Stratified coastal ocean interactions with tropical cyclones.

Hurricane-intensity forecast improvements currently lag the progress achieved for hurricane tracks. Integrated ocean observations and simulations during hurricane Irene (2011) reveal that the wind-forced two-layer circulation of the stratified coastal ocean, and resultant shear-induced mixing, led to significant and rapid ahead-of-eye-centre cooling (at least 6 °C and up to 11 °C) over a wide swath of the continental shelf. Atmospheric simulations establish this cooling as the missing contribution required to reproduce Irene's accelerated intensity reduction. Historical buoys from 1985 to 2015 show that ahead-of-eye-centre cooling occurred beneath all 11 tropical cyclones that traversed the Mid-Atlantic Bight continental shelf during stratified summer conditions. A Yellow Sea buoy similarly revealed significant and rapid ahead-of-eye-centre cooling during Typhoon Muifa (2011). These findings establish that including realistic coastal baroclinic processes in forecasts of storm intensity and impacts will be increasingly critical to mid-latitude population centres as sea levels rise and tropical cyclone maximum intensities migrate poleward.

Treatments for common superficial fungal infections.

Fungal infection of keratinized tissue is caused by any of the dermatophyte species. The topical allylamines and benzylamines have been especially effective in treating these infections because of their in vitro fungicidal activity and short treatment duration. With the development of new oral azoles and allylamine antifungal agents, there has been a renewed interest in treating superficial skin fungal infections. The use of topical and oral antifungal agents in treating cutaneous fungal infections is examined.

Using lasers in diabetic wound healing.

Lasers are a treatment choice that appeals to patients. Early research suggests that laser therapy may have a role in hastening wound healing. Attempts have been made to use helium neon, CO2, and KTP lasers in encouraging wound healing in diabetics. We will review the English literature related to laser use in diabetic wound healing and discuss the concept of the use of nondestructive lasers for biostimulation. Further research is needed to assess effectiveness of biostimulation for diabetic wound healing.

Activation times for "emergency backup" programs.

A bench study was performed on 42 different pulse generators (PGs) to evaluate the time required to actuate and "emergency backup" (EBU) program. PGs were programmed to loss of capture before the EBU programming key was activated. Activation times for the EBU pause were measured on an ECG strip from the first noncaptured beat to the first recaptured beat while the total pause was measured between the two captured beats. Each test was performed five times. Special features for temporary threshold testing were also evaluated. Mean activation times for EBU pauses ranged from 1.46-11.90 seconds with total pauses of 2.18-12.94 seconds. Significant differences were observed for EBU activation times from the same PG but utilizing older and newer generation programmers, e.g., 10.90 (old) versus 4.54 seconds (new) for a mean EBU pause. Extreme variations existed in EBU activation times for programmers with multiple "EBU keys" for the same PG, e.g., 12.94 versus 4.96 seconds for the mean total pause. The special features for temporary threshold testing resulted in mean EBU pauses measuring 0.62-2.88 seconds and mean total pauses of 1.21-3.76 seconds. The special features were significantly faster than manual activation of the "EBU key" for regaining capture with few exceptions. Activation times were complicated by multiple programmers for the same PG and several "EBU keys" on the same programmer.

No output or runaway?

A 75-year-old male was implanted with a Telectronics Meta DDDR model 1250 pacemaker 47 months ago. The patient was evaluated in-office for symptomatic complaints of dizziness, palpitations, and "too slow or too fast" pulse rates. Upon examination, the device displayed sudden no output manifestations for which the device had been recalled. However, the device further displayed erratic paced rates to 200 ppm, switching between VVIR and DDDR modes. To the best of our knowledge, this is a previously unreported manifestation in this recalled device and needs to be addressed due to its potentially hazardous patient effects.

A verified report of spurious programming: a case study.

A case of unintentional misprogramming is described in which a DDDR pacemaker, programmed to the VVIR mode, reverted to the originally programmed parameters and mode. The misprogramming requires that a particular sequence of steps be followed and has been verified by the manufacturer. This misprogramming may be clinically significant and can be reproduced in an entire family of current pacemakers based on the same software platform.

Analysis of the effectiveness of in-office and transtelephonic follow-up in terms of pacemaker system complications.

A study was undertaken to determine the most effective method of pacemaker follow-up in terms of the total number of complications detected and yield per follow-up in single and dual chamber pacing systems. The analysis involved 9,786 patient records from 635 patients. The records were reviewed with respect to method of follow-up, number of chambers paced, and complications detected. Complications included: oversensing, undersensing, noncapture, pocket and diaphragmatic stimulation, pacemaker mediated tachycardia, crosstalk, pulse generator malfunction, lead malfunction, infection/erosion, premature end of service, exit block, and other miscellaneous problems. Eight thousand two hundred eighty-eight of the 9,786 follow-ups were performed in the office while 1,498 were transtelephonic. Single chamber pacing systems were implanted in 329 patients and 306 were dual chamber systems. A total of 599 complications were detected. Analysis yielded a per patient complication rate of 5.1% (single chamber) and 8.4% (dual chamber) for in-office follow-up. This compared to a transtelephonic follow-up per patient complication rate of only 0.3% (single chamber) and 1.0% (dual chamber). In-office pacemaker follow-up is significantly more effective (P < 0.001) than transtelephonic follow-up in detecting both single and dual chamber pacemaker system complications.

