Immediate Catheter Directed Thrombolysis for Thromboembolic Stroke During Carotid Endarterectomy.

BACKGROUND: Carotid artery endarterectomy (CEA) is a common procedure undertaken by vascular surgeons with over 5,000 procedures performed annually worldwide. Published rates of perioperative stroke range from 1.3% to 6.3%. CASE REPORT: A case is presented in which on-table intra-cranial angiography and catheter directed thrombolysis were used for a thromboembolic occlusion of the distal internal carotid artery (ICA) and proximal middle cerebral artery (MCA). An 83-year-old lady developed a dense right hemiparesis while undergoing a CEA under local anaesthetic (LA). Immediate re-exploration of the endarterectomy did not reveal technical error. Intraoperative duplex scanning of the internal carotid artery revealed no detectable diastolic flow. On-table angiogram showed complete occlusion of the distal ICA and proximal MCA. Catheter directed administration of TPA was undertaken. The entire ICA and MCA were completely clear on a completion angiogram. The patient made a full neurological recovery. DISCUSSION AND CONCLUSION: Prompt diagnosis and treatment with intraoperative catheter directed thrombolysis can resolve thromboembolic occlusion of the ICA/MCA. It is argued that performing CEA under LA is useful for immediate recognition of perioperative stroke. Furthermore, the advantage is highlighted of vascular surgeons having both the resources and skillset to perform on-table angiography and thrombolysis.

Micro-environment changes inside impermeable protective clothing during a continuous work exposure.

Protective clothing (PC) results in a micro-environment between itself and the body. Workers are then exposed to a heat stress greater than the ambient environment alone, which is a reflection of micro-environment, metabolic rate and time. Adjustments to the ambient environment to account for the micro-environment have been formulated as a means to predict heat strain for safety and productivity purposes. Measurement of the actual micro-environment was made for a mean of 63.1 +/- 7.9 min using a remote sensor at the shoulder, hip and thigh levels on 15 subjects during a continuous work protocol (300 kcal/h) in impermeable PC at an ambient temperature of 30.1 degrees C wet bulb globe temperature (WBGT) (32 degrees C dry, 29 degrees C wet, 33 degrees C globe). Micro-environment temperature increased over the duration of the work period. There was no statistically significant difference (p>0.05) between the measurements made at the three different body sites for temperature or humidity. The mean micro-environmental WBGT at the end of work was 34.6 degrees C WBGT. Micro-environment WBGT increased rapidly in the first 20 min of work then slowed, rising only 0.5 degrees C WBGT from 40 to 60 min. These results suggest that at this particular high ambient temperature (30.1 degrees C WBGT) an adjustment factor of 5 degrees C WBGT would give a more accurate indication of thermal stress for up to 1 h of continuous moderate work within PC. For shorter work durations, an even smaller adjustment would be appropriate.

Prediction of rectal temperature from ear canal temperature.

Personal heat strain monitoring provides the best means for maximizing worker safety and productivity in hot jobs. The present study compared methods for reducing the environmental effect on aural canal temperature in an attempt to reduce the predictive error of a personal heat stress monitor (QST) and a simple ear thermistor (EAR). Subjects underwent three exposures in impermeable protective clothing (PC) in an environment of 30.1 degrees C wet bulb globe temperature (WBGT) wearing either ear plugs (PLG), ear moulds (MLD) or ear moulds and earmuffs (MFS). Mean work time across all trials was 63.1 +/- 7.9 min, with a mean rectal temperature at 60 min of 38.5 +/- 0.1 degrees C and a sweat production rate of 29.7 +/- 8.6 g/min. Rectal temperature was used as the criterion measure of core temperature. Although group mean predictions were satisfactory, large SD of mean differences (+/- 0.36) meant that predictive ability of QST for individuals was greatly impaired. A simple well-insulated ear thermistor showed slightly better accuracy (+/- 0.28) as a predictor of rectal temperature across time, particularly at peak temperatures. Incorporating the predictive error of aural temperature still extended the duration of safe work times relative to ACGIH guidelines. Further investigation is still necessary to ensure that predictions based on aural temperature are accurate and safe for the worker population across varying conditions.

Rapid cooling techniques in joggers experiencing heat strain.

