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Biomedical subjects

J F Smith

Publications and source records attributed to J F Smith.

At least 271 records · Page 15Linked to original sources

Single dose cefazolin prophylaxis for postcesarean infections: before vs. after cord clamping.

The objective of this study was to test the hypothesis that 1 g of cefazolin administered preoperatively is no more effective than the same dose administered after cord clamping in preventing postcesarean infectious morbidity. Ninety consecutive laboring subjects undergoing cesarean delivery at > or = 37 weeks gestation were randomized by computer to receive 1 g of cefazolin intravenously preoperatively or after cord clamping in a double-blinded, placebo-controlled study. The 2 groups were compared for differences in maternal and neonatal demographics, and intrapartum and operative characteristics associated with postcesarean infection. Primary maternal outcome variables were endometritis or wound infection. Secondary outcomes included intra-abdominal abscess formation, septic pelvic thrombophlebitis, pneumonia, or urinary tract infection. Neonatal outcomes included sepsis screens, sepsis, pneumonia, and meningitis. Subjects were followed 6 weeks postoperatively for late complications. Subjects receiving cefazolin preoperatively or after cord clamping had similar maternal and neonatal demographics, and intrapartum and operative characteristics. One patient in the former group experienced both endometritis and wound infection. In the latter group, 2 wound infections and 1 case of endometritis occurred (P = 0.35). There were no secondary maternal infections. Two infants treated for pneumonia and 2 other infants readmitted with febrile illnesses were born to mothers receiving cefazolin preoperatively. Overall, 8 neonates were evaluated for suspected sepsis and all had negative studies. Six of these infants' mothers received cefazolin preoperatively (P = 0.28). In conclusion, 1 gram of cefazolin preoperatively is no more effective than the same dose administered after cord clamping in preventing postcesarean infectious morbidity, but is associated with a trend toward increased suspected sepsis in the newborn. However, this trend may be related to differences between the study groups' risk factors for infection.

Bacterial Infections↗

Commotio cordis in a lacrosse goalie.

A case of commotio cordis has been documented in a male lacrosse goalie. The development of this injury is attributed to a defect in the design of the lacrosse chest protector. Insufficient foam padding over the sternum makes the goalie vulnerable to cardiac concussion. An improvement in the design of the chest protector is now being instituted by the manufacturers that should prevent this serious injury.

Adolescent↗

Anesthetic properties and toxicity of bupivacaine and lidocaine for infiltration anesthesia.

The purpose of this study was to measure the toxicity and anesthetic properties of two anesthetic agents, bupivacaine and lidocaine. These anesthetic agents did not damage tissue defenses or invite infection in experimental animals. In addition, the pain of subdermal injection, the onset of anesthesia, and the frequency of satisfactory anesthesia in human volunteers were remarkably similar. Because the duration of anesthesia induced by bupivacaine was nearly four times longer than that by lidocaine, bupivacaine is recommended for infiltration anesthesia of lacerations treated in the emergency department.

Anesthesia↗

Comparison of in vitro and in vivo systems for propagation of Rift Valley fever virus from clinical specimens.

Several cell cultures and animals were compared for their relative sensitivity as primary isolation systems for Rift Valley fever virus (RVFV) and to determine if virulence characteristics of the isolates were altered in these systems. Eleven human sera from known cases of Rift Valley fever (RVF) were obtained from the 1987 epidemic in Mauritania and served as the source of virus for these studies. Sera were inoculated directly into cell cultures (Vero, C6/36 and DBS-FRhL-2) and animals (ICR suckling mice, Lak:LVG(SYR) hamsters and WF rats) concurrently. The cell lines provided a quick method to propagate, quantitate and identify these specimens without prior adaption. The isolates were highly virulent for suckling mice and hamsters, but not for WF rats, even after cell culture passage, which indicated that the Mauritanian isolates more closely resembled those strains from sub-Saharan Africa than those from the 1977-78 Egyptian epidemic.

