Recurrent bilateral renal calculi in a tetraplegic patient

An 18-year-old male developed C-5 complete tetraplegia following a motor-cycle accident in May 1975. The neuropathic bladder was managed by an indwelling urethral catheter. He developed recurrent episodes of urinary infection with Proteus species. In September 1975, an X-ray of the abdomen revealed small calculi in both the kidneys. In July 1976, he underwent transurethral resection of the bladder neck and division of the external urethral sphincter; subsequently, he was put on a penile sheath drainage. He continued to suffer from repeated episodes of urinary tract infection with Proteus, Providencia, and Pseudomonas species, and he was treated with antibiotics. In 1980, intravenous urography (IVU) showed two large stones in the left kidney with marked caliectasis. The IVU performed in 1984 showed an increase in the size of the calculi in the left kidney which was grossly hydronephrotic. There were clusters of small calculi in the right kidney. The left renal calculi were treated by percutaneous lithotripsy in two sessions. In 1988, an X-ray of the abdomen revealed staghorn calculus in the right kidney and recurrence of stones in the left kidney. The staghorn calculus in the right kidney was treated by percutaneous nephrostolithotomy in two sessions. In 1991, he was admitted with acute urinary infection. IVU showed a stone in the pelviureteric junction with no excretion of contrast in the left kidney. Percutaneous nephrostomy drainage was established followed by left percutaneous nephrostolithotomy. In 1992, he was found to retain large amount of urine in the bladder; subsequently, his mother was taught to perform regular intermittent catheterisations. In 1995, he was admitted with acute urine infection. Abdominal X-ray revealed recurrence of large stones in both kidneys. With multiple sessions of Extracorporeal Shockwave Lithotripsy (ESWL), about 80% clearance was achieved on the left side. Right staghorn renal stone awaits treatment. This case shows that recurrent urinary infection in spinal cord injury patients is a predisposing factor for renal lithiasis. These patients require annual urological evaluation. Urinary tract calculi, if detected, should be dealt with promptly to prevent renal damage due to urinary obstruction and urosepsis. Renal calculi can be treated effectively and safely by ESWL in spinal cord injury patients, thus avoiding the need for an invasive procedure. It is essential to achieve low-pressure, adequate emptying of the urinary bladder in patients with spinal cord injury in order to prevent recurrent urinary infection and its sequelae. Social issues involved in the care of a tetraplegic patient play a vital role in the implementation of ideal medical treatment and need to be addressed promptly to avoid any compromise in the quality of medical care.     

Factors which alter the relationship between ventilation and carbon dioxide production during exercise in normal subjects

The slope of the linear relationship between ventilation (V(E)) and carbon dioxide production (VC0(2)) has been thought to indicate that VC0(2) is one of the major stimuli to V(E). A group of 15 normal subjects undertook different incremental treadmill exercise protocols to explore the relationship between V(E) and VCO(2). An incremental protocol using 1 instead of 3-min stages of exercise resulted in an increase in the V E to VCO(2) ratio [26.84 (SEM 1.23) vs 31.08 (SEM 1.36) (P <0.008) for the first stage, 25.24 (SEM 0.86) vs 27.83 (SEM 0.91) (P <0.005) for the second stage and 23.90 (SEM 0.86) vs 26.34 (SEM 0.81) (P = 0.001) for the third stage]. Voluntary hyperventilation to double the control level of V(E) during exercise resulted in an increase in the V(E) to VCO(2) slope [from 21.3 (SEM 0.71) for the control run to 35.1 (SEM 1.2) for the hyperventilation run (P <0.001)]. Prolonged hyperventilation (5 min) during exercise at stage 2 of the Bruce protocol resulted in a continued elevation of VCO(2) and the V(E)/VCO(2) slope. A steady state of V(E) and metabolic gas exchange can only be said to have been present after at least 3 min of exercise. Voluntary hyperventilation increased the slope of the relationship between V(E) and VCO(2). End-tidal carbon dioxide fell, but remained within the normal range. These results would suggest that a non-carbon dioxide factor may have been responsible for the increase we found in V(E) during exercise, and that factors other than increased dead space ventilation can cause an increased ventilation to VCO(2) slope, such as that seen in some pathophysiological conditions, such as chronic heart failure.     