This study examined subjects that exercised on three occasions in a heated environment (WBGT = 39 degrees C] until they experienced heat strain. Since morbidity and mortality due to heat injury increase with the duration of elevated core temperature, it is important that techniques to lower core temperature be evaluated. Following three exercise sessions, subjects underwent each of three core cooling treatments in random order: 1) Torso immersion in cool water, 2) Hands and feet immersion in cool water, and 3) Sit-in-shade with a 1.5mph breeze provided. Subjects (n=5) consistently reached peak rectal temperatures of 38.8 (+/-0.1) degrees C following each exercise bout in the heated environment. Torso immersion produced a significantly (p<0.05) greater rate of decline in rectal temperature (0.25+/-0.10 degrees C/min) than the hands and feet immersion technique (0.16+/-0.05 degrees C/min) and the sit in the shade technique (0.11+/-0.04 degrees C/min). After only 10 minutes of cooling, the differences among cooling techniques were evident. Similar trends were observed for mean heart rate readings, albeit not significant (p>0.05). It was concluded that rectal temperatures can be reduced rapidly through the use of a cool water torso-immersion technique.

Purification and identification of a human dermal extract component inhibitory to fibroblast proliferation.

It was previously shown that a citric acid buffer extract of human dermis (extract D) inhibited growth of human diploid fibroblasts in monolayer culture (Muir et al., 1997). Further fractionation has shown that the active principle is probably a proteoglycan, and that retention of its inhibitory activity is dependent on the use protease inhibitors throughout the extraction procedure. Elution of extract D from a DEAE-cellulose column produced four major peaks, each of which was subjected to SDS-PAGE as well as being tested for inhibitory activity on the growth of fibroblasts in culture. Peaks III and IV had no inhibitory effect, but peak I contained highly active material. Gels of this peak showed prominent bands of 120 kDa (corresponding to dermatan sulphate proteoglycan II, DS-PG II) and at 45 kDa (corresponding to the core protein). The latter band became more prominent when extract D which had been treated with chrondroitinase ABC was electrophoresed. Their identities were verified by Western blotting. Peak II also contained some slower-acting inhibitory material which has as yet to be identified, but contains little or no protein corresponding to the decorin core-protein. The data indicate that the intact decorin molecule, DS-PG II, is the main inhibitory principle in human skin.

Inhibition of the contraction of collagen gels by extracts from human dermis.

Extracts from the human dermis were prepared and evaluated with respect to their ability to influence fibroblasts to contract collagen gels in vitro. The extract which had the most inhibitory effect on fibroblasts to cause contraction of collagen gels was extract D. It also inhibited fibroblast growth. Inhibition of contraction was not simply related to fibroblast cell numbers and the data suggests a specific effect upon the ability of fibroblasts to cause contraction. Other extracts were without significant effect.

Prospective analysis of a scoring system to predict choledocholithiasis.

BACKGROUND: The management of choledocholithiasis in the laparoscopic era remains debatable. A common policy is to perform preoperative endoscopic retrograde cholangiopancreatography (ERCP) on patients suspected of having common bile duct (CBD) stones, using standard risk criteria. The aim of this study was to evaluate prospectively a scoring system designed to improve the accuracy of CBD stone prediction before laparoscopic cholecystectomy. METHODS: Known clinical, biochemical and radiological risk factors for CBD stones were analysed retrospectively in 233 patients. The presence (n = 77) or absence (n = 156) of CBD stones was determined by preoperative ERCP and/or laparoscopic cholangiography. Using multivariate analysis, the significant risk factors for CBD stones were identified and a new preoperative scoring system was developed. A score of 3 or more was taken as the cut-off point to suggest CBD stones and the need for preoperative ERCP. This scoring system was then tested prospectively in 211 consecutive patients with symptomatic gallstones requiring surgery. Patients whose bile ducts could not be demonstrated by ERCP or operative cholangiography were excluded. RESULTS: Fifty-five patients scored 3 or more (predicted ERCP rate of 29 per cent), of whom 23 (42 per cent) had proven CBD stones. Intraoperative cholangiography was successful in 87 per cent. Five patients (4 per cent) who scored less than 3 had small stones (less than 5 mm) demonstrated at operative cholangiography. The overall sensitivity and specificity of this scoring were 82 and 80 per cent respectively. CONCLUSION: Formal risk assessment of the presence of CBD stones using this scoring system is simple and may be used for preoperative selection of patients for biliary tract imaging by magnetic resonance cholangiography or ERCP.

