shukoor65/lab-rag-model huggingface dataset:
Cardiovascular neural regulation explored in the frequency domain. A consistent link appears to exist between predominance of vagal or sympathetic activity and predominance of HF or LF oscillations, respectively: RR variability contains both of these rhythms, and their relative powers appear to subserve a reciprocal relation like that commonly found in sympathovagal balance. In this respect, it is our opinion that rhythms and neural components always interact, just like flexor and extensor tones or excitatory and inhibitory cardiovascular reflexes, and that it is misleading to separately consider vagal and sympathetic modulations of heart rate. In humans and experimental animals, functional states likely to be accompanied by an increased sympathetic activity are characterized by a shift of the LF-HF balance in favor of the LF component; the opposite occurs during presumed increases in vagal activity. In addition, LF oscillation evaluated from SAP variability appears to be a convenient marker of the sympathetic modulation of vasomotor activity. Although based on indirect markers, the exploration in the frequency domain of cardiovascular neural regulation might disclose a unitary vision hard to reach through the assemblage of more specific but fragmented pieces of information.
Direct sequencing from touch preparations of human carcinomas: analysis of p53 mutations in breast carcinomas A new technique for characterizing somatic mutations in very small samples of cellularly heterogeneous human cancer tissue was developed and tested using mutations in the p53 gene in breast carcinomas as a model system. The technique combines touch preparation of specimens to obtain homogeneous clusters of carcinoma cells free of normal cells with a nested pair of polymerase chain reaction (PCR) amplifications of DNA to increase the amount of target gene sequence sufficiently to permit direct sequencing of the p53 gene. Touch preparations of fresh or previously frozen tissue from human adenocarcinomas derived from several organs were stained, and clusters of 10-50 malignant cells were transferred by pipette into microfuge tubes for PCR amplification. Exons 5-9 of the p53 gene, which contain the major mutational hot spots associated with most human cancers, were sequenced by the following steps: 1) two rounds of PCR amplification using DNA Taq polymerase and two sets of oligonucleotide primers, the second set being nested within the segment amplified by the first set and having attached T7 and SP6 phage promoter sequences, 2) transcription of the amplified DNA sequences with T7 and SP6 RNA polymerases, and 3) dideoxy sequencing of single-stranded RNA transcripts with reverse transcriptase and with additional oligonucleotide primers to achieve specificity for this unique region of the genome. The utility of this approach is illustrated by our success in detecting and analyzing point mutations in cell clusters from four of 11 primary adenocarcinomas of the human breast.
Changing pattern of bone and joint infections due to Staphylococcus aureus: study of cases of bacteremia in Denmark, 1959-1988. Of the 15,170 cases of bacteremia due to Staphylococcus aureus that occurred in Denmark between 1959 and 1988, we review 525 cases of acute hematogenous osteomyelitis and 185 cases of septic arthritis that developed subsequent to the bacteremia and 134 cases of contiguous osteomyelitis in which the bacteremia developed secondarily. The pattern of acute infections of bones and joints has changed over the three decades studied. The frequency of secondary bone or joint infections due to S. aureus bacteremia has changed, as have the phage-type pattern and antibiotic resistance of the infective strains. The prevalence of hospital-acquired cases has increased and the age distribution of patients has changed, as is reflected in an increasing number of older patients. The localization of hematogenous osteomyelitis has shifted, and the vertebral column is now the most common site of infection. The rate of chronic cases of osteomyelitis that occur following acute hematogenous osteomyelitis has been reduced from 34% to 6%. The mortality associated with S. aureus bacteremic infections of bones or joints is low compared to that associated with other cases of S. aureus bacteremia.