Glutathone and glutathione ethyl ester supplementation of mice alter glutathione homeostasis during exercise

The present study examined the effect of glutathione (GSH) and glutathione ethyl ester (GSH-E) supplementation on GSH homeostasis and exercise-induced oxidative stress. Male Swiss-Webster mice were randomly divided into 4 groups: starved for 24 h and injected with GSH or GSH-E (6 mmol/kg body wt, i.p.) 1 h before exercise, starved for 24 h and injected with saline (S); and having free access to food and injected with saline (C). Half of each group of mice was killed either after an acute bout of exhaustive swimming (E) or after rest (R). Plasma GSH concentration was 100-160% (P < 0.05) higher in GSH mice vs. C or S mice at rest, whereas GSH-E injection had no effect. Plasma GSH was not affected by exercise in C or S mice, but was 44 and 34% lower (P < 0.05) in E vs. R mice with GSH or GSH-E injection, respectively. S, GSH- and GSH-E-treated mice had significantly lower liver GSH concentration and the GSH:glutathione disulfide (GSSG) ratio than C mice. Hepatic and renal GSH and the GSH:GSSG ratio were significantly lower in E vs. R mice in all groups. GSH-E-treated mice had a significantly smaller exercise-induced decrease in GSH vs. C, S, and GSH-treated mice and no difference in the GSH:GSSG ratio in the kidney. Activities of gamma-glutamylcysteine synthetase and gamma-glutamyltranspeptidase in the liver and kidney were not affected by either GSH treatment or exercise. GSH concentration and the GSH:GSSG ratio in quadriceps muscle were not different among C, S and GSH-treated mice, but significantly lower in GSH-E-treated mice (P < 0.05). Hepatic malondialdehyde (MDA) content was greater in exercised mice in all but GSH-E-treated groups. GSH and GSH-E increased MDA levels in the kidney of E vs. R mice, but attenuated exercise-induced lipid peroxidation in muscle. Swim endurance time was approximately 2 h longer in GSH (351 +/- 22 min) and GSH-E (348 +/- 27) than S mice (237 +/- 17). We conclude that 1) acute GSH and GSH-E supplementation at the given doses does not increase tissue GSH content or redox status; 2) both GSH and GSH-E improve endurance performance and prevent muscle lipid peroxidation during prolonged exercise; and 3) while both compounds may impose a metabolic and oxidative stress to the kidney, this side effect is smaller with GSH-E supplementation.     

Gorlin's syndrome: the role of the carbon dioxide laser in patient management

The treatment of multiple basal cell carcinomas in patients with Gorlin's syndrome presents a therapeutic challenge. The carbon dioxide laser presents a unique treatment option due to increased surgical speed, a bloodless operating field, reduced postoperative pain and discomfort, and acceptable scars. Six patients with Gorlin's syndrome have been treated with the carbon dioxide laser. Between 14 and 110 lesions were treated in one session under local anesthesia. Pre- and postlaser biopsies of the lesions confirm complete eradication of the tumors. Mean follow-up is 20 months. No local recurrence has been observed.     

钢铁生产过程二氧化碳排放计算方法与实践

 钢铁生产过程二氧化碳排放量的精确计算是钢铁行业节能减排的基础。对钢铁生产流程二氧化碳排放的3种常用温室气体排放计算方法进行介绍,并基于A钢厂2014年的生产数据进行计算和分析对比。《省级温室气体清单编制指南》、《钢铁碳排放指南》两种计算方法都是基于投入产出的统计方法,两者温室气体计算结果数值相近,前者吨钢二氧化碳排放结果为2.116 t,后者吨钢二氧化碳排放结果为2.013 t ,后一种方法在计算时考虑了固碳产品的抵扣,所以结果比前种方法结果偏小。基于ISO标准的钢铁产品生命周期计算方法,计算边界从铁矿石、煤炭等原材料的采掘、洗选、运输,焦化,烧结,高炉,炼钢,轧制等直到钢铁产品的出厂,计算结果吨钢产品二氧化碳排放量为2.309 t,相比前两种方法计算结果数值较大,这是因为在计算时包含了铁矿石、煤炭等在开采、洗选、运输阶段产生的二氧化碳。     

Expression of myosin isoforms in denervated, cross-reinnervated, and electrically stimulated rabbit muscles