Gender differences in sweat lactate.

Sweat rate may affect sweat lactate concentration. The current study examined potential gender differences in sweat lactate concentrations because of varying sweat rates. Males (n = 6) and females (n = 6) of similar age, percentage body fat, and maximal oxygen consumption (VO2max) completed constant load (CON) cycling (30 min--approximately 40% VO2max) and interval cycling (INT) (15 1-min intervals each separated by 1 min of rest) trials at 32 (1) degrees C wet bulb globe temperature (WBGT). Trials were preceded by 15 min of warm-up (0.5 kp, 60 rpms) and followed by 15 min of rest. Blood and sweat samples were collected at 15, 25, 35, 45, and 60 min during each trial. Total body water loss was used to calculate sweat rate. Blood lactate concentrations (CON approximately equal to 2 mmol.l-1, INT approximately equal to 6 mmol.l-1) and sweat lactate concentrations (CON and INT approximately equal to 12 mmol.l-1) were not significantly different (P > 0.05) at any time between genders for CON or INT. Overall sweat rates (ml.h-1) were not significantly different (P > 0.05) between trials but were significantly greater (P < or = 0.05) for males than for females for CON [779.7 (292.6) versus 450.3 (84.6) ml.h-1] and INT [798.0 (268.3) versus 503.0 (41.4) ml.h-1]. However, correcting for surface area diminished the difference [CON: 390.7 (134.4) versus 277.7 (44.4) ml.h-1, INT: 401.5 (124.1) versus 310.6 (23.4) ml.h-1 (P < or = 0.07)]. Estimated total lactate secretion was significantly greater (P < or = 0.05) in males for CON and INT. Results suggest that sweat rate differences do not affect sweat lactate concentrations between genders.

Effects of high and low blood lactate concentrations on sweat lactate response.

Sweat lactate results from eccrine gland metabolism, however, the possible clearance of blood lactate through sweat has not been resolved. On separate days in an environmental chamber (32 +/- 1 C) 12 subjects completed a constant load (CON) (30 min at 40% VO2 max) and an interval cycling trial (INT) (15 one-min intervals at 80% VO2 max, each separated by one min rest) each designed to elicit different blood lactate responses. Each 30 min cycling trial was preceded by 15 min warm-up (30 watts) and followed by 15 min passive rest. Sweat and blood were analyzed for lactate concentration at 15, 25, 35, 45, and 60 min during CON and INT. Total body water loss was used to calculate sweat rate (ml/hr). Blood lactate was significantly greater (p < or = 0.05) at 25, 35, 45, and 60 min during INT compared to CON (approximately 5 mmol/L vs 1.5 mmol/L). Sweat lactate was not significantly different (p>0.05) between trials at any time (approximately 10 mmol/L). Sweat rates (approximately 600ml/hr) and estimated total lactate secretion were not significantly different (CON vs. INT) (p > 0.05). Elevated blood lactate was not associated with changes in sweat lactate concentration. Sweat lactate seems to originate in eccrine glands independent of blood lactate.

Effect of a static calf-stretching exercise on the resistive torque during passive ankle dorsiflexion in healthy subjects.

STUDY DESIGN: A within-subject experimental design was used with to measure the effect of calf-stretching exercises on the resistive torque during passive ankle dorsiflexion in a group of 20 healthy men (aged 21 to 40). OBJECTIVES: The purpose of this study was to determine if the performance of calf-stretching exercises would produce a decrease in resistive torque during passive ankle dorsiflexion. BACKGROUND: Calf-stretching exercises are widely used in sporting, fitness, and rehabilitation settings yet the effects of stretching on the passive mechanics of the ankle joint are not well understood. METHODS AND MEASURES: A KIN-COM isokinetic dynamometer was used to measure the passive resistive torque of the ankle while the joint complex was moved through return cycles from 10 degrees plantarflexion to 10 degrees dorsiflexion at a constant velocity of 6 degrees/s. Each subject's right or left ankle was randomly assigned to either a control or an experimental condition. The latter underwent a total of 4 static stretches, each lasting 30 seconds. RESULTS: The main findings of the study were that the calf-stretching exercises did not produce a significant reduction in the resistive torque during ankle dorsiflexion, as measured by the peak to peak torque at 10 degrees of ankle dorsiflexion or in the center range of the hysteresis loop at 0 degree dorsiflexion. CONCLUSION: Static calf-stretching exercises of short duration did not reduce the passive resistance of the connective tissue within the surrounding muscle and joint structures in the ankles of healthy young men.

