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Biomedical subjects

M Parker

Publications and source records attributed to M Parker.

At least 253 records · Page 14Linked to original sources
PubMed1978

The validity of determinations of pulmonary wedge pressure during mechanical ventilation.

Changes in the mean pulmonary wedge pressure were measured during temporary disconnection from a ventilator in 29 patients to assess the effects of therapy with controlled-volume ventilation on determinations of pulmonary wedge pressure. In 16 observations performed during therapy with intermittent positive-pressure ventilation, the mean value for the pulmonary wedge pressure was the same (10.3 mm Hg) with the patients connected to or disconnected from the ventilator. Thirteen of the patients were also maintained on therapy with positive end-expiratory pressure (PEEP); the mean (+/- SD) of 17 measurements of pulmonary wedge pressure did not show a significant variation on cessation of mechanical ventilation (12.5 +/- 6.7 mm Hg vs 11.7 +/- 6.9 mm Hg; P greater than 0.05). We conclude that pulmonary wedge pressure can be measured accurately at the end of exhalation during the administration of positive-pressure ventilation with 10 cm H2O of PEEP. The suggested practice of discontinuing mechanical ventilation in order to obtain a more exact measurement is not warranted.

Blood Pressure↗
PubMed1977

Propoxyphene on demand. Analgesic-seeking behavior in psychiatric inpatients.

Although anxiety is known to enhance a patient's response to pain, the exact relationship is unclear. This problem is particularly acute among psychiatric patients where analgesics are frequently both used and abused. This study attempts to evaluate factors associated with analgesic use among these patients with the hypothesis that anxiety, other measures of psychopathology, and ward tension would be associated with frequent analgesic use. An unselected series of psychiatric admissions during a three month period were administered the State-Trait Anxiety Inventory, MMPI, and a questionnaire dealing with prior drug use. Propoxyphene napsylate (Darvon-N) was made freely available on request from nurses who recorded details of the interaction on a prepared card. The nursing staff also recorded unusual incidents on the unit and evaluated daily the level of ward tension. The results indicate that, when made freely available to psychiatric inpatients, propoxyphene was used very conservatively and for appropriate complaints. Factors associated with drug seeking behavior are discussed in relation to other research regarding the use and abuse of analgesics.

Adult↗
PubMed1976

Immunoglobulin G complex interactions with rheumatoid factor and neutrophils: 51CrCl3 labelling and 14CO2 hexose monophosphate shunt studies.

The interactions of soluble and insoluble IgG complexes with macromolecular rheumatoid factor (RF) and neutrophils have been examined in an in vitro system allowing the separate assay of the biologic activities of these elements in the rheumatoid inflammatory process. Studies utilizing soluble and insoluble 51CrCl3 labelled human IgG complexes have demonstrated uptake of only the insoluble complexes by human neutrophils. A burst of hexose monophosphate shunt activity, as evidenced by increased oxidation of glucose-l-14C to 14CO2, has been shown to occur only when neutrophils are exposed to these insoluble complexes. High titer RF sera added to the insoluble complexes prior to their incubation with neutrophils did not affect either the uptake of the complexes or the magnitude of hexose monophosphate shunt activity. Native IgG and soluble IgG complexes were not taken up by the neutrophils and did not stimulate hexose monophosphate shunt activity in the presence or absence of rheumatoid sera. The addition of high titer RF sera to soluble IgG complexes produced precipitation of RF-IgG complexes which were capable of stimulating hexose monophosphate shunt activity in normal neutrophils. RF thus has been shown to change functionally inactive soluble complexes into functionally active insoluble complexes capable of stimulating normal neutrophils. Neutrophil stimulation by insoluble complexes may be important in the continuing inflammatory process occurring in the joints of patients with rheumatoid arthritis.

Arthritis, Rheumatoid↗
PubMed1976

Neutrophil and rheumatoid factor-Immunoglobulin G insoluble complex interactions: phagocytosis and sequelae.

Studies utilizing 51CrCl3 labelled human immunoglobulin G have demonstrated a quantitative, time-related increase in the uptake of insoluble rheumatoid factor-immunoglobulin G complexes by human neutrophils. A burst of hexose monophosphate shunt activity occurs when these complexes are phagocytized by neutrophils as evidenced by the increased oxidation of glucose-l-14C to 14CO2. Metabolic and electron micrographic studies suggest that a heat stable serum factor is needed for maximum complex uptake and shunt activity. Phagocytosis of complexes did not affect the adherence of neutrophils to nylon fiber columns, but did not produce selective release of lysosomal enzymes. This study has delineated in an in vitro system, functional and metabolic sequelae of neutrophil phagocytosis of insoluble rheumatoid factor-immunoglobulin G complexes, which may be important components of the inflammation occurring in the joints of patients with rheumatoid arthritis.

Glucuronidase↗
PubMed1975

Persistent parotid pain due to guanacline.

