Peripartum anesthetic management of a patient with brittle cornea syndrome.

Brittle cornea syndrome (BCS) is a rare autosomal recessive disease that affects the connective tissue. The syndrome is caused by genetic changes in the 4.7-Mb interval between the D16S3423 and D16S3425 markers on the 16q24 chromosome and mutations in the Zinc-Finger 469 gene (ZNF469). BCS is characterized by thin and fragile cornea that tends to perforate spontaneously or as a result of minor trauma to the eye. In addition, the patient usually suffers from hearing loss, mental retardation, hyperextensibility of skin and joints, as well as varying degrees of scoliosis. This phenotypical expression presents an interesting challenge to anesthetic care. We briefly present the perioperative management of a patient with BCS who underwent three cesarean sections.

The association between the renin-angiotensin-aldosterone system and arterial stiffness in young healthy subjects.

Aldosterone might affect arterial stiffening, in both the short- and long-term. We investigated a possible association between excess aldosterone, reflected by an increased aldosterone : renin ratio (ARR) and pulse wave velocity (PWV) in young healthy adults. In a single-centre study, 60 subjects were evaluated for lipid profile, glucose, hs-CRP, renin and aldosterone. PWV was performed as a simple non-invasive recording and computer analysis of the two artery sites pressure waveform using SphygmoCor (version 7.1, AtCor Medical, Sydney, Australia). The ARR was significantly, positively associated with PWV: r = 0.298, P = 0.02. ARR was not associated with anthropometric variables, blood pressure (BP), metabolic and inflammatory parameters. In conclusion, the ARR was significantly associated with PWV and may exhibit direct effects of aldosterone on the vascular wall, which are not related to changes in conventional cardiovascular risk factors.

Psoriasis and diabetes: a population-based cross-sectional study.

BACKGROUND: Previous reports have shown an association between psoriasis and the metabolic syndrome, but there are only a few studies on the association between psoriasis and diabetes. OBJECTIVES: To study the association between psoriasis and diabetes. METHODS: A cross-sectional study was performed utilizing the database of Clalit Health Services (CHS). Patients who were diagnosed with psoriasis were compared with CHS enrolees without psoriasis regarding the prevalence of diabetes. Patients with diabetes were identified using the CHS chronic diseases registry. Chi-squared tests were used to compare categorical parameters. Logistic regression models were used for multivariate analyses. RESULTS: The study included 16 851 patients with psoriasis and 74 987 subjects without psoriasis (control patients). The proportion of diabetes was significantly higher in patients above 35 years (P < 0.05). The age-adjusted proportion of diabetes was significantly higher in psoriasis patients as compared to the control group [odds ratio (OR), 1.38, P < 0.05] and was similar in men and women (OR, 1.32, 1.45, respectively). A multivariate logistic regression model showed that psoriasis was significantly associated with diabetes, independently of age and gender (OR, 1.58, P < 0.001). CONCLUSIONS: Our study supports previous reports of an association between psoriasis and diabetes. Dermatologists taking care of patients with psoriasis should be aware of this association and advise the patients to reduce additional risk factors such as smoking, hypertension or dyslipidemia.

Heat intolerance induced by antidepressants.

A case in which prescription medications induced heat intolerance which led to heat stroke is presented. A subject who suffered from depression and was treated with fluoxetine HCL (prozac) and lithium carbonate was engaged in mild intermittent work for 4 hours under hot/dry climatic conditions (Ta = 37 degrees C, rh = 15%). The subject lost consciousness, was hyperthermic and suffered from disseminated intravascular coagulation. A year later residual cerebellar symptoms were still evident and severe atrophy of the cerebellar tissue was demonstrated in a CT scan. It is suggested that drug-induced heat intolerance was the predisposing factor that reduced the patient ability to sustain exercise-heat stress, and under the favorable environmental circumstances led to excessive heat accumulation which ultimately caused heat stroke. This is the first description, to our knowledge, of heat intolerance of a patient treated by a combination of fluoxetine and lithium carbonate.

