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Biomedical subjects

M Ford

Publications and source records attributed to M Ford.

At least 91 records · Page 5Linked to original sources

Treatment of angina pectoris with nifedipine and atenolol: efficacy and effect on cardiac function.

The antianginal effects of nifedipine 20 mg three times a day and atenolol 100 mg once a day singly and in combination were investigated in 16 patients with angina pectoris. The amount of work that could be done before angina and ST depression appeared was significantly increased by atenolol and the combination but not by nifedipine. At peak exercise the number of leads on a 16 point precordial electrocardiogram map that demonstrated greater than or equal to 1 mm ST segment depression was significantly reduced from a mean (SD) of 5.0 (0.4) on placebo to 3.7 (0.6), 2.8 (0.4), and 2.3 (0.7) on nifedipine, atenolol, and the combination respectively. Mean resting left ventricular ejection fraction, assessed by gated radionuclide ventriculography, did not change during any active treatment phase but increased significantly during exercise only on nifedipine and the combination. The nifedipine/atenolol combination was the most effective treatment, and the data suggest that nifedipine may be used to best advantage in combination with a beta blocker.

Angina Pectoris↗

Advanced cardiac life support.

It is important for all physicians to be familiar with the equipment and medications needed for advanced cardiac life support. The most important aspect in advanced life support is the establishment and maintenance of an airway and ventilation of the patient. Office personnel should be trained in Basic Cardiac Life Support, so that the physician can intubate the patient, start an intravenous line, and administer intravenous medications to support the patient. Appropriate drug dosage tables and defibrillation tables are included in this article.

Adult↗

Isolation of a gene enhancer within an amplified inverted duplication after "expression selection".

We have attempted to isolate and identify cellular expression sequences from F9 teratocarcinoma DNA by utilizing their ability to reactivate a selectable gene devoid of its own expression sequences (expression selection). Restriction nuclease-digested F9 cellular DNA was ligated to a polyoma virus (Py) DNA fragment which contains an intact transforming region but is incapable of inducing transformation because it lacks the viral 5' enhancer sequence. The ligation mixture was used to transfect Rat-1 cells and a transformed cell line, 3B, was isolated. The 3B cell line contained a single type of Py DNA insert, which was molecularly cloned as an 18-kilobase BglII fragment. A weak cellular enhancer was identified in a 4.7-kilobase BamHI fragment upstream from the Py sequences. Both the Py DNA and the enhancer sequences were found to be present in an inverted duplication in the 3B clone. The presence of this structure in 3B genomic DNA was confirmed by the analysis of selectively isolated inverted duplicated sequences, and the structure was found to be at least 22 kilobases long. In the 3B cell line, the inverted duplicated sequences containing the Py and enhancer sequences are quite stable and are amplified 20- to 40-fold. The strongly transformed phenotype of the 3B cells may be a result of this amplification. The formation of inverted duplications as a part of the amplification mechanism as well as a general strategy for the cloning of inverted duplicated (amplified) sequences is discussed.

Animals↗

Case-control study of waterborne giardiasis in Reno, Nevada.

An outbreak of Giardia lamblia gastroenteritis occurred in Reno, Nevada, in 1982, during which 324 laboratory-confirmed infections were reported. During the outbreak, Reno was supplied in part by surface water that was chemically coagulated, settled, and chlorinated, but was not filtered. Giardia cysts were recovered from the water supply, and a beaver infected with Giardia was found in one of the reservoirs. A case-control study indicated that, during the outbreak but not afterwards, persons with giardiasis drank more municipal water than did controls. Corrective measures, which included removing the infected beaver and increasing the chlorine concentration, were followed by a rapid decrease in reports of giardiasis.

Adolescent↗

Chevron osteotomy for the treatment of hallux valgus.

Seventy-six chevron osteotomies with follow-up periods ranging from six months to eight years were reviewed. The majority of patients had pain over the bunion prior to operation, and 27 also presented with second metatarsalgia. After surgery there was a marked decrease of pain in the first metatarsophalangeal joint, and in 18 feet the second metatarsalgia was either eliminated or markedly decreased. Most patients were pleased with the appearance of the feet after surgery, but almost one-third of the women complained of difficulty in wearing high heels. The surgical technique is straightforward, but careful attention to detail is necessary to obtain a consistent and satisfactory result.