Aedes↗

Antigenic and biological properties of Rift Valley fever virus isolated during the 1987 Mauritanian epidemic.

The antigenic and biological properties of three strains of Rift Valley fever virus (RVFV) isolated during the 1987 epidemic in Mauritania were compared with those of strains isolated previously in West Africa and with other selected African strains. Neither the antigenic characteristics of the Mauritanian isolates, as monitored by the binding of 59 monoclonal antibodies, nor the electrophoretic migration of the virus-specific structural and non-structural proteins were significantly different from other strains of RVFV isolated in this region or elsewhere in sub-Saharan Africa. Biological and antigenic traits which distinguished the strains isolated from the 1977 Egyptian epidemic were not associated with the Mauritanian isolates.

Animals↗

Effects of carbohydrate-electrolyte content of beverages on voluntary hydration in a simulated industrial environment.

This study examined the effects of ingesting beverages of varying electrolyte-carbohydrate (ECHO) composition on hydration, sensory response, physiological function, and work performance during 4 hours of simulated industrial work for subjects wearing impermeable protective clothing (PC). Male subjects (N=18) completed four separate work sessions. Each session consisted of 30 min of treadmill walking with intermittent arm curls at 300 kcal per hour (moderate work rate), followed by 30 min of rest, for a total of 4 hours at 33 degrees C wet-bulb globe temperature. Excessive physiological strain prevented only four subjects from completing the 4-hour protocol. A different beverage was provided for consumption ad libitum for each work trial in a repeated measures, double-blind design. The beverages included lime colored water (W), lemon-lime placebo (P), lemon-lime ECHO with 18 mEq/L NaCl (ECHO18), and lemon-lime ECHO with 36 mEq/L NaCl (ECHO36). There was no difference in sweat production among the four trials (p = 0.61). Mean (standard deviation [SD]) fluid consumption was significantly greater for the ECHO36 [771 (+/-264) mL per hour] as compared with the W [630.6 (+/-234) mL per hour] and the P [655.2 (+/-228) mL per hour] (p<0.05), but not significantly greater than the ECHO18 [740.4 (+/-198) mL per hour]. Also, consumption of the ECHO18 was significantly greater than the W. Mean (SD) weight change, expressed as a percentage of total body weight (pre minus post), was -0.55(+/-0.8) for W, -0.31(+/-1.0) for P, -0.01(+/-1.1) for ECHO18, and +0.11(+/-1.1) for ECHO36 (p = 0.06). Subjects drank less and tended to experience greater weight loss in trials in which W or P were provided compared with trials in which either ECHO was provided. Thus, ECHO beverages, when provided ad libitum to workers wearing PC in a hot environment, produced better hydration than water.

Adult↗

Influence of gender and age on the behind-the-back reach test.

The behind-the-back reach test is a reproducible and reliable physical fitness test for musculoskeletal extensibility of the upper extremities, shoulder girdles, and upper back. Requiring only a rigid ruler and marking pen, administration of this test can be learned easily both by medical and nonmedical personnel. Normative data derived from a study of healthy subjects of different ages demonstrated that extensibility decreases with age. Moreover, musculoskeletal extensibility for women was significantly greater than that for men. The test results were not influenced significantly by anthropometric measurements.

Adolescent↗

Monoamniotic twins discordant for anencephaly: diagnosis by CT amniography.

Prenatal diagnosis of monoamnionicity is necessary for optimal care of a twin gestation. When the fetuses are discordant for a lethal anomaly, unequivocal confirmation is imperative. Ultrasound evaluation of our patient revealed a twin gestation discordant for anencephaly and with possible monoamnionicity. When sonography was inconclusive, CT amniography confirmed a single amniotic cavity, permitting appropriate parental counseling and pregnancy management. CT amniography is a useful adjunct to ultrasound in evaluating twins discordant for a lethal anomaly when monoamnionicity is suspected.

Adult↗

Exercise intensity increased by addition of handheld weights to rebounding exercise.

