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Biomedical subjects

D R Graham

Publications and source records attributed to D R Graham.

14 recordsLinked to original sources
PubMed1992

Assembly of an MCP receptor, CheW, and kinase CheA complex in the bacterial chemotaxis signal transduction pathway.

We examined the binding interactions of the methylation-dependent chemotaxis receptors Tsr and Tar with the chemotaxis-specific protein kinase CheA and the coupling factor CheW. Receptor directly bound CheW, but receptor-CheA binding was dependent upon the presence of CheW. These observations in combination with our previous identification of a CheW-CheA complex suggest that CheW physically links the kinase to the receptor. The ternary complex of receptor, CheW, and CheA is both kinetically and thermodynamically stable at physiological concentrations. Stability is not significantly altered by changes associated with attractant or repellent binding to the receptor. Such binding greatly modulates the kinase activity of CheA. Our results demonstrate that modulation of the kinase activity does not require association-dissociation of the ternary complex. This suggests that the receptor signal is transduced through conformational changes in the ternary complex rather than through changes in the association of the kinase CheA with receptor and/or CheW.

Bacterial Proteins↗
PubMed1992

Comparison of three different methods used to achieve local anesthesia for fiberoptic bronchoscopy.

A patient's tolerance of fiberoptic bronchoscopy depends on the effectiveness of local anesthesia. This study compares the three different methods of local anesthesia in common use After sedation, patients (n = 53) received either 4 ml of 2.5 percent cocaine by intratracheal injection (TI) (n = 18), by bronchoscopic injection (BI) (n = 19), or had 4 ml of 4 percent lidocaine delivered by nebulizer 20 min before the procedure (NEB) (n = 16). Patients and bronchoscopists scored the procedure using visual analog (VAS) and severity scales. Objective measurements of cough counts and episodes of stridor were recorded by phonopneumography. Patients' VAS scores showed a clear preference for the transtracheal method compared with either bronchoscopically injected cocaine (p less than 0.001) or nebulized lidocaine (p less than 0.001). Patients also reported that the TI method produced less cough during intubation of the larynx and inspection of the airways (BI and NEB, p less than 0.01). The TI method was also preferred by the bronchoscopists (BI and NEB, p less than 0.001); they reported less cough and easier tracheal intubation. The mean cough count was significantly lower for the TI group, 49 (43) compared with 95 (52) for BI (p less than 0.01), and 81 (43) for the NEB group (p less than 0.05). Patients' and bronchoscopists' VAS showed significant correlation with cough (r = 0.63-69, p less than 0.01). Stridor occurred in only two patients after TI, compared with 15 in the other two groups. Extra local anesthesia was required by 16 patients after BI, by all the NEB group, but by only one patient after TI. Subjective and objective measurement shows that 4 ml of 2.5 percent cocaine injected into the trachea produced excellent local anesthesia for fiberoptic bronchoscopy, there were no extra complications, and it was the method preferred by both patients and bronchoscopists.

Aerosols↗
PubMed1992

Operating safely in an underdeveloped country.

The visiting surgical team doing cleft lip and cleft palate repair in an underdeveloped country may find long hours and adverse conditions. Some of the trips are undertaken for resident education. It is the responsibility of the expedition leader to implement safety precautions for protection of both the patients and the volunteers in the operative party as suggested in this article. Equipment maintenance and modified sterilization techniques are also described.

Airway Obstruction↗
PubMed1991

Infectious complications among patients receiving home intravenous therapy with peripheral, central, or peripherally placed central venous catheters.

Rates of bacteremia among hospitalized patients with central venous catheters range up to 21%. Few data exist for home intravenous therapy (IVT). We studied 300 patients from two hospital-based home IVT services in 29 months. Diagnoses included 92 cases of osteomyelitis, 33 of pneumonia, 35 of malnutrition, 26 of chronic pain, and 114 of other diseases. Peripheral IVT was given to 97 patients. Mean age was 39.4 years (range, 0.3-98). Hickman, Infuse-A-Port, Broviac, Arrow triple lumen, Hohn, and peripherally inserted central catheters (PICC) were used for a mean of 44 days. Six bacteremias (one death) (2%, 4.6/10,000 catheter days), two subclavian thromboses, 13 catheter site infections, and one additional death occurred. PICC experience included 76 patients, mean age 46 years (range, 4-76), primarily with infections, chronic pain, or dehydration. Mean duration of therapy was 24 days (0-67) and was completed in 51 patients; others completed therapy with standard peripheral catheters a mean of 6 days later. Complications included 17 obstructions by clot, 11 cases of phlebitis, six catheter fractures, five punctures, two accidental removals, and one infiltration. Liquid silicone repaired holes; urokinase opened clots. Successful completion of therapy was more common in the second year, 88% versus 57%. Despite more complications, patients, home IVT nurses, and physicians preferred PICCs. We conclude that home IVT is safe via many means of access, with fewer infections than with hospital care. Such infections may be termed "nosohusial."

