Variable levels of carry over on platelet counts < or = 20 x 10(9)/l with the Bayer Advia 120.

Accurate platelet counts are essential for the safe management of severe thrombocytopenia (platelet counts < or = 20 x 10(9)/l). The effect of carry over on platelet counting in severe thrombocytopenia was investigated by performing counts before and after saline rinses on three Bayer Advia 120 automated blood counters. Counts were performed in both primary and manual closed tube system modes on two instruments and in manual open tube mode on a third. A total of 194 samples with platelet counts < or = 20 x 10(9)/l were studied. First counts were significantly higher in all groups. The magnitude of the difference varied both by analyser and counting mode. Carry over was minimal with one analyser in primary mode and second counts were on average only 5.5% lower; on a second analyser in manual closed tube system mode second counts were on average 37.7% lower. A first count of > or = 10 x 10(9)/l fell to <10 x 10(9)/l on the second count in 35 of 145 samples (24.1%). In five such samples, all tested on one analyser, the second count was <50% of the value of the first count. Two of 49 (4.1%) first counts of <10 x 10(9)/l increased to > or = 10 x 10(9)/l on repeat. These results show a variable and often potentially clinically important carry-over effect on severely thrombocytopenic samples using the Advia 120.

Unexpected presentation of type 2N von Willebrand disease in pregnancy.

The finding of low factor VIII levels in pregnancy immediately raises concern of haemophilia A carriage, especially with a history of bleeding in the maternal grandfather. However, the diagnosis of type 2N von Willebrand disease (2N vWD) should also be considered as illustrated here. This is also the first reported case of the management of 2N vWD in pregnancy.

Ophthalmoplegia resulting from an intraorbital hematoma.

BACKGROUND: A case is described in which an intraorbital hematoma was found to complicate recovery from attempted aneurysm clipping 5 days into the postoperative period. The etiology, management, and complication avoidance are discussed. CASE DESCRIPTION: Five days after attempted surgical clipping of an internal carotid artery aneurysm via a frontotemporal craniotomy with orbital osteotomy, a patient underwent coiling of the aneurysm. Shortly after the endovascular procedure, the patient developed exophthalmos and ophthalmoplegia involving the right side followed by decline in her level of consciousness. An emergency computed tomography (CT) scan revealed an epidural hematoma with intraorbital extension. After evacuation of the hematoma, the patient recovered extraocular function and returned to her baseline mental status. CONCLUSION: Exophthalmos and ophthalmoplegia in a patient recovering from cranial surgery using skull base techniques warrants immediate attention, especially after endovascular procedures. Delay in intervention may result in loss of neurologic function or life. The authors discuss the relevant literature and management of this uncommon complication.

Chronic dermal studies of petroleum streams in mice.

During petroleum refining, a large number of products are generated which have varying chemical and physical properties. These are known in the industry as petroleum streams. In order to characterize their carcinogenic activity, a number of these commercially produced streams were administered to C3H/HeJ mice in chronic dermal bioassays. The bioassays were conducted using one of two study designs: the first set of test materials was applied for a lifetime and the second set for 24 months. In the lifetime study, the last mice in the test groups survived for periods of 31 to 32 months. Middle distillates, boiling in the range 115-390 degrees C, were found to decrease the lifespan of exposed mice compared to controls or streams of higher and lower boiling ranges. These middle distillate streams included straight run kerosine, hydrodesulfurized middle distillate, straight run middle distillate, light catalytic cracked distillate, and 90/10% and 70/30% mixtures of the last two. The middle distillate streams also proved to be active as carcinogens, with tumor incidence ranging from 16 to 67%. Light alkylate naphtha, heavy catalytic reformed naphtha, vacuum residuum, and unleaded gasoline did not demonstrate significant carcinogenic potency. Heavy thermal cracked naphtha, heavy catalytic cracked naphtha, and hydrotreated light naphthenic distillate were dermal carcinogens of low potency in this study. Administration of light catalytic cracked naphtha led to a low incidence of very late developing tumors with a mean latency of 118 weeks. Application of the 0.1% solution of catalytic cracked clarified oil in toluene did not result in a significant incidence of tumors, but the 10% solution caused almost 100% mortality and 100% tumor incidence in 12 months. There was no correlation between carcinogenic potency and the indices of irritation, alopecia, erythema, and scabbing. Only two of the streams tested, hydrotreated light naphthenic distillate and 10% catalytic cracked clarified oil, contain polynuclear aromatic hydrocarbons (PNAs) and may be presumed to be complete carcinogens. The middle distillates and heavy naphthas are nonmutagenic and essentially free of PNAs. Their activity may result from promotion of already-initiated skin sites. Where comparisons could be made, reducing the exposure period from a lifetime (29-32 months) to 24 months did not change the evaluations of stream carcinogenicity except in the case of light catalytic cracked naphtha where six of the seven mice that developed tumors did so after 24 months.