Effect of an acute bout of exercise on glucose disposal in human obesity.

The effect of acute exercise on insulin action has been studied in six obese (150-250% ideal body weight) non-insulin-dependent diabetics (OD), seven obese normoglycemics (ON), and six lean healthy controls (LC). Using a three-stage euglycemic clamp, the metabolic clearance rate (MCR) of glucose under increasing insulin concentrations was measured. The insulin dose-response curve was assessed on two separate occasions: 1) a base-line test and 2) 1 h after aerobic treadmill exercise at a steady-state heart rate of 150-160 beats/min. In the base-line test, under all insulin levels, glucose MCR was significantly lower in obese compared with lean individuals (P less than 0.01). Exercise increased glucose MCR at the highest hormonal concentrations applied to 124 and 134% of base line in OD and in ON, respectively (P less than 0.05); the insulin concentration required for one-half of the maximal clearance rate of glucose achieved in this study decreased from 200 to 130 and from 160 to 95 microU/ml in OD and ON, respectively (P less than 0.05). The changes in these parameters were insignificant in LC. It is suggested that acute exercise affected the insulin dose-response curve in OD and in ON but not in LC; although enhanced by exercise, glucose MCR remained significantly lower in both obese groups compared with control subjects. We concluded that insulin resistance, which accompanies extreme obesity, could be markedly decreased but not completely reversed by one bout of exercise.

Predicting heart rate response to various metabolic rates, environments, and clothing.

A mathematical model that describes heart rate (HR) responses to different combinations of metabolic levels, climatic conditions, and clothing ensembles was developed. The database that served to construct the model consisted of 48 variations representing a wide range of environmental conditions, clothing ensembles, and metabolic rates. The model, which correlates highly with the observed values (r = 0.88, P < 0.0001), is based on physiological and environmental parameters: HR = 57.1 + 0.6HRi + [0.07M - 19.06 - 0.011(Emax - Ereq)] log t, where HRi is initial HR in beats per minute (at rest before the exposure), t is the time of exposure in minutes, M is the metabolic rate in watts, Ereq is the required sweat evaporation for thermal equilibrium in watts, and Emax is the maximal evaporative capacity of the environment in watts. The model's validity was tested by using two independent databases representing wide ranges of conditions; the correlation between measured and predicted values was found to be highly significant (r = 0.83, P < 0.001 and r = 0.77, P < 0.001, respectively). In summary, the present study suggests a valid predictive model for HR that overcomes some of the difficulties observed in other models.

Behavioral evidence for the existence of two pools of cellular inositol.

Lithium reduces brain inositol levels by inhibiting inositol monophosphatase. In a previous study it was found that administration of pilocarpine to Li-treated rats causes limbic seizure behavior which can be reversed by i.c.v. myo-inositol but not chiro-inositol, suggesting that this behavior is related to inositol depletion in the PI cycle. Hyponatremia can lower brain inositol and hypernatremia can raise brain inositol. We now report that induction of low brain inositol by hyponatremia followed by pilocarpine did not cause limbic seizures. Induction of high brain inositol using hypernatremia followed by Li-pilocarpine administration did not reverse limbic seizures. These data support the concept that inositol available for P1 synthesis and inositol for osmotic function are sequestered in different cellular pools.

The effect of standardised submaximal work load on intraocular pressure.

A relatively small decrease in intraocular pressure secondary to submaximal work can be demonstrated when factors other than the work load itself are eliminated--diurnal variation, body position, and the effect of repeated examinations. A feedback mechanism that causes a return of IOP towards its normal value after work-induced decreases is postulated.

Intervesicular phospholipid exchange. An NMR study.