Effects of a novel ice-cooling technique on work in protective clothing at 28 degrees C, 23 degrees C, and 18 degrees C WBGTs.

This study tested a new ice cooling system that permits ice cooling system recharge without personal protective clothing removal. Six male volunteers (22.1 +/- 1.2 years) underwent tests with the new ice cooling system (COOL) and without (NOCL) at a moderate work rate (450 W) in three environments of 28, 23, and 18 +/- 1 degrees C wet bulb globe temperature. Walks at 28 degrees C were carried out first with NOCL and COOL counterbalanced, then test order and environment were counterbalanced. At 28 degrees C, mean work time in COOL significantly increased by 37.5 min (188%) over NOCL (p < 0.05). At 23 degrees C mean work time in COOL was significantly increased by 44.3 min (171%) compared with NOCL (p < 0.05). Mean work times at 18 degrees C were not significantly different, although all subjects completed the 120 minutes of work in COOL compared with a mean work time of 109 +/- 20 min for NOCL. During rest, mean reductions in rectal temperature were significantly greater in COOL than NOCL (p < 0.05) at 28 and 23 degrees C. Mean heart rate calculated for the same point in both treatments was significantly lower for COOL at 28, 23, and 18 degrees C (p < 0.05). Thermal comfort rating was significantly different at 18 and 23 degrees C (p < 0.05). This new design seemed to provide comparable cooling to conventional vests and also provides greater practicality for field use. Even in experimental form the suit demonstrated increased productivity due to extended tolerance time.

Laparoscopic cholangiography: a prospective study.

BACKGROUND: The place of cholangiography has been controversial in the conventional and now in the laparoscopic setting. The aim of this study was to evaluate laparoscopic cholangiography and compare use of a portable C-arm image intensifier with conventional radiography. METHODS: One hundred and ninety-seven consecutive patients undergoing laparoscopic cholecystectomy were randomized before operation to cholangiography by either C-arm image intensifier or conventional radiography. Data were collected on a pro forma completed immediately after the operation. RESULTS: Cholangiography was successful in 93.0 per cent of patients. Cholangiography with an image intensifier was significantly faster. In 19 patients the ductal system was obscured by a cannula; in 17 of these cases a metal cannula was used. In 31.6 per cent of patients the clip on the cystic duct was within 1 cm or less of the common bile duct (CBD). CONCLUSION: Laparoscopic cholangiography is a safe procedure. Use of an image intensifier should be the preferred method of obtaining images. Metal cannulas are more likely to obscure the ductal system. The proximity of the clip on the cystic duct to the CBD highlights the potential for injury caused by electrocautery or erroneous clip application.

Growth inhibition of cultured fibroblasts by extracts from human dermis.

In incised wounds and deep partial thickness burns the resident fibroblasts in the dermis remain inactive. The fibroblasts responsible for repair at the dermal level come from the subdermal layer. The hypothesis is that the inactivity of the dermal fibroblasts is due to an inhibitory substance in the dermis. To test this hypothesis extracts were made of normal dermis and of mature scar tissue and these extracts were applied to fibroblasts growing in monolayer culture. Both extracts and cells were obtained from human tissue. It was shown that extracts, particularly the extract made with citric acid/citrate buffer, pH 3.5, caused inhibition of fibroblast growth. Present evidence suggests that the active principle may be a proteoglycan.

Effects of plane mechanical forces in wound healing in humans.

The effects of the application of external forces acting in the plane of the skin on early scars during healing were investigated. A simple apparatus was developed for this purpose. The scars were followed up for a minimum of 12 months postoperatively and all settled well.

Aggressive pilomatricoma in childhood.

Pilomatricoma (calcifying epithelioma) is a benign tumor of the hair matrix cells that presents most frequently in childhood. Most are benign and slow growing and do not recur after excision. A small number of aggressive or malignant variants have been reported that recur if not widely excised. We report on an aggressive variant occurring in a 4-year-old boy and advise caution in treating cutaneous "cysts."