Adolescent↗
PubMed1991

Screening for tuberculosis: current practices and attitudes of hospital workers.

To examine the current practices and attitudes of health workers to the prevention of tuberculosis in our 55-bed chest unit, we investigated the tuberculin reactor status, reviewed pre-employment screening and reviewed the action taken after contact with tuberculosis by staff members. We assessed all 61 staff members, including 44 nurses, 1 physiotherapist, 11 doctors and 5 domestic workers. 47/61 staff members had had BCG vaccination. Heaf testing revealed 3 Heaf-negative subjects and, of the remainder, 52 had grade 3 or stronger reactions. Only 3/11 doctors, 36/44 nurses and 4/5 domestic workers had had any pre-employment screening. No action was taken by any doctor after their last contact with tuberculosis, whereas 10/44 nurses and 3/5 domestic workers had had chest X-rays. This study shows the low importance with which the risk of tuberculosis is perceived, particularly by doctors and demonstrates the need for stricter supervision and improved quality of pre-employment screening.

Adult↗
PubMed1990

Recurrent bacterial endocarditis in a man with tetralogy of Fallot: earliest recurrence on record.

Enterococcal endocarditis occurred in a young man with tetralogy of Fallot who had just completed therapy for staphylococcal endocarditis. The patient had a transient reversal of flow through the ventricular septal defect during staphylococcal endocarditis with lung abscesses and had persistently elevated teichoic acid antibody titers during the second episode caused by enterococcus. Our review of the literature on recurrent infective endocarditis indicates that our case represents one of the shortest intervals of recurrence with a second organism.

Adult↗
PubMed1990

Vertebral osteomyelitis secondary to Streptococcus agalactiae.

Vertebral osteomyelitis due to hematogenous seeding of Streptococcus agalactiae occurred in a 29-year-old farmer. The patient was treated with immobilization and parenteral antibiotics but developed recurrent back pain requiring a posterior spinal fusion. In a review of the literature, Group B streptococcal vertebral osteomyelitis seems not to have been previously reported in an adult.

Adult↗
PubMed1979

Guidelines for the care of patients hospitalized with viral hepatitis.

For years patients hospitalized with viral hepatitis have been placed in two categories of isolation--enteric precautions and blood precautions. This strategy was based on the inability to differentiate between hepatitis A and B and on the assumption that feces and blood from patients with either type might be infective. It is now known that patients with hepatitis A do not pose a problem of disease transmission through direct contact with blood, and although blood of patients with hepatitis B may be infective, the virus is not transmitted via feces. The enteric route is the principal mode of transmission for hepatitis A, but maximal levels of hepatitis A virus excretion occur before the onset of jaundice. Non-A, non-B hepatitis is similar epidemiologically to hepatitis B. Thus, the major thrust for caring for patients hospitalized with viral hepatitis is toward blood precautions; the same precautions used when handling feces, urine, and excretions from all other hospitalized patients are appropriate for patients admitted with a diagnosis of hepatitis A.

Bedding and Linens↗
PubMedDate not supplied

Susceptibility testing of topical antibacterials against methicillin-resistant Staphylococcus aureus.

Methicillin-resistant Staphylococcus aureus (MRSA) isolates that were collected from 44 consecutive patients during 1 year in a community hospital were tested for susceptibility to five commonly used topical antibacterial agents. Agar-well susceptibility testing, which was based on zones of inhibition, was used to compare the effectiveness of the antibacterials against MRSA. Nitrofurazone was effective in inhibition of bacterial growth and was relatively inexpensive. Mupirocin was found to be effective but more costly for treatment of MRSA. Varying degrees of susceptibility to silver sulfadiazine, mafenide acetate, and bacitracin were noted in the cultures that were obtained at this medical center. On the basis of our findings from susceptibility tests compared with those of another center, we recommend that all hospitals undertake topical sensitivity testing of their MRSA isolates. Appropriate and effective topical antibacterial therapy can then be planned within each center.

Anti-Infective Agents, Local↗
PubMedDate not supplied

Low cost surgical drill.

A low cost cordless electric drill originally designed for the home workshop has been adapted for use in the operating room and extensively employed for over a year. Permitting one-hand operation, unencumbered by power cords or air hoses, and positively free from shock hazard, this type of drill will perform the majority of drilling tasks needed by the orthopedic surgeon. The cost compares with many currently used "disposable" operating room items.

Bone Diseases↗