Phospholipid exchange between phosphatidylinositol and phosphatidylcholine ?vesicles has been studied by NMR spectroscopy with use of hydrophilic paramagnetic lanthanide probes (Pr-3+ and Eu-3+ ions). The dependence of the lanthanide induced shifts in the1-H and 31-P NMR spectra on the phospholipid composition of the vesicles could be used for its quantitative evaluation. The method has been proved to be applicable for studying phospholipid exchange stimulated by soluble proteins (postmicrosomal supernatant fraction) from rat liver. Furthermore it has been shown that the phospholipid molecules newly introduced by protein-stimulated exchange are predominantly incorporated into the outermonolayer of the vesicular bilayer membrane. This makes it possible to produce liposomes with asymmetric distribution of the phospholipids across the bilayer.

13-C NMR investigation of phospholipid membranes with the aid of shift reagents.

13-C NMR spectra of sonicated phospholipid dispersions have been investigated with the aid of paramagnetic ions (Pr-3+) as shift reagents. This method permits discrimination between the outer and the inner surfaces of the vesicular membrane and gives a larger variety of signals than 1-H NMR. The lanthanide induced shifts have been found to depend on other ions present and on the lipid composition of the membrane.

Field and clinical observations of exertional heat stroke patients.

Exertional heatstroke (EH) occurs when heat production, generated by muscular exercise, exceeds the body's heat dissipation capacities. This illness has been reported among young, active individuals, laborers, and religious pilgrims. Although EH includes a rectal temperature above 39.5 degrees C (depending on the timing of the measurement) and elevation of serum enzymes, altered mental status is the universally accepted sign which distinguishes EH from heat exhaustion. Once EH is suspected, cooling therapy should be initiated immediately and investigation of multiple-system involvement should be undertaken. Delay in diagnosis occurs more commonly in moderate environments, when suspicion of EH is low. Complications of EH include the central nervous, cardiovascular, pulmonary, and gastrointestinal systems, often with renal and hematologic involvement. Treatment at the point of collapse should focus on clearing the airway, measurement of rectal temperature, whole body cooling, intravenous therapy, and prompt evacuation. Hospital treatment should emphasize whole body cooling, control of convulsions, monitoring of acid-base status, cardiac function, and renal function. The incidence of EH has been reduced markedly in Israel, by using the following simple guidelines: rest periods during exercise in heat, medical monitoring of strenuous activities, use of meteorological indices, and evaluation of medical history.

The effects of glucose polymer beverage ingestion during prolonged outdoor exercise in the heat.

The aim of this study was to examine the effect of ingestion of a glucose polymer drink on fluid and metabolic balance during a 30 km outdoor march in the heat (ambient temperature, 26-31 degrees C; relative humidity, 53-34%). The subjects were randomly assigned to one of three groups: 7.2% glucose polymer-electrolyte beverage (GP) (N = 16), flavored sweetened placebo drink (SP) (N = 15), and tap water (TW) (N = 18). The subjects in the three groups consumed similar volumes of fluid, and no differences were found in sweat rate and percent dehydration. Changes in plasma volume were smaller, though not statistically significant, for GP than for SP and TW (-2.8%, -5.4%, -9.4%, respectively). Changes in sodium concentrations and serum osmolality were similar in the three groups. Subjects consuming GP maintained during exercise a significantly higher (P less than 0.001) blood glucose concentration (range: 6.5-7.4 mmol.l-1) than the SP and TW groups. They were also found to have increased levels of serum insulin (29.3 +/- 18.5 mU.l-1) and no change in serum free fatty acids (0.52 +/- 0.19 mmol.l-1). In contrast, subjects ingesting SP or TW had significantly elevated (P less than 0.001) concentrations of free fatty acids (range: 1.35-1.74 mmol.l-1) compared with subjects consuming GP (0.35-0.52 mmol.l-1), with no significant change in blood glucose and serum insulin levels over the exercise period. We conclude that highly trained endurance athletes may maintain a higher blood glucose level by consuming GP during prolonged exercise in the heat without impairing fluid replacement.

Exertional heat stroke: a case series.