The expression of myosin heavy (MyHC) and light (MyLC) chain isoforms was analyzed after denervation and cross-reinnervation by a fast nerve of the slow-twitch Semimembranosus proprius (SMp) muscle, and after denervation and electrical stimulation at low frequency of the fast-twitch Semimembranous accessorius (SMa) muscle of the rabbit. The control SMp (100% type I fibers) expressed 100% type I MyHC and 100% slow-type (1S', 1S and 2S) MyLC isoforms. Five month denervation did not alter significantly the MyHC expression of the muscle, but induced the expression of a new type 1 MyLC corresponding most probably to an embryonic MyLC. Five-month cross-reinnervation of the SMp by the fast SMa nerve induced a large change of its fiber type properties. As shown by immunocytochemistry, almost all fibers were stained by fast myosin antibody, but a high proportion of them co-expressed slow myosin. This result was in agreement with biochemical data showing that fast MyHC and MyLC isoforms became predominant. The control SMa (nearly 100% type II fibers) expressed almost 100% type II MyHC (70% type IIb and 22% IIx/d) and 100% fast-type (1F, 2F and 3F) MyLC isoforms. Five month denervation of the SMa induced a shift in its MyHC, with 98% type IIx/d and 2% type IIb isoforms, and no change in the proportions of its MyLC. Three month electrical stimulation at 10 Hz of the SMa transformed its fiber type composition. All fibers reacted with the slow myosin antibody and a minor proportion of them were stained by the fast myosin antibody. These observations were in agreement with the biochemical analysis showing a large predominance of the slow-type MyHC and MyLC isoforms. Taken together, these results obtained from rabbit muscles which are normally homogeneous in either fast-twitch or slow-twitch fiber types, further support the idea that the different myosin isoforms, particularly the MyHC, are differentially regulated by motor innervation. Type I MyHC is maintained in denervated SMp muscle, but is not expressed in denervated SMa. Type IIb isoform is the most sensitive to neural influence, as it disappears rapidly in denervated and electrically stimulated fast-twitch SMa muscle, and is barely expressed in cross-reinnervated slow-twitch SMp muscle. In contrast, type IIa and type IIx/d are less dependent upon motor innervation. In addition to the previous studies of d'Albis et al. analysis of these results leads us to conclude that, in the rabbit, sensitivity to motor innervation increases from the glycolytic to the oxydative types of fibers, in the order IIB > IIX/IID > IIA > I.     

Respiratory and thermoregulatory responses of rabbits breathing carbon dioxide during heat exposure

1. Rabbits were clipped and exposed in turn to three environmental conditions: control (C), cold exposure (CE) and water deprivation (WD). Following each type of treatment, the rabbits were exposed to an ambient temperature (Ta) of 35 degrees C for 1 hr. Throughout this period they breathed either normal atmospheric air or 6% CO2 in air. 2. During heat exposure, measurements were made of the respiratory responses and of the O2 consumption (Vo2) of the rabbits. Rectal temperature (Tre) was measured immediately before and again immediately after heat exposure. 3. When subjected to cold exposure or water deprivation the rabbits showed an initial decrease in respiratory frequency (RF) and an initial increase in VT when compared with controls. There was no difference in VE. Rabbits breathing 6% CO2 showed an increase in VT and VE and a decrease in RF when compared with rabbits breathing atmospheric air. In all cases a change in VT or RF was associated with a reciprocal change in the other parameter. 4. The respiratory responses to breathing 6% CO2 were essentially similar in treated and control rabbits, from which it is concluded that neither cold exposure nor water deprivation alter the sensitivity of the medullary respiratory centre to the respiratory drive from the central chemosensors. 5. The increase in Tre during heat exposure was significantly less in rabbits breathing 6% CO2 than in rabbits breathing atmospheric air. However, there was no significant over-all difference in VO2 between rabbits breathing CO2 and those breathing air. From this it is concluded that increased ventilation induced by CO2 causes a greater dissipation of heat than does thermally-induced panting. 6. It is concluded that VT is controlled by the level of blood PCO2 whereas RF is controlled by thermoregulatory requirements. It is further concluded that the reciprocal relationship between VT and RF is regulated in such a way as to maintain VE at the appropriate level for effecting gaseous exchange and evaporative heat loss.     

Ventilation/carbon dioxide production ratio in early exercise predicts poor functional capacity in congestive heart failure

Production of cytokines by immunocompetent cells in vitro may be assessed after stimulation with polyclonal activators. Because it mimics the natural environment, diluted whole blood (WB) culture may be the most appropriate milieu in which to study cytokine production in vitro. We tested TNF alpha production by small volume of whole blood (25 microliters) from HIV-1 positive patients by using a one-step procedure that combines WB stimulation with LPS and PHA and cytokine measurement. We studied 30 patients without secondary infection or at distance of secondary infection staged according to the classification proposed by the CDC and 12 healthy seronegative subjects. The mean values of TNF alpha from patients were not statistically different from those from normal controls however in certain patients at different stages of the disease higher values than the mean +2 SD of controls and lower values than the mean -2 SD of controls were obtained. Heparinized blood from 5 control subjects had been collected sequentially during a period of 5 months. The individual variation of TNF alpha production were limited for all these individuals. For each of 6 HIV-1 patients, whole blood samples were collected sequentially during a period of 5 months and in most of patients large variations of levels of TNF alpha were observed from one sample to another one. Our method can detect abnormal cytokine production in HIV-1 positive individuals and can become a useful tool to investigate the role of cytokines in the outcome of HIV-1 infection.     