Details are given of 17 patients who developed parotid pain during treatment with guanacline and which persisted after cessation of guanacline for upto five and a half years. These patients are compared with 17 patients who received similar treatment with guanacline and who did not develop parotid pain. There was no significant difference between patients who experienced parotid pain and those who did not with respect to sex, age, clinical diagnosis, blood urea, previous hypotensive therapy or other drugs given concurrently with guanacline. There was a slightly greater association of parotid pain with other side effects and with a larger daily dose of guanacline. It is suggested that persistent parotid pain after guanacline therapy is due to prolonged or permanent selective sympathetic nerve damage in the region of the cervical sympathetic nerve supply to the salivary glands.

Adolescent↗
PubMedDate not supplied

Prognostic evaluation in geriatric oncology: problems and perspectives.

The optimal management of older patients with malignant diseases may be prevented by two antithetic conditions: inadequate treatment and excessive treatment. A likely root of this problem appears to be paucity of prognostic information, which may hamper management-related decisions in the older person with cancer. The prognostic value of performance status and nutritional status may fade with aging, while the influence of mental, emotional and socioeconomic status on the outcome of neoplastic diseases may become more prominent. The Comprehensive Geriatric Evaluation (CGE), which encompasses emotional mental and social domains in addition to physical health and function, may prove a valuable clue for the selection of those older patients who are suitable candidates for antineoplastic treatment.

Journal Article↗
PubMedDate not supplied

Uptake across the cell envelope and insertion into the inner membrane of ion channel-forming colicins in E coli.

Pore-forming colicins exert their lethal effect on E coli through formation of a voltage-dependent channel in the inner (cytoplasmic-membrane) thus destroying the energy potential of sensitive cells. Their mode of action appears to involve 3 steps: i) binding to a specific receptor located in the outer membrane; ii) translocation across this membrane; iii) insertion into the inner membrane. Colicin A has been used as a prototype of pore-forming colicins. In this review, the 3 functional domains of colicin A respectively involved in receptor binding, translocation and pore formation, are defined. The components of sensitive cells implicated in colicin uptake and their interactions with the various colicin A domains are described. The 3-dimensional structure of the pore-forming domain of colicin A has been determined recently. This structure suggests a model of insertion into the cytoplasmic membrane which is supported by model membrane studies. The role of the membrane potential in channel functioning is also discussed.

Amino Acid Sequence↗
PubMedDate not supplied

Prevention of oral bacterial flora transmission by using mouth-to-mask ventilation during CPR.

The Emergency Cardiac Care Committee of the American Heart Association has recently recommended utilizing protective barrier precautions during CPR (1,2). We assessed 17 mask and faceshield resuscitation devices for adequacy of barrier protection. Eight of the devices were faceshields (CPR Microshield, Hygenic, MedCare Mask, Resusci, Samaritan, Sealeasy, Portex); 8 were mask devices (Laerdal, Dyna Med, MTM Emergency Lung Ventilator, MTM Emergency Resuscitator, Res-Q-Flo, Rightway Mouth-to-Mask Resuscitation, Trufit), and one of the devices did not meet the criteria for either faceshield or mask (Lifesaver). All masks were disinfected, applied to the investigator's face as directed by the manufacturers' instructions, and then cultured for oral aerobic bacterial flora on the rescuer side. No mask devices cultured positive for oral aerobic bacterial flora, while 6 of 8 faceshield devices cultured positive for oral aerobic bacterial flora (P less than 0.007). The CPR Microshield and the Portex faceshield were the only devices that did not develop a positive culture. We conclude that all ventilation devices with a one-way valve, except the Sealeasy device, provide adequate barrier type protection from oral aerobic bacterial flora when simulating mouth-to-barrier type protection when performing mouth-to-mouth ventilation.

Cross Infection↗
PubMedDate not supplied

Paramedics: knowledge base and attitudes towards AIDS and hepatitis.

We surveyed 420 paramedics employed by a large metropolitan fire department to determine the effects of educational seminars on their knowledge base, perceptions, and attitudes about AIDS and hepatitis B. All surveys were completed on an anonymous, voluntary, and confidential basis. Our educational efforts improved the paramedics' knowledge base concerning the medical manifestations of AIDS, identification of risk factors, modes of transmission, and means of infection control, but had no impact on paramedics' fear of contracting AIDS. While paramedics have a strong fear of contracting AIDS, we note that they underestimate their risk of acquiring hepatitis B. Only 17% of paramedics surveyed had received the hepatitis vaccine, despite attending an infectious disease seminar addressing the occupational risks of acquiring hepatitis B infections during the previous year. Further educational efforts to address the paramedics' attitudes about AIDS, as well as to encourage paramedics to recognize hepatitis B exposure as a significant personal health risk, are currently being pursued.

Acquired Immunodeficiency Syndrome↗