Alkane biosynthesis by decarbonylation of aldehyde catalyzed by a microsomal preparation from Botryococcus braunii.

The final step in the synthesis of n-hydrocarbons in an animal and a higher plant involves enzymatic decarbonylation of aldehydes to the corresponding alkanes by loss of the carbonyl carbon. Whether such a novel reaction is involved in hydrocarbon synthesis in the colonial microalga, Botryococcus braunii, which is known to produce unusually high levels (up to 32% of dry weight) of n-C27, C29, and C31 alka-dienes and -trienes, was investigated. Dithioerythritol severely inhibited the incorporation of [1-14C]acetate into these hydrocarbons with accumulation of the label in the aldehyde fraction in the B. braunii cells. Microsomal preparations of the alga synthesized alkane from fatty acid and aldehyde in the absence of O2. Conversion of fatty acid to alkane required CoA, ATP, and NADH, whereas conversion of aldehyde to alkane did not require the addition of cofactors. That the alkane synthesis involves a decarbonylation was shown by the production of CO and heptadecane from octadecanal. CO was identified by adsorption to RhCl[(C6H6)3P]3. The decarbonylase had a pH optimum at 7.0, an apparent Km of 65 microM, a Vmax of 1.36 nmol/min/mg and was inhibited by the metal chelators EDTA, O-phenanthroline and 8-hydroxyquinoline. It was stimulated nearly threefold by 2 mM ascorbate and inhibited by the presence of O2. A partial (28%) retention of the aldehydic hydrogen of [1-3H]octadecanal in the heptadecane was observed; the remaining 3H was lost to H2O. The microsomal preparation also catalyzed the oxidation of 14CO to 14CO2, with a pH optimum of 7.0. This accounts for the nonstoichiometry of CO to heptadecane observed. In vivo studies with 14CO showed that the label was incorporated into metabolic products. This metabolic conversion of CO, not found in the previously examined hydrocarbon synthesizing systems, may be necessary for organisms that produce large amounts of hydrocarbons such as the present alga. The mechanism of the decarbonylation and the nature of the decarbonylase remain to be elucidated.

The history of the neurosurgical engine.

The opening of the skull of a living human being dates back to early civilization. The procedure may have been performed as early as the Neolithic period. Surgeons have continued to search for a better, easier, quicker, and safer method to open the skull. Today, most neurosurgeons are well acquainted with the surgical drill; however, few are familiar with the development of this instrument from its beginnings in dentistry to its use in modern neurosurgery. As cerebral localization advanced in the late 19th century, so, too, did the demands for better techniques for entering the cranial cavity and exposing more extensive areas of the brain. Mechanical devices began to appear in operating theaters throughout the world. Despite the enthusiasm of its inventors, the surgical engine was used by but a few pioneer cranial surgeons. The use of a surgical engine in the operating room has become commonplace. Its presence continues to demand respect. There is no doubt that this instrument has helped advance neurosurgery. Its development and refinement are rich in history and closely parallel the development of modern neurosurgery.

Comparative acute toxicity of shale and petroleum derived distillates.

In anticipation of the commercialization of its shale oil retorting and upgrading process, Unocal Corp. conducted a testing program aimed at better defining potential health impacts of a shale industry. Acute toxicity studies using rats and rabbits compared the effects of naphtha, Jet-A, JP-4, diesel and "residual" distillate fractions of both petroleum derived crude oils and hydrotreated shale oil. No differences in the acute oral (greater than 5 g/kg LD50) and dermal (greater than 2 g/kg LD50) toxicities were noted between the shale and petroleum derived distillates and none of the samples were more than mildly irritating to the eyes. Shale and petroleum products caused similar degrees of mild to moderate skin irritation. None of the materials produced sensitization reactions. The LC50 after acute inhalation exposure to Jet-A, shale naphtha, (greater than 5 mg/L) and JP-4 distillate fractions of petroleum and shale oils was greater than 5 mg/L. The LC50 of petroleum naphtha (greater than 4.8 mg/L) and raw shale oil (greater than 3.95 mg/L) also indicated low toxicity. Results demonstrate that shale oil products are of low acute toxicity, mild to moderately irritating and similar to their petroleum counterparts. The results further demonstrate that hydrotreatment reduces the irritancy of raw shale oil.

Maximum growth rate of Mycobacterium avium in continuous culture or chronically infected BALB/c mice.

Mycobacterium avium is a human pathogen which may cause either chronic or disseminated disease and the organism exhibits a slow rate of growth. This study provides information on the growth rate of the organism in chronically infected mice and its maximal growth rate in vitro. M. avium was grown in continuous culture, limited for nitrogen with 0.5 mM ammonium chloride and dilution rates that ranged from 0.054 to 0.153 h-1. The steady-state concentration of ammonia nitrogen and M. avium cells for each dilution rate were determined. The bacterial saturation constant for growth-limiting ammonia was 0.29 mM (4 micrograms nitrogen/ml) and, from this, the maximal growth rate for M. avium was estimated to be 0.206 h-1 or a doubling time of 3.4 h. BALB/c mice were infected intravenously with 3 x 10(6) colony-forming units and a chronic infection resulted, typical of virulent M. avium strains. During a period of 3 months, the number of mycobacteria remained constant in the lungs, but increased 30-fold and 8,900-fold, respectively, in the spleen and mesenteric lymph nodes. The latter increase appeared to be due to proliferation in situ. The generation time of M. avium in the mesenteric lymph nodes was estimated to be 7 days.