Transcutaneous oxygen and carbon dioxide during treatment of critical limb ischemia with iloprost, a prostacyclin derivative

The effect of intravenous iloprost treatment (median rate: 1.6; range 1-2 ng/kg/min; 6 h daily over 4 weeks) on transcutaneous pO2 and pCO2 was studied in 8 patients with bilateral peripheral obstructive arterial disease and monolateral critical limb ischemia. Tensiometric determinations were obtained at both metatarsi in the supine and dependent position. In critically ischemic limbs, supine transcutaneous p)2 changed erratically during iloprost treatment, increasing in only three out of eight lower limbs. At variance with its inconsistent behavior in the supine position, dependent pO2 increased during drug administration (p<0.02). Transcutaneous pCO2 was unchanged by iloprost. In the contralateral, non-symptomatic limb, both supine and dependent pO2 values were increased by the drug, suggesting that systemic hemodynamic changes may participate in its effect on transcutaneous gas tension, even at infusion rates clinically titrated to avoid evident changes in blood pressure and heart rate.     

Exercise-induced overexpression of key regulatory proteins involved in glucose uptake and metabolism in tetraplegic persons: molecular mechanism for improved glucose homeostasis

Complete spinal cord lesion leads to profound metabolic abnormalities and striking changes in muscle morphology. Here we assess the effects of electrically stimulated leg cycling (ESLC) on whole body insulin sensitivity, skeletal muscle glucose metabolism, and muscle fiber morphology in five tetraplegic subjects with complete C5-C7 lesions. Physical training (seven ESLC sessions/wk for 8 wk) increased whole body insulin-stimulated glucose uptake by 33+/-13%, concomitant with a 2.1-fold increase in insulin-stimulated (100 microU/ml) 3-O-methylglucose transport in isolated vastus lateralis muscle. Physical training led to a marked increase in protein expression of GLUT4 (378+/-85%), glycogen synthase (526+/-146%), and hexokinase II (204+/-47%) in vastus lateralis muscle, whereas phosphofructokinase expression (282+/-97%) was not significantly changed. Hexokinase II activity was significantly increased, whereas activity of phosphofructokinase, glycogen synthase, and citrate synthase was not changed after training. Muscle fiber type distribution and fiber area were markedly altered compared to able-bodied subjects before ESLC training, with no change noted in either parameter after ECSL training. In conclusion, muscle contraction improves insulin action on whole body and cellular glucose uptake in cervical cord-injured persons through a major increase in protein expression of key genes involved in the regulation of glucose metabolism. Furthermore, improvements in insulin action on glucose metabolism are independent of changes in muscle fiber type distribution.     

Site of action of inhaled 6 per cent carbon dioxide in the lungs of asthmatic subjects before and after exercise

We studied 10 nonsmoking young adults before and after inducing asthmatic attacks by treadmill exercise. We used body plethysmography, flow-volume curves with air and a mixture of 80% helium and 20% oxygen, pressure-volume diagrams, and arterial blood gas analyses to characterize the effects of exercise and acute inhalation of 6% CO2. Even when exercise produced no change in arterial CO2 tension, inhalation of 6% CO2 relieved obstruction to airflow. It also altered the volume-pressure ralationship of the lungs so that total lung capacity was reduced within minutes, and elastic recoil was increased at fixed lung volume. A large increase in density dependence of airflow was seen in some cases, suggesting relief of obstruction in peripheral airways. Atropine sulfate did not prevent obstruction after exercise and did not prevent relief during CO2 inhalation. We concluded that CO2 inhalation can relax both central and peripheral airways in young asthmatic adults, both at rest and after exercise, and that both total lung capacity and density dependence of airflow can change acutely in these subjects.     