UNLABELLED: Exertional heat stroke (EHS) is a state of extreme hyperthermia that occurs when excess heat that is generated by muscular exercise exceeds the body's ability to dissipate it at the same rate. EHS is thought to coincide with previously healthy, highly motivated, and relatively untrained individuals exerting in hot environments for long periods. PURPOSE: To establish this notion, the present study was aimed to follow the trends in the incidence of EHS in the period 1988-1996. METHODS: During these years, 150 cases of male soldiers (age = 20+/-3 yr) were reported to our institute as suffering from heat illnesses. According to the files, 82 cases were definitely diagnosed as EHS. RESULTS: More than 50% of the cases occurred during the first 6 months in service. Most of the cases occurred during the summer season (June-September), but 30% of the cases occurred during the spring. EHS was not related to time in the day. Many cases occurred during the night or early morning, even under mild heat load. Forty percent of the cases occurred during very short activities, and about 60% occurred already during the first 2 h of exercise. The results were discussed in view of the regulations which prevail in the Israeli army. CONCLUSIONS: It seems that almost all EHS cases occurred when regulations were not strictly followed.

High-dose peripheral inositol raises brain inositol levels and reverses behavioral effects of inositol depletion by lithium.

Lithium (Li) reduces brain inositol levels. Berridge has suggested that this effect is related to Li's mechanism of action. It had previously been shown that pilocarpine causes a limbic seizure syndrome in lithium treated rats, and that these lithium-pilocarpine seizures are reversible by intracerebroventricular inositol administration to rats. We now show that although inositol passes the blood-brain barrier poorly, large doses of intraperitoneal (IP) inositol can also reverse Li-pilocarpine seizures. Using gas chromatography, IP inositol can raise brain inositol levels. Demonstration that inositol enters brain after peripheral administration provides a basis for possible pharmacological intervention in psychiatric disorders at the level of second messengers linked to the phosphatidylinositol cycle.

Scoliosis in young men with spondylolysis or spondylolisthesis. A comparative study in symptomatic and asymptomatic subjects.

While an increased incidence of scoliosis in symptomatic spondylolysis and spondylolisthesis has been established previously, a comparison of its occurrence in symptomatic and asymptomatic individuals has not been performed. The present study is a comparison of symptomatic and asymptomatic young men with analysis as to the incidence of scoliosis. Idiopathic scoliosis was not found and all cases were due to spasm scoliosis or olisthetic scoliosis with the spasm type being much more common. Scoliotic curves were divided into mild (0-9 degrees) and moderate (10-20 degrees). No case of a curve greater than 20 degrees was seen. Scoliosis incidence in asymptomatic individuals without a pars break was 6.65%. In the groups of: (1) asymptomatic unilateral spondylolysis, (2) asymptomatic bilateral spondylolysis, (3) symptomatic bilateral spondylolysis, and (4) asymptomatic spondylolisthesis the scoliosis incidence was similar, ranging from 13.3-23.8%. These figures are significantly higher than those seen in the asymptomatic subjects without a pars break, but they are in the same range as in symptomatic patients without a pars break, suggesting that muscle spasm is the principal cause of the scoliosis.

Significance of bone scintigraphy in symptomatic spondylolysis.

In a prospective study, the authors evaluated the usefulness of bone scintigraphy in the work-up of young military personnel with lumbar spondylolysis and persistent low back pain. Ten out of 23 spondylolytic individuals with a recent history of low back pain had positive scintigrams, and none of a group of painless spondylolytic individuals had positive scans. We believe these results indicate that bone scintigraphy is of value in determining whether a spondylolysis in a young individual can be attributed to recent physical exertion or a specific recent traumatic incident.

Peripheral target contact regulates Ca2+ channels in the cell bodies of bullfrog sympathetic ganglion B-neurons.