Hormone replacement therapy in general practice: a survey of doctors in the MRC's general practice research framework. OBJECTIVES--To survey current prescribing practice for hormone replacement therapy among general practitioners and to elicit their views on the role of hormone replacement therapy in the prevention of osteoporosis and cardiovascular disease; to determine whether they would participate in randomised controlled trials to evaluate the long term beneficial and adverse effects of hormone replacement therapy. DESIGN--Postal questionnaires to general practitioners throughout the United Kingdom. PARTICIPANTS--1268 general practitioners in the Medical Research Council's general practice research framework. RESULTS--1081 (85%) doctors in 220 (95%) practices responded. The doctors were currently prescribing hormone replacement therapy to an estimated 9% of their female patients aged 40 to 64, and 55% of doctors were prescribing opposed hormone replacement therapy (oestrogen plus progestogen) to more patients than a year previously. Over half the doctors would consider prescribing hormone replacement therapy for prevention of osteoporosis (670, 62%) and cardiovascular disease (611, 57%) to asymptomatic women. Overall, 79% of the doctors (851) would definitely or probably consider entering women who have had a hysterectomy into a randomised controlled trial comparing unopposed (oestrogen only) hormone replacement therapy with opposed hormone replacement therapy; 49% (524) would enter patients with a uterus into such a trial. Among a subsample, 85% (180/210) would consider entering patients without menopausal symptoms into a trial comparing hormone replacement therapy with no treatment (unopposed in patients who have had a hysterectomy, opposed in those with a uterus). CONCLUSION--There is considerable uncertainty among general practitioners as to the balance of beneficial and harmful effects of hormone replacement therapy in the long term, particularly relating to its use for prevention of osteoporosis and cardiovascular disease. Most of these doctors would be prepared to participate in randomised controlled trials to determine the long term effects of this increasingly widely used treatment.
Coronary patency, infarct size and left ventricular function after thrombolytic therapy for acute myocardial infarction: results from the tissue plasminogen activator: Toronto (TPAT) placebo-controlled trial. TPAT Study Group Infarct size, left ventricular function and infarct-related coronary artery patency were examined in 108 patients who took part in a previously reported placebo-controlled trial of recombinant tissue-type plasminogen activator (rt-PA) in acute myocardial infarction. Coronary angiography was performed 17 +/- 0.8 h after initiation of treatment in 47 patients (group A) or at 10 days in 61 patients (group B). Both groups underwent radionuclide ventriculography 3.8 +/- 0.8 h and again on day 9 after treatment and quantitative thallium scintigraphy on day 8. In group A, the infarct-related artery was patent in 53%; these patients had a smaller global (15.1 +/- 2.5% vs. 25.7 +/- 4.7%, p = 0.029) and regional (14.7 +/- 2.5% vs. 24.1 +/- 4.7%, p = 0.044) fixed thallium defect than did those with an occluded artery. Infarct regional ejection fraction improved by 10.1 +/- 2.1% between early and late studies when the infarct-related artery was patent and by 4.8 +/- 1.4% if it was occluded (p = 0.048); changes in global and noninfarct regional ejection fraction were similar irrespective of perfusion status. Infarct regional ejection fraction and fixed thallium defect were inversely related only when the infarct-related artery was occluded (r = -0.83, p less than 0.0001). In group B, 10 day patency of the infarct-related artery was 67%; there was no difference in patency by treatment assignment or in left ventricular function or infarct size between patients with and without infarct-related artery patency. There was no evidence of an effect of rt-PA therapy beyond that expressed through coronary patency alone in either group A or group B.
CT and pathologic predictive features of residual mass histologic findings after chemotherapy for nonseminomatous germ cell tumors: can residual malignancy or teratoma be excluded? Forty-eight patients with disseminated nonseminomatous germ cell tumors were studied retrospectively to determine whether initial pathologic features and pre- and post-chemotherapy computed tomographic (CT) features could be used to exclude malignancy or teratoma in residual masses that were excised after chemotherapy. Neither CT findings (residual mass size, attenuation, and degree of shrinkage during chemotherapy) nor type of primary testicular tumor cell was significantly correlated with malignancy or teratoma versus necrosis in residual masses. No significant correlation was demonstrated between the combined features of (a) the absence of teratoma in a histologic specimen of the primary testicular tumor and (b) greater than 90% shrinkage of masses during chemotherapy and the absence of malignancy or teratoma in residual masses as suggested in the literature. Of nine patients with both of these findings, two had malignancy and two had teratoma. Radiographic and pathologic features cannot be used to reliably exclude malignancy or teratoma in residual abdominal masses after chemotherapy for nonseminomatous testicular cancer.