Host response to bovine ocular squamous cell carcinoma.

Specific humoral and cellular immunologic responses to autologous and heterologous tumors were evaluated in 35 Hereford cows with ocular squamous cell tumors and in 6 healthy cows. Sera from 5 healthy cows and 23 ocular tumor-bearing cows were evaluated for antibody to tumor, using radioimmunoassay, passive hemagglutination, agglutination, and microagglutination assays with various soluble tumor antigen and whole tumor cell preparations. Antibody to tumor was detected in only 2 cows. Using the microagglutination assay, antibody to autologous and heterologous tumor cells was found in the sera of 2 cows inoculated intraocularly with purified, viable autologous tumor cells. Twenty-eight tumor-bearing cows and 3 healthy cows were evaluated for delayed-type hypersensitivity responses, using 5 tumor preparations; positive skin test responses were not observed.

Autotransplantation of bovine ocular squamous cell carcinoma and effects on primary tumor growth.

Autologous transplantation of ocular squamous cell carcinoma was done in 7 Hereford cows in 17 trials. Three preparations of tumor were used in orthotopic transplantation to 5 sites on the eye and eyelid. None of the transplants was successful. However, in 2 of 5 cows given autografts of a pure, viable tumor cell suspension, marked regression of the primary tumor was observed after transplantation.

Rabbit immunization to xenogeneic red blood cells following anterior eye chamber inoculation.

Inoculation of human red blood cells (HRBC) into the anterior chamber of the eye (AC) of rabbits effectively stimulated systemic antibody production. Intraocular (i.o.) inoculation was observed to be more effective a route of immunization than i.v. or i.m. inoculation of antigen. These results contradict the accepted belief that the AC is an immunologically privileged site in the body.

Traumatic posterior atlantoaxial dislocation without neurological deficit: case report.

A case is presented in which a patient sustained a closed head injury with subsequent acute subdural hematoma and delayed posterior dislocation of the atlas without fracture of the odontoid process and with an intact C-1 arch. The subdural hematoma was treated operatively. The atlas dislocation was managed with closed reduction without manipulation and subsequent posterior fusion of C-1, C-2, and C-3. The patient was intact neurologically on admission and remained so throughout his hospitalization.

Infectivity of Chlamydia psittaci of bovine and ovine origins for cultured cells.

The infectivity of 2 strains of Chlamydia psittaci of mammalian origin were studied in mouse L cells. Infectivity was enhanced by centrifuging the chlamydial inoculum onto the cell monolayer. Infectivity increased as force of centrifugation increased. The enhanced infectivity was not caused by centrifugal sedimentation of chlamydiae, since centrifugation longer than 10 minutes and an inoculum dose larger than 0.4 ml did not further enhance infectivity. Centrifuge-enhanced adsorption was temperature dependent, because infection was not detected when stationary or centrifuge-assisted adsorption occurred at less than 15 C. Infectivity was higher in cultures centrifuged at 37 degrees C than in cultures centrifuged at room temperature. Treatments of cells with cycloheximide, colchicine, and hydrocortisone enhanced infectivity of chlamydiae above that of untreated cells. In addition, developing chlamydial inclusions were larger and easier to observe in colchicine-treated cells. Infectivity was thought to be enhanced in colchicine-treated cells, because cells with depolymerized microtubules provided favorable conditions for the early phases of chlamydial multiplication. Treatment of cells with cytochalasin B, carbachol, cGMP, lumicolchicine, or vinblastine did not significantly alter chlamydial infectivity.

Cranial CT findings in patients with meningomyelocele.

The association between meningomyelocele and various cranial abnormalities, particularly Chiari II malformation is well established. Cranial CT scans in 47 patients with meningomyelocele proved to be a safe and effective method of elucidating the type and extent of anatomic abnormalities associated with this disorder, and evaluating and following the degree of hydrocephalus seen in these patients. Of the 47 patients, 43 (92%) showed CT findings indicative of an abnormally low fourth ventricle, the hallmark finding in Chiari II malformation. In 67% the fourth ventricle was not visualized, and in 25% it was directly visualized in an abnormally caudal position. Other findings included hydrocephalus (85%), a striking and possibly unique heart-shaped psuedomass in the posterior fossa (58%), and abnormal configuration of the lateral ventricles ("vampire bat" configuration). Calvarial abnormalities, in particular lacunar skull, were also noted at CT.