Heat and mass transfer limitations in gasification of carbon by carbon dioxide

Rates of gasification of carbon by carbon dioxide were measured in the laboratory using a thermogravimetry apparatus. The experiments were conducted at various temperatures and sample bed depths using powders of graphite and coconut char as sources of carbon, under flowing gas of CO₂. Various CO–CO₂ mixtures were also employed for the study of coconut char. The measured rate data were subjected to a heat and mass transfer analysis to find out the values of isothermal and non-isothermal effectiveness factors. These values were utilized to predict the intrinsic chemical reactivities of graphite and coconut char samples, free from heat and mass-transfer limitations. Extrapolation of experimental data to hypothetical zero bed depth showed good agreements with the above at various temperatures, thus providing valuable cross-checks. The activation energies were found to be 260 and 250 kJ/mol for graphite and coconut char, respectively, under CO₂. Carbon monoxide was found to decrease the rate of gasification but not as drastically as some literature reports predict.     

Viable cultured neurons in ambient carbon dioxide and hibernation storage for a month

Neurobasal is a bicarbonate-buffered medium optimized for the growth of embryonic rat hippocampal neurons at pH 7.3 in 5% CO2. Neurons die within hours in this or in other 26 mM bicarbonate buffers when transferred to ambient CO2 (0.2%). Death is associated with a rapid rise in medium pH to 8.1. A new CO2-independent modification of Neurobasal (Hibernate E), when supplemented with B27, can maintain neuron viability for at least 2 days in ambient CO2. This same medium can also be used to store viable brain tissue for up to a month with refrigeration. These advances should facilitate studies of neuron physiology outside the incubator as well as storing and transporting neuronal tissue.     

低碳钢中铁素体动态再结晶的粒子激发形核

利用淬、回火工艺得到具有弥散分布的渗碳体粒子+铁素体双相组织的低碳钢,采用Gleeble-1500型模拟机进行热压缩变形实验,研究了在700℃、0.01 s^-1条件下变形过程中渗碳体粒子对低碳钢铁素体动态再结晶过程的影响.结果表明:在700℃、0.01 s^-1条件下变形时,存在以粒子激发形核机制为主的铁素体动态再结晶过程,在形变初期粒子激发形核主要在大尺寸渗碳体粒子(〉1μm)附近发生,大应变量下应变累积促进粒子激发形核在小尺寸渗碳体粒子(0.5~1μm)附近发生.     

Apnoea and oximetric desaturation in patients receiving epidural morphine after gastrectomy: a comparison of intermittent bolus and patient controlled administration

The number of apnoeic episodes and arterial oxygen desaturations were measured preoperatively and for sixty hours postoperatively in twenty ASA status 1-2 patients scheduled for elective gastrectomy. Monitoring included continuous pulse oximetry, respiratory inductive plethysmography and repeated arterial blood gas analysis. The number and magnitude of apnoeas and desaturation episodes were compared between two postoperative analgesic regimens of epidural morphine; intermittent bolus injection (Group B, n = 10), and patient controlled administration with continuous infusion (Group P, n = 10). Morphine dose, P(a)CO2 and mean SpO2 values were similar between the two groups. Although the number of central apnoeas with SpO2 < 90% was greater in Group B, other episodes of apnoea or desaturation were similarly seen preoperatively. In the postoperative period, central apnoeas with SpO2 < 90% were significantly increased in Group B, while no change was seen in Group P. Apnoeas with SpO2 < 80% were only seen in Group B. We conclude from these results that postoperative apnoeas and episodic desaturations are greatly influenced by the different modes of opioid administration.     

Does mixed venous desaturation during a bed bath indicate cardiopulmonary decompensation in postoperative cardiac patients?]

The bed bath procedure consists of cleansing patients' body, passive position change, changing gown and making a bed. During the procedure, mixed venous desaturation was observed consistently in postoperative cardiac patients. We investigated the cause of the phenomenon in 22 patients undergoing cardiac surgery in their first postoperative day. The patients were breathing oxygen-enriched air via a Venturi mask. Cardiac index (CI), transluminal SvO2, arterial blood gas, Hb, DO2, VO2, FIO2, A-aDO2 and Qp/Qs were measured before and during the bed bath, while the patients were in the supine and left lateral position, respectively. Mean 8.5 +/- 1.5 minutes were required to complete the bed bath. During the bed bath, SvO2 decreased from 71 +/- 7% to 59 +/- 9% (P < 0.001), and returned to the baseline 6.5 +/- 7.4 minutes after the completion of the bed bath. VO2 increased markedly from 128 +/- 27 to 194 +/- 47 ml.min-1.m-2 (P < 0.001), while DO2 increased slightly from 480 +/- 91 to 513 +/- 110 ml.min-1.m-2 (P < 0.05). Among the determinants of DO2, CI increased slightly from 3.3 +/- 0.6 to 3.6 +/- 0.8 l.min-1.m-2, Hb remained unchanged and SaO2 decreased from 98.5 +/- 0.8 to 98.0 +/- 1.1%. FIO2 also decreased, while A-aDO2 and Qp/Qs remained unchanged. There was a negative correlation between VO2 change and SvO2 change, but no correlation between DO2 change and SvO2 change. There was a positive correlation between SaO2 change and SvO2 change, as well as between FIO2 change and SaO2 change. Therefore, the major cause of mixed venous desaturation was not the decreased DO2 or cardiopulmonary decompensation but the increased VO2 due to increased activity of the skeletal muscles. However, the decrease in SaO2 due to markedly increased O2 demand and the limited increase in CI might partially contribute to the marked decline in SvO2 through the limited increase in DO2.     