Jamaican vomiting sickness in Toledo, Ohio.

The endemic illness of Jamaica known as ackee poisoning is reported for the first time in the United States. The toxic exposure resulted from the consumption of canned ackee. The epidemiology, diagnosis, theoretical mechanism, and possible therapy of this disease are discussed.

Performance of a 3.2-mm to 6-mm adaptor.

A study was undertaken to evaluate the performance of a 366-08 adaptor that adapts an in-line bipolar 3.2-mm connector to a 6-mm pulse generator connector. A total of 14 adaptors were implanted in individual patients. Eight of the 14 adaptors failed, an additional failure is probable. The average follow-up time was 32.1 months. The most likely cause of failure was the spring-loaded mechanism of the adaptor, which fatigues with time. All eight of the documented failures presented with loss of capture and were accompanied by increased measured lead impedances. In addition, some failed systems demonstrated loss of sensing. As a result, prophylactic replacement of ventricular lead systems incorporating this adaptor would be advisable. Otherwise, more frequent monitoring with lead impedance measurements may suffice.

Evaluation of an in-line bipolar polyurethane ventricular pacing lead.

A study was undertaken to evaluate the performance of the Medtronic 4012 polyurethane in-line bipolar pacing electrode. One hundred twenty six patients implanted with the 4012 lead were followed by our clinic with 116 of these leads implanted at our institution. Patients were followed a minimum of every 4 months. Testing included the performance of stimulation thresholds, sensing thresholds, and provocative maneuvers to evaluate for myopotential inhibition testing a minimum of every eight months. There were 12 documented lead failures of the total 126 patients. Further analysis was limited to the ten failures occurring in the 116 leads implanted at our center. All ten failed leads utilized the suture anchoring sleeve. Six of the leads were left cephalic implants, three were right cephalic, and one was right subclavian. Manifestations of failure included: seven oversensing abnormalities, three undersensing, four loss of ventricular capture, one premature end of service, four lead impedance decreases to < 250 omega and some presentations in combination. No leads were explanted for evaluation. The Kaplan-Meier product limit method was used to estimate the time to lead failure. The probability of not experiencing a lead failure within the first 4 years of implant is estimated to be 0.9103 (SE = 0.0338). Pacemaker dependent patients implanted with the 4012 lead should be given special consideration for prophylactic replacement.

Activation times for "emergency back-up" programs.

A bench study was performed on 34 different pulse generators to evaluate the time necessary to actuate an "emergency back-up" (EBU) program. Pacemakers were programmed to loss of capture before the EBU was activated. Two pauses were measured that included the total pause from captured beat to captured beat and the time from the first pacing artifact showing loss of capture to the first captured beat resulting from EBU activation. Special features for threshold testing such as temporary pacing, auto threshold, Vario, and an alternating pulse ventricular threshold test were also evaluated. Activation times of the EBU ranged from 1.8 to 11.1 seconds with total pauses of 2.7 to 13.2 seconds, respectively. There were considerable variations in EBU times even within a single manufacturers' pulse generators. The special features for threshold testing resulted in pauses measuring 0.6 to 3.0 seconds with total pauses of 1.2 to 4.0 seconds, respectively, and in all cases were faster than using the EBU. Utilization of the EBU to regain capture during threshold testing in pacemaker dependent patients may result in prolonged pauses and syncope or near syncopal episodes.

Comparison of low rate dual chamber pacing to activity responsive rate variable ventricular pacing.

A study was undertaken to evaluate exercise performance in 18 dual chamber pacemaker patients believed to be chronotropically incompetent. All patients were paced in a DDD AV synchronous mode at 80 beats per minute (beats/min) as well as an externally triggered, activity responsive VVIR mode. Patients underwent two single blind, randomized symptom-limited treadmill tests (Sheffield protocol). Four of the 18 patients achieved intrinsic rates greater than 100 beats/min and were deleted from the primary study. It was noted that all four of these patients performed best with intrinsic rate response and AV synchrony. Thirteen of the remaining 14 patients demonstrated improved exercise tolerance in the VVIR mode. Average exercise time in the VVIR mode (7:25 +/- 3:12 min) was significantly greater (P less than 0.05) than the DDD mode (6:01 +/- 2:27 min). Work performed was significantly greater (P less than 0.05) in the VVIR mode (4.77 +/- 1.97 METS) than in the DDD mode (3.78 +/- 0.77 METS). Maximum heart rates were 83.86 +/- 5.11 beats/min in DDD mode versus 116.00 +/- 10.56 beats/min in VVIR mode. The results demonstrated that improved exercise tolerance can be achieved with single chamber rate variable pacing compared to DDD pacing in patients with chronotropic incompetence. However, potential symptoms associated with loss of AV synchrony should be ruled out.