Primary soft tissue tumours of the pelvis causing referred pain in the leg. Referred pain in the leg is occasionally due to a pelvic soft tissue tumour. Among 11 patients who presented this way, one had a lymphoma, one had a benign schwannoma, and nine had soft tissue sarcomas. Most patients had undergone a variety of procedures, including laminectomy, before the correct diagnosis was established. In five cases, an accurate diagnosis was obtained by needle biopsy. The lymphoma responded to chemotherapy, and the benign schwannoma was excised. Of the nine patients with soft tissue sarcoma, six underwent marginal/intracapsular excision, three receiving supplementary radiotherapy, and two were treated by nonsurgical means. Hindquarter amputation was technically impossible or inappropriate in these cases. All those with high-grade tumours have died or have metastases. Of four patients with low-grade tumours, three have exhibited only slow disease progression. Careful judgment and a precise histopathological diagnosis are required in planning treatment for patients with pelvic soft tissue tumours causing referred pain in the leg.
Genetic predisposition to iatrogenic Creutzfeldt-Jakob disease. The spongiform encephalopathy Creutzfeldt-Jakob disease (CJD) has been transmitted to man via administration of growth hormone and gonadotropin extracted from large pooled batches of human cadaveric pituitary glands. In the UK, 1908 individuals were exposed to potentially contaminated growth hormone, of whom 6 have so far manifested CJD. Examination of the prion protein genes of all these cases and of a single case of gonadotropin-related CJD showed that 4 had the uncommon valine 129 homozygous genotype indicating genetic susceptibility to prion infection. Such genetic susceptibility may be important in the aetiology of sporadic CJD disease.
The mast cell in health and disease. The presence of mast cells, often in an activated state or increased numbers, has been noted in various cutaneous disorders. Recent studies suggest that mast cells are of primary importance in these conditions and their presence does not merely represent a secondary event. This review focuses on atopic dermatitis, contact hypersensitivity reactions, bullous pemphigoid, fibrosing conditions, neurofibromatosis, wound healing, polycythemia vera, and psoriasis, in which there is significant evidence to indicate a pathophysiologic role for mast cells.
Evaluation of restenosis after balloon dilatation in adult aortic stenosis by repeat catheterization. To evaluate the restenosis rate after successful balloon aortic valvuloplasty, clinical evaluation and repeat catheterization were performed in 96 patients who had undergone balloon dilatation 7 +/- 5 months earlier. Restenosis, defined as a loss of greater than 50% of the benefit in aortic valve area obtained after balloon valvuloplasty, was observed in 48% of the patients. Actuarial analysis showed that the restenosis rate was time dependent and was 80% at 15 months. However, functional improvement was observed in most of the patients with or without restenosis. The restenosis rate was not correlated with the degree of enlargement of the aortic orifice produced by the valvuloplasty procedure. Because of the high incidence of restenosis, balloon aortic valvuloplasty should be limited to patients who have a contraindication to surgery or are at high risk for surgery, or as a bridge to surgery.
A method for estimating catechol estrogen metabolism from excretion of noncatechol estrogens. The relationship of catechol estrogen metabolism to disease has seldom been investigated because of analytic difficulties. Estradiol (E2) and estrone (E1) are oxidized simultaneously at either ring A or ring D, and the rate of catechol estrogen formation (r2) is reciprocally related to the rate of 16 alpha-hydroxylation (r3). The rate of ovarian estrogen production (X10) can be summarized as to metabolic outcome: X10 = r10 + r2 + r3 + r(u), where r10 is the loss of E1 and E2 in urine, and ru is the fecal and urinary loss of unknown oxidative products. Assuming a constant r(u) between subjects: constancy of the X10 concentration between subjects during similar menstrual cycle phases. In the absence of xenobiotics, r2 x r3 are reciprocally interrelated: r2 x r3 = K (an oxidation constant whose limiting factor is the biologically available estrogen at the cell surface). To the extent that r10 approximates estrogens available for cellular metabolism, the rate of catechol estrogen metabolism may be determined from (Formula; see text) From published data K = 12.4 +/- 0.8 of the standard error of the mean. Pearson correlation coefficients between actual and estimated catechol estrogen excretion in groups of subjects ranged from 0.61 to 0.97 (median, 0.88). This method has been useful for clinical investigation of the relationship of catechol estrogen metabolism to disease until better methods to measure catechol estrogen directly are available.