Adult↗

Burn appearance and spontaneous healing: a prospective study.

In a prospective study to correlate initial burn wound appearance with burn wound appearance after 21 days of conservative wound care, it was found that all burn appearances (except the presence of thrombosed capillaries and charred, "leathery" skin) were associated with a high probability of spontaneous healing. These findings emphasize the difficulty of selecting those burn wounds likely to benefit from early excision and grafting unless, of course, the burn is obviously full-thickness.

Adolescent↗

Maintenance and generalization of 40-Hz EEG biofeedback effects.

Maintenance of conditioning of 40-Hz EEG activity was investigated in six adults 1 to 3 years after they had experienced biofeedback training to increase 40-Hz EEG. Subjects were first retrained to alternately increase and suppress 40-Hz EEG. All six subjects achieved a preset performance criterion in 16-20 minutes. Five of these subjects also subsequently demonstrated significant control of 40-Hz EEG without feedback. The sixth subject did not demonstrate control after 76 minutes and four sessions of attempted retraining with feedback. Transfer of 40-Hz EEG control to a problem-solving task was tested in all subjects in a final session. Cognitive test items were presented and subjects were instructed to alternately increase and suppress 40-Hz EEG while solving the problems. Rates of 40-Hz EEG in suppression periods during problem solving wer significantly greater than during suppression periods without problems. No significant differences in problem-solving performance were found comparing 40-Hz increase and suppression periods. This study supports previous research suggesting an association between 40-Hz EEG and mental activity, and suggests methods for further study of transfer of EEG biofeedback effects.

Adult↗

Medical care for vacationers: health services at Yellowstone National Park.

Medical services provided to vacationers and employees in Yellowstone National Park were reviewed for the years 1975 through 1977. Both ambulatory and inpatient data were obtained, including diagnoses, place of residence, medications prescribed, and methods of payment. The types of problems and modes of treatment did not differ from typical primary care practices. Health maintenance was the most common reason for outpatient visits. The distribution of diagnoses among park visitors and employees was the same within age categories, although the employees' rate of utilization was nearly twice that of the visitors. Distance from home was directly related to the frequency with which visitors used clinic services.

Camping↗

Nephelometric detection of soluble immune complexes: methodology and clinical applications.

We have developed a method for the detection of immune complexes by laser nephelometry which is simple, reproducible, suitable for automation, and generally adaptable for diagnostic testing. Light dispersion by antigen-antibody complexes in the test samples is measured after addition of polymeric buffer, which enhances the aggregation of complexes but does not significantly affect unbound immunoglobulins. The method was used to measure immune complexes formed in vitro by incubation of tetanus toxoid with serum from a rabbit previously hyperimmunized with the same antigen, and to compare the levels of immune complexes in human sera obtained from normal adults and from 37 patients with collagen vascular diseases or endocarditis. When precautions were taken to avoid interference produced by the presence of lipoproteins or by freezing of the samples, the results obtained with human sera were consistent with those expected for normal controls and for patients with conditions thought to be associated with the presence of soluble immune complexes.

Animals↗

Biofeedback training of 40-Hz EEG in humans.

This study was a preliminary evaluation of biofeedback training of human subjects to control high-frequency EEG responses in the 35- to 45-Hz (40-Hz) and 21- to 31-Hz ranges. A total of 22 adult males divided into three groups were successfully trained for increases or suppression of 40-Hz EEG, or increases of 21- to 31-Hz EEG. Dissociation of rates of 40-Hz EEG recorded from scalp leads and 40-Hz EMG responses from prominent muscle contaminators, and partial dissociation of 40-Hz and 21- to 31-Hz EEG responses were noted. After biofeedback training, 8 subjects demonstrated increase and suppression of 40-Hz EEG without feedback. No consistent descriptors of subjective experiences accompanying EEG changes were reported by subjects in any of the groups. The study suggests the utility of biofeedback procedures in research on high-frequency EEG activity.