The chlorination kinetics of zirconium dioxide in the presence of carbon and carbon monoxide

Chlorination of zirconium dioxide, an important step in the commercial production of reactor grade zirconium metal, has been studied using carbon and carbon monoxide as reductants. Zirconium tetrachloride was produced when the oxide was reacted with chlorine alone above 1000°C; by introducing carbon the reaction temperatures could be lowered 200°C, and when carbon monoxide was used the reaction temperatures necessary for similar rates were even lower. With carbon monoxide the chlorination of zirconium dioxide is described by two regions differentiated by temperature and the dependence of reaction rate upon chlorine and carbon monoxide pressures.     

The influence of CSF calcium and magnesium on the ventilatory response to carbon dioxide during hyperoxia

Respiratory responses to inhaled carbon dioxide were measured in anaesthetized cats during perfusion of the ventriculocisternal system with artificial cerebrospinal fluid. A study was performed to evaluate the effect of changes in the magnesium and/or calcium concentration of the CSF on the CO2 response curve which was described as VE = S (PCSF, CO2 -- B). A decrease of S was observed when the magnesium concentration of the perfusion fluid was increased; the B-value remaining the same. The reverse was true down to magnesium concentrations of 0.6 mmol-1-1. Below this concentration S remained the same or decreased; the B-value was lowered. When both the calcium and magnesium concentrations of the CSF were changed, the relation between S and these concentrations could be described as to be proportional to CCAa-CMgb. The effect of changes in the calcium concentration was much more pronounced than comparable changes of the magnesium concentration as reflected by the magnitude of the exponents a and b which were found to be -2.80 (S.D. 0.11) and -0.60 (S.D. 0.03) respectively.     

Changes in alveolar oxygen and carbon dioxide concentration and oxygen consumption during lung preservation. The maintenance of aerobic metabolism during lung preservation

Adult human liver microsomes supplemented with NADPH catalyzed the regioselective N-oxygenation of the aliphatic tertiary amine and S-oxidation of the phenothiazine sulfur atom of several 10-(N,N-dimethylaminoalkyl)phenothiazines. In addition, (+)- and (-)-4-bromophenyl-1,3-oxathiolane were converted to the corresponding S-oxides in the presence of NADPH and adult human liver microsomes. The (+) and (-) enantiomers of 4-bromophenyl-1,3-oxathiolane were converted to the S-oxides with low and high stereoselectivity, respectively. Studies on the biochemical mechanism for N-oxygenation of 10-(N,N-dimethylaminoalkyl)phenothiazines suggested that this reaction was catalyzed by the flavin-containing monooxygenase (form II), although cytochrome P-450 2D6 may also have contributed to N-oxide formation. S-Oxidation of chlorpromazine was catalyzed mainly by cytochrome P-450 3A. S-Oxidation of 10-(N,N-dimethylaminoalkyl)phenothiazines was catalyzed by a number of cytochromes P-450, including cytochromes P-450 2A6, 2C8, and 2D6. S-Oxygenation of (+)-4-bromophenyl-1,3-oxathiolane produced a mixture of the cis- and trans diastereomers in a process probably dependent on both hepatic monooxygenase systems. (-)-4-Bromophenyl-1,3-oxathiolane was converted almost exclusively to the trans-S-oxide in a process likely dependent on the adult human liver flavin-containing monooxygenase (form II). Development of regio- and stereochemical probes of adult human liver flavin-containing monooxygenase (form II) and cytochromes P-450 activity may be useful for eventual in vitro-in vivo correlations, but may require approaches quite distinct from that currently used for animal monooxygenases.