An autopsy study of the incidence of lacunes in relation to age, hypertension, and arteriosclerosis. We investigated selected features of lacunes in 1,086 necropsy cases. Lacunes were found in brains from patients above the age of 40 years and were most common in brains from persons in their sixties but decreased in number in brains from older persons. The most common site of lacunes was the frontal lobe white matter, followed by the putamen, pons, parietal lobe white matter, thalamus, and caudate nucleus in descending order of frequency. By dividing the 1,086 cases into three groups according to blood pressure, we found more lacunes in the hypertensive and borderline hypertensive groups than in the normotensive group; the average number of lacunes per brain in each group was 3.61, 2.77, and 1.15, respectively. Diastolic hypertension was more closely related to the number of lacunes than was systolic hypertension. The extent of arteriolosclerosis of the medullary arteries in the frontal lobe white matter was measured and compared with the number of lacunes. There was a close correlation between lacunes and arterioloslerosis in all age groups.
Treatment of recurrent urethral strictures using clean intermittent self-catheterisation. The treatment of urethral strictures has been greatly improved by the use of the optical urethrotome. However, there remains a group of patients with recurrent strictures for whom the alternatives remain long-term dilatation/urethrotomy or urethroplasty. Over the last 3 years we have treated 65 such patients using clean intermittent self-catheterisation as a method of self-dilatation. This has resulted in a dramatic decrease in the number of operations performed on these patients, with no significant reduction in urinary flow rate over an average follow-up period of 20 months. The method offers the possibility of long-term cure and should be offered to all all such patients, reducing still further the number of patients who require urethroplasty.
Immunoturbidimetric assay for estimating free light chains of immunoglobulins in urine and serum. An immunoturbidimetric assay for the assessment of free kappa and lambda light chains of immunoglobulins was developed using a commercial polyclonal antiserum with reactivity towards epitopes on the light chains, which are not expressed when they are bound to heavy chains. The assay, on a centrifugal analyser, is simple and rapid. The limit of detection is 5 mg/l of free light chain, with an assay range of 5-120 mg/l, intrabatch precisions from 1.5-6.4%, and interbatch precisions from 6.5-8.9%. The assay was only slightly less sensitive than colloidal gold staining of cellulose acetate electrophoreses for the detection of Bence-Jones protein in urine. For the serial monitoring of response to chemotherapy in patients with myeloma, the assay correlated well with serum paraprotein estimates obtained by densitometric scanning of Ponceau stained cellulose acetate electrophoreses, but not with serum beta-2 microglobulin measurements, even after correction for the effects of creatinine. These assays may prove to be of use for the monitoring of tumour response in the treatment of Bence-Jones myeloma.
Avoidance of tolerance and lack of rebound with intermittent dose titrated transdermal glyceryl trinitrate. The Transdermal Nitrate Investigators. OBJECTIVES--To investigate the efficacy of transdermal glyceryl trinitrate given continuously and with a nocturnal nitrate free period. DESIGN--Double blind placebo controlled study with two parallel limbs. SETTING--Multicentre trial. PATIENTS--52 patients randomised to receive either continuous treatment (23 patients) or intermittent treatment with an individually titrated dose (29 patients) for 14 days: both treatments were compared with placebo in a cross-over fashion. INTERVENTION--Continuous treatment with 10 mg per 24 hours of transdermal glyceryl trinitrate or intermittent transdermal glyceryl trinitrate titrated to give an arbitrary 10 mm Hg drop in systolic blood pressure (mean dose 18.2 mg) given over approximately 16 hours. MAIN OUTCOME MEASURE--Treadmill exercise stress testing and ambulatory monitoring of the ST segment after 14 days' treatment. RESULTS--After 14 days' intermittent treatment resting supine and standing systolic blood pressure fell by 7.5 mm Hg (95% confidence interval 2.7 to 12.2) and 9.0 mm Hg (95% CI 3.4 to 14.5) respectively (p less than 0.01); resting heart rate was unchanged. Mean heart rate at 1 mm ST segment depression rose by 11.9 beats/min (CI 1.1 to 23.7) (p less than 0.05), mean time to onset of angina increased by 59 seconds (CI 10.8 to 108) (p less than 0.05), and total exercise duration increased by 40 seconds (p less than 0.05). These changes were not seen after continuous treatment. The frequency of ischaemic episodes was not reduced with either regimen nor was the circadian distribution of these episodes altered, in particular nocturnal episodes did not increase during intermittent treatment. CONCLUSION--Tolerance to glyceryl trinitrate was avoided by the use of individually titrated doses administered with a nocturnal nitrate free period. There was no evidence of "rebound" on ambulatory monitoring during this treatment.