Adolescent↗

Behavioral and electroencephalographic correlates of 40-Hz EEG biofeedback training in humans.

Two groups of eight adults successfully trained with biofeedback for increases in 40-Hz EEG responses in left or right hemispheres also demonstrated significant 40-Hz EEG increases during baseline periods, and increases in the contralateral hemisphere during training periods. No changes in heart rate, 40-Hz EMG, or 21- or 31-Hz beta, alpha, or theta EEG occurred over training days. Three subjects returning for additional training demonstrated suppression of 40-Hz EEG. A group of four subjects experiencing daily bidirectional training produced substantial within-session control of 40-Hz EEG but no changes over days. Data from posttraining tests without feedback for successful subjects in both groups indicated significant control of 40-Hz EEG responses in the initial parts of these sessions, and some correlated changes in other EEG responses. Measures of successful subjects' experiences during training and control tests indicated awareness of changes in subjective concomitants of EEG responses. This study suggests further strategies for research on behavioral correlates of EEG activity.

Adolescent↗

Toward the measurement of primary care.

The renaissance of rhetoric about primary care--"continuous, coordinated, comprehensive, family-centered"--has paralleled the growth of entrants into formal training programs. The extent to which primary care is actually practiced this way has not been examined, nor have the routes to preparing for it. A preliminary set of measurements is suggested.

Adolescent↗

Studies of membrane fusion. I. Paramyxovirus-induced cell fusion, a scanning electron-microscope study.

Fusion of erythrocytes and HeLa cells with Sendai and Newcastle disease viruses has been studied by scanning electron microscopy. Most virus particles are spherical but vary in diameter from approximately 200 to approximately 600 nm. At 4 degrees C virus particles bind randomly to the cell surface and at high cell densities cross-linking of adjacent cells by virus particles results in cell agglutination. Cell-cell fusion takes place when the agglutinated cell suspension is warmed to 37 degrees C. Fusion is initiated at sites of cell-cell contact and is accompanied in all cases by cell swelling. In the case of suspension HeLa cells, virally mediated cell swelling involves an 'unfolding' of cell surface microvilli and results in the formation of smooth-surfaced single or fused cells. With erythrocytes, swelling results in haemolysis. There is a dramatic reduction in the numbers of virus particles bound to cells following fusion.

Cell Aggregation↗

Effect of hypertension on myocardial rupture after acute myocardial infarction.

Fifty-three of 4,369 patients with acute myocardial infarction died of myocardial rupture. The incidence of rupture varied directly, among men, with the systolic blood pressure on admission to the coronary care unit (CCU), and the highest systolic pressure while in the CCU. Rupture occurred in 0.3% of the men with systolic pressures on admission to the CCU between 110-129 mm Hg, increasing to 2.0% of men with pressures between 170-189 mm Hg. Similarly, 0.3% of the men with a highest systolic pressure less than 150 mm Hg had a rupture, while 1.6% of those with pressures between 170-189 mm Hg ruptured. Diastolic blood pressure, past history of hypertension, and sustained hypertension after infarction were not related to the occurrence of rupture. Eighteen of the 53 patients who sustained rupture had systolic hypertension (greater than or equal to 150 mm Hg) sometime during the 24 hours before rupture, and 14 had diastolic hypertension (greater than or equal to 95 mm Hg). Hypertension appears to be one of several variables interacting to influence the occurrence of myocardial rupture.

Acute Disease↗

Sudden death in the late hospital phase of acute myocardial infarction.

Forty-seven patients died suddenly during the late hospital phase of acute myocardial infarction. Risk factors associated with late in-hospital sudden death included prior cardiovascular disease, circulatory failure while in the coronary care unit, and certain arrhythmias and conduction disturbances while in the coronary care unit. These were associated with a twofold to sixfold increase in late in-hospital phase sudden death. The most prevalent risk factor occured in 62% of the sudden-death patients; the highest incidence of sudden death with a single risk factor was 2.6%, and the greatest relative risk was 6.0. Relative risks were uniformly greater for males than females. Multiple factors were associated with a greater risk than single factors. These risk factors characterize the group of sudden-death patients as a whole but do not allow precise identification of individual patients at high risk.

Acute Disease↗