorphism

The majority of human T cells express an antigen receptor consisting of a disulphide-linked heterodimer (Ti) of relative molecular mass 80,000-90,000 (Mr 80-90K) which is noncovalently associated with a set of at least three proteins of Mr 20-28K termed CD3 (Leu4, T3). Whereas both chains of Ti, an acidic alpha-chain of Mr 48-54K and a more basic beta-chain of Mr 40-44K, contain variable and constant region domains, the component peptides of CD3 are invariant. Several laboratories have more recently reported the expression of CD3 in association with a novel protein. On the surface of long-term T-cell lines and one thymocyte clone this novel structure consists of a 40K protein noncovalently linked to a 55 or 62K protein identified as the protein product of the Ti gamma-chain gene, a T-cell specific gene which like the Ti alpha- and Ti beta-chain genes undergoes rearrangement of variable (V) and joining (J) region gene segments. On the human T-cell leukaemic line PEER we have detected only a single 55K glycoprotein associated with CD3. We here demonstrate that an anti-Ti gamma-peptide antiserum reacts with the 55K CD3-associated protein on PEER. Most previously described human Ti gamma-chain complementary DNA clones encode the products of non-functional rearrangements. One of the Ti gamma cDNAs isolated from PEER, however, represents a functional rearrangement reported for the first time in a cell which expresses a Ti gamma-chain protein product on the cell surface. Interestingly, a 48-base-pair (bp) sequence in the constant (C) region domain of this functional Ti gamma-chain cDNA is triplicated in PEER and duplicated in other cDNAs isolated from PEER and other cell lines.

Antibody to human T-lymphotropic virus type 1 in West-Indian-born UK residents with spastic paraparesis

Of 13 West-Indian-born UK residents with spastic paraparesis of unknown cause, 11 were tested for serum antibody to human T-cell lymphotropic virus type 1 and all were positive. Their magnetic resonance imaging scans were normal or showed only minor abnormalities in the brain, and the spinal cord was normal in the 5 investigated. Of 48 patients with multiple sclerosis, mainly caucasian, none had antibody to HTLV-1 in the blood.

Contrast injection bradycardia during coronary angiography: effects in the denervated human heart

To assess the contribution of cardiac innervation toward understanding the mechanisms of bradycardia during contrast coronary angiography, heart rate (HR) responses in eight patients after heart transplantation were compared with 10 normal patients (control), 10 patients with coronary artery disease (CAD) and normal ventricular function, and 10 patients with congestive cardiomyopathy and normal coronary arteries. The longest P-P interval was measured beat to beat before (HR 1) and after (HR 2) coronary angiography. The coronary vessel perfusing the sinus node did not influence HR 2 responses within each group. HR 1 was significantly different from HR 2 (p less than 0.05) in the control and CAD groups but was not different in the transplant and cardiomyopathy groups. Compared with the control group, the percent decrease in HR was significantly less in transplant patients than in patients with cardiomyopathy. Thus contrast injection bradycardia is absent in denervated patients after heart transplant, and this response is markedly blunted in cardiomyopathy patients who are known to have diminished vasodepressor reflexes. These findings suggest that the bradycardia response is probably a neurally mediated phenomenon.

Primary structure of acetylcholinesterase: implications for regulation and function

A cDNA encoding acetylcholinesterase (AChE) (EC 3.1.1.7) from Torpedo californica was isolated and from its nucleotide sequence the entire amino acid sequence of the processed protein and a portion of the leader peptide has been deduced. Approximately 70% of the tryptic peptides from the catalytic subunit of the 11 S form have been sequenced, and a comparison of the peptide sequences with the sequence inferred from the cDNA suggests that the cDNA sequence derives from mRNA for the 11 S form of the enzyme. The amino acid sequence is preceded by a hydrophobic leader peptide and contains an open reading frame encoding for 575 amino acids characteristic of a secreted globular protein. Eight cysteines, most of which are disulfide linked, are found along with four potential sites of N-linked glycosylation. The active-site serine is located at residue 200. Local homology is found with other serine hydrolases in the vicinity of the active site, but the enzyme shows striking global homology with the COOH-terminal portion of thyroglobulin. Further comparison of the amino acid sequences of the individual enzyme forms with other cDNA clones that have been isolated should resolve the molecular basis for polymorphism of the AChE species.

Expression of T3 in association with a molecule distinct from the T-cell antigen receptor heterodimer

The T-cell antigen receptor consists of a disulfide-linked heterodimer (Ti) that is associated with another set of three nonpolymorphic, noncovalently linked peptides termed "T3." The cell surface expression of T3 has been thought to depend upon association with Ti. In this study, we demonstrate that T3 can be expressed in the absence of an associated Ti molecule on a T-cell leukemic line, PEER. Instead, on this cell line, T3 appears to be expressed in association with a 55- to 60-kDa glycoprotein that has a peptide backbone of 29 kDa. PEER fails to express Ti alpha-chain transcripts but does express Ti beta- and gamma-chain transcripts. Using a monoclonal antibody that reacts with nonpolymorphic epitopes expressed on Ti, WT31, we demonstrate that PEER fails to react with this antibody but does react with three independently derived anti-T3 antibodies. Moreover, a small subpopulation of T3-positive peripheral blood lymphocytes, like PEER, fails to express the antigenic determinants recognized by WT31. These results suggest that, on these normal lymphocytes, T3 may likewise be associated with a non-Ti molecule. The possibility that the 55- to 60-kDa molecule expressed on PEER, termed "Tp55-60," represents the protein product of the previously identified Ti gamma-chain gene is discussed.