Double dissociation of short-term and long-term memory for nonverbal material in Parkinson's disease and global amnesia. A further analysis. The traditional concept of memory disorder is deficiency of the long-term (LTM) but not short-term (STM) component of memory. STM impairment with LTM sparing is seldom reported. The present study investigated STM and LTM for nonverbal material in three neurological conditions associated with memory impairment: bilateral medial temporal lobe lesions (patient H.M.), Parkinson's disease (PD) and Alzheimer's disease (AD). Subjects received 3 tests of nonverbal memory: forward block span, immediate and delayed recall of the Wechsler Memory Scale drawings, and immediate and delayed recognition of abstract designs. Compared with the normal control group, the patient groups displayed different patterns of sparing and loss of the two components of memory: in PD, only STM was impaired; in medial temporal lobe amnesia, only LTM was impaired; and in AD, STM and LTM were both impaired. The contrasting patterns of sparing and loss of STM and LTM in PD and global amnesia were present for both recognition and recall. These results provide evidence that STM and LTM are dissociable processes and are served by separate neurological systems: STM depends upon intact corticostriatal systems, whereas LTM depends upon intact medial temporal lobe systems.
Traumatic anterior fossa cerebrospinal fluid fistulae and craniofacial considerations. Traumatic cerebrospinal fluid fistulae may present a diagnostic and treatment challenge to the head and neck surgeon. The clinical presentation may be obscured by associated injuries. This article serves as a guide in the understanding, diagnosis, and management of patients with dural fistulae of the anterior cranial fossa.
Morphologic features and nuclide composition of infarction-associated cardiac myocyte mineralization in humans. Low dietary Mg results in Ca loading of cardiac myocytes, which increases the likelihood of myocyte calcification in the event of acute myocardial infarction (AMI), and possibly increases myocyte vulnerability to necrosis. Bloom and Peric-Golia1 previously reported an autopsy study of cases from the Washington, D.C. area (a region with low levels of Mg in the drinking water), demonstrating AMI-associated mineralization in myocytes with histologically normal nuclei and cross striations, as well as in obviously necrotic myocytes. The authors have re-examined mineralized myocytes from the same autopsy material, using electron probe microanalysis, light microscopy, and transmission electron microscopy. Microprobe analysis identified Ca and P as the nuclides composing the inorganic phase of the mineral deposits. Ultrastructurally, all Ca deposits, regardless of size or intracellular location, were composed of aggregates of needlelike hydroxyapatite crystals. The mildest form of intracellular Ca deposition was observed as small Ca deposits limited to some mitochondria of myocytes, which demonstrated intact nuclei and regular sarcomere pattern. More advanced stages of intracellular calcification, in the form of Ca deposits associated with mitochondria, Z-band regions and nuclei, were observed in other myocytes that also retained intact nuclei and sarcomeres. Massive Ca deposits were associated with myocytes which showed morphologic features of advanced necrosis, including loss of nuclei, disruption of sarcomere structure and masses of cellular debris. These observations support the theory originally proposed by Bloom and Peric-Golia1 suggesting that Ca loading of myocytes, possibly related to Mg deficiency in humans, increased vulnerability of the myocytes to subsequent AMI-associated necrosis and dystrophic calcification. In addition, the light microscopic impression of calcification of otherwise normal myocytes is contradicted by the electron microscopic identification of hydroxyapatite crystals free in the sarcoplasm, a condition unlikely to be compatible with viability. Lastly, the fact that all Ca deposits were in the form of hydroxyapatite supports the view that they were formed in a Mg-poor environment, which favors conversion of the more common amorphous form of Ca phosphate into the needlelike crystals of hydroxyapatite.