Tyrosine-hydroxylase immunohistochemistry demonstrated that a single injection of 120 mg/kg 6-hydroxydopamine (6-OHDA) reversibly disconnected bullfrog sympathetic ganglia from their peripheral targets. This was correlated with a decrease in sympathetic outflow to the eyes and a reversible decrease in pupil diameter. 6-OHDA did not damage the cell bodies of ganglionic neurons. Calcium channel current in ganglionic B-neurons, (measured at -10 mV; holding potential -60 mnV; Ba2+ as charge carrier; IBa) was reduced. It reached a minimum of about 40% of control amplitude 7-14 days after 6-OHDA injection and recovered to 73% of control amplitude after 63 days. 6-OHDA induced loss and recovery of functional sympathetic innervation of peripheral target tissues, as determined by measurement of pupil diameter, occurred at a similar rate. Thus, pupil diameter attained mininum values 7-14 days after 6-OHDA treatment and recovered to 81% of control after 63 days. The properties of Ca2+ channels in sympathetic neurons are, therefore, determined by continuity of contact with peripheral target. 6-OHDA also decreased the peak amplitude and duration of the afterhyperpolarization (a.h.p) that follows the action potential (a.p.). The rate of recovery of a.h.p duration was more rapid than the rate of recovery of peak a.h.p. amplitude. This may reflect known differences in properties of two types of Ca2+-sensitive K currents. IC and IAHP, IC, which is responsible for the peak amplitude of the a.h.p has a low affinity for Ca2+, whereas IAHP, which determines a.h.p. duration, has higher Ca2+ affinity.

Vasopressin in thermoregulation--competitive demands: experimental evidence and theoretical considerations.

Previous studies have substantiated the antipyretic role played by extrahypothalamic limbic system (EXHY-LS) AVP during fever. Repeated attempts to elucidate other thermoregulatory functions of this hormone have failed. Circumstantial evidence, however, suggest central role for this hormone in thermoregulation under hypohydration. Hypohydration, hyperosmolarity and hypovolaemia induced upward shifts in temperature thresholds for activation of heat dissipating mechanisms. When hypovolaemia is superimposed on hyperosmolarity these shifts are additive. Analogously, these two stressors when combined, decrease the osmotic threshold for AVP release. In rats, the elevated temperature thresholds for evaporative cooling and peripheral vasodilation occurring with hypohydration are positively correlated with lower Hypothalamic/EXHY-LS AVP ratio. Reciprocal relations between limbic system and blood AVP contents suggest competitive interaction between central and peripheral demands. Hypothesis for the possible mode of action of central AVP in thermoregulation under hypohydration is discussed.

Heat tolerance in patients with extensive healed burns.

Some thermoregulatory parameters of 10 subjects with healed burns were studied. The subjects, 4 of whom had healed burns of over 40 percent (group A) and 6 with burns smaller than 30 percent (group B) were assigned in a climatic chamber to 3 hours bench stepping (30 cm height) under 40 degrees C and 50 percent relative humidity. Rectal temperature, weighted skin temperature, heat storage, and heart rate were all found to be significantly higher in group A than in group B or group C (control group of normal subjects). No significant difference was observed between groups B and C. A highly significant linear correlation (r = 0.89) was found between the sweat rate and percentage of burned area. In addition, 3 subjects of group A terminated the study after less than 90 minutes. Two subjects in group B terminated the study after 120 and 135 minutes, while all subjects of group C finished the entire 3 hour work. The study indicates that subjects with burns of over 40 percent could be classified as heat intolerant due to a pronounced reduction in perspiration area.

Fatal heatstroke after a short march at night: a case report.

A case of heatstroke is reported in a young recruit who participated in a 4-km march at night. Body temperature was not measured at the time of collapse. Hyperventilation and aggressive behavior misled to the incorrect diagnosis of hysteric reaction. Upon arrival at the Medical Center 4h later, the patient experienced deep coma, renal failure, shock, and uncontrolled bleeding. Inspite of intensive treatment, the patient died 27 h after collapse. A positive blood culture suggests the involvement of septicemia in the fulminant picture of the disease. The importance of immediate measurement of rectal temperature in any case of collapse after exercise is emphasized.