The use of single sample clearance estimates to probe hepatic drug metabolism: handprinting the influence of cigarette smoking on human hepatic drug metabolism.

1. Conditions were examined under which estimates of drug clearance made from a single measurement of plasma concentration effectively represented multiple-sample estimates of clearance for quinidine, valproic acid, unbound valproic acid, and lorazepam. When plasma concentrations were measured at various post-dose times, both individual and mean values of single-sample clearance estimates, CL, corresponded closely to multiple-sample clearance estimates. Best post-dose sampling times were: quinidine, 8 h; valproic acid, 24 h; and lorazepam, 24 h. 2. Single-sample clearance estimates, CL, were calculated for seven drugs employed as probes of human hepatic drug-metabolizing enzymes. Valproic acid was used to probe microsomal and peroxisomal beta-oxidase activity; antipyrine, phenytoin, quinidine, carbamazepine, and theophylline were used as probes of hepatic mixed-function oxidases (MFO), and lorazepam as a probe for UDP-glucuronosyltransferase activity. 3. A clearance index (CI, namely probe CL for smokers divided by probe CL for non-smokers) was calculated for each probe. The effect of cigarette smoking (and presumably polycyclic aromatic hydrocarbon exposure) on all probe CL values was consolidated and plotted as the logarithm of the CI to produce a handprint of drug metabolizing enzyme activity for cigarette smokers. 4. Only theophylline CL was significantly faster among smokers than non-smokers (P less than 0.01). 5. We conclude that the use of multiple probes of MFO activity when given in a single-dose, single-sample protocol for structuring handprints represents a minimally invasive and useful approach to characterize xenobiotic-mediated effects on hepatic MFO.

Optimal dosing of phenytoin: an evaluation of the timing and appropriateness of serum level monitoring.

The appropriateness of all serum phenytoin concentrations measured at this 294-bed, tertiary care institution over a 7-week period were evaluated. Each serum level was determined to be justified or unjustified based on either pharmacokinetic or clinical criteria. A total of 234 serum levels were measured in 58 patients. Thirty-eight (16%) of the levels were justified on a pharmacokinetic basis, whereas 70 (30%) were justified for clinical assessment of the patient. One hundred thirty (56%) of the serum levels could not be justified on any grounds. Also identified were distinct clinical situations for 13 patients for which monitoring of serum levels was warranted but not performed. Most phenytoin serum level measurements at this institution were not reasonably justified and may have been unnecessary. A yearly reduction in laboratory costs in excess of $9,000 was predicted if such serum levels had been ordered only when clearly indicated.

Cardiac blood pH as a possible indicator of postmortem interval.

Postmortem changes in the pH of blood and selected tissues in rats were evaluated at intervals ranging from 2 min to 96 h. Cardiac blood pH was significantly and reproducibly decreased in all groups at all postmortem intervals, independent of the method of sacrifice used. A preliminary study using cardiac blood obtained at autopsy from a limited number (n = 11) of human subjects demonstrated a significant negative correlation (r = -0.908, P less than 0.01) between postmortem interval (range 2 to 20 h) and cardiac blood pH.

Crosstalk during bipolar pacing.

Bipolar sensing pulse generators were thought to have eliminated crosstalk problems evident in unipolar systems. Crosstalk has been observed in the Model 284-02 bipolar sensing pacemakers. These intermittent problems were resolved by decreasing atrial output, decreasing ventricular sensitivity or increasing the ventricular blanking period. Three patients had pacemaker crosstalk, two experienced symptoms analogous to pacemaker syndrome.

Heroin, morphine, and hydromorphone determination in postmortem material by high performance liquid chromatography.

A procedure has been developed for the simultaneous determination of heroin, morphine, and hydromorphone from postmortem tissues by reversed phase high performance liquid chromatography (HPLC) using electrochemical detection. This method permits the direct determination of unmetabolized heroin from antemortem or postmortem urine as evidence of illegal drug use. Presumptive confirmation of heroin was based on the ability to hydrolyze the HPLC heroin fraction to morphine. Heroin was also confirmed in urine by gas chromatographic/mass spectroscopic (GC/MS) analysis of the HPLC fraction. Analysis of postmortem blood, gastric contents, urine, and injection site tissues have revealed the presence of morphine and hydromorphone, while heroin has only been identified in urine.