PURPOSE: Researchers who studied the effects of rebound exercise on fitness have concluded that the intensity of rebound exercise elicited only minimal improvements in fitness. This study determined how the addition of arm pumping with handheld weights (HHW) would increase exercise intensity while rebounding. METHODS: Fifteen male subjects (20 to 43 years) ran in place on a mini-trampoline at a stride frequency of 120 foot strikes per minute, with the sole of the foot 15 cm above the rebounder rim. Oxygen uptake (VO2) and heart rate (HR) were measured while rebounding alone, and also while pumping 0.45 kg, 0.91 kg, and 1.36 kg HHW to heights of 61 and 91 cm. RESULTS: All combinations of weights and pumping levels resulted in significantly (P < .05) higher VO2 and HR than rebounding alone. The estimated mean increase in VO2 was 3.2 mL/kg/min when the weight was increased from 0.91 kg to 1.36 kg at the 91 cm pumping height. The corresponding HR increase was 10.1 bpm. Similarly, when 1.36 kg weights were pumped at 91 cm instead of 61 cm, the mean increase in VO2 and HR was 6.2 mL/kg/min and 11.4 bpm, respectively. CONCLUSIONS: The addition of HHW exercise to rebounding substantially increases exercise intensity. Because rebounding without weights results in a relatively low intensity, the addition of HHW should be considered in the use of rebounding for cardiovascular training.

Adult↗

Cellular reactions to subependymal plate haemorrhage in the human neonate.

The most important cause of death in human premature babies at the present time is intraventricular haemorrhage consequent to haemorrhage in the subependymal plate. Lesser degrees of plate haemorrhage can also have serious effects. It was possible to observe the reaction to such haemorrhages in twenty-seven cases whose range of gestational age extended from 23 to 36 weeks and survival from 4 to 59 days. The haemorrhage occurs in the first week of life, usually in the first few days. The earliest reaction at 4 days was the presence of mononuclear phagocytes around the haemorrhage, these evolved to iron pigment macrophages which were present in eighteen of the twenty-two cases in which some reaction was detected. Subependymal astrocytic proliferation was seen at 11 days, related to ependymal disruption, but an astrocytic reaction around the haemorrhage and related to it was not seen until 14 days. Within the subependymal plate this reaction was scanty in fibril production and the cells were thought to be derived from differentiating astrocytes in the plate. In one case a more marked reaction was detected to hypoxic damage in the adjacent thalamus. The source of the phagocytes in these sites and the reasons for the rather slow astrocytic reaction are discussed.

Astrocytes↗

Bilirubin encephalopathy.

In babies of low birth weight dying in the first week of life, bilirubin encephalopathy involving the thalamus only or the thalamus and one or two other areas occurred in nineteen of 376 cases examined over a 10 year period. Although coexistent germinal layer haemorrhage was present in sixteen, this was not thought to be an aetiological factor. Bile stained hyaline membranes in nine of the nineteen were considered to indicate the possibility of protein-bound bilirubin traversing a vascular barrier in these cases. This pattern of predominant lateral thalamic involvement may indicate selective vulnerability of this area in this group. It contrasts sharply with the localization in classical kernicterus (three cases) and in a disparate group where yellow discolouration of future white matter areas was observed (thirteen cases).

Bilirubin↗

Spinal cord transection, cerebral ischaemic and brain-stem injury in a baby following a Kielland's forceps rotation.

A full-term infant suffered a high cervical cord transection after a Kielland 's forceps rotation and extraction. Quadriplegia developed immediately and initial cerebral swelling was followed by atrophy with ventricular dilatation on CT examination. Death occurred at 60 days. At post-mortem complete necrosis of the cervical cord at C2-C3 with old haemorrhage in the meninges was found, with damage to the inferior corpora quadrigemina , the thalamus, striatum, cerebellar and cerebral cortex. The mechanism is discussed briefly.

Adult↗