Neurologic syndrome associated with low levels of vitamin E in primary biliary cirrhosis

A 41-yr-old woman with primary biliary cirrhosis developed weakness and wasting in proximal muscles, areflexia, and decreased proprioceptive and vibratory sensation. Investigations revealed law serum levels of vitamin E and electromyographic and muscle biopsy changes consistent with a neuropathy. Sural nerve histology demonstrated axonal dystrophy with patchy demyelination. These features closely resemble a neurologic syndrome associated with chronic cholestatic liver disease and vitamin E deficiency in children. Adults with chronic cholestasis may also be susceptible to neurologic damage from prolonged malabsorption of vitamin E.

Prevalence of the fragile X syndrome in an institution for the mentally handicapped

In an investigation to find the prevalence of the fragile X (Martin Bell) syndrome in a mental handicap hospital, chromosomal investigations were carried out in 196 males selected out of a total of 512, and also in 20 female patients who were related to some of the selected males. Fragile X cells were found in 41 of the males and two of the females; in 21 of the males it was associated with macro-orchidism. The overall prevalence in the hospital for males (8.0%) ranks this syndrome next in importance to Down's syndrome as a known cause for mental handicap.

Probably Norrie's disease due to mutation. Two sporadic sibships of two males each, a necropsy of one case, and, given Norrie's disease, a calculation of the gene mutation frequency

Two sibships, each with two affected males but no other affected family members, are described. All four patients at birth had small eyes with white masses visible behind clear lenses. Support for a diagnosis of Norrie's disease lies in the probable mental retardation and sudden death of one child and mental retardation in the other in one of the families, and strong support in the sensorineural deafness in one child in the other family. A necropsy was performed on the dead child. Both eyes showed the retinae to be totally non-attached. The optic nerves were thin. If the diagnosis is Norrie's disease (highly probable), the birth of the second affected child in each family supports the postulate of a mutation in the X chromosome of a germ cell of a maternal grandparent or an earlier maternal ancestor, no previous member of the family having been affected. That implies a 50% risk of the disease in future male siblings and a 50% risk of the carrier state in female sibs. When only one child is affected, the explanation could also be a mutation in that individual. Given Norrie's disease, we have calculated a mutation rate of 3.9 per million chromosomes in the Scottish population--remarkably similar to the mutation rates calculated for many dominant diseases. A diagnosis of autosomal recessive non-attachment of retina implies a 25% risk to later siblings.

Primary structure of Torpedo californica acetylcholinesterase deduced from its cDNA sequence

Acetylcholinesterase, an essential enzyme of the nervous system, rapidly terminates the action of acetylcholine released into the synapse. Acetylcholinesterase is also found (in lower abundance) in extrajunctional areas of muscle and nerve and on erythrocyte membranes. Hydrodynamic analyses of the native enzyme and characterization of its dissociated subunits have revealed multiple enzyme forms which can be divided into two classes: dimensionally asymmetric forms which are usually found within the synapse and contain a collagen-like structural subunit disulphide-linked to the catalytic subunits; and globular forms which appear to be widely distributed on the outer surface of cell membranes. Both forms have been characterized in the ray Torpedo californica and, although their catalytic behaviours seem to be identical, they differ slightly in amino-acid composition, peptide maps and reactivity with certain monoclonal antibodies. Here, we report the complete amino-acid sequence of an acetylcholinesterase inferred from the sequence of a complementary DNA clone. The 575-residue protein shows significant homology with the C-terminal portion of thyroglobulin.

Chylous ascites: a sequel of pelvic radiation therapy

Chylous ascites is an unusual condition with many causes. Two cases are presented in which it appeared to be related to whole pelvis irradiation in one patient for carcinoma of the vagina and in another for carcinoma of the vulva. The diagnosis is made by paracentesis and analysis of the fluid. The underlying disease usually requires identification by exploratory laparotomy. Although a malignant process is the most common cause, the only findings in the authors' cases were widespread radiation changes in the intestine. After diagnosis treatment by low-fat diet with medium-chain triglyceride supplements resulted in disappearance of chylous ascites.

Outcomes of surgery among the Medicare aged: mortality after surgery

This study examines post-surgical mortality, up to 1 year after surgery, for eight common operations among aged Medicare enrollees. The operations with the highest mortality in the 1.5 months after surgery were femur fracture reduction, hip arthroplasty (other, i.e., not total replacement), and coronary artery bypass. Mortality was still above average for femur fracture reduction, hip arthroplasty (other), and transurethral prostatectomy 1 year after surgery. The highest mortality rates following surgery were for people 85 years of age or over. This raises the following question: Should certain elective surgery be performed at younger ages if it appears that surgery may eventually be needed?