Increased heritability for lower IQ levels?

Dettermanet al. (1990) presented evidence based on twins that the heritability of IQ may be higher in the lower part of the IQ range. We first offer an alternative test for differential heritability across the IQ range, based on the analysis of absolute intrapair differences of monozygotic versus dizygotic twins. We then review two previous studies, each containing more twins than the sample of Dettermanea al., which examined the distribution of intrapair absolute differences. In contrast to the study of Dettermanet al., both yielded results more compatible with higher heritability in the upper range of IQ. We discuss various interpretations of these findings and show how our proposed test might aid in distinguishing among them.     

A high performance liquid chromatography method for the detection of brodifacoum in serum

A procedure for the detection of brodifacoum (BDF) in serum was developed. Extraction of BDF was achieved by acidification of 2 ml of serum with 1 ml of 1.5% acetic acid followed by dual extractions with 10 ml diethyl ether and ether: acetonitrile [1:1]. In spiking experiments, 68 +/- 3, 61 +/- 4 and 65 +/- 5% of added BDF was recovered from serum containing 1000, 100 and 25 ng BDF/ml, respectively. Two high performance liquid chromatography solvent systems were used for chromatographic separation (A: 1.5% acetic acid, pH 4.5: acetonitrile [1:2] with 1% dibutylamine; and B:O.2 M tris(hydroxymethyl)aminomethane, pH 7.5:acetonitrile [1:3]). Detection limits were 75 and 3 ng BDF/ml of serum using ultraviolet absorption (254 nm) and fluorescence measurement (313 nm excitation, 375 nm emission), respectively. This method has been used successfully to monitor serum concentrations of BDF in experimental and field cases of exposure.     

Acute peripheral arterial and graft occlusion: treatment with selective infusion of urokinase and lysyl plasminogen

Thirty-five patients hospitalized for recent angiographically documented arterial occlusion in the legs (27 femoropopliteal arteries and eight grafts) benefited from local fibrinolytic therapy delivered at the site of the occlusion with a 4- or 5-F catheter. This therapy combined a continuous urokinase (UK) infusion of 1,000 U/kg/hour and a lysyl plasminogen (LYS-PLG) infusion of 15 microkatals every 30 minutes. Angiographically confirmed lysis was obtained in 85% of the cases. Only 3% of the patients had major and 6% had minor groin hematomas. Only two patients had concentrations of fibrinogen as low as 100 mg/dl. Intravascular infusion of UK-LYS-PLG is as effective as streptokinase. Its excellent tolerance makes it a good alternative in the treatment of acute ischemia in the lower limbs.     

On the dual structure of the auditory brainstem response in dogs.

OBJECTIVE: To use the over-complete discrete wavelet transform (OCDWT) to further examine the dual structure of auditory brainstem response (ABR) in the dog. METHODS: ABR waveforms recorded from 20 adult dogs at supra-threshold (90 and 70dBnHL) and threshold (0-15dBSL) levels were decomposed using a six level OCDWT and reconstructed at individual scales (frequency ranges) A6 (0-391Hz), D6 (391-781Hz), and D5 (781-1563Hz). RESULTS: At supra-threshold stimulus levels, the A6 scale (0-391Hz) showed a large amplitude waveform with its prominent wave corresponding in latency with ABR waves II/III; the D6 scale (391-781Hz) showed a small amplitude waveform with its first four waves corresponding in latency to ABR waves I, II/III, V, and VI; and the D5 scale (781-1563Hz) showed a large amplitude, multiple peaked waveform with its first six waves corresponding in latency to ABR waves I, II, III, IV, V, and VI. At threshold stimulus levels (0-15dBSL), the A6 scale (0-391Hz) continued to show a relatively large amplitude waveform, but both the D6 and D5 scales (391-781 and 781-1563Hz, respectively) now showed relatively small amplitude waveforms. CONCLUSIONS: A dual structure exists within the ABR of the dog, but its relative structure changes with stimulus level. SIGNIFICANCE: The ABR in the dog differs from that in the human both in the relative contributions made by its different frequency components, and the way these components change with stimulus level.     

Propylene glycol as a vehicle for percutaneous absorption of therapeutic agents.

Propylene glycol (PG) was evaluated as a vehicle for the in vivo percutaneous absorption of the hydrochloride salts of desipramine, nortriptyline, procainamide, and N-acetyl-procainamide. Each drug was administered topically to hairless (hr-1/hr-1) mice in water and in aqueous 10% and 50% PG. Mean drug concentrations in blood, brain, heart, liver, and lung were measured by high-pressure liquid chromatography after either two or three hours of topical absorption. The presence of PG generally enhanced the absorption of each drug, and the degree of enhancement appeared to be related to the percentage of PG in the dosing solution.     

No increase in carcinogen-DNA adducts in the lungs of monkeys exposed chronically to marijuana smoke.

Rhesus monkeys exposed to marijuana smoke either 7 or 2 days/weeks (HI and LO groups, respectively), or ethanol-extracted marijuana smoke for 7 days/week (EM) or sham treatment (SH) for 1 year were sacrificed 7 months following the last exposure. Pulmonary levels of carcinogen-DNA adducts were determined. Although mean or median adduct levels were not statistically different, 15 of 22 adduct measures were highest in the EM group and lowest 12 of 22 times in the SH group. The levels of aromatic carcinogen-DNA adducts seem no higher in the lungs of animals exposed to marijuana smoke than in untreated animals. Ethanol-extracted marijuana may have effects greater than marijuana itself.     

Ciprofloxacin-induced acute interstitial nephritis.

Acute renal failure is a complication attributed to numerous medications. Few cases linked to the newer fluoroquinolones have been described. We report a case of acute interstitial nephritis confirmed by renal biopsy that developed in a patient within days of starting ciprofloxacin therapy. A review of the literature reveals common clinical manifestations of this rare adverse effect. Clinicians should be aware of this potential complication of ciprofloxacin use.