Fatal tetanus in a drug abuser with "protective" antitetanus antibodies

Tetanus is a rare disease in the United States. From 1995-1997, the average annual incidence of tetanus was 0.15/1,000,000 population. Injecting-drug users, particularly those who use heroin, are among the highest risk population for acquiring tetanus. We present a case of an injecting-drug user who was seen in the emergency department with worsening diffuse midthoracic back pain and spasms. He subsequently developed acute respiratory failure and central nervous system hypoxic injury. Serum obtained before administration of tetanus immune globulin showed a tetanus antibody titer greater than 16 times the level considered protective. Because of limited human data on the minimum protective level of neutralizing antibody, as well as reports of tetanus among individuals with "protective" antibody titers, the diagnosis of tetanus should not be excluded solely on the basis of antitetanus titers.     

Effects of inhibitory timing on contrast enhancement in auditory circuits in crickets (Teleogryllus oceanicus)

In crickets (Teleogryllus oceanicus), the paired auditory interneuron Omega Neuron 1 (ON1) responds to sounds with frequencies in the range from 3 to 40 kHz. The neuron is tuned to frequencies similar to that of conspecific songs (4.5 kHz), but its latency is longest for these same frequencies by a margin of 5-10 ms. Each ON1 is strongly excited by input from the ipsilateral ear and inhibits contralateral auditory neurons that are excited by the contralateral ear, including the interneurons ascending neurons 1 and 2 (AN1 and AN2). We investigated the functional consequences of ON1's long latency to cricket-like sound and the resulting delay in inhibition of AN1 and AN2. Using dichotic stimuli, we controlled the timing of contralateral inhibition of the ANs relative to their excitation by ipsilateral stimuli. Advancing the stimulus to the ear driving ON1 relative to that driving the ANs "subtracted" ON1's additional latency to 4.5 kHz. This had little effect on the spike counts of AN1 and AN2. The response latencies of these neurons, however, increased markedly. This is because in the absence of a delay in ON1's response, inhibition arrived at AN1 and AN2 early enough to abolish the first spikes in their responses. This also increased the variability of AN1 latency. This suggests that one possible function of the delay in ON1's response may be to protect the precise timing of the onset of response in the contralateral AN1, thus preserving interaural difference in response latency as a reliable potential cue for sound localization. Hyperpolarizing ON1 removed all detectable contralateral inhibition of AN1 and AN2, suggesting that ON1 is the main, if not the only, source of contralateral inhibition.     

Factors that predict incomplete colonoscopy: thinner is not always better

OBJECTIVE: The aim of this study was to determine whether anatomic factors such as body mass index (BMI) impacts the success rate of cecal intubation during colonoscopy. METHODS: We retrospectively reviewed the cecal intubation rate of 2000 colonoscopies performed at our institution from March 1997 to March 1999. The analysis sample was composed of charts for all incomplete procedures and a sample (23%) of complete examinations that were randomly selected. Data collected included age, gender, height, weight, bowel habits, abdominal surgery, psychiatric medication use, the presence of diverticular disease, amount of sedation administered, and location and reason for halting the examination. Patients were divided by BMI: thin (BMI < or = 22.1), average weight (BMI > 22.1-25.0), overweight (BMI = 25.1-29.9), and obese (BMI > 30). RESULTS: Colonoscopies in women had a lower adjusted completion rate (94.8%) than in men (98.2%) (p < 0.005). A low BMI in women was predictive of an incomplete examination (p < 0.001). Factors that did not predict incomplete examinations in women included age and previous hysterectomy. The small number of male patients with an incomplete examination (n = 16) precluded accurate identification of any factors. CONCLUSIONS: Women with a low BMI (especially < 22) were more likely to have an incomplete procedure. This finding may have implications for colorectal cancer screening in female patients.     

Enhanced development in nature of larval Anopheles arabiensis mosquitoes feeding on maize pollen

To determine whether pollen produced by maize (Zea m. mays) may contribute to the development of larval Anopheles gambiae complex mosquitoes, the main African vectors of malaria, we correlated duration of larval development, pupation success, and size of the resulting adults with degree of access to this potential nutriment. Maize pollen is abundant during the wet season on the surface of water near maize plantings in a malaria-endemic region of Ethiopia, and larval Anopheles arabiensis readily ingest these particles in nature. Larvae develop to the pupal stage more rapidly, more frequently, and produce larger adults where maize pollen is abundant than do those that have little access to this food. The force of transmission of malaria in sub-Saharan Africa might be reduced if maize plantings were excluded from the immediate vicinity of homes or, perhaps, if pollen of such maize were to express entomotoxins.     

High dose intravenous gamma-globulin in intractable epilepsy of childhood

Eight children aged between 1.3 and 13 years suffering from epilepsy refractory to conventional anticonvulsive therapy were treated with high dose intravenous gamma globulin (200 mg/kg, 3 times per week, repeated after 3 weeks). Immunological studies after therapy showed normal results. In four children, clinical and EEG findings markedly improved. In one other case a partial response was noted. No improvement was observed in the remaining three cases. We confirm that although the mechanism is still obscure, high doses of i.v. gammaglobulin may have a beneficial effect in a significant number of children with intractable epilepsy.     

Perineal endometriosis. A case report

Perineal endometriosis was found unexpectedly in a 32-year-old woman with primary infertility. Since there had been no prior perineal trauma, the transport of endometrium through a venous or lymphatic route could have accounted for the location of the endometriosis.     

Magnesium sulfate and promethazine do not interact to cause hypotension in gravid ewes

The purpose of this study was to determine whether magnesium sulfate and promethazine interact to cause hypotension in gravid ewes. Fifteen experiments were performed in five chronically instrumented animals between 125 and 130 days of timed gestation (term = 145 days). In one group of experiments each animal received magnesium sulfate (4 gm intravenous bolus followed by 4 gm/hr intravenous infusion) then promethazine (50 mg intravenously). In a second group each animal received magnesium sulfate then saline solution as a control. In a third group each animal received saline solution then promethazine. Infusion of magnesium sulfate increased the mean (+/- SEM) serum magnesium concentration to 5.7 +/- 0.6 and 6.6 +/- 0.6 mg/dl in the magnesium sulfate-promethazine and magnesium sulfate-saline solution groups, respectively. Magnesium sulfate slightly decreased maternal mean arterial pressure (p less than 0.05) and increased cardiac output (p less than 0.05) in both the magnesium sulfate-promethazine and magnesium sulfate-saline solution groups. Otherwise there were no significant changes in maternal mean arterial pressure or cardiac output in any group. Promethazine increased maternal heart rate (p = 0.0001) in both the magnesium sulfate-promethazine and saline solution-promethazine groups. Magnesium sulfate increased uterine blood flow (p less than 0.01) in both the magnesium sulfate-promethazine and magnesium sulfate-saline solution groups, but promethazine blunted the increase in uterine blood flow associated with magnesium sulfate. Similarly, magnesium sulfate decreased uterine vascular resistance (p less than 0.01) in both the magnesium sulfate-promethazine and magnesium sulfate-saline solution groups, but promethazine eliminated the decrease in uterine vascular resistance associated with magnesium sulfate. Maternal and fetal arterial blood gas and acid-base values did not change in any group, except that there was a small, near-significant decrease (p = 0.06) in fetal pH 10 minutes after promethazine was given in the magnesium sulfate-promethazine group. We conclude that magnesium sulfate and promethazine did not interact to cause maternal hypotension in normovolemic gravid ewes. However, promethazine increased maternal heart rate and blunted the increase in uterine blood flow associated with magnesium sulfate.