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Biomedical subjects

A M Ho

Publications and source records attributed to A M Ho.

At least 19 recordsLinked to original sources

Inhibition of bacterial IF2 binding to fMet-tRNA((fMet)) by aminoglycosides.

Screening for inhibitors of bacterial protein synthesis Initiation Factor 2 (IF2) binding to N-formyl-Methionyl-transfer RNA (fMet-tRNA((fMet))) identified a series of aminoglycosides, that included amikacin and kanamycin A1, as inhibitors of this interaction. Subsequent testing revealed that aminoglycosides displayed a wide range of inhibitory activity. However, the failure of these compounds to completely inhibit binding of IF2 to fMet-tRNA((fMet)), the known ability of aminoglycosides to bind RNA, and the ability of the aminoglycosides to displace PicoGreen bound to fMet-tRNA((fMet)) suggest these compounds act by binding fMet-tRNA((fMet)). This hypothesis is further supported by isothermal denaturation experiments that failed to show any interaction between the IF2 protein and the aminoglycosides.

Amikacin↗

Airway difficulties caused by improperly applied cricoid pressure.

Cricoid pressure, when properly applied, may prevent gastric regurgitation and may improve the view of laryngoscopy. When improperly applied, however, it can impede laryngoscopy and mask-ventilation. When faced with a "cannot intubate" or "cannot mask-ventilate" situation, clinicians should reevaluate the manner with which the assistant is applying cricoid pressure and must be prepared to adjust or even to release it.

Adult↗

"Apnea-volume" warning during normal ventilation of the lungs: an unusual leak in the Narkomed 4 Anesthesia System.

We report a case of an unusual breathing circuit leak in the Narkomed 4 Anesthesia System due to a loose retaining ring at the junction of the expiratory valve assembly and the Spiromed Respiratory Volume Monitor. In the presence of the leak, the monitor panel displayed the messages "apnea volume" and "minute volume low," yet the low airway pressure alarm was not triggered and other parameters and clinical signs pointed to normal ventilation of the lungs. These conflicting data led to some delay in localizing the leak. After conclusion of the case, we found that occult loosening of this ring without causing leaks large enough to fail the FDA generic or manufacturer-recommended leak checks can occur. We recommend checking the tightness of this ring during routine leak checks and after rotating the expiratory valve assembly during re-positioning of the anesthetic system.

Anesthesiology↗

'Awareness' and 'recall' during emergence from general anaesthesia.

A case is presented in which memory of events during emergence from anaesthesia resulted in serious psychological sequelae. Communication with patients should begin almost immediately after anaesthesia has been terminated and should have prevented this unfortunate incident.

Anesthesia Recovery Period↗

Ipsilateral thoraco-lumbar anaesthesia and paravertebral spread after low thoracic paravertebral injection.

We report ipsilateral thoraco-lumbar anaesthesia and paravertebral spread of contrast after injection through a thoracic paravertebral catheter that was placed at the right T8-9 spinal level for pain management in a patient with multiple fractured ribs. We review the literature and describe the subendothoracic fascial communication between the thoracic paravertebral space and the retroperitoneal lumbar paravertebral region, which we propose, is the anatomical basis for ipsilateral thoraco-lumbar anaesthesia and paravertebral spread of contrast in our patient.

Extravasation of Diagnostic and Therapeutic Materi↗

Role of the mouse ank gene in control of tissue calcification and arthritis.

Mutation at the mouse progressive ankylosis (ank) locus causes a generalized, progressive form of arthritis accompanied by mineral deposition, formation of bony outgrowths, and joint destruction. Here, we show that the ank locus encodes a multipass transmembrane protein (ANK) that is expressed in joints and other tissues and controls pyrophosphate levels in cultured cells. A highly conserved gene is present in humans and other vertebrates. These results identify ANK-mediated control of pyrophosphate levels as a possible mechanism regulating tissue calcification and susceptibility to arthritis in higher animals.

Animals↗

Lung isolation for the prevention of air embolism in penetrating lung trauma. A case report.

PURPOSE: To illustrate a new airway and ventilatory management strategy for patients with unilateral penetrating lung injury. Emphasis is placed on avoiding positive pressure ventilation (PPV)-induced systemic air/gas embolism (SAE) through traumatic bronchiole-pulmonary venous fistulas. CLINICAL FEATURES: A 14-yr-old male, stabbed in the left chest, presented with hypovolemia, left hemopneumothorax, an equivocal acute abdomen, and no cardiac or neurological injury. In view of the risk of SAE, we did not ventilate the left lung until any fistulas, if present, had been excised. After pre-oxygenation, general anesthesia was induced and a left-sided double-lumen tube (DLT) was placed to allow right-lung ventilation. Bronchoscopy was performed. The surgeons performed a thorascopic wedge resection of the lacerated lingula. Upon completion of the repair, two-lung ventilation was instituted while the ECG, pulse oximetry, PETCO2, and blood pressure were monitored. Peak inflation pressure was increased slowly and was well tolerated up to 50 cm H2O. The patient's intravascular status was maintained normal. CONCLUSION: Patients with lung trauma are at risk of developing SAE when their lungs are ventilated with PPV. In a unilateral case, expectant non-ventilation of the injured lung until after repair is recommended.

Adolescent↗

Previous cholecystectomy and choledochal sphincter spasm after morphine sedation.

PURPOSE: To describe a patient with probable choledochal sphincter spasm after preoperative morphine, and to suggest a history of cholecystectomy as a predisposing factor. CLINICAL FEATURES: A 60 yr old man for femoral-popliteal artery bypass grafting developed right upper quadrant abdominal pain after preoperative morphine and scopolamine. He had a previous cholecystectomy. His pain was relieved with naloxone. CONCLUSION: Choledochal sphincter spasm should be part of a differential diagnosis in right upper quadrant pain after sedative doses of morphine, especially if there is a previous cholecystectomy.

Cholecystectomy↗

Contamination susceptibility of three needleless and one standard needle injection systems.

PURPOSE: To compare in vitro the contamination susceptibility of three needleless and one standard needle injection systems. METHODS: The Baxter InterLink, St. Paul Medical Key-Lok, Braun SafSite, and Becton Dickinson heparin lock, were compared. Fifty of each were studied. Each system was connected to a culture bottle and injected 30 times over 72 hr. The manufacturers' directions were followed except for Braun's, which recommend that a new sterile cap be used after each injection. Instead, the same cap was used after each injection to reflect day-to-day clinical practice. Culture bottles were subsequently analyzed for bacterial growth. RESULTS: The contamination rates for the heparin lock, InterLink, Key-Lok, and SafSite were 3/50 (6%), 6/50 (12%), 4/50 (8%), and 36/50 (72%), respectively. All positive cultures grew coagulase-negative staphylococcus species. There was no difference in contamination rates between the InterLink, Key-Lok, and heparin lock designs. The contamination rate of the SafSite was higher (P < 0.001) than the other three systems. CONCLUSIONS: The InterLink and Key-Lok systems had a similarly low contamination susceptibility as a standard needle injection system. It was not clear if the high contamination rate found with the SafSite system was due to non-adherence to the manufacturer's directions for handling.

Bacteria↗